22 Jan 2013

QRSS3 tests with QRP on 137.685kHz.

This afternoon I started my tests on the 137kHz band again. With my 8W (RF out from the unit - ERP will be uW level) crystal controlled beacon sending QRSS3 feeding the 20m spaced earth electrodes, currently under 8cm of snow, I ventured forth in the car complete with an E-field probe built into the bottom of a mag-mount antenna on the car roof. The E-field probe whip is about 12-15cm long only. It looks like a small UHF quarter wave, rather than an antenna for 2200m! The TX frequency is currently around 137.685kHz and this QRSS3 beacon will remain on overnight. I am hoping that stations out to around 100km will take a look for it.
QRP earth-electrode antenna signal at 8.2km on 137kHz band
Well, results have been spectacular with some excellent signals around 8.2km away in the line of the earth-electrodes. Orthogonally, the signal was not copyable at all at a similar range. This is classic loop directionality again.
/M RX signal at 6km orthogonal to TX antenna.
The receiver consists of the 10-15cm long E-field probe feeding the FT817 with IPO button pressed (improves sensitivity when ON at 137kHz) feeding the PC running Spectran at 0.34Hz resolution.

I do find it unbelievable that such a TX "antenna" buried under the snow with NOTHING in the air at all and with earth rods just 20m apart can put out such a decent signal on the 2200m band.

No comments: