A blog mainly about my favourite hobby-amateur radio, shortwave listening and radio in its many forms.
Thursday, 19 August 2010
On 20 my antenna seems to want to resonate on 13.9Mhz, there is no moving it, shortening the whip section results in a very poor SWR. This means the antenna is just about useable uo to 14.2Mhz, its a very good match on the CW end of 20 but I am not sure CW mobile is a good idea!
I have heard mixed reviews of this type of antenna, some users have reported they cannot get a reasonable match at all so perhaps I am doing fairly well. In any case I have head Indonesia and a mobile VK station on 20 so far so the antenna is certainly receiving ok.
Both antennas are the kind with a rigid helically wound base and an adjustable steel whip. The total antenna is around 7 foot (2 metres) long with the adjustable whip section being around 4 feet (1.2 metres). I also need to change the site of the HF antenna to the right (offside) of the car, the spot where the VHF antenna is located. The reason for this is the HF whip keeps hitting overhanging tree branches. changing the antennas over will mean re routeing the cables in the car so that may have to wait for a while. I have now added a spring at the base of the mount to give a bit more flexibility.
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Thanks for the offer. nit might be interesting to see how the whips compare. It is strange but i can't seem to bring the resonant frequency much above 13.9 mhz on mine.
Not tried my 20m whip but you are welcome to try it, I will dig it out soon.
I have an 80m version too.