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Re: Packaging external filters

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  • 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 1 of 27 , May 6 8:07 PM
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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 2 of 27 , May 7 8:12 AM
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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 3 of 27 , May 7 8:36 AM
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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 4 of 27 , May 7 8:47 AM
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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 5 of 27 , May 7 11:58 AM
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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 6 of 27 , May 7 12:46 PM
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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 7 of 27 , May 7 1:09 PM
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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 8 of 27 , May 7 1:40 PM
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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 9 of 27 , May 7 2:01 PM
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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 10 of 27 , May 7 2:19 PM
                      • 0 Attachment
                        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 11 of 27 , May 7 5:08 PM
                        • 0 Attachment
                          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 12 of 27 , May 7 6:10 PM
                          • 0 Attachment
                            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 13 of 27 , May 7 6:47 PM
                            • 0 Attachment
                              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 14 of 27 , May 7 6:53 PM
                              • 0 Attachment
                                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 15 of 27 , May 7 7:15 PM
                                • 0 Attachment
                                  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 16 of 27 , May 7 7:25 PM
                                  • 0 Attachment
                                    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 17 of 27 , May 7 7:31 PM
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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 18 of 27 , May 7 7:38 PM
                                      • 0 Attachment
                                        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 19 of 27 , May 7 7:55 PM
                                        • 0 Attachment
                                           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 20 of 27 , May 7 8:10 PM
                                          • 0 Attachment
                                            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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