SDR Placemarker

18 Apr

Just a quick note to capture some thoughts on a possible use for SDR. This was spawned by a lament I came across on G4ILO’s blog today viz using WSPR for testing antennas and doing comparisons. Just wondering out loud (and please forgive me the raw nature of this) if an SDR radio along with an antenna, computer and network connection standing alone and isolated from your other LAN devices could be made to function with a VPN as an antenna test range? I envision you at your desk able to connect to my radio and desktop via VPN and thusly manipulate my radio such that it can be tuned toward your signal for as long as the connection is up. A/B/C yourself into oblivion and over many days, times of day etc etc. Ive always drooled over the display’s that show signal strength in DBm a la Flex 3000 et al.¬† So there you sit watching the same bandwidth from 1, 2 or 3 thousand miles away or perhaps in the next village say, 1000 wavelengths distant able to A/B with measured results. I admit I have not paid much attention to SDR and this may be off table for any number of reasons but I often forget unless I write things down and perhaps someone more knowledgeable than I can shoot holes in it or offer up suggestions to improve the thought.

Thanks for reading my Blog. Best, Chas W5PG


Posted by on April 18, 2010 in Radio, Stuff


2 responses to “SDR Placemarker

  1. Julian G4ILO

    April 18, 2010 at 9:13 am

    I think that would be possible. In fact I think people have used web SDRs and online receivers for exactly that task. The benefit of using WSPR is that you can get a lot more reports from all over and you also get some fairly accurate SNR reports, which are harder to judge from a regular receiver.

    • w5pg

      April 18, 2010 at 10:18 am

      It would seem that there should be an easy work around for this problem. Forgive me if I misunderstood or didnt read your blog entry close enough….could you not just set your callsign on stn 1 to G4ILO and the other to G4ILO-1 or some such marker? Is that illegal?

      On SDR test range I was thinking that you the user could have the SDR console on your computer so you could see your signal as a pip at say -47 DBm. Then you could reduce/increase power on the second setup to match set up Nr 1 and convert power to DB and read the difference. A second method would be to modulate in SSB driven with a signal generator which has a step attenuator in line. Diddle to get equal readings on the remote receiver. Admittedly not as convenient but if an on line resource was available it would be an easy chore.

      I have to admit I had never thought about using WSPR for this but it is easy and simple with the side benefit of coverage maps as well.

      Best, Chas


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