On 4/20/2011 7:03 PM, K8RI on TT wrote:
> It's been mentioned that with fan dipoles the lowest frequency band has
> it's band width increased
Correction -- In a fan dipole made from parallel wires, the lowest
frequency band has the full SWR bandwidth as if no other antenna were in
the fan. The higher frequency band(s) have their SWR bandwidth reduced
by roughly one half. This works out just fine when the lowest frequency
is 75/80M, because the higher bands are a relatively low percentage
bandwidth.
Another VERY important point -- coax, especially BIG coax, has VERY
little loss on 160M, and only a bit more on 75/80M, so moderately high
SWR (up to 5:1, for example) that might be present far off frequency
still doesn't add much loss. You WILL need a decent antenna tuner to
work at the band limits. I use Ten Tec 229 and 238 tuners, which have
better than average efficiency and, because of their design, once they
are tuned, they tend to maintain a match over a much wider bandwidth
than T-section tuners.
73, Jim Brown K9YC
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