Tuesday, 12 October 2010

4m handheld experiment

I'd got my new Garex 70 MHz flexi whip for the handheld but it still didn't seem that good compared to a handheld on a higher frequency. So I tried a few different lengths of wire and other cables as a counterpoise.
A data cable plugged into the speaker/mic sockets on the side made an improvement in my transmitted signal, this cable was around 90cm or just under 1/4 wavelength on 70 MHz. Other cables such as plugging the speaker mic in made little improvement, so the length was quite important.
In the end I went for 90cm of insulated wire, with a few cm bare wrapped round the SMA connector. This wire was left to hang down behind the radio.
I then tried using the original Wouxun rubber duck with the wire counterpoise and the result was better than the Garex whip + no counterpoise. I'm guessing about 6dB improvement from the longer whip and 10dB difference from the wire counterpoise. It meant the difference between signal or noise to G7RNX who is about 5Km away, while I was stood indoors.
On a different handheld such as an ex-PMR one where there will be a bigger area of metal (battery pack, metalwork on the case) there might not be as much of an improvement but it would definitely help.

The lift conditions are still there on VHF/UHF and have been for over 2 days. Today I left my APRS station receiving on 144.800 all day and there were packets being received from France and Belgium, as well as some in the south west of Ireland.

Last night I fixed the power socket on my FT-817, the centre pin of the socket had been pushed back inside (this might have been because of a damaged plug) and this had broken the solder connection with the circuit board. I put the centre pin back in place and soldered it. The rest of the socket was OK.

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