XPost: rec.radio.amateur.moderated
PE4BAS Amateur Radio Weblog
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Concept antenna concept
Posted: 28 Sep 2021 12:53 PM PDT
https://pe4bas.blogspot.com/2021/09/concept-antenna-concept.html
Another concept antenna or is it an antenna concept? Previously tried quarter wave wires direct on my antenna with less success. Couldn't get a
good SWR on 12m and 10m with the ATU. I even tried to attach quarter wave
wires as counterpoise instead of my tower. Then I did read some articles
that multiband dipole antenna wires should at least be separate 10cm from
each other to minimize the interaction. Another challenge is to make
quarter wave radiators the right length. Measuring is no option since I
always use an ATU at the feedpoint. So I calculated some wire lengths and
made a practical experience wild guess. Counterpoise is again my tower. You
can see this whole thing as a massive OCF vertical dipole with a ATU in the feedpoint. I also keep my wide band 1:1 balun between the antenna and
tuner, not shure if this helps? A 1:4 balun could be a better choice?
Since I had to remove the duoband 6m/4m beam for the winter I decided that
it was time for another antenna experiment.
Somewhere on the internet I saw a video from someone that had a nice idea
to separate the quarter wave wires. So I lend the idea to implement on my
own vertical as experiment. The secret to build this thing is "shockcord"
to keep the wires straight under all circumstances. I ordered 20m from it
on the internet. The only wire I could not attach shockcord was the 4,9m
long wire for 20m since the antenna is basically too short, but I don't see that as a big problem.
If you think this is a strange contraption....look at our sunflower...
Last time I counted it had 12 flowers in it. And it grows wildly.
You can see the results I have with this antenna and 100W RTTY in the
previous post. Not that it is always the antenna that gives good results
since we all depend on propagation. But I'm very satisfied with it so far.
SWR is good on all 5 bands I designed it for. I measured it with the
IC-7300 and took some pictures. I will publish that in a separate post
since I found some strange behaviour on my IC-7300 measuring SWR on 10m
above 28.500 MHz.
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