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Re: Packaging external filters

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  • dan
    nice work, kees....73, w5xz, dan
    Message 1 of 27 , May 5, 2013
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      nice work, kees....73, w5xz, dan
    • Graeme Jury
      There is a couple of things which may be useful when designing switched banks of filters. 1. Use a transmission line down the relay chain. In my case I used
      Message 2 of 27 , May 6, 2013
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        There is a couple of things which may be useful when designing switched
        banks of filters.

        1. Use a transmission line down the relay chain. In my case I used
        RG-179 with the cover stripped back 5 mm or so and the braid tinned. Two
        knife cuts 2 mm apart were rolled around the centre of the tinned braid
        and then bent to snap at the knife cuts. The 2 mm piece of braid was
        pried away and the centre of the coax bared. This was done opposite each
        relay. The braids were soldered to the earth plane and the centre
        connected to the relay contact. It did not take long to prepare the coax
        and avoids the tricky and less reliable design of a printed transmission
        line.

        2. Bypass the coils of each relay. I ran my filter bank through my VNA
        and could not understand why the roll off at the HF end of the filter
        went down to about 40 dB and then flattened. They were mesh Chebyshev
        filters and should have kept going down. In the end I found that a 0.1
        smt cap on the coil on the 12 Volt common side of the relays fixed the
        problem. As I added caps to more of the coils it got better and when I
        had done half of them it was improved to the noise floor of the VNA.
        Naturally for the negligible cost I did them all and also the switched
        grounded side of the coils too. It is an obscure fault and maybe if I
        had used RF relays it would not have happened but I used standard 2 pole
        changeover miniature ones which switch 30 watts from my RD16HHF1 linear
        on CW just fine.

        73 Graeme ZL2APV
      • Pascal
        Nice idea, that would be great for my next remote sdr TX/RX...on the one I did this year with a Softrock 6,3, I use the WB6DHW BPF at RX input and the K5OOR
        Message 3 of 27 , May 7, 2013
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          Nice idea, that would be great for my next remote sdr TX/RX...on the one I did this year with a Softrock 6,3, I use the WB6DHW BPF at RX input and the K5OOR LPF after a 10W QRPproject amplifier - K5OOR LPF is motorized with a servomotor (!), and the two filters are controlled through an Arduino card and a web interface.

          --- In softrock40@yahoogroups.com, "Kees & Sandy" <windy10605@...> wrote:
          >
          > Here is another alternative I've been thinking about relative to using the same symmetrical Chebychev filters for Rx and Tx. Each symmetrical 5th order Chebychev BPF filter is on it's own 2.5" x 0.6" board which terminates in 4 header pins on each end (redundant contacts). Up to 8 of these plug into a 3" x 5" motherboard which provides relay selection of the 8 filters via 3 bits. Eight filters work very well to cover 160m to 6m.....fewer filters, not so much. The filters are also staggered by 1/2" to further reduce filter to filter coupling. The idea is to make them pluggable for other/new bands and designs (LPFs?). The other design point was to make them as small as possible to reduce lead inductances and to make them "tuneable". This was achieved by going to high voltage NPO ceramic smt capacitors (1KV). The 1206 size capacitors are located on adjacent footprints on the reverse side of the board. They can also be stacked if needed.....much less space is taken up than with Mica capacitors. Testing has shown no problems using these capacitors at 20W power levels. I have some pictures of the filters on my website (last section). http://www.qsl.net/k5bcq/Kits/Kits.html You might ask, why the higher voltage ceramic caps ? Well, with the relays down the sides of the board, that provides a nice open space in the middle of the board for a single RD16HHF1 MOSFET amplifier layout if you want to use it. Testing has shown that BPF design is a whole other story from LPF design because of the large inductances required for narrow BWs on the lower bands (17uH for 160m, for instance). I had wanted to keep the toroid size to T-50 or smaller while running 10W of power. For the higher bands 30m and up T-37 cores are not a problem at all, T50 cores are fine down to 80m . On the lower bands, such as 160m, a T50-1 core with 35 turns becomes quite hot at 5W continuous. Back to more board layout................. 73 Kees K5BCQ
          >
        • Kees & Sandy
          Very good info, Graeme. I ran board traces down the two sides of the board, one for input and one for output and made the traces 60-70mil wide. I ve found that
          Message 4 of 27 , May 7, 2013
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            Very good info, Graeme.
             
            I ran board traces down the two sides of the board, one for input and one for output and made the traces 60-70mil wide. I've found that on a 62mil board, using 1oz copper, over a ground plane it comes pretty close to 50 ohms. It would still be nice to not have the unterminated stubs (to the unused filters), but I don't know what to do about that.
             
            The relays all have bifurcated, gold covered, contacts which are also paralleled for reliability (DPDT contacts). The other point is to only have one common connection between the antenna/earth ground and the logic ground for controlling the relays. Right now I'm using SMA connectors but may go back to BNC.
             
            Roger, on the bypass capacitor (and diode) across each coil. Always good to have bypass caps on DC circuits in an RF environment.
             
            The only "tricky" layout is that I'm putting a single RD16HHF1 right in the middle of the board as an Amp (couldn't see all that space going to waste). 
             
            Have you ever used NPO, high voltage, ceramic smt capacitors in the filters ? Have you found any reason to use 5V relays vs 12V relays ? .....I got it in my mind that the lower 5V coils (less impedance) would be less suceptible to RF pickup. Probably a DNW (Does Nothing What-so-ever).
             
            73 Kees K5BCQ

            ---------- Original Message ----------
            From: Graeme Jury <gvjury@...>
            To: softrock40@yahoogroups.com
            Subject: [softrock40] Re: Packaging external filters
            Date: Tue, 07 May 2013 15:07:23 +1200

             

            There is a couple of things which may be useful when designing switched
            banks of filters.

            1. Use a transmission line down the relay chain. In my case I used
            RG-179 with the cover stripped back 5 mm or so and the braid tinned. Two
            knife cuts 2 mm apart were rolled around the centre of the tinned braid
            and then bent to snap at the knife cuts. The 2 mm piece of braid was
            pried away and the centre of the coax bared. This was done opposite each
            relay. The braids were soldered to the earth plane and the centre
            connected to the relay contact. It did not take long to prepare the coax
            and avoids the tricky and less reliable design of a printed transmission
            line.

            2. Bypass the coils of each relay. I ran my filter bank through my VNA
            and could not understand why the roll off at the HF end of the filter
            went down to about 40 dB and then flattened. They were mesh Chebyshev
            filters and should have kept going down. In the end I found that a 0.1
            smt cap on the coil on the 12 Volt common side of the relays fixed the
            problem. As I added caps to more of the coils it got better and when I
            had done half of them it was improved to the noise floor of the VNA.
            Naturally for the negligible cost I did them all and also the switched
            grounded side of the coils too. It is an obscure fault and maybe if I
            had used RF relays it would not have happened but I used standard 2 pole
            changeover miniature ones which switch 30 watts from my RD16HHF1 linear
            on CW just fine.

            73 Graeme ZL2APV

             

             

          • Kees & Sandy
            Well, that sure shows there is a desire for something which combines filters and the Amp. The tricky part is that you want filters which have less than 1dBm
            Message 5 of 27 , May 7, 2013
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              Well, that sure shows there is a desire for something which combines filters and the Amp. The tricky part is that you want filters which have less than 1dBm insertion loss (across the whole band) especially if you are using it for receive and a reasonably flat/stable return loss. Many designs have very erratic return loss in the band you are using and that makes the filter VSWR vary all over the place depending on the frequency.
               
              73 Kees K5BCQ


              ---------- Original Message ----------
              From: "Pascal" <pascal@...>
              To: softrock40@yahoogroups.com
              Subject: [softrock40] Re: Packaging external filters
              Date: Tue, 07 May 2013 15:12:05 -0000

               

              Nice idea, that would be great for my next remote sdr TX/RX...on the one I did this year with a Softrock 6,3, I use the WB6DHW BPF at RX input and the K5OOR LPF after a 10W QRPproject amplifier - K5OOR LPF is motorized with a servomotor (!), and the two filters are controlled through an Arduino card and a web interface.

              --- In softrock40@yahoogroups.com, "Kees & Sandy" <windy10605@...> wrote:
              >
              > Here is another alternative I've been thinking about relative to using the same symmetrical Chebychev filters for Rx and Tx. Each symmetrical 5th order Chebychev BPF filter is on it's own 2.5" x 0.6" board which terminates in 4 header pins on each end (redundant contacts). Up to 8 of these plug into a 3" x 5" motherboard which provides relay selection of the 8 filters via 3 bits. Eight filters work very well to cover 160m to 6m.....fewer filters, not so much. The filters are also staggered by 1/2" to further reduce filter to filter coupling. The idea is to make them pluggable for other/new bands and designs (LPFs?). The other design point was to make them as small as possible to reduce lead inductances and to make them "tuneable". This was achieved by going to high voltage NPO ceramic smt capacitors (1KV). The 1206 size capacitors are located on adjacent footprints on the reverse side of the board. They can also be stacked if needed.....much less space is taken up than with Mica capacitors. Testing has shown no problems using these capacitors at 20W power levels. I have some pictures of the filters on my website (last section). http://www.qsl.net/k5bcq/Kits/Kits.html You might ask, why the higher voltage ceramic caps ? Well, with the relays down the sides of the board, that provides a nice open space in the middle of the board for a single RD16HHF1 MOSFET amplifier layout if you want to use it. Testing has shown that BPF design is a whole other story from LPF design because of the large inductances required for narrow BWs on the lower bands (17uH for 160m, for instance). I had wanted to keep the toroid size to T-50 or smaller while running 10W of power. For the higher bands 30m and up T-37 cores are not a problem at all, T50 cores are fine down to 80m . On the lower bands, such as 160m, a T50-1 core with 35 turns becomes quite hot at 5W continuous. Back to more board layout................. 73 Kees K5BCQ
              >

               

               

            • Graeme
              Hi Kees, Looks like you are already using best practice construction and yes the printed transmission lines are just fine. Only reason I avoided them is they
              Message 6 of 27 , May 7, 2013
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                Hi Kees,

                Looks like you are already using "best practice" construction and yes the printed transmission lines are just fine. Only reason I avoided them is they are a bit tricky for home made pcb. Yes you get a stub on the unused filters so I make the through filter the last in the chain them 6 M, 10 M etc. to keep the stub short. On 160 M with the longest stub it shows a a little bit of capacitance on the input and output but does not affect the response. My relays were recovered from an old telephone exchange and probably are good contacts but really unknown although they work just fine.

                I am using 1206 smt ceramic NPO capacitors rated at 200 Volts and have not had a failure even when testing into open circuit. The RD16HHF1's survived also. I am very impressed with them.

                73 Graeme ZL2APV

                --- In softrock40@yahoogroups.com, "Kees & Sandy" <windy10605@...> wrote:
                >
                > Very good info, Graeme. I ran board traces down the two sides of the board, one for input and one for output and made the traces 60-70mil wide. I've found that on a 62mil board, using 1oz copper, over a ground plane it comes pretty close to 50 ohms. It would still be nice to not have the unterminated stubs (to the unused filters), but I don't know what to do about that. The relays all have bifurcated, gold covered, contacts which are also paralleled for reliability (DPDT contacts). The other point is to only have one common connection between the antenna/earth ground and the logic ground for controlling the relays. Right now I'm using SMA connectors but may go back to BNC. Roger, on the bypass capacitor (and diode) across each coil. Always good to have bypass caps on DC circuits in an RF environment. The only "tricky" layout is that I'm putting a single RD16HHF1 right in the middle of the board as an Amp (couldn't see all that space going to waste). Have you ever used NPO, high voltage, ceramic smt capacitors in the filters ? Have you found any reason to use 5V relays vs 12V relays ? .....I got it in my mind that the lower 5V coils (less impedance) would be less suceptible to RF pickup. Probably a DNW (Does Nothing What-so-ever). 73 Kees K5BCQ
                > ---------- Original Message ----------
                > From: Graeme Jury <gvjury@...>
                > To: softrock40@yahoogroups.com
                > Subject: [softrock40] Re: Packaging external filters
                > Date: Tue, 07 May 2013 15:07:23 +1200
                >
                >
                > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
                > There is a couple of things which may be useful when designing switched
                > banks of filters.
                >
                > 1. Use a transmission line down the relay chain. In my case I used
                > RG-179 with the cover stripped back 5 mm or so and the braid tinned. Two
                > knife cuts 2 mm apart were rolled around the centre of the tinned braid
                > and then bent to snap at the knife cuts. The 2 mm piece of braid was
                > pried away and the centre of the coax bared. This was done opposite each
                > relay. The braids were soldered to the earth plane and the centre
                > connected to the relay contact. It did not take long to prepare the coax
                > and avoids the tricky and less reliable design of a printed transmission
                > line.
                >
                > 2. Bypass the coils of each relay. I ran my filter bank through my VNA
                > and could not understand why the roll off at the HF end of the filter
                > went down to about 40 dB and then flattened. They were mesh Chebyshev
                > filters and should have kept going down. In the end I found that a 0.1
                > smt cap on the coil on the 12 Volt common side of the relays fixed the
                > problem. As I added caps to more of the coils it got better and when I
                > had done half of them it was improved to the noise floor of the VNA.
                > Naturally for the negligible cost I did them all and also the switched
                > grounded side of the coils too. It is an obscure fault and maybe if I
                > had used RF relays it would not have happened but I used standard 2 pole
                > changeover miniature ones which switch 30 watts from my RD16HHF1 linear
                > on CW just fine.
                >
                > 73 Graeme ZL2APV
                >
              • Brad Thompson
                On 5/7/2013 11:36 AM, Kees & Sandy wrote: ... Hello, Kees and the group-- One point to keep in mind centers on magnetic interactions among the
                Message 7 of 27 , May 7, 2013
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                  On 5/7/2013 11:36 AM, Kees & Sandy wrote:
                  <snip>

                  > The relays all have bifurcated, gold covered, contacts which are also
                  > paralleled for reliability (DPDT contacts). The other point is to only
                  > have one common connection between the antenna/earth ground and the
                  > logic ground for controlling the relays.
                  <snip>

                  Hello, Kees and the group--

                  One point to keep in mind centers on magnetic interactions
                  among the relays. IIRC, the plastic-housed box-shaped little
                  relays offered by Nais and other manufacturers may require
                  at least a minimum separation between the relays, so check
                  the data sheets for whatever relays you plan to use.

                  73--

                  Brad AA1IP
                • Dave
                  Kees and all: Don t know what substrate your pcb is. But, FR4 epoxy glass, .062 thick, 1 oz copper, 50 ohms is real close to .100 wide. Dave - WB6DHW
                  Message 8 of 27 , May 7, 2013
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                    Kees and all:
                      Don't know what substrate your pcb is.  But, FR4 epoxy glass, .062" thick, 1 oz copper, 50 ohms is real close to .100" wide. 

                    Dave - WB6DHW
                    <http://wb6dhw.com>

                    On 5/7/2013 11:58 AM, Graeme wrote:
                     

                    Hi Kees,

                    Looks like you are already using "best practice" construction and yes the printed transmission lines are just fine. Only reason I avoided them is they are a bit tricky for home made pcb. Yes you get a stub on the unused filters so I make the through filter the last in the chain them 6 M, 10 M etc. to keep the stub short. On 160 M with the longest stub it shows a a little bit of capacitance on the input and output but does not affect the response. My relays were recovered from an old telephone exchange and probably are good contacts but really unknown although they work just fine.

                    I am using 1206 smt ceramic NPO capacitors rated at 200 Volts and have not had a failure even when testing into open circuit. The RD16HHF1's survived also. I am very impressed with them.

                    73 Graeme ZL2APV

                    --- In softrock40@yahoogroups.com, "Kees & Sandy" <windy10605@...> wrote:
                    >
                    > Very good info, Graeme. I ran board traces down the two sides of the board, one for input and one for output and made the traces 60-70mil wide. I've found that on a 62mil board, using 1oz copper, over a ground plane it comes pretty close to 50 ohms. It would still be nice to not have the unterminated stubs (to the unused filters), but I don't know what to do about that. The relays all have bifurcated, gold covered, contacts which are also paralleled for reliability (DPDT contacts). The other point is to only have one common connection between the antenna/earth ground and the logic ground for controlling the relays. Right now I'm using SMA connectors but may go back to BNC. Roger, on the bypass capacitor (and diode) across each coil. Always good to have bypass caps on DC circuits in an RF environment. The only "tricky" layout is that I'm putting a single RD16HHF1 right in the middle of the board as an Amp (couldn't see all that space going to waste). Have you ever used NPO, high voltage, ceramic smt capacitors in the filters ? Have you found any reason to use 5V relays vs 12V relays ? .....I got it in my mind that the lower 5V coils (less impedance) would be less suceptible to RF pickup. Probably a DNW (Does Nothing What-so-ever). 73 Kees K5BCQ
                    > ---------- Original Message ----------
                    > From: Graeme Jury <gvjury@...>
                    > To: softrock40@yahoogroups.com
                    > Subject: [softrock40] Re: Packaging external filters
                    > Date: Tue, 07 May 2013 15:07:23 +1200
                    >
                    >
                    > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
                    > There is a couple of things which may be useful when designing switched
                    > banks of filters.
                    >
                    > 1. Use a transmission line down the relay chain. In my case I used
                    > RG-179 with the cover stripped back 5 mm or so and the braid tinned. Two
                    > knife cuts 2 mm apart were rolled around the centre of the tinned braid
                    > and then bent to snap at the knife cuts. The 2 mm piece of braid was
                    > pried away and the centre of the coax bared. This was done opposite each
                    > relay. The braids were soldered to the earth plane and the centre
                    > connected to the relay contact. It did not take long to prepare the coax
                    > and avoids the tricky and less reliable design of a printed transmission
                    > line.
                    >
                    > 2. Bypass the coils of each relay. I ran my filter bank through my VNA
                    > and could not understand why the roll off at the HF end of the filter
                    > went down to about 40 dB and then flattened. They were mesh Chebyshev
                    > filters and should have kept going down. In the end I found that a 0.1
                    > smt cap on the coil on the 12 Volt common side of the relays fixed the
                    > problem. As I added caps to more of the coils it got better and when I
                    > had done half of them it was improved to the noise floor of the VNA.
                    > Naturally for the negligible cost I did them all and also the switched
                    > grounded side of the coils too. It is an obscure fault and maybe if I
                    > had used RF relays it would not have happened but I used standard 2 pole
                    > changeover miniature ones which switch 30 watts from my RD16HHF1 linear
                    > on CW just fine.
                    >
                    > 73 Graeme ZL2APV
                    >



                  • Kees & Sandy
                    Hello Graeme, Yes, I am very impressed with the durability of the RD16HHF1 also and it s ability to withstand really bad SWR loads (intentional or not ;o). The
                    Message 9 of 27 , May 7, 2013
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                      Hello Graeme,
                       
                      Yes, I am very impressed with the durability of the RD16HHF1 also and it's ability to withstand really bad SWR loads (intentional or not ;o). The only failure I've had was when I used a "normal" 50V capacitor in the feedback loop and it failed, effectively tying the Drain to the Gate.......didn't last long.
                       
                      I found some 1206size  633V and 1KV (and up) NPO caps. They are apparently more readily available in Europe than here. Sure cuts the overall filter size down.
                       
                      73 Kees K5BCQ


                      ---------- Original Message ----------
                      From: "Graeme" <gvjury@...>
                      To: softrock40@yahoogroups.com
                      Subject: [softrock40] Re: Packaging external filters
                      Date: Tue, 07 May 2013 18:58:51 -0000

                       

                      Hi Kees,

                      Looks like you are already using "best practice" construction and yes the printed transmission lines are just fine. Only reason I avoided them is they are a bit tricky for home made pcb. Yes you get a stub on the unused filters so I make the through filter the last in the chain them 6 M, 10 M etc. to keep the stub short. On 160 M with the longest stub it shows a a little bit of capacitance on the input and output but does not affect the response. My relays were recovered from an old telephone exchange and probably are good contacts but really unknown although they work just fine.

                      I am using 1206 smt ceramic NPO capacitors rated at 200 Volts and have not had a failure even when testing into open circuit. The RD16HHF1's survived also. I am very impressed with them.

                      73 Graeme ZL2APV

                      --- In softrock40@yahoogroups.com, "Kees & Sandy" <windy10605@...> wrote:
                      >
                      > Very good info, Graeme. I ran board traces down the two sides of the board, one for input and one for output and made the traces 60-70mil wide. I've found that on a 62mil board, using 1oz copper, over a ground plane it comes pretty close to 50 ohms. It would still be nice to not have the unterminated stubs (to the unused filters), but I don't know what to do about that. The relays all have bifurcated, gold covered, contacts which are also paralleled for reliability (DPDT contacts). The other point is to only have one common connection between the antenna/earth ground and the logic ground for controlling the relays. Right now I'm using SMA connectors but may go back to BNC. Roger, on the bypass capacitor (and diode) across each coil. Always good to have bypass caps on DC circuits in an RF environment. The only "tricky" layout is that I'm putting a single RD16HHF1 right in the middle of the board as an Amp (couldn't see all that space going to waste). Have you ever used NPO, high voltage, ceramic smt capacitors in the filters ? Have you found any reason to use 5V relays vs 12V relays ? .....I got it in my mind that the lower 5V coils (less impedance) would be less suceptible to RF pickup. Probably a DNW (Does Nothing What-so-ever). 73 Kees K5BCQ
                      > ---------- Original Message ----------
                      > From: Graeme Jury <gvjury@...>
                      > To: softrock40@yahoogroups.com
                      > Subject: [softrock40] Re: Packaging external filters
                      > Date: Tue, 07 May 2013 15:07:23 +1200
                      >
                      >
                      > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
                      > There is a couple of things which may be useful when designing switched
                      > banks of filters.
                      >
                      > 1. Use a transmission line down the relay chain. In my case I used
                      > RG-179 with the cover stripped back 5 mm or so and the braid tinned. Two
                      > knife cuts 2 mm apart were rolled around the centre of the tinned braid
                      > and then bent to snap at the knife cuts. The 2 mm piece of braid was
                      > pried away and the centre of the coax bared. This was done opposite each
                      > relay. The braids were soldered to the earth plane and the centre
                      > connected to the relay contact. It did not take long to prepare the coax
                      > and avoids the tricky and less reliable design of a printed transmission
                      > line.
                      >
                      > 2. Bypass the coils of each relay. I ran my filter bank through my VNA
                      > and could not understand why the roll off at the HF end of the filter
                      > went down to about 40 dB and then flattened. They were mesh Chebyshev
                      > filters and should have kept going down. In the end I found that a 0.1
                      > smt cap on the coil on the 12 Volt common side of the relays fixed the
                      > problem. As I added caps to more of the coils it got better and when I
                      > had done half of them it was improved to the noise floor of the VNA.
                      > Naturally for the negligible cost I did them all and also the switched
                      > grounded side of the coils too. It is an obscure fault and maybe if I
                      > had used RF relays it would not have happened but I used standard 2 pole
                      > changeover miniature ones which switch 30 watts from my RD16HHF1 linear
                      > on CW just fine.
                      >
                      > 73 Graeme ZL2APV
                      >

                       

                       

                    • Kees & Sandy
                      Hello Brad and the gang, I figured you would jump in with some good techie advice and/or experience. Very good point. That, I did not think about and look
                      Message 10 of 27 , May 7, 2013
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                        Hello Brad and the gang,

                        I figured you would jump in with some good techie advice and/or experience.

                        Very good point. That, I did not think about and look into. The spec for the G6H OMRON relay does say "low magnetic interference enables high-density mounting", but gives no additional details. I took one apart looking for shielding but can't tell if there is any u metal ? in there. The cross-bar Au contacts look nice though and they were really inexpensive in the 2F package.

                        73 Kees K5BCQ


                        ---------- Original Message ----------
                        From: Brad Thompson <brad.thompson@...>
                        To: softrock40@yahoogroups.com
                        Cc: Kees & Sandy <windy10605@...>
                        Subject: Re: [softrock40] Re: Packaging external filters
                        Date: Tue, 07 May 2013 15:46:25 -0400

                        On 5/7/2013 11:36 AM, Kees & Sandy wrote:
                        <snip>

                        > The relays all have bifurcated, gold covered, contacts which are also
                        > paralleled for reliability (DPDT contacts). The other point is to only
                        > have one common connection between the antenna/earth ground and the
                        > logic ground for controlling the relays.
                        <snip>

                        Hello, Kees and the group--

                        One point to keep in mind centers on magnetic interactions
                        among the relays. IIRC, the plastic-housed box-shaped little
                        relays offered by Nais and other manufacturers may require
                        at least a minimum separation between the relays, so check
                        the data sheets for whatever relays you plan to use.

                        73--

                        Brad AA1IP
                      • Kees & Sandy
                        Hi Dave and the group. Great data, Dave. This is FR-4 (Advanced Circuits) so 70mils may be a little too narrow. I haven t measured it and just took data I
                        Message 11 of 27 , May 7, 2013
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                          Hi Dave and the group.
                           
                          Great data, Dave. 
                           
                          This is FR-4 (Advanced Circuits) so 70mils may be a little too narrow. I haven't measured it and just took data I found on the Internet (has to be correct, right ?). I defer to your experience and will widen the traces to 100mils.
                           
                          73 Kees K5BCQ


                          ---------- Original Message ----------
                          From: Dave <dave@...>
                          To: softrock40@yahoogroups.com
                          Subject: Re: [softrock40] Re: Packaging external filters
                          Date: Tue, 07 May 2013 13:09:15 -0700

                           

                          Kees and all:
                            Don't know what substrate your pcb is.  But, FR4 epoxy glass, .062" thick, 1 oz copper, 50 ohms is real close to .100" wide. 

                          Dave - WB6DHW
                          <http://wb6dhw.com>

                          On 5/7/2013 11:58 AM, Graeme wrote:
                           

                          Hi Kees,

                          Looks like you are already using "best practice" construction and yes the printed transmission lines are just fine. Only reason I avoided them is they are a bit tricky for home made pcb. Yes you get a stub on the unused filters so I make the through filter the last in the chain them 6 M, 10 M etc. to keep the stub short. On 160 M with the longest stub it shows a a little bit of capacitance on the input and output but does not affect the response. My relays were recovered from an old telephone exchange and probably are good contacts but really unknown although they work just fine.

                          I am using 1206 smt ceramic NPO capacitors rated at 200 Volts and have not had a failure even when testing into open circuit. The RD16HHF1's survived also. I am very impressed with them.

                          73 Graeme ZL2APV

                          --- In softrock40@yahoogroups.com, "Kees & Sandy" <windy10605@...> wrote:
                          >
                          > Very good info, Graeme. I ran board traces down the two sides of the board, one for input and one for output and made the traces 60-70mil wide. I've found that on a 62mil board, using 1oz copper, over a ground plane it comes pretty close to 50 ohms. It would still be nice to not have the unterminated stubs (to the unused filters), but I don't know what to do about that. The relays all have bifurcated, gold covered, contacts which are also paralleled for reliability (DPDT contacts). The other point is to only have one common connection between the antenna/earth ground and the logic ground for controlling the relays. Right now I'm using SMA connectors but may go back to BNC. Roger, on the bypass capacitor (and diode) across each coil. Always good to have bypass caps on DC circuits in an RF environment. The only "tricky" layout is that I'm putting a single RD16HHF1 right in the middle of the board as an Amp (couldn't see all that space going to waste). Have you ever used NPO, high voltage, ceramic smt capacitors in the filters ? Have you found any reason to use 5V relays vs 12V relays ? .....I got it in my mind that the lower 5V coils (less impedance) would be less suceptible to RF pickup. Probably a DNW (Does Nothing What-so-ever). 73 Kees K5BCQ
                          > ---------- Original Message ----------
                          > From: Graeme Jury <gvjury@...>
                          > To: softrock40@yahoogroups.com
                          > Subject: [softrock40] Re: Packaging external filters
                          > Date: Tue, 07 May 2013 15:07:23 +1200
                          >
                          >
                          > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
                          > There is a couple of things which may be useful when designing switched
                          > banks of filters.
                          >
                          > 1. Use a transmission line down the relay chain. In my case I used
                          > RG-179 with the cover stripped back 5 mm or so and the braid tinned. Two
                          > knife cuts 2 mm apart were rolled around the centre of the tinned braid
                          > and then bent to snap at the knife cuts. The 2 mm piece of braid was
                          > pried away and the centre of the coax bared. This was done opposite each
                          > relay. The braids were soldered to the earth plane and the centre
                          > connected to the relay contact. It did not take long to prepare the coax
                          > and avoids the tricky and less reliable design of a printed transmission
                          > line.
                          >
                          > 2. Bypass the coils of each relay. I ran my filter bank through my VNA
                          > and could not understand why the roll off at the HF end of the filter
                          > went down to about 40 dB and then flattened. They were mesh Chebyshev
                          > filters and should have kept going down. In the end I found that a 0.1
                          > smt cap on the coil on the 12 Volt common side of the relays fixed the
                          > problem. As I added caps to more of the coils it got better and when I
                          > had done half of them it was improved to the noise floor of the VNA.
                          > Naturally for the negligible cost I did them all and also the switched
                          > grounded side of the coils too. It is an obscure fault and maybe if I
                          > had used RF relays it would not have happened but I used standard 2 pole
                          > changeover miniature ones which switch 30 watts from my RD16HHF1 linear
                          > on CW just fine.
                          >
                          > 73 Graeme ZL2APV
                          >

                           

                           

                        • Dave
                          Kees: I haven t actually measured the impedance of my traces. But, there are a number of calculators on the internet that calculate either the impedance or
                          Message 12 of 27 , May 7, 2013
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                            Kees:
                              I haven't actually measured the impedance of my traces.  But, there are a number of calculators on the internet that calculate either the impedance or the width.  Note also, the .100" is if there is not a ground near the trace.  The protoype board for the LF2uW, I put ground on the top .01" away from the trace.  According to the calculator, this is 50 ohms.  If the ground is .008", as .040 trace is 50 ohms.

                            Dave - WB6DHW
                            <http://wb6dhw.com>

                            On 5/7/2013 2:19 PM, Kees & Sandy wrote:
                             
                            Hi Dave and the group.
                             
                            Great data, Dave. 
                             
                            This is FR-4 (Advanced Circuits) so 70mils may be a little too narrow. I haven't measured it and just took data I found on the Internet (has to be correct, right ?). I defer to your experience and will widen the traces to 100mils.
                             
                            73 Kees K5BCQ


                            ---------- Original Message ----------
                            From: Dave <dave@...>
                            To: softrock40@yahoogroups.com
                            Subject: Re: [softrock40] Re: Packaging external filters
                            Date: Tue, 07 May 2013 13:09:15 -0700

                             

                            Kees and all:
                              Don't know what substrate your pcb is.  But, FR4 epoxy glass, .062" thick, 1 oz copper, 50 ohms is real close to .100" wide. 

                            Dave - WB6DHW
                            <http://wb6dhw.com>

                            On 5/7/2013 11:58 AM, Graeme wrote:
                             

                            Hi Kees,

                            Looks like you are already using "best practice" construction and yes the printed transmission lines are just fine. Only reason I avoided them is they are a bit tricky for home made pcb. Yes you get a stub on the unused filters so I make the through filter the last in the chain them 6 M, 10 M etc. to keep the stub short. On 160 M with the longest stub it shows a a little bit of capacitance on the input and output but does not affect the response. My relays were recovered from an old telephone exchange and probably are good contacts but really unknown although they work just fine.

                            I am using 1206 smt ceramic NPO capacitors rated at 200 Volts and have not had a failure even when testing into open circuit. The RD16HHF1's survived also. I am very impressed with them.

                            73 Graeme ZL2APV

                            --- In softrock40@yahoogroups.com, "Kees & Sandy" <windy10605@...> wrote:
                            >
                            > Very good info, Graeme. I ran board traces down the two sides of the board, one for input and one for output and made the traces 60-70mil wide. I've found that on a 62mil board, using 1oz copper, over a ground plane it comes pretty close to 50 ohms. It would still be nice to not have the unterminated stubs (to the unused filters), but I don't know what to do about that. The relays all have bifurcated, gold covered, contacts which are also paralleled for reliability (DPDT contacts). The other point is to only have one common connection between the antenna/earth ground and the logic ground for controlling the relays. Right now I'm using SMA connectors but may go back to BNC. Roger, on the bypass capacitor (and diode) across each coil. Always good to have bypass caps on DC circuits in an RF environment. The only "tricky" layout is that I'm putting a single RD16HHF1 right in the middle of the board as an Amp (couldn't see all that space going to waste). Have you ever used NPO, high voltage, ceramic smt capacitors in the filters ? Have you found any reason to use 5V relays vs 12V relays ? .....I got it in my mind that the lower 5V coils (less impedance) would be less suceptible to RF pickup. Probably a DNW (Does Nothing What-so-ever). 73 Kees K5BCQ
                            > ---------- Original Message ----------
                            > From: Graeme Jury <gvjury@...>
                            > To: softrock40@yahoogroups.com
                            > Subject: [softrock40] Re: Packaging external filters
                            > Date: Tue, 07 May 2013 15:07:23 +1200
                            >
                            >
                            > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
                            > There is a couple of things which may be useful when designing switched
                            > banks of filters.
                            >
                            > 1. Use a transmission line down the relay chain. In my case I used
                            > RG-179 with the cover stripped back 5 mm or so and the braid tinned. Two
                            > knife cuts 2 mm apart were rolled around the centre of the tinned braid
                            > and then bent to snap at the knife cuts. The 2 mm piece of braid was
                            > pried away and the centre of the coax bared. This was done opposite each
                            > relay. The braids were soldered to the earth plane and the centre
                            > connected to the relay contact. It did not take long to prepare the coax
                            > and avoids the tricky and less reliable design of a printed transmission
                            > line.
                            >
                            > 2. Bypass the coils of each relay. I ran my filter bank through my VNA
                            > and could not understand why the roll off at the HF end of the filter
                            > went down to about 40 dB and then flattened. They were mesh Chebyshev
                            > filters and should have kept going down. In the end I found that a 0.1
                            > smt cap on the coil on the 12 Volt common side of the relays fixed the
                            > problem. As I added caps to more of the coils it got better and when I
                            > had done half of them it was improved to the noise floor of the VNA.
                            > Naturally for the negligible cost I did them all and also the switched
                            > grounded side of the coils too. It is an obscure fault and maybe if I
                            > had used RF relays it would not have happened but I used standard 2 pole
                            > changeover miniature ones which switch 30 watts from my RD16HHF1 linear
                            > on CW just fine.
                            >
                            > 73 Graeme ZL2APV
                            >

                             

                             


                          • Brad Thompson
                            ... Hello, Kees-- Thanks for your comments. I looked at the G6E data sheet... http://www.omron.com/ecb/products/pdf/en-g6e.pdf ...And found a drawing on page 4
                            Message 13 of 27 , May 7, 2013
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                              On 5/7/2013 5:01 PM, Kees & Sandy wrote:
                              > Hello Brad and the gang,
                              >
                              > I figured you would jump in with some good techie advice and/or experience.
                              >
                              > Very good point. That, I did not think about and look into. The spec for the G6H OMRON relay does say "low magnetic interference enables high-density mounting", but gives no additional details. I took one apart looking for shielding but can't tell if there is any u metal ? in there. The cross-bar Au contacts look nice though and they were really inexpensive in the 2F package.
                              >
                              > 73 Kees K5BCQ
                              >

                              Hello, Kees--

                              Thanks for your comments. I looked at the G6E data sheet...

                              http://www.omron.com/ecb/products/pdf/en-g6e.pdf

                              ...And found a drawing on page 4 that shows effects
                              of nearby relays; If my interpretation is correct,
                              packing the relays closer together than in the drawing will
                              increase the effects. With the spacings shown, operate and
                              release voltages change by something less than 1 percent.

                              Also, note that the G6E is a relative of the G6H, so we
                              may be contemplating apples and oranges<g>.

                              73--

                              Brad AA1IP
                            • Kees & Sandy
                              Dave, I tried several of those and found them confusing because the focus seems to be on GHz stripline impedances where you have one stripline on one side and
                              Message 14 of 27 , May 7, 2013
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                                Dave,
                                 
                                I tried several of those and found them confusing because the focus seems to be on GHz stripline impedances where you have one stripline on one side and a ground plane on the other and no soldermask. ....and yes, one stripline over a ground plane 62 mills away is around 50 ohms if it is about 110 mills wide. This is QRP power at HF frequencies so I was also using floodfill ground on the trace side....separated by say, 20 mils on one or two sides and 62 mills away from a full ground plane on the other side. Assume 1oz Cu is 1.37 mills and permeablity varies from 1 for air to 4.3 for the Advanced Circuits FR-4 board. Guess the only way to really know is to build it and measure it (but that costs) ......got any ideas ? 
                                 
                                Or just light'er up and check for smoke.
                                 
                                73 kees K5BCQ
                                 
                                --------- Original Message ----------
                                From: Dave <dave@...>
                                To: softrock40@yahoogroups.com
                                Subject: Re: [softrock40] Re: Packaging external filters
                                Date: Tue, 07 May 2013 17:08:49 -0700

                                 
                                Kees:
                                � I haven't actually measured the impedance of my traces.� But, there are a number of calculators on the internet that calculate either the impedance or the width.� Note also, the .100" is if there is not a ground near the trace.� The protoype board for the LF2uW, I put ground on the top .01" away from the trace.� According to the calculator, this is 50 ohms.� If the ground is .008", as .040 trace is 50 ohms.

                                Dave - WB6DHW
                                <http://wb6dhw.com>

                                On 5/7/2013 2:19 PM, Kees & Sandy wrote:
                                Hi Dave and the group.
                                Great data, Dave.�
                                This is FR-4 (Advanced Circuits) so 70mils may be a little too narrow. I haven't measured it and just took data I found on the Internet (has to be correct, right ?). I defer to your experience and will widen the traces to 100mils.
                                73 Kees K5BCQ


                                ---------- Original Message ----------
                                From: Dave <dave@...>
                                To: softrock40@yahoogroups.com
                                Subject: Re: [softrock40] Re: Packaging external filters
                                Date: Tue, 07 May 2013 13:09:15 -0700

                                Kees and all:
                                � Don't know what substrate your pcb is.� But, FR4 epoxy glass, .062" thick, 1 oz copper, 50 ohms is real close to .100" wide.�

                                Dave - WB6DHW
                                <http://wb6dhw.com>

                                On 5/7/2013 11:58 AM, Graeme wrote:

                                Hi Kees,

                                Looks like you are already using "best practice" construction and yes the printed transmission lines are just fine. Only reason I avoided them is they are a bit tricky for home made pcb. Yes you get a stub on the unused filters so I make the through filter the last in the chain them 6 M, 10 M etc. to keep the stub short. On 160 M with the longest stub it shows a a little bit of capacitance on the input and output but does not affect the response. My relays were recovered from an old telephone exchange and probably are good contacts but really unknown although they work just fine.

                                I am using 1206 smt ceramic NPO capacitors rated at 200 Volts and have not had a failure even when testing into open circuit. The RD16HHF1's survived also. I am very impressed with them.

                                73 Graeme ZL2APV

                                --- In softrock40@yahoogroups.com, "Kees & Sandy" <windy10605@...> wrote:
                                >
                                > Very good info, Graeme. I ran board traces down the two sides of the board, one for input and one for output and made the traces 60-70mil wide. I've found that on a 62mil board, using 1oz copper, over a ground plane it comes pretty close to 50 ohms. It would still be nice to not have the unterminated stubs (to the unused filters), but I don't know what to do about that. The relays all have bifurcated, gold covered, contacts which are also paralleled for reliability (DPDT contacts). The other point is to only have one common connection between the antenna/earth ground and the logic ground for controlling the relays. Right now I'm using SMA connectors but may go back to BNC. Roger, on the bypass capacitor (and diode) across each coil. Always good to have bypass caps on DC circuits in an RF environment. The only "tricky" layout is that I'm putting a single RD16HHF1 right in the middle of the board as an Amp (couldn't see all that space going to waste). Have you ever used NPO, high voltage, ceramic smt capacitors in the filters ? Have you found any reason to use 5V relays vs 12V relays ? .....I got it in my mind that the lower 5V coils (less impedance) would be less suceptible to RF pickup. Probably a DNW (Does Nothing What-so-ever). 73 Kees K5BCQ
                                > ---------- Original Message ----------
                                > From: Graeme Jury <gvjury@...>
                                > To: softrock40@yahoogroups.com
                                > Subject: [softrock40] Re: Packaging external filters
                                > Date: Tue, 07 May 2013 15:07:23 +1200
                                >
                                >
                                > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
                                > There is a couple of things which may be useful when designing switched
                                > banks of filters.
                                >
                                > 1. Use a transmission line down the relay chain. In my case I used
                                > RG-179 with the cover stripped back 5 mm or so and the braid tinned. Two
                                > knife cuts 2 mm apart were rolled around the centre of the tinned braid
                                > and then bent to snap at the knife cuts. The 2 mm piece of braid was
                                > pried away and the centre of the coax bared. This was done opposite each
                                > relay. The braids were soldered to the earth plane and the centre
                                > connected to the relay contact. It did not take long to prepare the coax
                                > and avoids the tricky and less reliable design of a printed transmission
                                > line.
                                >
                                > 2. Bypass the coils of each relay. I ran my filter bank through my VNA
                                > and could not understand why the roll off at the HF end of the filter
                                > went down to about 40 dB and then flattened. They were mesh Chebyshev
                                > filters and should have kept going down. In the end I found that a 0.1
                                > smt cap on the coil on the 12 Volt common side of the relays fixed the
                                > problem. As I added caps to more of the coils it got better and when I
                                > had done half of them it was improved to the noise floor of the VNA.
                                > Naturally for the negligible cost I did them all and also the switched
                                > grounded side of the coils too. It is an obscure fault and maybe if I
                                > had used RF relays it would not have happened but I used standard 2 pole
                                > changeover miniature ones which switch 30 watts from my RD16HHF1 linear
                                > on CW just fine.
                                >
                                > 73 Graeme ZL2APV
                                >

                                 

                              • Kees & Sandy
                                Ahhhh. My OMRON G6H documentation has no such drawing on page 4 ....but it does have a Discontinued stamp on page 1. those always make the best and least
                                Message 15 of 27 , May 7, 2013
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                                  Ahhhh. My OMRON G6H documentation has no such drawing on page 4 ....but it does have a "Discontinued" stamp on page 1. those always make the best and least expensive surplus parts.

                                  73 Kees K5BCQ

                                  ---------- Original Message ----------
                                  From: Brad Thompson <brad.thompson@...>
                                  To: softrock40@yahoogroups.com
                                  Cc: Kees & Sandy <windy10605@...>
                                  Subject: Re: [softrock40] Re: Packaging external filters
                                  Date: Tue, 07 May 2013 21:10:30 -0400

                                  On 5/7/2013 5:01 PM, Kees & Sandy wrote:
                                  > Hello Brad and the gang,
                                  >
                                  > I figured you would jump in with some good techie advice and/or experience.
                                  >
                                  > Very good point. That, I did not think about and look into. The spec for the G6H OMRON relay does say "low magnetic interference enables high-density mounting", but gives no additional details. I took one apart looking for shielding but can't tell if there is any u metal ? in there. The cross-bar Au contacts look nice though and they were really inexpensive in the 2F package.
                                  >
                                  > 73 Kees K5BCQ
                                  >

                                  Hello, Kees--

                                  Thanks for your comments. I looked at the G6E data sheet...

                                  http://www.omron.com/ecb/products/pdf/en-g6e.pdf

                                  ...And found a drawing on page 4 that shows effects
                                  of nearby relays; If my interpretation is correct,
                                  packing the relays closer together than in the drawing will
                                  increase the effects. With the spacings shown, operate and
                                  release voltages change by something less than 1 percent.

                                  Also, note that the G6E is a relative of the G6H, so we
                                  may be contemplating apples and oranges<g>.

                                  73--

                                  Brad AA1IP
                                • Dave
                                  Kees: As you bring the floodfill ground closer to the trace, the impedance goes down. Some of the calculators will figure that out. At .020 , you width of
                                  Message 16 of 27 , May 7, 2013
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                                    Kees:
                                      As you bring the floodfill ground closer to the trace, the impedance goes down.  Some of the calculators will figure that out.  At .020", you width of .06 to .07 should be close to 50 ohms.

                                    Dave -wb6dhw.com
                                    <http://wb6dhw.com>

                                    On 5/7/2013 6:47 PM, Kees & Sandy wrote:
                                     
                                    Dave,
                                     
                                    I tried several of those and found them confusing because the focus seems to be on GHz stripline impedances where you have one stripline on one side and a ground plane on the other and no soldermask. ....and yes, one stripline over a ground plane 62 mills away is around 50 ohms if it is about 110 mills wide. This is QRP power at HF frequencies so I was also using floodfill ground on the trace side....separated by say, 20 mils on one or two sides and 62 mills away from a full ground plane on the other side. Assume 1oz Cu is 1.37 mills and permeablity varies from 1 for air to 4.3 for the Advanced Circuits FR-4 board. Guess the only way to really know is to build it and measure it (but that costs) ......got any ideas ? 
                                     
                                    Or just light'er up and check for smoke.
                                     
                                    73 kees K5BCQ
                                     
                                    --------- Original Message ----------
                                    From: Dave <dave@...>
                                    To: softrock40@yahoogroups.com
                                    Subject: Re: [softrock40] Re: Packaging external filters
                                    Date: Tue, 07 May 2013 17:08:49 -0700

                                     
                                    Kees:
                                    � I haven't actually measured the impedance of my traces.� But, there are a number of calculators on the internet that calculate either the impedance or the width.� Note also, the .100" is if there is not a ground near the trace.� The protoype board for the LF2uW, I put ground on the top .01" away from the trace.� According to the calculator, this is 50 ohms.� If the ground is .008", as .040 trace is 50 ohms.

                                    Dave - WB6DHW
                                    <http://wb6dhw.com>

                                    On 5/7/2013 2:19 PM, Kees & Sandy wrote:
                                    Hi Dave and the group.
                                    Great data, Dave.�
                                    This is FR-4 (Advanced Circuits) so 70mils may be a little too narrow. I haven't measured it and just took data I found on the Internet (has to be correct, right ?). I defer to your experience and will widen the traces to 100mils.
                                    73 Kees K5BCQ


                                    ---------- Original Message ----------
                                    From: Dave <dave@...>
                                    To: softrock40@yahoogroups.com
                                    Subject: Re: [softrock40] Re: Packaging external filters
                                    Date: Tue, 07 May 2013 13:09:15 -0700

                                    Kees and all:
                                    � Don't know what substrate your pcb is.� But, FR4 epoxy glass, .062" thick, 1 oz copper, 50 ohms is real close to .100" wide.�

                                    Dave - WB6DHW
                                    <http://wb6dhw.com>

                                    On 5/7/2013 11:58 AM, Graeme wrote:

                                    Hi Kees,

                                    Looks like you are already using "best practice" construction and yes the printed transmission lines are just fine. Only reason I avoided them is they are a bit tricky for home made pcb. Yes you get a stub on the unused filters so I make the through filter the last in the chain them 6 M, 10 M etc. to keep the stub short. On 160 M with the longest stub it shows a a little bit of capacitance on the input and output but does not affect the response. My relays were recovered from an old telephone exchange and probably are good contacts but really unknown although they work just fine.

                                    I am using 1206 smt ceramic NPO capacitors rated at 200 Volts and have not had a failure even when testing into open circuit. The RD16HHF1's survived also. I am very impressed with them.

                                    73 Graeme ZL2APV

                                    --- In softrock40@yahoogroups.com, "Kees & Sandy" <windy10605@...> wrote:
                                    >
                                    > Very good info, Graeme. I ran board traces down the two sides of the board, one for input and one for output and made the traces 60-70mil wide. I've found that on a 62mil board, using 1oz copper, over a ground plane it comes pretty close to 50 ohms. It would still be nice to not have the unterminated stubs (to the unused filters), but I don't know what to do about that. The relays all have bifurcated, gold covered, contacts which are also paralleled for reliability (DPDT contacts). The other point is to only have one common connection between the antenna/earth ground and the logic ground for controlling the relays. Right now I'm using SMA connectors but may go back to BNC. Roger, on the bypass capacitor (and diode) across each coil. Always good to have bypass caps on DC circuits in an RF environment. The only "tricky" layout is that I'm putting a single RD16HHF1 right in the middle of the board as an Amp (couldn't see all that space going to waste). Have you ever used NPO, high voltage, ceramic smt capacitors in the filters ? Have you found any reason to use 5V relays vs 12V relays ? .....I got it in my mind that the lower 5V coils (less impedance) would be less suceptible to RF pickup. Probably a DNW (Does Nothing What-so-ever). 73 Kees K5BCQ
                                    > ---------- Original Message ----------
                                    > From: Graeme Jury <gvjury@...>
                                    > To: softrock40@yahoogroups.com
                                    > Subject: [softrock40] Re: Packaging external filters
                                    > Date: Tue, 07 May 2013 15:07:23 +1200
                                    >
                                    >
                                    > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
                                    > There is a couple of things which may be useful when designing switched
                                    > banks of filters.
                                    >
                                    > 1. Use a transmission line down the relay chain. In my case I used
                                    > RG-179 with the cover stripped back 5 mm or so and the braid tinned. Two
                                    > knife cuts 2 mm apart were rolled around the centre of the tinned braid
                                    > and then bent to snap at the knife cuts. The 2 mm piece of braid was
                                    > pried away and the centre of the coax bared. This was done opposite each
                                    > relay. The braids were soldered to the earth plane and the centre
                                    > connected to the relay contact. It did not take long to prepare the coax
                                    > and avoids the tricky and less reliable design of a printed transmission
                                    > line.
                                    >
                                    > 2. Bypass the coils of each relay. I ran my filter bank through my VNA
                                    > and could not understand why the roll off at the HF end of the filter
                                    > went down to about 40 dB and then flattened. They were mesh Chebyshev
                                    > filters and should have kept going down. In the end I found that a 0.1
                                    > smt cap on the coil on the 12 Volt common side of the relays fixed the
                                    > problem. As I added caps to more of the coils it got better and when I
                                    > had done half of them it was improved to the noise floor of the VNA.
                                    > Naturally for the negligible cost I did them all and also the switched
                                    > grounded side of the coils too. It is an obscure fault and maybe if I
                                    > had used RF relays it would not have happened but I used standard 2 pole
                                    > changeover miniature ones which switch 30 watts from my RD16HHF1 linear
                                    > on CW just fine.
                                    >
                                    > 73 Graeme ZL2APV
                                    >

                                     

                                    _

                                  • David Turnbull
                                    ... http://oshpark.com/pricing a 2 square inch board would cost $10 and you’d get three 73 David AE9RB http://AE9RB.com/ On Tue, May 7, 2013 at 6:47 PM,
                                    Message 17 of 27 , May 7, 2013
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                                      On Tue, May 7, 2013 at 6:47 PM, Kees & Sandy <windy10605@...> wrote:
                                      Guess the only way to really know is to build it and measure it (but that costs) ......got any ideas ? 

                                      "a 2 square inch board would cost $10 and you’d get three"

                                      73 David AE9RB

                                    • Kees & Sandy
                                      Dave, That s great. Do you have a link to one that takes floodfill into accont. I never found one of those. 73 Kees K5BCQ ... From: Dave To:
                                      Message 18 of 27 , May 7, 2013
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                                        Dave,
                                         
                                        That's great. Do you have a link to one that takes floodfill into accont. I never found one of those.
                                         
                                        73 Kees K5BCQ


                                        ---------- Original Message ----------
                                        From: Dave <dave@...>
                                        To: softrock40@yahoogroups.com
                                        Subject: Re: [softrock40] Re: Packaging external filters
                                        Date: Tue, 07 May 2013 19:15:41 -0700

                                         

                                        Kees:
                                        � As you bring the floodfill ground closer to the trace, the impedance goes down.� Some of the calculators will figure that out.� At .020", you width of .06 to .07 should be close to 50 ohms.

                                        Dave -wb6dhw.com
                                        <http://wb6dhw.com>

                                        On 5/7/2013 6:47 PM, Kees & Sandy wrote:
                                        Dave,
                                        I tried several of those and found them confusing because the focus seems to be on GHz stripline impedances where you have one stripline on one side and a ground plane on the other and no soldermask. ....and yes, one stripline over a ground plane 62 mills away is around 50 ohms if it is about 110 mills wide. This is QRP power at HF frequencies so I was also using floodfill ground on the trace side....separated by say, 20 mils on one or two sides and 62 mills away from a full ground plane on the other side. Assume 1oz Cu is 1.37 mills and permeablity varies from 1 for air to 4.3 for the Advanced Circuits FR-4 board. Guess the only way to really know is to build it�and measure it (but that costs)�......got any ideas ?�
                                        Or just light'er up and check for smoke.
                                        73 kees K5BCQ
                                        --------- Original Message ----------
                                        From: Dave <dave@...>
                                        To: softrock40@yahoogroups.com
                                        Subject: Re: [softrock40] Re: Packaging external filters
                                        Date: Tue, 07 May 2013 17:08:49 -0700

                                        Kees:
                                        � I haven't actually measured the impedance of my traces.� But, there are a number of calculators on the internet that calculate either the impedance or the width.� Note also, the .100" is if there is not a ground near the trace.� The protoype board for the LF2uW, I put ground on the top .01" away from the trace.� According to the calculator, this is 50 ohms.� If the ground is .008", as .040 trace is 50 ohms.

                                        Dave - WB6DHW
                                        <http://wb6dhw.com>

                                        On 5/7/2013 2:19 PM, Kees & Sandy wrote:
                                        Hi Dave and the group.
                                        Great data, Dave.�
                                        This is FR-4 (Advanced Circuits) so 70mils may be a little too narrow. I haven't measured it and just took data I found on the Internet (has to be correct, right ?). I defer to your experience and will widen the traces to 100mils.
                                        73 Kees K5BCQ


                                        ---------- Original Message ----------
                                        From: Dave <dave@...>
                                        To: softrock40@yahoogroups.com
                                        Subject: Re: [softrock40] Re: Packaging external filters
                                        Date: Tue, 07 May 2013 13:09:15 -0700

                                        Kees and all:
                                        � Don't know what substrate your pcb is.� But, FR4 epoxy glass, .062" thick, 1 oz copper, 50 ohms is real close to .100" wide.�

                                        Dave - WB6DHW
                                        <http://wb6dhw.com>

                                        On 5/7/2013 11:58 AM, Graeme wrote:

                                        Hi Kees,

                                        Looks like you are already using "best practice" construction and yes the printed transmission lines are just fine. Only reason I avoided them is they are a bit tricky for home made pcb. Yes you get a stub on the unused filters so I make the through filter the last in the chain them 6 M, 10 M etc. to keep the stub short. On 160 M with the longest stub it shows a a little bit of capacitance on the input and output but does not affect the response. My relays were recovered from an old telephone exchange and probably are good contacts but really unknown although they work just fine.

                                        I am using 1206 smt ceramic NPO capacitors rated at 200 Volts and have not had a failure even when testing into open circuit. The RD16HHF1's survived also. I am very impressed with them.

                                        73 Graeme ZL2APV

                                        --- In softrock40@yahoogroups.com, "Kees & Sandy" <windy10605@...> wrote:
                                        >
                                        > Very good info, Graeme. I ran board traces down the two sides of the board, one for input and one for output and made the traces 60-70mil wide. I've found that on a 62mil board, using 1oz copper, over a ground plane it comes pretty close to 50 ohms. It would still be nice to not have the unterminated stubs (to the unused filters), but I don't know what to do about that. The relays all have bifurcated, gold covered, contacts which are also paralleled for reliability (DPDT contacts). The other point is to only have one common connection between the antenna/earth ground and the logic ground for controlling the relays. Right now I'm using SMA connectors but may go back to BNC. Roger, on the bypass capacitor (and diode) across each coil. Always good to have bypass caps on DC circuits in an RF environment. The only "tricky" layout is that I'm putting a single RD16HHF1 right in the middle of the board as an Amp (couldn't see all that space going to waste). Have you ever used NPO, high voltage, ceramic smt capacitors in the filters ? Have you found any reason to use 5V relays vs 12V relays ? .....I got it in my mind that the lower 5V coils (less impedance) would be less suceptible to RF pickup. Probably a DNW (Does Nothing What-so-ever). 73 Kees K5BCQ
                                        > ---------- Original Message ----------
                                        > From: Graeme Jury <gvjury@...>
                                        > To: softrock40@yahoogroups.com
                                        > Subject: [softrock40] Re: Packaging external filters
                                        > Date: Tue, 07 May 2013 15:07:23 +1200
                                        >
                                        >
                                        > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
                                        > There is a couple of things which may be useful when designing switched
                                        > banks of filters.
                                        >
                                        > 1. Use a transmission line down the relay chain. In my case I used
                                        > RG-179 with the cover stripped back 5 mm or so and the braid tinned. Two
                                        > knife cuts 2 mm apart were rolled around the centre of the tinned braid
                                        > and then bent to snap at the knife cuts. The 2 mm piece of braid was
                                        > pried away and the centre of the coax bared. This was done opposite each
                                        > relay. The braids were soldered to the earth plane and the centre
                                        > connected to the relay contact. It did not take long to prepare the coax
                                        > and avoids the tricky and less reliable design of a printed transmission
                                        > line.
                                        >
                                        > 2. Bypass the coils of each relay. I ran my filter bank through my VNA
                                        > and could not understand why the roll off at the HF end of the filter
                                        > went down to about 40 dB and then flattened. They were mesh Chebyshev
                                        > filters and should have kept going down. In the end I found that a 0.1
                                        > smt cap on the coil on the 12 Volt common side of the relays fixed the
                                        > problem. As I added caps to more of the coils it got better and when I
                                        > had done half of them it was improved to the noise floor of the VNA.
                                        > Naturally for the negligible cost I did them all and also the switched
                                        > grounded side of the coils too. It is an obscure fault and maybe if I
                                        > had used RF relays it would not have happened but I used standard 2 pole
                                        > changeover miniature ones which switch 30 watts from my RD16HHF1 linear
                                        > on CW just fine.
                                        >
                                        > 73 Graeme ZL2APV
                                        >

                                        _

                                         

                                      • Kees & Sandy
                                        Cool ! Is that what you use for your Peaberry boards ? what files are required ? gerber? 73 Kees K5BCQ ... From: David Turnbull To:
                                        Message 19 of 27 , May 7, 2013
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                                          Cool !  Is that what you use for your Peaberry boards ? what files are required ? gerber?
                                           
                                          73 Kees K5BCQ

                                          ---------- Original Message ----------
                                          From: David Turnbull <dturnbull@...>
                                          To: softrock40@yahoogroups.com
                                          Subject: Re: [softrock40] Re: Packaging external filters
                                          Date: Tue, 7 May 2013 19:25:30 -0700

                                           

                                          On Tue, May 7, 2013 at 6:47 PM, Kees & Sandy <windy10605@...> wrote:
                                          Guess the only way to really know is to build it�and measure it (but that costs)�......got any ideas ?�
                                           
                                           
                                          "a 2 square inch board would cost $10 and you�d get three"
                                           
                                          73 David AE9RB
                                           

                                           

                                        • Dave
                                          Kees: The latest version of KICAD includes a pcb calculator. The grounded coplanar calculates the impedance with a trace over a groundplane and ground areas
                                          Message 20 of 27 , May 7, 2013
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                                             Kees:
                                              The latest version of KICAD includes a pcb calculator.  The "grounded coplanar" calculates the impedance with a trace over a groundplane and ground areas on the sides.

                                            Dave - WB6DHW
                                            <http://wb6dhw.com>

                                            On 5/7/2013 7:31 PM, Kees & Sandy wrote:
                                             
                                            Dave,
                                             
                                            That's great. Do you have a link to one that takes floodfill into accont. I never found one of those.
                                             
                                            73 Kees K5BCQ


                                            ---------- Original Message ----------
                                            From: Dave <dave@...>
                                            To: softrock40@yahoogroups.com
                                            Subject: Re: [softrock40] Re: Packaging external filters
                                            Date: Tue, 07 May 2013 19:15:41 -0700

                                             

                                            Kees:
                                            � As you bring the floodfill ground closer to the trace, the impedance goes down.� Some of the calculators will figure that out.� At .020", you width of .06 to .07 should be close to 50 ohms.

                                            Dave -wb6dhw.com
                                            <http://wb6dhw.com>

                                            On 5/7/2013 6:47 PM, Kees & Sandy wrote:
                                            Dave,
                                            I tried several of those and found them confusing because the focus seems to be on GHz stripline impedances where you have one stripline on one side and a ground plane on the other and no soldermask. ....and yes, one stripline over a ground plane 62 mills away is around 50 ohms if it is about 110 mills wide. This is QRP power at HF frequencies so I was also using floodfill ground on the trace side....separated by say, 20 mils on one or two sides and 62 mills away from a full ground plane on the other side. Assume 1oz Cu is 1.37 mills and permeablity varies from 1 for air to 4.3 for the Advanced Circuits FR-4 board. Guess the only way to really know is to build it�and measure it (but that costs)�......got any ideas ?�
                                            Or just light'er up and check for smoke.
                                            73 kees K5BCQ
                                            --------- Original Message ----------
                                            From: Dave <dave@...>
                                            To: softrock40@yahoogroups.com
                                            Subject: Re: [softrock40] Re: Packaging external filters
                                            Date: Tue, 07 May 2013 17:08:49 -0700

                                            Kees:
                                            � I haven't actually measured the impedance of my traces.� But, there are a number of calculators on the internet that calculate either the impedance or the width.� Note also, the .100" is if there is not a ground near the trace.� The protoype board for the LF2uW, I put ground on the top .01" away from the trace.� According to the calculator, this is 50 ohms.� If the ground is .008", as .040 trace is 50 ohms.

                                            Dave - WB6DHW
                                            <http://wb6dhw.com>

                                            On 5/7/2013 2:19 PM, Kees & Sandy wrote:
                                            Hi Dave and the group.
                                            Great data, Dave.�
                                            This is FR-4 (Advanced Circuits) so 70mils may be a little too narrow. I haven't measured it and just took data I found on the Internet (has to be correct, right ?). I defer to your experience and will widen the traces to 100mils.
                                            73 Kees K5BCQ


                                            ---------- Original Message ----------
                                            From: Dave <dave@...>
                                            To: softrock40@yahoogroups.com
                                            Subject: Re: [softrock40] Re: Packaging external filters
                                            Date: Tue, 07 May 2013 13:09:15 -0700

                                            Kees and all:
                                            � Don't know what substrate your pcb is.� But, FR4 epoxy glass, .062" thick, 1 oz copper, 50 ohms is real close to .100" wide.�

                                            Dave - WB6DHW
                                            <http://wb6dhw.com>

                                            On 5/7/2013 11:58 AM, Graeme wrote:

                                            Hi Kees,

                                            Looks like you are already using "best practice" construction and yes the printed transmission lines are just fine. Only reason I avoided them is they are a bit tricky for home made pcb. Yes you get a stub on the unused filters so I make the through filter the last in the chain them 6 M, 10 M etc. to keep the stub short. On 160 M with the longest stub it shows a a little bit of capacitance on the input and output but does not affect the response. My relays were recovered from an old telephone exchange and probably are good contacts but really unknown although they work just fine.

                                            I am using 1206 smt ceramic NPO capacitors rated at 200 Volts and have not had a failure even when testing into open circuit. The RD16HHF1's survived also. I am very impressed with them.

                                            73 Graeme ZL2APV

                                            --- In softrock40@yahoogroups.com, "Kees & Sandy" <windy10605@...> wrote:
                                            >
                                            > Very good info, Graeme. I ran board traces down the two sides of the board, one for input and one for output and made the traces 60-70mil wide. I've found that on a 62mil board, using 1oz copper, over a ground plane it comes pretty close to 50 ohms. It would still be nice to not have the unterminated stubs (to the unused filters), but I don't know what to do about that. The relays all have bifurcated, gold covered, contacts which are also paralleled for reliability (DPDT contacts). The other point is to only have one common connection between the antenna/earth ground and the logic ground for controlling the relays. Right now I'm using SMA connectors but may go back to BNC. Roger, on the bypass capacitor (and diode) across each coil. Always good to have bypass caps on DC circuits in an RF environment. The only "tricky" layout is that I'm putting a single RD16HHF1 right in the middle of the board as an Amp (couldn't see all that space going to waste). Have you ever used NPO, high voltage, ceramic smt capacitors in the filters ? Have you found any reason to use 5V relays vs 12V relays ? .....I got it in my mind that the lower 5V coils (less impedance) would be less suceptible to RF pickup. Probably a DNW (Does Nothing What-so-ever). 73 Kees K5BCQ
                                            > ---------- Original Message ----------
                                            > From: Graeme Jury <gvjury@...>
                                            > To: softrock40@yahoogroups.com
                                            > Subject: [softrock40] Re: Packaging external filters
                                            > Date: Tue, 07 May 2013 15:07:23 +1200
                                            >
                                            >
                                            > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
                                            > There is a couple of things which may be useful when designing switched
                                            > banks of filters.
                                            >
                                            > 1. Use a transmission line down the relay chain. In my case I used
                                            > RG-179 with the cover stripped back 5 mm or so and the braid tinned. Two
                                            > knife cuts 2 mm apart were rolled around the centre of the tinned braid
                                            > and then bent to snap at the knife cuts. The 2 mm piece of braid was
                                            > pried away and the centre of the coax bared. This was done opposite each
                                            > relay. The braids were soldered to the earth plane and the centre
                                            > connected to the relay contact. It did not take long to prepare the coax
                                            > and avoids the tricky and less reliable design of a printed transmission
                                            > line.
                                            >
                                            > 2. Bypass the coils of each relay. I ran my filter bank through my VNA
                                            > and could not understand why the roll off at the HF end of the filter
                                            > went down to about 40 dB and then flattened. They were mesh Chebyshev
                                            > filters and should have kept going down. In the end I found that a 0.1
                                            > smt cap on the coil on the 12 Volt common side of the relays fixed the
                                            > problem. As I added caps to more of the coils it got better and when I
                                            > had done half of them it was improved to the noise floor of the VNA.
                                            > Naturally for the negligible cost I did them all and also the switched
                                            > grounded side of the coils too. It is an obscure fault and maybe if I
                                            > had used RF relays it would not have happened but I used standard 2 pole
                                            > changeover miniature ones which switch 30 watts from my RD16HHF1 linear
                                            > on CW just fine.
                                            >
                                            > 73 Graeme ZL2APV
                                            >

                                            _

                                             


                                          • David Turnbull
                                            ... I use OSH Park for the prototypes and Advanced Circuits for production. I saw Laen yesterday and showed him the Advanced Circuits boards that resulted from
                                            Message 21 of 27 , May 7, 2013
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                                              On Tue, May 7, 2013 at 7:38 PM, Kees & Sandy <windy10605@...> wrote:
                                              Cool !  Is that what you use for your Peaberry boards ? what files are required ? gerber?

                                              I use OSH Park for the prototypes and Advanced Circuits for production. I saw Laen yesterday and showed him the Advanced Circuits boards that resulted from his prototypes.

                                              I send gerbers but he takes other formats too. It's all automated. Uploads are processed immediately so just try what you got and you'll know within minutes if it's good.

                                              73 David AE9RB
                                              http://AE9RB.com/
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