AD5X wrote: "I built several base matching networks that work great for
160- and 80-meters. Info is in the "Articles" section of my website at
www.ad5x.com."...
I noticed you didn't calculate the temperature rise in the cores. There
is a very nice piece of FREE software that will do that for an
auto-transformer (or for an inductor, or for any device where the signal
is transferred totally thru core flux).
http://www.dl5swb.de/html/mini_ring_core_calculator.htm
This will give you the temperature rise due to flux. You will have to
manually add the effect of dissipation due to resistive losses in the wire.
You may be surprised by the answer.
Jerry, K4SAV
Phil & Debbie Salas wrote:
> Well, bigger is always better. A HyTower will be a more efficient solution
> than a 43-foot vertical. That being said, I like the 43-foot vertical as it
> is less obtrusive, and mine isn't permanently mounted (slides on and off a
> mounting post) so I got around my "permit required for permanant structures
> over 25 feet" city requirement. I built my own (I live close to Texas
> Towers) and I used an 8-foot CB whip at the top which reduces visibility and
> wind loading even more.
>
> The SWR of the 43-footer is not bad on 40-10 meters, and so SWR related
> losses are pretty much negligable if you use good coax. And the higher
> radiation resistance of this antenna on these bands makes the antenna more
> efficient over a less-than-perfect ground. Above 20 meters the antenna may
> not be as good a DX antenna as a shorter vertical, but my main use for this
> antenna is 160-20 meters.
>
> However, for 160- and 80-meter operation you should really match the 43-foot
> antenna at the base. The SWR is horrible on those bands. I built several
> base matching networks that work great for 160- and 80-meters. Info is in
> the "Articles" section of my website at www.ad5x.com.
>
> Phil - AD5X
>
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