Sunday, 10 January 2010

Portable WSPR test

Tried out my portable WSPR station this afternoon. Parked in a layby on Dalton bypass (SD238750) and ran about 50 metres of wire along the fence up the hill as an antenna, fed through the red 'long wire balun'.

With 5 watts from my FT-817 I was received by these stations:

Freq
SNR Call Locator DX Km
18.10613
-22 PJ4NX FK52ud 7303
10.1402
-22 SM5LEI JP80rh 1415
10.1402
-15 HB9AFZ JN46 1208
10.14017
1 DL1HMJ JO62qk 1116
10.1402
-7 HB9JAQ JN36su 1106
7.040093
-21 DH2RAL JO41lu 851
7.040118
-5 DK5AI JO51go 962
7.040098
-17 DL2FE JO40vu 950
7.040099
-7 PA1SOP JO22hh 558
7.040096
-4 DL1FX JN49gs 937
3.594099
-17 G7JVN JO00gv 438
3.594096
-11 DB5BZ JO42kx 807
3.594105
-15 DL0TUH JO43xl 866
18.10609
-22 N2NOM FN22bg 5294

I didn't use any tuner, the SWR meter on the 817 showed 1 bar or less on all bands. A few metres of the wire was along the ground between the transformer and the fence. I used a Garmin Etrex GPS for timing when to press play on the phone. There was no connection between the radio and car electrics/body, the radio was powered from a separate 3.3Ah SLAB.

The cable between the phone and the microphone connector on the FT-817 had a resistive divider made from a 47K and 2 parallel 2.7K resistors. I also connected capacitors across the input and output of this divider (47nF and 22nF) to remove any RF that might be picked up. With this circuit, the phone volume had to be at half way to give full RF output (with the 817's mic gain at 70). I set the VOX gain to 50, it didn't seem to work any lower than about 50.
View from the top end of the antenna towards the East.

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