Topband: Inverted L loading wire dialmma

[Herbert Schoenbohm]

The "witches hat" as you call it makes an excellent top loading medium for
Marconi antennas.  I use them here on an AM tower with great success in
improving the base impedance of a less than 1/4 tower. Care must be taken
that these angled down wires are not to long. (I think 30% of the antena
height is about maximum.  Use 4 or more wires if possible. Addionally good
insulators able to handle the very high RF voltage should be used.  Never
use rope or any medium that can accumulate moisture. In the DX Engineering
catalog is a version of the witches hat antenna for 160 using sloping guys
for the top hat. The price is USD$1000 but this model has been used on TB
for  several DX- peditions.  There are several other add ons you can try as
you may require.  Rather th.  Accrodingly, if you connect the top slop down
wires an using a single vertical drop wire or insulated pole, I would use a
4 wire cage made from 4-6 inchsquare sheets of plastic. Additinally, if you
connect all the slope down wires together from one to the other you will
make even a better capacity hat and improlve things.  If you measure your
base impedence against ground as you make these improvements, you should
see how things are progressing. But take care and make sure your ground
system is adequate or else you readings may be confusing.  For example you
might see 50 ohms and not realize that this value is the result of a poor
ground and a good po9rtion of your RF is thus dissapated rather than being
radiated.

Good luck,
Herb, KV4FZ

On Thu, Mar 14, 2019 at 5:11 PM Dave G4GED via Topband <
topband at contesting.com> wrote:

> For many years my 160m antenna has been a very successful classic 21m
> tall Inv L mast with a horizontal loading wire.
> The only problem, a big one, has been the loading wire getting tangled
> up in the surrounding trees in very windy weather.
> Chopping the trees down is not an option and I've had enough of the agro
> of untangling, to be honest.
> I know I could provide loading at the feed point but it's not as efficient.
> So, I wondered if anyone have had success with providing the loading
> wire(s) at say 45deg from the mast top down to ground level? (Witches
> Hat style).
> Thanks in advance for any advice.
> Dave G4GED
>
>
>
>
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