[UK-CONTEST] What antenna for AFS?

[G3SJJ]

Be interesting to know if you actually noticed the 0.1dB gain!!  
Seriously though, might be worth trying to calculate what take off angle 
is required to put maximum signal into say Berkshire from a location in 
central Scotland and then designing the 2 el array spacing for that.

What I find interesting about that article, which John LZQ sent me a 
couple of years ago, is that for "good" ground my antenna at 55ft is 
very close to the optimum height for max NVIS gain, and for "very good" 
ground it is a few feet too high. I would class the heavy clay soil 
around here as "Good to Very Good." My AFS/80m Cums results over the 
last few years appear to verify this.

We came to the conclusion that a parasitic reflector would not have any 
major effect, although I am tempted to try a 140ft wire apex about 15ft, 
sloping to about 5ft to mimic the slope characteristic of the driven 
element.

Interestingly I notice on 160m that the dipole (which is the 80m dipole 
with 60ft extensions on each leg, jumper dissed for 80m) always performs 
similar to dipoles 15 to 20 higher at other locations. Again I have put 
this down to local ground conductivity and that it is uninterrupted for 
many wave lengths.

Chris G3SJJ


col wrote:

>Hi Stewart HNY
>
>have a look at w4rnl's site lots of info on NVIS antennas for 80m
>http://www.cebik.com/wire/cb.html
>
>John mm0ccc and I used the 2 el wire yagi firing straight up approach at 
>gm6nx
>
>Colin GM0RLZ
>----- Original Message ----- 
>From: "Cooper, Stewart" <coopers at odl.co.uk>
>To: <uk-contest at contesting.com>
>Sent: Monday, January 02, 2006 3:31 PM
>Subject: [UK-CONTEST] What antenna for AFS?
>
>
>  
>
>>HNY contesters! AFS is only a few days away, and I wondered what antenna 
>>would be best? I have a vertical and a delta loop. Perhaps I ought to put 
>>up a dipole? Last year my crappy old dipole seemed to perform the best as 
>>I recall.
>>
>>Stewart
>>GM4AFF
>>
>>P.S. Perhaps the dipole ought to be in Oxfordshire, but that's another 
>>matter.
>>
>>
>>
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