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Re: [perseus_SDR] calibration question

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  • Mauno Ritola
    Do you mean that it still 20 Hz off after warming up or right after the start? 73, Mauno
    Message 1 of 19 , Jul 15, 2012
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      Do you mean that it still 20 Hz off after warming up or right after the start?

      73, Mauno

      15.7.2012 11:25, max_netherlands kirjoitti:
       

      Since the last weeks I notice a zero beat problem.
      Tuning on MW is no problem, but on SW, every time after I start Perseus, I find that I have to tune 0,02 khz higher in frequeny than the station is transmitting. After calibration everthing seems to be OK, but the next day after a new start of Perseus, the same problem occurs. Can anybody help to solve this problem?
      Thanks,
      Max
      The Netherlands



    • wa4hhg
      Chris et al, Interesting points. I expect the calibration procedures in the manual are done in the Perseus software and compensate for any differences between
      Message 2 of 19 , Jul 15, 2012
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        Chris et al,

        Interesting points. I expect the calibration procedures in the manual are done in the Perseus software and compensate for any differences between the master oscillator in Perseus and the transmit frequency of of an actual station being received. Thus, the "calibration" has a "local" effect.

        I've come to this conclusion after logging in remotely to various Perseus' and noticing slight calibration errors from site to site.

        The real fix, IMHO is to determine if there is a master oscillator calibration in the Perseus hardware, disable the calibration offset in the software then calibrate the master oscillator in Perseus to WWV on 15 or 20 mhz.

        Back to my own computer or Perseus issues....

        Chuck Rippel
        Chesapeake, VA


        --- In perseus_SDR@yahoogroups.com, "Chris Black" <n1cp@...> wrote:
        >
        > Being a relatively new user of this great receiver, I naturally want to be sure to take advantage of all its features and I noticed about 12 lines in the manual under section 6.6.12 concerning Frequency Calibration.
      • max_netherlands
        Thanks Mauno for your remarks. I find it quite often on recordings, so I suppose the Perseus has had enough warming up time. Do you know how long a warming up
        Message 3 of 19 , Jul 15, 2012
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          Thanks Mauno for your remarks.
          I find it quite often on recordings, so I suppose the Perseus has had enough warming up time.
          Do you know how long a warming up time will last?
          Max

          --- In perseus_SDR@yahoogroups.com, Mauno Ritola <Mauno.Ritola@...> wrote:
          >
          > Do you mean that it still 20 Hz off after warming up or right after the
          > start?
          >
          > 73, Mauno
          >
          > 15.7.2012 11:25, max_netherlands kirjoitti:
          > >
          > > Since the last weeks I notice a zero beat problem.
          > > Tuning on MW is no problem, but on SW, every time after I start
          > > Perseus, I find that I have to tune 0,02 khz higher in frequeny than
          > > the station is transmitting. After calibration everthing seems to be
          > > OK, but the next day after a new start of Perseus, the same problem
          > > occurs. Can anybody help to solve this problem?
          > > Thanks,
          > > Max
          > > The Netherlands
          > >
          > >
          >
        • Mauno Ritola
          Full warming up has been measured as about 70 minutes, but already after 15 minutes the difference is very small. And it is relative to frequency; on MW you
          Message 4 of 19 , Jul 16, 2012
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            Full warming up has been measured as about 70 minutes, but already after 15 minutes the difference is very small. And it is relative to frequency; on MW you don't necessary pay attention to it.

            Mauno

            16.7.2012 0:15, max_netherlands kirjoitti:
             

            Thanks Mauno for your remarks.
            I find it quite often on recordings, so I suppose the Perseus has had enough warming up time.
            Do you know how long a warming up time will last?
            Max

            --- In perseus_SDR@yahoogroups.com, Mauno Ritola <Mauno.Ritola@...> wrote:
            >
            > Do you mean that it still 20 Hz off after warming up or right after the
            > start?
            >
            > 73, Mauno
            >
            > 15.7.2012 11:25, max_netherlands kirjoitti:
            > >
            > > Since the last weeks I notice a zero beat problem.
            > > Tuning on MW is no problem, but on SW, every time after I start
            > > Perseus, I find that I have to tune 0,02 khz higher in frequeny than
            > > the station is transmitting. After calibration everthing seems to be
            > > OK, but the next day after a new start of Perseus, the same problem
            > > occurs. Can anybody help to solve this problem?
            > > Thanks,
            > > Max
            > > The Netherlands
            > >
            > >
            >



          • Werner Karn
            it is also highly dependent on ambient temperature changes and on changes in the internal power consumption ( will change when switching from 250ks/s to 2000
            Message 5 of 19 , Jul 16, 2012
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              it is also highly dependent on ambient temperature changes and on changes in the internal power consumption ( will change when switching from 250ks/s to 2000 ks/s). You can measure it yourself using a stable carrier ( like WWV ) CW mode and an audio analysis program like e.g. SpecLab. There is some data in the files section as well as some threads available on this. Overall the Perseus frequency stability after warm-up is excellent.
               
              73,
               
              Werner 
              2012/7/16 Mauno Ritola <Mauno.Ritola@...>
               

              Full warming up has been measured as about 70 minutes, but already after 15 minutes the difference is very small. And it is relative to frequency; on MW you don't necessary pay attention to it.

              Mauno

              16.7.2012 0:15, max_netherlands kirjoitti:
               

              Thanks Mauno for your remarks.
              I find it quite often on recordings, so I suppose the Perseus has had enough warming up time.
              Do you know how long a warming up time will last?
              Max

              --- In perseus_SDR@yahoogroups.com, Mauno Ritola <Mauno.Ritola@...> wrote:
              >
              > Do you mean that it still 20 Hz off after warming up or right after the
              > start?
              >
              > 73, Mauno
              >
              > 15.7.2012 11:25, max_netherlands kirjoitti:
              > >
              > > Since the last weeks I notice a zero beat problem.
              > > Tuning on MW is no problem, but on SW, every time after I start
              > > Perseus, I find that I have to tune 0,02 khz higher in frequeny than
              > > the station is transmitting. After calibration everthing seems to be
              > > OK, but the next day after a new start of Perseus, the same problem
              > > occurs. Can anybody help to solve this problem?
              > > Thanks,
              > > Max
              > > The Netherlands
              > >
              > >
              >




            • max_netherlands
              Thansk Mauno, that is clear. I will check if this also occurs after 70 minutes of warming up. I think this is possibly the reason that the Perseus is a bit off
              Message 6 of 19 , Jul 17, 2012
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                Thansk Mauno, that is clear.
                I will check if this also occurs after 70 minutes of warming up.
                I think this is possibly the reason that the Perseus is a bit off frequency.
                73
                Max


                --- In perseus_SDR@yahoogroups.com, Mauno Ritola <Mauno.Ritola@...> wrote:
                >
                > Full warming up has been measured as about 70 minutes, but already after
                > 15 minutes the difference is very small. And it is relative to
                > frequency; on MW you don't necessary pay attention to it.
                >
                > Mauno
                >
                > 16.7.2012 0:15, max_netherlands kirjoitti:
                > >
                > > Thanks Mauno for your remarks.
                > > I find it quite often on recordings, so I suppose the Perseus has had
                > > enough warming up time.
                > > Do you know how long a warming up time will last?
                > > Max
                > >
                > > --- In perseus_SDR@yahoogroups.com
                > > <mailto:perseus_SDR%40yahoogroups.com>, Mauno Ritola
                > > <Mauno.Ritola@> wrote:
                > > >
                > > > Do you mean that it still 20 Hz off after warming up or right after the
                > > > start?
                > > >
                > > > 73, Mauno
                > > >
                > > > 15.7.2012 11:25, max_netherlands kirjoitti:
                > > > >
                > > > > Since the last weeks I notice a zero beat problem.
                > > > > Tuning on MW is no problem, but on SW, every time after I start
                > > > > Perseus, I find that I have to tune 0,02 khz higher in frequeny than
                > > > > the station is transmitting. After calibration everthing seems to be
                > > > > OK, but the next day after a new start of Perseus, the same problem
                > > > > occurs. Can anybody help to solve this problem?
                > > > > Thanks,
                > > > > Max
                > > > > The Netherlands
                > > > >
                > > > >
                > > >
                > >
                > >
                >
              • i3rgh
                ... Hello Chuck, what IMHO is important to remember is that the Calibration as Local Receiver and as Server are NOT the same! So a locally calibrated receiver
                Message 7 of 19 , Jul 17, 2012
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                  --- In perseus_SDR@yahoogroups.com, "wa4hhg" <Chuck.Rippel@...> wrote:
                  >
                  > Chris et al,
                  >
                  > Interesting points. I expect the calibration procedures in the manual are done in the Perseus software and compensate for any differences between the master oscillator in Perseus and the transmit frequency of of an actual station being received. Thus, the "calibration" has a "local" effect.
                  >
                  > I've come to this conclusion after logging in remotely to various Perseus' and noticing slight calibration errors from site to site.
                  >

                  Hello Chuck,
                  what IMHO is important to remember is that the Calibration as Local Receiver and as Server are NOT the same!
                  So a locally calibrated receiver can be appear uncalibrated once operated by remote.

                  To calibrate the server it is *necessary* to log in, starting first the Server software, then Client software, Net, Adr ( using address 127.0.0.1 , obviously port 8014 AND the password set in Server settings to have FULL access ) and calibrate with the same sequence than in local mode.
                  ONLY THIS WAY the server (remote receiver) will appear calibrated to remote users.

                  I often use remote receivers and found someone off-calibrated up to 200 hertz on 7 MHz!
                  Best 73
                  Bruno i3rgh
                • doug12455
                  Is there any security issues with having a password and publishing it for Perseus users to use? I d prefer to have it PW protected to allow those that need to,
                  Message 8 of 19 , Jul 17, 2012
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                    Is there any security issues with having a password and publishing it for Perseus users to use? I'd prefer to have it PW protected to allow those that need to, adjust the calibration.

                    Brian - W8GTX

                    --- In perseus_SDR@yahoogroups.com, "i3rgh" <bruno.rod@...> wrote:
                    >
                    >
                    >
                    >
                    >
                    >
                    > --- In perseus_SDR@yahoogroups.com, "wa4hhg" <Chuck.Rippel@> wrote:
                    > >
                    > > Chris et al,
                    > >
                    > > Interesting points. I expect the calibration procedures in the manual are done in the Perseus software and compensate for any differences between the master oscillator in Perseus and the transmit frequency of of an actual station being received. Thus, the "calibration" has a "local" effect.
                    > >
                    > > I've come to this conclusion after logging in remotely to various Perseus' and noticing slight calibration errors from site to site.
                    > >
                    >
                    > Hello Chuck,
                    > what IMHO is important to remember is that the Calibration as Local Receiver and as Server are NOT the same!
                    > So a locally calibrated receiver can be appear uncalibrated once operated by remote.
                    >
                    > To calibrate the server it is *necessary* to log in, starting first the Server software, then Client software, Net, Adr ( using address 127.0.0.1 , obviously port 8014 AND the password set in Server settings to have FULL access ) and calibrate with the same sequence than in local mode.
                    > ONLY THIS WAY the server (remote receiver) will appear calibrated to remote users.
                    >
                    > I often use remote receivers and found someone off-calibrated up to 200 hertz on 7 MHz!
                    > Best 73
                    > Bruno i3rgh
                    >
                  • i3rgh
                    ... Why publishing? Once calibrated, it s calibrated... the main issue is not drift (of course, it is anyway better to wait almost 20-30 minutes after the
                    Message 9 of 19 , Jul 17, 2012
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                      --- In perseus_SDR@yahoogroups.com, "doug12455" <doug124@...> wrote:
                      >
                      > Is there any security issues with having a password and publishing it for Perseus users to use? I'd prefer to have it PW protected to allow those that need to, adjust the calibration.
                      >
                      > Brian - W8GTX

                      Why publishing?
                      Once calibrated, it's calibrated... the main issue is not drift (of course, it is anyway better to wait almost 20-30 minutes after the switch-on), is the calibration itself, which in most cases has not been performed AT ALL on many Perseus SERVERs.
                      So before making his Perseus available to others, the owner "should" calibrate it... and forget.
                      The "owner" knows the pw (it is in Server settings) and can use it, without revealing to anybody.
                      Best 73
                      Bruno i3rgh
                    • max_netherlands
                      Regarding the frequencies that are not zero beat after recording: I did a calibration 3 hours after starting up Perseus. Than I started recordings with Mestor.
                      Message 10 of 19 , Jul 20, 2012
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                        Regarding the frequencies that are not zero beat after recording:
                        I did a calibration 3 hours after starting up Perseus.
                        Than I started recordings with Mestor.
                        I found that MW recordings are OK, but again I found a difference on SW. For example, I have to tune the recorded frequencies in the 49 mb 0,02 khz higher to get them zero beat.
                        I also made recordings with Perseus : no difference was noted, all stations were zero beat.
                        So, I am suspecting Mestor is giving the problem.
                        Anybody noticed this ? And ofcourse the question: what can be done about this?
                        Many thanks,
                        Max
                        The Netherlands
                      • Thomas Nilsson
                        Hello, In the Mestor manual you can read: Mestor can t utilize Perseus calibration. When creating Mestor recordings there will be a minor Hz deviation in the
                        Message 11 of 19 , Jul 20, 2012
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                          Hello,
                          In the Mestor manual you can read:
                          Mestor can't utilize Perseus calibration. When creating Mestor recordings there will be a minor Hz deviation in the exact frequencies (10Hz or so). This deviation seems to be hardware unit dependent. You have to get this deviation into account if you want to
                          estimate the exact frequencies of signals at Hz level when looking at the "visible peak" with Perseus.exe. You can measure this deviation after calibrating your hardware with Perseus.exe and making one sample Mestor recording to reveal the exact difference.
                          73
                          Thomas Nilsson


                          --- In perseus_SDR@yahoogroups.com, "max_netherlands" <mvarnhem@...> wrote:
                          >
                          >
                          > Regarding the frequencies that are not zero beat after recording:
                          > I did a calibration 3 hours after starting up Perseus.
                          > Than I started recordings with Mestor.
                          > I found that MW recordings are OK, but again I found a difference on SW. For example, I have to tune the recorded frequencies in the 49 mb 0,02 khz higher to get them zero beat.
                          > I also made recordings with Perseus : no difference was noted, all stations were zero beat.
                          > So, I am suspecting Mestor is giving the problem.
                          > Anybody noticed this ? And ofcourse the question: what can be done about this?
                          > Many thanks,
                          > Max
                          > The Netherlands
                          >
                        • Jurgen Bartels
                          ... Even when you recorded with Perseus.exe you will see deviations, depending on the temperature the h/w box had at that time, which chances with room
                          Message 12 of 19 , Jul 20, 2012
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                            > Mestor can't utilize Perseus calibration. When creating Mestor
                            > recordings there will be a minor Hz deviation in the exact frequencies
                            > (10Hz or so). This deviation seems to be hardware unit dependent. You
                            > have to get this deviation into account if you want to estimate the
                            > exact frequencies of signals at Hz level when looking at the "visible
                            > peak" with Perseus.exe. You can measure this deviation after
                            > calibrating your hardware with Perseus.exe and making one sample
                            > Mestor recording to reveal the exact difference.

                            Even when you recorded with Perseus.exe you will see deviations, depending on
                            the temperature the h/w box had at that time, which chances with room
                            temperature.
                            The crystal isn't as good as it should be, for example with Winradio G305 the
                            temperature stability is much better, I don't need to recalibrate it on MW, it
                            is only required for TV carrier monitoring (above 48MHz)

                            So for Perseus I let it record uncalibrated, and do the calibration afterwards
                            for each wav separately, by using a reference signal that is recorded with it,
                            like 810-BBC or 972-NDR. It is done automatically with StationList and SpecLab.
                            With that I get high precision calibration over years, no matter in what state
                            the h/w box was during recording, even whe it did a cold start in winter.



                            Jurgen Bartels Suellwarden, N. Germany
                            Antennas hor.: 45-87MHz: 11-ele, FM: 15.11, Band-III:13-ele, UHF:48-ele,
                            TV: Winradio G305 / Fly2000 + video noise filter & variable IF BW
                            FM: Downconverter + Perseus + Speclab as WFM demod.
                            MW: 90m bev 220°, 30 x 4m EWE 320° with JB-terminator, Winradio & Perseus
                            http://zeiterfassung.3sdesign.de/station_list.htm
                          • Willi Passmann
                            ... Hello Max, while Thomas already explained the Mestor related part, I d like to remind to the general basics of frequency calibration. (Mis)calibration is
                            Message 13 of 19 , Jul 20, 2012
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                              Am 20.07.2012 09:20, schrieb max_netherlands:
                              > I found that MW recordings are OK, but again I found a difference on SW.

                              Hello Max,

                              while Thomas already explained the Mestor related part, I'd like to
                              remind to the general basics of frequency calibration. (Mis)calibration
                              is related to the receiving frequency. If you calibrate a SDR on, let's
                              say 5 MHz, with an unnoted error of 10 Hz, you will encounter an offset
                              of 20 Hz on 10 MHz, 30 Hz on 15 MHz, and so on. So an unnoted
                              calibration error on a low frequency will lead to a noticeable offset on
                              high frequencies.

                              That is the reason one should look for a calibration signal on the
                              highest possible frequency. Another factor one should observe is
                              selective fading of the calibration signal, which is common for distant
                              signals / multi hop propagation. If the signal peak changes in
                              frequency, you have selective fading, and the signal is not suited for
                              accurate calibration, no matter how high the frequency is.

                              So for a reliable calibration one should make sure the rx is warmed up
                              completely, that the signal is free of selective fading and that the
                              calibration frequency is as high as possible.

                              BTW: Do not use the signal of IBF Torino. It's not on frequency (as
                              discussed on A-DX mailing list).

                              vy 73,
                              Willi

                              http://www.radio-portal.org/sdr.html
                              SDR-Special
                              http://www.mediafire.com/?2lve8wq6y1ou2
                              Perseus Databases - Third Party Software Guide & more
                            • Vlad Titarev
                              Absolutely true, Willi. Yet... in real life one always faces dilemma: which factor is less important when one needs to choose :( For real life in Kremenchuk
                              Message 14 of 19 , Jul 20, 2012
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                                Absolutely true, Willi. 

                                Yet... in real life one always faces dilemma: which factor is less important when one needs to choose  :(
                                For real life in Kremenchuk ;)  I rarely go even up to 10 MHz, 
                                mostly using Moscow's RWM 4996 and rechecking with 1-2 reliable AMs.
                                Fortunately need to do that not so often (thanks Perseus).

                                73,
                                Vlad
                                 
                                On Jul 20, 2012, at 9:02 AM, Willi Passmann wrote:

                                So for a reliable calibration one should make sure the rx is warmed up 
                                completely, that the signal is free of selective fading and that the 
                                calibration frequency is as high as possible.

                              • Werner Karn
                                another possibility is to let Perseus running with an external LO frequency that is phase locked to a stable reference ( I do this on one Perseus with a GPS
                                Message 15 of 19 , Jul 20, 2012
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                                  another possibility is to let Perseus running with an external LO frequency that is phase locked to a stable reference  ( I do this on one Perseus with a GPS locked reference getting milli Hz deviations; disadvantage being a higher phase noise ).
                                   
                                  73,
                                   
                                  Werner 

                                  2012/7/20 Vlad Titarev <vlad.titarev@...>
                                   

                                  Absolutely true, Willi. 


                                  Yet... in real life one always faces dilemma: which factor is less important when one needs to choose  :(
                                  For real life in Kremenchuk ;)  I rarely go even up to 10 MHz, 
                                  mostly using Moscow's RWM 4996 and rechecking with 1-2 reliable AMs.
                                  Fortunately need to do that not so often (thanks Perseus).

                                  73,
                                  Vlad
                                   
                                  On Jul 20, 2012, at 9:02 AM, Willi Passmann wrote:

                                  So for a reliable calibration one should make sure the rx is warmed up 
                                  completely, that the signal is free of selective fading and that the 
                                  calibration frequency is as high as possible.


                                • max_netherlands
                                  Hi all who responded, Thanks for your info. That s all clear information. Happily, when listening with Perseus, no problems occur, while listening to
                                  Message 16 of 19 , Jul 20, 2012
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                                    Hi all who responded,

                                    Thanks for your info.
                                    That's all clear information.
                                    Happily, when listening with Perseus, no problems occur, while listening to recordings , made with Mestor, I find some offsett at higher frequencies, not on MW.
                                    Especially, thanks, Thomas for your explanation about Mestor and Willi about the Perseus calibration.
                                    Max



                                    and expalins --- In perseus_SDR@yahoogroups.com, Willi Passmann <wpassmann@...> wrote:
                                    >
                                    > Am 20.07.2012 09:20, schrieb max_netherlands:
                                    > > I found that MW recordings are OK, but again I found a difference on SW.
                                    >
                                    > Hello Max,
                                    >
                                    > while Thomas already explained the Mestor related part, I'd like to
                                    > remind to the general basics of frequency calibration. (Mis)calibration
                                    > is related to the receiving frequency. If you calibrate a SDR on, let's
                                    > say 5 MHz, with an unnoted error of 10 Hz, you will encounter an offset
                                    > of 20 Hz on 10 MHz, 30 Hz on 15 MHz, and so on. So an unnoted
                                    > calibration error on a low frequency will lead to a noticeable offset on
                                    > high frequencies.
                                    >
                                    > That is the reason one should look for a calibration signal on the
                                    > highest possible frequency. Another factor one should observe is
                                    > selective fading of the calibration signal, which is common for distant
                                    > signals / multi hop propagation. If the signal peak changes in
                                    > frequency, you have selective fading, and the signal is not suited for
                                    > accurate calibration, no matter how high the frequency is.
                                    >
                                    > So for a reliable calibration one should make sure the rx is warmed up
                                    > completely, that the signal is free of selective fading and that the
                                    > calibration frequency is as high as possible.
                                    >
                                    > BTW: Do not use the signal of IBF Torino. It's not on frequency (as
                                    > discussed on A-DX mailing list).
                                    >
                                    > vy 73,
                                    > Willi
                                    >
                                    > http://www.radio-portal.org/sdr.html
                                    > SDR-Special
                                    > http://www.mediafire.com/?2lve8wq6y1ou2
                                    > Perseus Databases - Third Party Software Guide & more
                                    >
                                  • Mauno Ritola
                                    Don t worry too much about selective fading and other propagational matters, just use waterfall with 6 kHz and narrowest span, wait 5-15 seconds you can
                                    Message 17 of 19 , Jul 24, 2012
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                                      Don't worry too much about selective fading and other propagational matters, just use waterfall with 6 kHz and narrowest span, wait 5-15 seconds you can determine reliably the center of the carrier, even if it varies a bit. I have used WWV/WWVH carrier at 15 MHz for years for calibration here in Finland and have had no trouble. Even if there were one Hz error at 15 MHz, it becomes insignificant for my accuracy needs on medium wave. Bigger trouble is tens of carriers on same frequency and THERE selective fading may mislead you ;-) Also for scheduled top-of-the hour recording I don't use automatic shutdown for computer and Perseus, so it is warm already and room temperature is rather stable with no direct sunshine allowed to Perseus hardware. Mostly calibration means just checking that nothing has changed.

                                      73, Mauno

                                      20.7.2012 21:21, max_netherlands kirjoitti:
                                       

                                      Hi all who responded,

                                      Thanks for your info.
                                      That's all clear information.
                                      Happily, when listening with Perseus, no problems occur, while listening to recordings , made with Mestor, I find some offsett at higher frequencies, not on MW.
                                      Especially, thanks, Thomas for your explanation about Mestor and Willi about the Perseus calibration.
                                      Max

                                      and expalins --- In perseus_SDR@yahoogroups.com, Willi Passmann <wpassmann@...> wrote:
                                      >
                                      > Am 20.07.2012 09:20, schrieb max_netherlands:
                                      > > I found that MW recordings are OK, but again I found a difference on SW.
                                      >
                                      > Hello Max,
                                      >
                                      > while Thomas already explained the Mestor related part, I'd like to
                                      > remind to the general basics of frequency calibration. (Mis)calibration
                                      > is related to the receiving frequency. If you calibrate a SDR on, let's
                                      > say 5 MHz, with an unnoted error of 10 Hz, you will encounter an offset
                                      > of 20 Hz on 10 MHz, 30 Hz on 15 MHz, and so on. So an unnoted
                                      > calibration error on a low frequency will lead to a noticeable offset on
                                      > high frequencies.
                                      >
                                      > That is the reason one should look for a calibration signal on the
                                      > highest possible frequency. Another factor one should observe is
                                      > selective fading of the calibration signal, which is common for distant
                                      > signals / multi hop propagation. If the signal peak changes in
                                      > frequency, you have selective fading, and the signal is not suited for
                                      > accurate calibration, no matter how high the frequency is.
                                      >
                                      > So for a reliable calibration one should make sure the rx is warmed up
                                      > completely, that the signal is free of selective fading and that the
                                      > calibration frequency is as high as possible.
                                      >
                                      > BTW: Do not use the signal of IBF Torino. It's not on frequency (as
                                      > discussed on A-DX mailing list).
                                      >
                                      > vy 73,
                                      > Willi
                                      >
                                      > http://www.radio-portal.org/sdr.html
                                      > SDR-Special
                                      > http://www.mediafire.com/?2lve8wq6y1ou2
                                      > Perseus Databases - Third Party Software Guide & more
                                      >


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