Today I built a breadboard version of my transverter for 137kHz and now I have it running WSPR-2 for the evening.
RF power from the IRF640 transverter PA is around 30-40W (depending on the PA voltage) and the ERP should be around 25-30uW using the earth-electrode antenna. At present, the transverter is only on 20% duty cycle TX and I have still to add the RX preamp and switching.
My recent 137.766kHz QRSS3 tests using a measured just 6.6uW ERP from the earth-electrode antenna have now concluded. Best reports were
G3WCB (101km),
G3XDV (61km) and
G4FEV (56.7km).
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| G3XBM just detectable on G3WCB's trace at 101km |
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| Stronger signal with G3XDV at 61km |
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| Similar signal at G4FEV at 56.7km |
Judging by the QRSS3 results with 6dB lower ERP than my WSPR signal, I think reports out to >100km should certainly be possible
as long as people are looking. WSPR2 is able to detect at about the same level as QRSS10, so overall I have around 11dB more "system gain" (5dB QRSS3 to WSPR, 6dB ERP improvement).
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