ANTENNAS:
Below are some of the antennas I used over the previous 10 years or so. Antennas are the one thing that change regularly at G4UCJ, as my interests vary over time, I need the right antenna for the job.
The main antenna now is a wire dipole for 15 and 10m mounted in my attic, due to a move of QTH. My old antenna was a 20m long OCF (Off Centre Fed) Dipole in an inverted Vee/L configuration due to the length restriction of the garden. The apex of the OCF is 10m above ground. I purchased this antenna as a ‘short’ OCF that covered from 20m thru 6m. However after a few weeks of use I decided to extend the antenna so that it would cover 40m (having done some careful calculations to ensure it would fit in the available space. This antenna was originally 10.5m long but I replaced the shorter, 3.5m, wire with a 13m wire. It has a slightly different element length ratio than the smaller one (which was 3:1). The longer element is now sloping at about 45 degrees instead of a much shallower slope, which could only be achieved by lengthening the support pole at the fence post from 3m to 5m or more, which at this time is impractical. Above are various shots of the OCF/Windom configuration. The drawing gives more detail of the actual installation. The SWR on 40, 20, 17 and 10m are all 2:1 or below, which is acceptable. 30 and 15m are extremely high and 12m is around 3-4:1. Now that I have an ATU, I can tune all bands, and show a good SWR to the radio (and hence keep the PA stresses due to impedance mismatch to a minimum).
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