This sort of power level could be generated by power harvesting, even rectified RF from the HF antenna. Now there's a thought - a free power TX.
14 Feb 2012
How little power do you need to communicate?
This sort of power level could be generated by power harvesting, even rectified RF from the HF antenna. Now there's a thought - a free power TX.
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7 comments:
A nice result there Roger.
I did some tests with a local station on 2m late last year. Managed a perfectly good SSB QSO with me transmitting about 500uW. I ran out of in-line attenuators at that point.
I really should fire up my 2m QRSS MEPT again too.
regards,
David G7UVW
It is a shame there is not more horizontal SSB/CW activity these days on 2m as it is a wonderful band to carry out this sort of QRPpp experiment.
Dont see the point in power harvesting
when a battery would last for years
permenantly on?!
yeah i know its the principle,but..
Dave g4dal
I need to fix my rotator on the roof when the weather improves, then I'll be active on 2m SSB & data again.
Located in JO01BN, so not a vast distance from Cambs, should be possible to try some QRPp tests in the near future.
David - G7UVW
Vy FB and tnx for posting your results, Roger.
Along the same lines, I operated today on 40m CW with crystal-controlled Pierce oscillator (a 2N78 made by General Electric in September 1956). The RF output was 6 milliWatts. My receiver used a 1950's vintage 1N34a diode as the heterodyne mixer (product detector) followed by a single stage of audio amplification (a 2N107 made in January 1957).
I only made one QSO (N1PVP @ 293km) but when I checked the RBN log I found that my signal had been logged 93 times today! Some of the capture SNRs were unbelievable (up to 38dB!). My signal was captured by five different receivers (dozens of times by both W3LPL @ 639km and WZ7I @ 451km). A nice QRPp day!
Dave G4DAL said, "Don't see the point in power harvesting....etc"
Well Dave, surely amateur radio is about experimentation, finding out what is or is not possible.
Michael - you continue to inspire us all by your boundary pushing experiments and well done on the 6mW rig and reports.
Hello Roger, it's great fun to use low power. Sometimes I can reduce the power to 8 mW or less in CW, when the propagation is extremely good. When the absorbing layer is gone, there is so little attenuation in the path.
73, Bert
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