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RXTX 6.1, bands and SSB

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  • rfneptune
    Happy New Year to all on the list. I ve been following the list for awhile, and plan to order some kits soon. There s been mention of being able to handle SSB
    Message 1 of 14 , Jan 1, 2007
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      Happy New Year to all on the list.

      I've been following the list for awhile, and plan to order some kits soon. There's been
      mention of being able to handle SSB with the Softrock kits. I can see how that would be
      possible since the signal would be processed in the SDR software. I don't see how the
      basic RX or RXTX kits would do this, given that their center frequencies are in the CW
      portion of the band and the bandwidth of the soundcards doesn't seem to reach far
      enough to get into the phone portion of the band.

      Example:

      40 m CW from 7.000 Mhz to 7.125 Mhz (for Extra)
      40 m phone from 7.125 to 7.300 Mhz (Extra again)

      Softrock 40m RX kit:

      7.032 Mhz to 7.080 Mhz (using 48Khz sampling card)
      7.008 Mhz to 7.106 Mhz (using 96Khz sampling card)

      So the top frequency doesn't get into the phone band for RX. For the new TX, the highest
      center frequency is 7.056 Mhz, plus 20 Khz, still well short of the lower edge of the phone
      band.

      Thanks in advance,

      Mike KC0NXN
    • Bill Dumke
      Mike, Until a kit of crystals is provided to cover all of 40 meters, questions like yours will always be asked. A set of 7.040, 7.120, 7.200, and 7.280 MHz
      Message 2 of 14 , Jan 1, 2007
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        Mike,

        Until a kit of crystals is provided to cover all of 40 meters, questions like yours will always be asked.

        "A set of 7.040, 7.120, 7.200, and 7.280 MHz center frequencies would cover the entire 40 meter band with some overlap with a 96 kHz sampling sound card.  Also setting Rocky to 0 center frequency it could be used to accurately determine operating frequencies.  Just need to add to or subtract from the chosen center frequency.

        Bill WA9PWR"

        rfneptune wrote:

        Happy New Year to all on the list.

        I've been following the list for awhile, and plan to order some kits soon. There's been
        mention of being able to handle SSB with the Softrock kits. I can see how that would be
        possible since the signal would be processed in the SDR software. I don't see how the
        basic RX or RXTX kits would do this, given that their center frequencies are in the CW
        portion of the band and the bandwidth of the soundcards doesn't seem to reach far
        enough to get into the phone portion of the band.

        Example:

        40 m CW from 7.000 Mhz to 7.125 Mhz (for Extra)
        40 m phone from 7.125 to 7.300 Mhz (Extra again)

        Softrock 40m RX kit:

        7.032 Mhz to 7.080 Mhz (using 48Khz sampling card)
        7.008 Mhz to 7.106 Mhz (using 96Khz sampling card)

        So the top frequency doesn't get into the phone band for RX. For the new TX, the highest
        center frequency is 7.056 Mhz, plus 20 Khz, still well short of the lower edge of the phone
        band.

        Thanks in advance,

        Mike KC0NXN

      • jabauzit
        Bill, WA9PWR wrote ... This is fine for receive, but for transmit I remember seeing something like +/-20kHz to comply with the FCC requirements regarding the
        Message 3 of 14 , Jan 1, 2007
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          Bill, WA9PWR wrote

          > A set of 7.040, 7.120, 7.200, and 7.280 MHz center frequencies would
          > cover the entire 40 meter band with some overlap with a 96 kHz
          > sampling sound card.

          This is fine for receive, but for transmit I remember seeing something
          like +/-20kHz to comply with the FCC requirements regarding the
          quality of the signal.

          > Also setting Rocky to 0 center frequency it could be used to
          > accurately determine operating frequencies. Just need to add to or
          > subtract from the chosen center frequency.

          Why not just enter the center frequency and use the multi band feature
          of Rocky, which you should do as you can calibrate amplitude/phase
          correction for each band.

          Jean-Claude, PJ2BVU
        • kd4e
          What would it cost to get a full set of those and a similar set for 80M? Would it be necessary to socket them or might they be outboarded and switched, please?
          Message 4 of 14 , Jan 1, 2007
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            What would it cost to get a full set of those and a
            similar set for 80M?

            Would it be necessary to socket them or might they
            be outboarded and switched, please?

            I am not familiar enough with the dynamics of the
            circuit design to speculate.

            > Until a kit of crystals is provided to cover all of 40 meters, questions
            > like yours will always be asked.
            >
            > "A set of 7.040, 7.120, 7.200, and 7.280 MHz center frequencies would
            > cover the entire 40 meter band with some overlap with a 96 kHz sampling
            > sound card. Also setting Rocky to 0 center frequency it could be used
            > to accurately determine operating frequencies. Just need to add to or
            > subtract from the chosen center frequency.
            >
            > Bill WA9PWR"


            --

            Thanks! & 73, doc, KD4E
            Have a joy-filled New Year!
            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            Projects: http://ham-macguyver.bibleseven.com
            Personal: http://bibleseven.com
            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          • Bill Dumke
            Tony, Is this true? Is the only purpose of a SoftRock TxRx to be on receive a panadapter? I was assuming that it could be used up to where the windowing gave
            Message 5 of 14 , Jan 1, 2007
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              Tony,

              Is this true?  Is the only purpose of a SoftRock TxRx to be on receive a panadapter? 

              I was assuming that it could be used  up to where the windowing gave out, on both Tx and Rx.  (For 96kHz sampling this would be about +/- 43 kHz.)

              Bill WA9PWR



              jabauzit wrote:

              Bill, WA9PWR wrote

              > A set of 7.040, 7.120, 7.200, and 7.280 MHz center frequencies would
              > cover the entire 40 meter band with some overlap with a 96 kHz
              > sampling sound card.

              This is fine for receive, but for transmit I remember seeing something
              like +/-20kHz to comply with the FCC requirements regarding the
              quality of the signal.

              > Also setting Rocky to 0 center frequency it could be used to
              > accurately determine operating frequencies. Just need to add to or
              > subtract from the chosen center frequency.

              Why not just enter the center frequency and use the multi band feature
              of Rocky, which you should do as you can calibrate amplitude/phase
              correction for each band.

              Jean-Claude, PJ2BVU

            • jabauzit
              See message 7604. Jean-Claude, PJ2BVU
              Message 6 of 14 , Jan 1, 2007
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                See message 7604.

                Jean-Claude, PJ2BVU
              • Tony Parks
                Hi Bill, The RX coverage with a SoftRock receiver or the RX function in the RXTX can be +/- 48 kHz from the center frequency if the soundcard can sample at 96
                Message 7 of 14 , Jan 1, 2007
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                  Hi Bill,
                   
                  The RX coverage with a SoftRock receiver or the RX function in the RXTX can be +/- 48 kHz from the center frequency if the soundcard can sample at 96 kHz.  The line-out stereo signal from soundcards is more band limited and in some soundcards has high noise above 20 kHz.  Thus the RXTX is limited to about +/-20 kHz TX tuning range from the center frequency.  Also there will be a few kHz lost round the center frequency.  I feel even with the more limited TX tuning range that the RXTX can still be a useful little rig and several who have been using the RXTX on the air have made a number of QSOs with various modes.
                   
                  Thanks for your interest in the project.
                   
                  73,
                  Tony KB9YIG
                   
                  ----- Original Message -----
                  Sent: Monday, January 01, 2007 6:04 PM
                  Subject: Re: [softrock40] Re: RXTX 6.1, bands and SSB

                  Tony,

                  Is this true?  Is the only purpose of a SoftRock TxRx to be on receive a panadapter? 

                  I was assuming that it could be used  up to where the windowing gave out, on both Tx and Rx.  (For 96kHz sampling this would be about +/- 43 kHz.)

                  Bill WA9PWR



                  jabauzit wrote:

                  Bill, WA9PWR wrote

                  > A set of 7.040, 7.120, 7.200, and 7.280 MHz center frequencies would
                  > cover the entire 40 meter band with some overlap with a 96 kHz
                  > sampling sound card.

                  This is fine for receive, but for transmit I remember seeing something
                  like +/-20kHz to comply with the FCC requirements regarding the
                  quality of the signal.

                  > Also setting Rocky to 0 center frequency it could be used to
                  > accurately determine operating frequencies. Just need to add to or
                  > subtract from the chosen center frequency.

                  Why not just enter the center frequency and use the multi band feature
                  of Rocky, which you should do as you can calibrate amplitude/phase
                  correction for each band.

                  Jean-Claude, PJ2BVU

                • Bill Dumke
                  Doc, Good question. I don t know. They would have to be fundamental mode at 4 times the crystal frequency I gave for Tony s oscillator circuit. Also I think it
                  Message 8 of 14 , Jan 1, 2007
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                    Doc,

                    Good question.  I don't know. 

                    They would have to be fundamental mode at 4 times the crystal frequency I gave for Tony's oscillator circuit.  Also I think it would be good to have a series trimmer capacitor with possibly a fixed capacitor in parallel with the trimmer to trim the frequency for best accuracy for each crystal.   And then order the crystals for 32 pf load capacitance or something like that.

                    I believe Tony has been getting his crystals from DigiKey and other vendors where the crystals are manufactured in high volume for specific tasks like computer clock oscillators, for example.  So there isn't much of a choice in frequencies, although they are very cheap.

                    I don't think this would be very practical for each band.  And I don't recommend using the dual band design anyway.  The front end filter in that radio's receiver is wide open to a lot of things.  I don't believe in chasing signals that are not there.

                    From an earlier post: 

                    "I just did a quick check on the RXTX V6.1 prototype and I needed to
                    inject an S8 Signal (30uV) on 3539 Khz to measure a 10dB Sinad
                    response when tuned to 7067 Khz. So there is a harmonic response
                    however I have not found too much of a problem listening in the current
                    band condx.

                    Jan G0BBL"

                    Let me give International Crystal a phone call Tuesday and find out how much it would cost for a set of 4 crystals for full coverage operation at 40 meters.

                    (Others are using DDS-60's for digital frequency control, but these have a lot of spurs.  I wouldn't trust them in transmit.)

                    Bill WA9PWR   

                    kd4e wrote:

                    What would it cost to get a full set of those and a
                    similar set for 80M?

                    Would it be necessary to socket them or might they
                    be outboarded and switched, please?

                    I am not familiar enough with the dynamics of the
                    circuit design to speculate.

                    > Until a kit of crystals is provided to cover all of 40 meters, questions
                    > like yours will always be asked.
                    >
                    > "A set of 7.040, 7.120, 7.200, and 7.280 MHz center frequencies would
                    > cover the entire 40 meter band with some overlap with a 96 kHz sampling
                    > sound card. Also setting Rocky to 0 center frequency it could be used
                    > to accurately determine operating frequencies. Just need to add to or
                    > subtract from the chosen center frequency.
                    >
                    > Bill WA9PWR"

                    --

                    Thanks! & 73, doc, KD4E
                    Have a joy-filled New Year!
                    ~~~~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~
                    Projects: http://ham-macguyve r.bibleseven. com
                    Personal: http://bibleseven. com
                    ~~~~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~

                  • Bill Dumke
                    Tony, Thanks for the reply. I am using a Delta 44 sound card so I should be fine. (Another good reason for a Delta 44) Bill WA9PWR Tony Parks wrote: Hi Bill,
                    Message 9 of 14 , Jan 1, 2007
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                      Tony,

                      Thanks for the reply.

                      I am using a Delta 44 sound card so I should be fine. (Another good reason for a Delta 44)

                      Bill WA9PWR

                      Tony Parks wrote:

                      Hi Bill,
                       
                      The RX coverage with a SoftRock receiver or the RX function in the RXTX can be +/- 48 kHz from the center frequency if the soundcard can sample at 96 kHz.  The line-out stereo signal from soundcards is more band limited and in some soundcards has high noise above 20 kHz.  Thus the RXTX is limited to about +/-20 kHz TX tuning range from the center frequency.  Also there will be a few kHz lost round the center frequency.  I feel even with the more limited TX tuning range that the RXTX can still be a useful little rig and several who have been using the RXTX on the air have made a number of QSOs with various modes.
                       
                      Thanks for your interest in the project.
                       
                      73,
                      Tony KB9YIG
                       
                      ----- Original Message -----
                      Sent: Monday, January 01, 2007 6:04 PM
                      Subject: Re: [softrock40] Re: RXTX 6.1, bands and SSB

                      Tony,

                      Is this true?  Is the only purpose of a SoftRock TxRx to be on receive a panadapter? 

                      I was assuming that it could be used  up to where the windowing gave out, on both Tx and Rx.  (For 96kHz sampling this would be about +/- 43 kHz.)

                      Bill WA9PWR



                      jabauzit wrote:

                      Bill, WA9PWR wrote

                      > A set of 7.040, 7.120, 7.200, and 7.280 MHz center frequencies would
                      > cover the entire 40 meter band with some overlap with a 96 kHz
                      > sampling sound card.

                      This is fine for receive, but for transmit I remember seeing something
                      like +/-20kHz to comply with the FCC requirements regarding the
                      quality of the signal.

                      > Also setting Rocky to 0 center frequency it could be used to
                      > accurately determine operating frequencies. Just need to add to or
                      > subtract from the chosen center frequency.

                      Why not just enter the center frequency and use the multi band feature
                      of Rocky, which you should do as you can calibrate amplitude/phase
                      correction for each band.

                      Jean-Claude, PJ2BVU

                    • kd4e
                      The best new prices I see are the Delta 44 at $149. and the Delta 66 at $189. Is the Delta 66 worth the $40. difference and is it a better long-term investment
                      Message 10 of 14 , Jan 1, 2007
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                        The best new prices I see are the Delta 44 at $149.
                        and the Delta 66 at $189.

                        Is the Delta 66 worth the $40. difference and is it
                        a better long-term investment tracking with the
                        future features of SoftRock hardware and software?

                        > The RX coverage with a SoftRock receiver or the RX function in the RXTX
                        > can be +/- 48 kHz from the center frequency if the soundcard can sample
                        > at 96 kHz. The line-out stereo signal from soundcards is more band
                        > limited and in some soundcards has high noise above 20 kHz. Thus the
                        > RXTX is limited to about +/-20 kHz TX tuning range from the center
                        > frequency. Also there will be a few kHz lost round the center
                        > frequency. I feel even with the more limited TX tuning range that the
                        > RXTX can still be a useful little rig and several who have been using
                        > the RXTX on the air have made a number of QSOs with various modes.
                        >
                        > Thanks for your interest in the project.
                        > 73, Tony KB9YIG


                        --

                        Thanks! & 73, doc, KD4E
                        Have a joy-filled New Year!
                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                        Projects: http://ham-macguyver.bibleseven.com
                        Personal: http://bibleseven.com
                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                      • Bill Dumke
                        Doc, My guess is the next generation of these SDR receivers will use a USB device instead of a sound card. But for right now, the Delta 44 is the best way to
                        Message 11 of 14 , Jan 1, 2007
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                          Doc,

                          My guess is the next generation of these SDR receivers will use a USB device instead of a sound card.   But for right now, the Delta 44 is the best way to go.  The Delta 66 doesn't offer anything more that would work with a SoftRock.   You still need analog audio.  It's just that in some places it is hard to find the Delta 44 cards now.

                          Bill WB5TCO 

                          kd4e wrote:

                          The best new prices I see are the Delta 44 at $149.
                          and the Delta 66 at $189.

                          Is the Delta 66 worth the $40. difference and is it
                          a better long-term investment tracking with the
                          future features of SoftRock hardware and software?

                          > The RX coverage with a SoftRock receiver or the RX function in the RXTX
                          > can be +/- 48 kHz from the center frequency if the soundcard can sample
                          > at 96 kHz. The line-out stereo signal from soundcards is more band
                          > limited and in some soundcards has high noise above 20 kHz. Thus the
                          > RXTX is limited to about +/-20 kHz TX tuning range from the center
                          > frequency. Also there will be a few kHz lost round the center
                          > frequency. I feel even with the more limited TX tuning range that the
                          > RXTX can still be a useful little rig and several who have been using
                          > the RXTX on the air have made a number of QSOs with various modes.
                          >
                          > Thanks for your interest in the project.
                          > 73, Tony KB9YIG

                          --

                          Thanks! & 73, doc, KD4E
                          Have a joy-filled New Year!
                          ~~~~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~
                          Projects: http://ham-macguyve r.bibleseven. com
                          Personal: http://bibleseven. com
                          ~~~~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~

                        • kd4e
                          Good info! Will focus on the Delta 44. I have found the Delta 44 for $139. on sale with free shipping and $129. refurbished. Now what can I sell to find that
                          Message 12 of 14 , Jan 1, 2007
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                            Good info! Will focus on the Delta 44.

                            I have found the Delta 44 for $139. on sale with
                            free shipping and $129. refurbished.

                            Now what can I sell to find that new money? :-)

                            > My guess is the next generation of these SDR receivers will use a USB
                            > device instead of a sound card. But for right now, the Delta 44 is the
                            > best way to go. The Delta 66 doesn't offer anything more that would
                            > work with a SoftRock. You still need analog audio. It's just that in
                            > some places it is hard to find the Delta 44 cards now.
                            > Bill WB5TCO

                            --

                            Thanks! & 73, doc, KD4E
                            Have a joy-filled New Year!
                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                            Projects: http://ham-macguyver.bibleseven.com
                            Personal: http://bibleseven.com
                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                          • Bill Dumke
                            Doc, Got a quote back from International Crystal: -----Original Message----- From: Mark Handley [ mailto:markh@icmfg.com ] Sent: Wednesday, January 03, 2007
                            Message 13 of 14 , Jan 5, 2007
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                              Doc,

                              Got a quote back from International Crystal: 

                              "-----Original Message-----
                              From: Mark Handley [mailto:markh@...] 
                              Sent: Wednesday, January 03, 2007 10:11 AM
                              To: Bill E Dumke
                              Subject: FW: Crystals for Oscillator
                              
                              
                              Mr. Dumke,
                              Darell asked me to answer your questions. For the four crystal
                              frequencies listed below, I would recommend our catalog number "49HL32-
                              Your freq" This should work just fine for you provided that the trimmer
                              shunt cap combination that you use has a total capacitance in the 50 to
                              60pf range.
                              The load capacitance of the catalog number above is 32pf. Pricing is
                              $15.95 per crystal plus shipping. Also as to the ground wire, the answer
                              is yes. If I can be of further assistance, please let me know.
                              
                              Regards,
                              Mark Handley
                              ICM"
                              These would be wire lead HC49U crystals.

                              It looks like they charge another $8.50 for shipping UPS as well.  (Shipping sounds kind of high to me.)  So the total would be $72.30.
                               
                              I think it would be a simple way to get full band coverage without the spurs from a DDS.  The crystals could be switched mechanically.   There have been several examples in the files and photos sections of  switched crystal SoftRocks, but never for complete single band coverage.   A Grayhill 4 or 5 position switch has been used successfully before.   A series trimmer cap either by itself or possibly with a shunt fixed cap, the total capacitance centered on 32 pF should be used on each crystal to calibrate the frequencies as close as possible.  This would insure accuracy when switching from one range to the other in the 40 meter band.   Again this would assume a 96 kHz sampling rate sound card like a Delta 44.

                              I'll have to see how much I have left this month after paying property taxes and my stack of bills.

                              Bill WA9PWR


                              Bill Dumke wrote:

                              Doc,

                              Good question.  I don't know. 

                              They would have to be fundamental mode at 4 times the crystal frequency I gave for Tony's oscillator circuit.  Also I think it would be good to have a series trimmer capacitor with possibly a fixed capacitor in parallel with the trimmer to trim the frequency for best accuracy for each crystal.   And then order the crystals for 32 pf load capacitance or something like that.

                              I believe Tony has been getting his crystals from DigiKey and other vendors where the crystals are manufactured in high volume for specific tasks like computer clock oscillators, for example.  So there isn't much of a choice in frequencies, although they are very cheap.

                              I don't think this would be very practical for each band.  And I don't recommend using the dual band design anyway.  The front end filter in that radio's receiver is wide open to a lot of things.  I don't believe in chasing signals that are not there.

                              >From an earlier post: 

                              "I just did a quick check on the RXTX V6.1 prototype and I needed to
                              inject an S8 Signal (30uV) on 3539 Khz to measure a 10dB Sinad
                              response when tuned to 7067 Khz. So there is a harmonic response
                              however I have not found too much of a problem listening in the current
                              band condx.

                              Jan G0BBL"

                              Let me give International Crystal a phone call Tuesday and find out how much it would cost for a set of 4 crystals for full coverage operation at 40 meters.

                              (Others are using DDS-60's for digital frequency control, but these have a lot of spurs.  I wouldn't trust them in transmit.)

                              Bill WA9PWR   

                              kd4e wrote:

                              What would it cost to get a full set of those and a
                              similar set for 80M?

                              Would it be necessary to socket them or might they
                              be outboarded and switched, please?

                              I am not familiar enough with the dynamics of the
                              circuit design to speculate.

                              > Until a kit of crystals is provided to cover all of 40 meters, questions
                              > like yours will always be asked.
                              >
                              > "A set of 7.040, 7.120, 7.200, and 7.280 MHz center frequencies would
                              > cover the entire 40 meter band with some overlap with a 96 kHz sampling
                              > sound card. Also setting Rocky to 0 center frequency it could be used
                              > to accurately determine operating frequencies. Just need to add to or
                              > subtract from the chosen center frequency.
                              >
                              > Bill WA9PWR"

                              --

                              Thanks! & 73, doc, KD4E
                              Have a joy-filled New Year!
                              ~~~~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~
                              Projects: http://ham-macguyve r.bibleseven. com
                              Personal: http://bibleseven. com
                              ~~~~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~

                            • Bill Dumke
                              Doc, Got a quote back from International Crystal: -----Original Message----- From: Mark Handley [ mailto:markh@icmfg.com ] Sent: Wednesday, January 03, 2007
                              Message 14 of 14 , Jan 7, 2007
                              • 0 Attachment
                                Doc,

                                Got a quote back from International Crystal: 

                                "-----Original Message-----
                                From: Mark Handley [mailto:markh@...] 
                                Sent: Wednesday, January 03, 2007 10:11 AM
                                To: Bill E Dumke
                                Subject: FW: Crystals for Oscillator
                                
                                
                                Mr. Dumke,
                                Darell asked me to answer your questions. For the four crystal
                                frequencies listed below, I would recommend our catalog number "49HL32-
                                Your freq" This should work just fine for you provided that the trimmer
                                shunt cap combination that you use has a total capacitance in the 50 to
                                60pf range.
                                The load capacitance of the catalog number above is 32pf. Pricing is
                                $15.95 per crystal plus shipping. Also as to the ground wire, the answer
                                is yes. If I can be of further assistance, please let me know.
                                
                                Regards,
                                Mark Handley
                                ICM"
                                These would be wire lead HC49U crystals.

                                It looks like they charge another $8.50 for shipping UPS as well.  (Shipping sounds kind of high to me.)  So the total would be $72.30.
                                 
                                I think it would be a simple way to get full band coverage without the spurs from a DDS.  The crystals could be switched mechanically.   There have been several examples in the files and photos sections of  switched crystal SoftRocks, but never for complete single band coverage.   A Grayhill 4 or 5 position switch has been used successfully before.   A series trimmer cap either by itself or possibly with a shunt fixed cap, the total capacitance centered on 32 pF should be used on each crystal to calibrate the frequencies as close as possible.  This would insure accuracy when switching from one range to the other in the 40 meter band.   Again this would assume a 96 kHz sampling rate sound card like a Delta 44.

                                I'll have to see how much I have left this month after paying property taxes and my stack of bills.

                                Bill WA9PWR


                                Bill Dumke wrote:

                                Doc,

                                Good question.  I don't know. 

                                They would have to be fundamental mode at 4 times the crystal frequency I gave for Tony's oscillator circuit.  Also I think it would be good to have a series trimmer capacitor with possibly a fixed capacitor in parallel with the trimmer to trim the frequency for best accuracy for each crystal.   And then order the crystals for 32 pf load capacitance or something like that.

                                I believe Tony has been getting his crystals from DigiKey and other vendors where the crystals are manufactured in high volume for specific tasks like computer clock oscillators, for example.  So there isn't much of a choice in frequencies, although they are very cheap.

                                I don't think this would be very practical for each band.  And I don't recommend using the dual band design anyway.  The front end filter in that radio's receiver is wide open to a lot of things.  I don't believe in chasing signals that are not there.

                                >From an earlier post: 

                                "I just did a quick check on the RXTX V6.1 prototype and I needed to
                                inject an S8 Signal (30uV) on 3539 Khz to measure a 10dB Sinad
                                response when tuned to 7067 Khz. So there is a harmonic response
                                however I have not found too much of a problem listening in the current
                                band condx.

                                Jan G0BBL"

                                Let me give International Crystal a phone call Tuesday and find out how much it would cost for a set of 4 crystals for full coverage operation at 40 meters.

                                (Others are using DDS-60's for digital frequency control, but these have a lot of spurs.  I wouldn't trust them in transmit.)

                                Bill WA9PWR   

                                kd4e wrote:

                                What would it cost to get a full set of those and a
                                similar set for 80M?

                                Would it be necessary to socket them or might they
                                be outboarded and switched, please?

                                I am not familiar enough with the dynamics of the
                                circuit design to speculate.

                                > Until a kit of crystals is provided to cover all of 40 meters, questions
                                > like yours will always be asked.
                                >
                                > "A set of 7.040, 7.120, 7.200, and 7.280 MHz center frequencies would
                                > cover the entire 40 meter band with some overlap with a 96 kHz sampling
                                > sound card. Also setting Rocky to 0 center frequency it could be used
                                > to accurately determine operating frequencies. Just need to add to or
                                > subtract from the chosen center frequency.
                                >
                                > Bill WA9PWR"

                                --

                                Thanks! & 73, doc, KD4E
                                Have a joy-filled New Year!
                                ~~~~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~
                                Projects: http://ham-macguyve r.bibleseven. com
                                Personal: http://bibleseven. com
                                ~~~~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~

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