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Re: Switching BPFs

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  • Christos Nikolaou
    Edson, It does Now! Just uploaded for your remark! :-) Thanks for pointing this out. 73 Christos SV1EIA ... samples. ... like a
    Message 1 of 12 , Aug 1, 2008
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      Edson,

      It does Now!
      Just uploaded for your remark! :-)
      Thanks for pointing this out.

      73
      Christos SV1EIA


      --- In softrock40@yahoogroups.com, Edson Pereira <ewp_jp@...> wrote:
      >
      >
      > Hi Christos,
      >
      > Does the sample compensation also work in trasmit?
      >
      > Regards,
      >
      > -- Edson, jf1afn
      >
      > Christos Nikolaou wrote:
      >
      > > Pete and Tony,
      > >
      > > Just popped into my mind.
      > > Sometimes so much deviation comes from sampling problems of cards.
      > > This can be rectified if you ommit one or two samples from one
      > > channel. Such compensation is there in Rocky but its only +/- 1 sample
      > > whereas it might need more.
      > > In the aforementioned PowerSDR version is provision for +/- 32
      samples.
      > >
      > > Just give it a try.
      > >
      > > 73
      > > Christos SV1EIA
      > >
      > > --- In softrock40@yahoogroups.com
      > > <mailto:softrock40%40yahoogroups.com>, "Tony Parks" <kb9yig@> wrote:
      > > >
      > > > Hi Pete,
      > > >
      > > > With the gain balance so far off it may be there is a soldering
      > > problem at U6, the FST3253. Please look carefully at the soldering of
      > > U6 pins 3, 6, 11 and 12.
      > > >
      > > > Can you measure the sensitivity of the receiver?
      > > >
      > > > 73,
      > > > Tony KB9YIG
      > > > ----- Original Message -----
      > > > From: Pete Smith
      > > > To: softrock40@yahoogroups.com <mailto:softrock40%40yahoogroups.com>
      > > > Cc: AQRP
      > > > Sent: Friday, August 01, 2008 9:31 AM
      > > > Subject: [softrock40] Switching BPFs
      > > >
      > > >
      > > > At 09:01 AM 8/1/2008, John H. Fisher wrote:
      > > > >We are providing three binary bits to be used by a hardware BPF
      > > > >switching board. The three hardware outputs represent memory
      > > locations
      > > > >100-199, 200-299, 300-399... depending on the most significant
      > > digit 1-8
      > > > >= 000-111. The actual BPF hardware will use those three lines to
      > > select
      > > > >a one of eight filters based on the memory location. This was an
      > > add on
      > > > >Kees thought of to use the last three pins on the chip. Seems
      like a
      > > > >good idea :-) Best of luck with your relay BPF board. I'm sorry the
      > > > >Si570 controller can't help you out with that particular problem:-)
      > > >
      > > > What you have there is really neat, John - I am wondering if
      > > anyone has a
      > > > hardware implementation of the BPF switching that will work with
      > > the Lite
      > > > 8.3, or if the 5-lead BPFs it uses are unique and difficult to
      > > interface
      > > > to. My problem seems to be related to lead lengths (maybe), and
      > > > secondarily to an apparent imbalance in both phase and gain in my
      > > Lite
      > > > 8.3. I can remotely locate the BPF on 160 and 80. By 40M I'm no
      > > longer
      > > > able to get the I/Q balance corrected reliably - sometimes it
      > > works and
      > > > sometimes not. Above 40, the auto balance routine won't even run.
      > > Here
      > > > are some examples:
      > > >
      > > > All of the following tests were run using Rocky 3.5, eyeballing
      > > the signal
      > > > levels off the spectrum display. All the image rejection tests
      > > were run
      > > > with the fundamental at x025 KHz - 1825, 3525, etc. and a local
      > > oscillator
      > > > frequency of x046 - 1846, 3546, etc. Levels expressed are high/low
      > > > extremes across 96 KHz audio bandwidth
      > > >
      > > > Band BPF location Image Rej (dB) Phase error (deg) Gain ratio
      > > > (one channel as % of other)
      > > >
      > > > 160 orig. >60 -.93 to -.33 .62-.64
      > > > remote >60 1.4 to 4.1 .61-.65
      > > >
      > > > 80 orig. >60 6.2 to 7.1 .59-.61
      > > > remote >60 4.1 to 7.2 .69-.70
      > > >
      > > > 40 orig. >60 7.3 to 8.1 .70-.71
      > > > remote no data at this and higher - auto I/Q balance
      > > > would not work
      > > >
      > > > 20 orig. >70 5.8 to 6.44 .66-.78
      > > >
      > > > 15 orig. >60 3.9 to 5.2 .74-.76
      > > >
      > > > 10 orig. >60 8.7 to 9.2 .77=.78
      > > >
      > > > 73, Pete N4ZR
      > > >
      > > > ...who is going to put this aside for a while and see if he can
      > > get his
      > > > scope working.
      > > >
      > >
      > >
      >
    • Pete Smith
      Tony, it s a good thing you re sworn to use your super-powers only for good - hi. I did in fact have a cold solder joint on pin 11 of the FST3253. After
      Message 2 of 12 , Aug 1, 2008
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        Tony, it's a good thing you're sworn to use your super-powers only for good
        - hi. I did in fact have a cold solder joint on pin 11 of the
        FST3253. After repairing it, the gain disparity between the two channels
        is only 1.145-1.733. I assume that's within normal limits for this circuit
        (?).

        Thanks again and 73, Pete N4ZR

        At 10:11 AM 8/1/2008, Tony Parks wrote:
        >Hi Pete,
        >
        >With the gain balance so far off it may be there is a soldering problem at
        >U6, the FST3253. Please look carefully at the soldering of U6 pins 3, 6,
        >11 and 12.
        >
        >Can you measure the sensitivity of the receiver?
        >
        >73,
        >Tony KB9YIG
        >----- Original Message -----
        >From: <mailto:n4zr@...>Pete Smith
        >To: <mailto:softrock40@yahoogroups.com>softrock40@yahoogroups.com
        >Cc: <mailto:AQRP@yahoogroups.com>AQRP
        >Sent: Friday, August 01, 2008 9:31 AM
        >Subject: [softrock40] Switching BPFs
        >
        >At 09:01 AM 8/1/2008, John H. Fisher wrote:
        > >We are providing three binary bits to be used by a hardware BPF
        > >switching board. The three hardware outputs represent memory locations
        > >100-199, 200-299, 300-399... depending on the most significant digit 1-8
        > >= 000-111. The actual BPF hardware will use those three lines to select
        > >a one of eight filters based on the memory location. This was an add on
        > >Kees thought of to use the last three pins on the chip. Seems like a
        > >good idea :-) Best of luck with your relay BPF board. I'm sorry the
        > >Si570 controller can't help you out with that particular problem:-)
        >
        >What you have there is really neat, John - I am wondering if anyone has a
        >hardware implementation of the BPF switching that will work with the Lite
        >8.3, or if the 5-lead BPFs it uses are unique and difficult to interface
        >to. My problem seems to be related to lead lengths (maybe), and
        >secondarily to an apparent imbalance in both phase and gain in my Lite
        >8.3. I can remotely locate the BPF on 160 and 80. By 40M I'm no longer
        >able to get the I/Q balance corrected reliably - sometimes it works and
        >sometimes not. Above 40, the auto balance routine won't even run. Here
        >are some examples:
        >
        >All of the following tests were run using Rocky 3.5, eyeballing the signal
        >levels off the spectrum display. All the image rejection tests were run
        >with the fundamental at x025 KHz - 1825, 3525, etc. and a local oscillator
        >frequency of x046 - 1846, 3546, etc. Levels expressed are high/low
        >extremes across 96 KHz audio bandwidth
        >
        >Band BPF location Image Rej (dB) Phase error (deg) Gain ratio
        >(one channel as % of other)
        >
        >160 orig. >60 -.93 to -.33 .62-.64
        >remote >60 1.4 to 4.1 .61-.65
        >
        >80 orig. >60 6.2 to 7.1 .59-.61
        >remote >60 4.1 to 7.2 .69-.70
        >
        >40 orig. >60 7.3 to 8.1 .70-.71
        >remote no data at this and higher - auto I/Q balance
        >would not work
        >
        >20 orig. >70 5.8 to 6.44 .66-.78
        >
        >15 orig. >60 3.9 to 5.2 .74-.76
        >
        >10 orig. >60 8.7 to 9.2 .77=.78
        >
        >73, Pete N4ZR
        >
        >...who is going to put this aside for a while and see if he can get his
        >scope working.
        >
        >
      • Pete Smith
        I should have added, though, that the phase disparity is still 4.7 to 5.4 degrees. The auto I/Q balancing works fine with the BPF plugged right into the RX
        Message 3 of 12 , Aug 1, 2008
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          I should have added, though, that the phase disparity is still 4.7 to 5.4
          degrees. The auto I/Q balancing works fine with the BPF plugged right into
          the RX board, but will not compensate when the BPF is a few inches away (on
          20M).

          Any thoughts on why so large? I suppose it could be this sound card
          (M-Audio Revolution 5.1). I'll try another just to be sure.


          73, Pete N4ZR

          At 05:38 PM 8/1/2008, Pete Smith wrote:
          >Tony, it's a good thing you're sworn to use your super-powers only for good
          >- hi. I did in fact have a cold solder joint on pin 11 of the
          >FST3253. After repairing it, the gain disparity between the two channels
          >is only 1.145-1.733. I assume that's within normal limits for this circuit
          >(?).
          >
          >Thanks again and 73, Pete N4ZR
          >
          >At 10:11 AM 8/1/2008, Tony Parks wrote:
          > >Hi Pete,
          > >
          > >With the gain balance so far off it may be there is a soldering problem at
          > >U6, the FST3253. Please look carefully at the soldering of U6 pins 3, 6,
          > >11 and 12.
          > >
          > >Can you measure the sensitivity of the receiver?
          > >
          > >73,
          > >Tony KB9YIG
          > >----- Original Message -----
          > >From: <mailto:n4zr@...>Pete Smith
          > >To: <mailto:softrock40@yahoogroups.com>softrock40@yahoogroups.com
          > >Cc: <mailto:AQRP@yahoogroups.com>AQRP
          > >Sent: Friday, August 01, 2008 9:31 AM
          > >Subject: [softrock40] Switching BPFs
          > >
          > >At 09:01 AM 8/1/2008, John H. Fisher wrote:
          > > >We are providing three binary bits to be used by a hardware BPF
          > > >switching board. The three hardware outputs represent memory locations
          > > >100-199, 200-299, 300-399... depending on the most significant digit 1-8
          > > >= 000-111. The actual BPF hardware will use those three lines to select
          > > >a one of eight filters based on the memory location. This was an add on
          > > >Kees thought of to use the last three pins on the chip. Seems like a
          > > >good idea :-) Best of luck with your relay BPF board. I'm sorry the
          > > >Si570 controller can't help you out with that particular problem:-)
          > >
          > >What you have there is really neat, John - I am wondering if anyone has a
          > >hardware implementation of the BPF switching that will work with the Lite
          > >8.3, or if the 5-lead BPFs it uses are unique and difficult to interface
          > >to. My problem seems to be related to lead lengths (maybe), and
          > >secondarily to an apparent imbalance in both phase and gain in my Lite
          > >8.3. I can remotely locate the BPF on 160 and 80. By 40M I'm no longer
          > >able to get the I/Q balance corrected reliably - sometimes it works and
          > >sometimes not. Above 40, the auto balance routine won't even run. Here
          > >are some examples:
          > >
          > >All of the following tests were run using Rocky 3.5, eyeballing the signal
          > >levels off the spectrum display. All the image rejection tests were run
          > >with the fundamental at x025 KHz - 1825, 3525, etc. and a local oscillator
          > >frequency of x046 - 1846, 3546, etc. Levels expressed are high/low
          > >extremes across 96 KHz audio bandwidth
          > >
          > >Band BPF location Image Rej (dB) Phase error (deg) Gain ratio
          > >(one channel as % of other)
          > >
          > >160 orig. >60 -.93 to -.33 .62-.64
          > >remote >60 1.4 to 4.1 .61-.65
          > >
          > >80 orig. >60 6.2 to 7.1 .59-.61
          > >remote >60 4.1 to 7.2 .69-.70
          > >
          > >40 orig. >60 7.3 to 8.1 .70-.71
          > >remote no data at this and higher - auto I/Q balance
          > >would not work
          > >
          > >20 orig. >70 5.8 to 6.44 .66-.78
          > >
          > >15 orig. >60 3.9 to 5.2 .74-.76
          > >
          > >10 orig. >60 8.7 to 9.2 .77=.78
          > >
          > >73, Pete N4ZR
          > >
          > >...who is going to put this aside for a while and see if he can get his
          > >scope working.
          > >
          > >
          >
          >
          >------------------------------------
          >
          >Yahoo! Groups Links
          >
          >
          >
        • drmail377
          Hi Pete, So you re using three sets of contacts per filter? Upload a schematic to the Files Temp area so we can take a look, hand-written is fine. Are you
          Message 4 of 12 , Aug 2, 2008
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            Hi Pete,

            So you're using three sets of contacts per filter? Upload a schematic
            to the Files > Temp area so we can take a look, hand-written is fine.

            Are you using coax to interconnect? If so, what type? Make sure all
            the wire and/or coax lengths are the same. 5 inches at 20 meters is
            around 2.3 degrees in free space and 1.5 degrees in typical coax.

            When you describe your phase error, do you mean it is 4.7 deg. with
            one filter and 5.4 with a different one? Or is the total phase
            disparity between 4.7 and 5.4 degrees, at different frequencies
            perhaps. Or is it between a switched BPF and one plugged directly into
            the main board? Please clarify.

            Remember with coax, if it is not properly terminated it will introduce
            reactance in likely significant amount even in inches of length (can't
            remember off-hand how to calculate this). This causes some concern
            because if you we 50 Ohm coax on the switched BPF transformer
            secondary the termination is at-best around 25 Ohms, not 50, or maybe
            not because of the commutating switch, hmmm...

            Again, at least keep all cabling lengths the same at all points. I'm
            wondering about the specifications of your relays. DIP relays are in
            almost all cases not so good at RF. The fact that you're using OMRON
            is a good sign, they're the only mfgr I've been able to find in a
            quick search that has some decent RF-capable DIP relays with decent
            isolation (around 60 dB if memory serves). What kind of relays are you
            using?

            I don't think the switch and switch wires to the relay coils should
            matter, but you might want to try bypassing them anyway.

            I presume the software you're using enables you to reset and restart
            the phase error and phase tracking routine at-will. Don't tell the
            software anything about frequency change when you change the SDR's
            frequency and BPF. Then try the opposite, do tell it about the
            frequency change. I'm concerned the software may be doing some sort of
            scaling with frequency change. Dunno - reaching for straws.

            Good Luck & 73's, David


            --- In softrock40@yahoogroups.com, Pete Smith <n4zr@...> wrote:
            >
            > I should have added, though, that the phase disparity is still 4.7
            to 5.4
            > degrees. The auto I/Q balancing works fine with the BPF plugged
            right into
            > the RX board, but will not compensate when the BPF is a few inches
            away (on
            > 20M).
            >
            > Any thoughts on why so large? I suppose it could be this sound card
            > (M-Audio Revolution 5.1). I'll try another just to be sure.
            >
            >
            > 73, Pete N4ZR
            >
            > At 05:38 PM 8/1/2008, Pete Smith wrote:
            > >Tony, it's a good thing you're sworn to use your super-powers only
            for good
            > >- hi. I did in fact have a cold solder joint on pin 11 of the
            > >FST3253. After repairing it, the gain disparity between the two
            channels
            > >is only 1.145-1.733. I assume that's within normal limits for this
            circuit
            > >(?).
            > >
            > >Thanks again and 73, Pete N4ZR
            > >
            > >At 10:11 AM 8/1/2008, Tony Parks wrote:
            > > >Hi Pete,
            > > >
            > > >With the gain balance so far off it may be there is a soldering
            problem at
            > > >U6, the FST3253. Please look carefully at the soldering of U6
            pins 3, 6,
            > > >11 and 12.
            > > >
            > > >Can you measure the sensitivity of the receiver?
            > > >
            > > >73,
            > > >Tony KB9YIG
            > > >----- Original Message -----
            > > >From: <mailto:n4zr@...>Pete Smith
            > > >To: <mailto:softrock40@yahoogroups.com>softrock40@yahoogroups.com
            > > >Cc: <mailto:AQRP@yahoogroups.com>AQRP
            > > >Sent: Friday, August 01, 2008 9:31 AM
            > > >Subject: [softrock40] Switching BPFs
            > > >
            > > >At 09:01 AM 8/1/2008, John H. Fisher wrote:
            > > > >We are providing three binary bits to be used by a hardware BPF
            > > > >switching board. The three hardware outputs represent memory
            locations
            > > > >100-199, 200-299, 300-399... depending on the most significant
            digit 1-8
            > > > >= 000-111. The actual BPF hardware will use those three lines
            to select
            > > > >a one of eight filters based on the memory location. This was
            an add on
            > > > >Kees thought of to use the last three pins on the chip. Seems
            like a
            > > > >good idea :-) Best of luck with your relay BPF board. I'm sorry the
            > > > >Si570 controller can't help you out with that particular problem:-)
            > > >
            > > >What you have there is really neat, John - I am wondering if
            anyone has a
            > > >hardware implementation of the BPF switching that will work with
            the Lite
            > > >8.3, or if the 5-lead BPFs it uses are unique and difficult to
            interface
            > > >to. My problem seems to be related to lead lengths (maybe), and
            > > >secondarily to an apparent imbalance in both phase and gain in my
            Lite
            > > >8.3. I can remotely locate the BPF on 160 and 80. By 40M I'm no
            longer
            > > >able to get the I/Q balance corrected reliably - sometimes it
            works and
            > > >sometimes not. Above 40, the auto balance routine won't even run.
            Here
            > > >are some examples:
            > > >
            > > >All of the following tests were run using Rocky 3.5, eyeballing
            the signal
            > > >levels off the spectrum display. All the image rejection tests
            were run
            > > >with the fundamental at x025 KHz - 1825, 3525, etc. and a local
            oscillator
            > > >frequency of x046 - 1846, 3546, etc. Levels expressed are high/low
            > > >extremes across 96 KHz audio bandwidth
            > > >
            > > >Band BPF location Image Rej (dB) Phase error (deg) Gain ratio
            > > >(one channel as % of other)
            > > >
            > > >160 orig. >60 -.93 to -.33 .62-.64
            > > >remote >60 1.4 to 4.1 .61-.65
            > > >
            > > >80 orig. >60 6.2 to 7.1 .59-.61
            > > >remote >60 4.1 to 7.2 .69-.70
            > > >
            > > >40 orig. >60 7.3 to 8.1 .70-.71
            > > >remote no data at this and higher - auto I/Q balance
            > > >would not work
            > > >
            > > >20 orig. >70 5.8 to 6.44 .66-.78
            > > >
            > > >15 orig. >60 3.9 to 5.2 .74-.76
            > > >
            > > >10 orig. >60 8.7 to 9.2 .77=.78
            > > >
            > > >73, Pete N4ZR
            > > >
            > > >...who is going to put this aside for a while and see if he can
            get his
            > > >scope working.
            > > >
            > > >
            > >
            > >
            > >------------------------------------
            > >
            > >Yahoo! Groups Links
            > >
            > >
            > >
            >
          • Pete Smith
            ... Schematic is now there - a little rough but readable. It s the only file currently in the folder. I am using 4PDT relays to do the switching - switching
            Message 5 of 12 , Aug 2, 2008
            • 0 Attachment
              At 04:36 AM 8/2/2008, drmail377 wrote:
              >Hi Pete,
              >
              >So you're using three sets of contacts per filter? Upload a schematic
              >to the Files > Temp area so we can take a look, hand-written is fine.

              Schematic is now there - a little rough but readable. It's the only file
              currently in the folder. I am using 4PDT relays to do the switching -
              switching pins 2 and 3 of P101 (the transformer output) and each pin of
              P100 (antenna input and return). I have no doubt that PIN diodes would
              make for a more compact switching scheme, but frankly didn't know how to
              implement it - relays, I more or less understand.


              >Are you using coax to interconnect? If so, what type? Make sure all
              >the wire and/or coax lengths are the same. 5 inches at 20 meters is
              >around 2.3 degrees in free space and 1.5 degrees in typical coax.


              No, using #24 hookup wire. I did not pay any particular attention to
              keeping lead lengths equal, and that may well be the source of my
              problems. Tony has suggested testing with one BPF using RG-174 for the
              outputs (pins 3 and 4 of P101, with the shields connected together to pin
              1) and feeding the antenna straight to P100 on the BPF, to see if it is any
              better behaved. I plan to do that next.


              >When you describe your phase error, do you mean it is 4.7 deg. with
              >one filter and 5.4 with a different one? Or is the total phase
              >disparity between 4.7 and 5.4 degrees, at different frequencies
              >perhaps. Or is it between a switched BPF and one plugged directly into
              >the main board? Please clarify.

              The numbers (4.7 to 5.4) define the range of values along the curve
              produced by the phase display of the I/Q balance routine. In the message
              you quoted, I recorded the ranges both for mounting on the RX and remote
              mounting, on the bands where I was able to get the auto I/Q balancing to
              work on the remote mounting. On 40 and above I could not.


              >Remember with coax, if it is not properly terminated it will introduce
              >reactance in likely significant amount even in inches of length (can't
              >remember off-hand how to calculate this). This causes some concern
              >because if you we 50 Ohm coax on the switched BPF transformer
              >secondary the termination is at-best around 25 Ohms, not 50, or maybe
              >not because of the commutating switch, hmmm...

              Don't know, but if this is a problem it probably isn't practical to do
              anything else.

              >Again, at least keep all cabling lengths the same at all points. I'm
              >wondering about the specifications of your relays. DIP relays are in
              >almost all cases not so good at RF. The fact that you're using OMRON
              >is a good sign, they're the only mfgr I've been able to find in a
              >quick search that has some decent RF-capable DIP relays with decent
              >isolation (around 60 dB if memory serves). What kind of relays are you
              >using?


              The relays I used are Omron, specifically designed for small signal use,
              part no. G6A-474P-ST40-US. They are in 14-pin DIP packages.


              >I don't think the switch and switch wires to the relay coils should
              >matter, but you might want to try bypassing them anyway.
              >
              >I presume the software you're using enables you to reset and restart
              >the phase error and phase tracking routine at-will. Don't tell the
              >software anything about frequency change when you change the SDR's
              >frequency and BPF. Then try the opposite, do tell it about the
              >frequency change. I'm concerned the software may be doing some sort of
              >scaling with frequency change. Dunno - reaching for straws.

              If I tell the software what band, it goes back and finds the correction
              curves for that band, which were stored the last time the band was
              changed. When you start collecting phase and gain data again, it seemingly
              starts at zero. I know that if the level difference between the
              fundamental and the image signal is too close (say less than 10 dB) then
              the auto balance routine cannot determine how to correct, because it
              doesn't know which signal is which. but that's all I know about how it
              does its magic.

              73, Pete N4ZR
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