Topband: beverage lobes

[Rick Karlquist]

k3bu at optonline.net wrote:
>
> One has to realize the properties of the long Beverages, they lower the
> vertical angle and narrow the horizontal beamwidth. For example (according
> to EZNEC) going from 500 ft Beverage to 2000 ft, V angle gets down to
> about 20 deg and gain goes up about 10dB. Where there was a wide lobe at
> about 40 deg. with 500 footer, there is a 20 dB null at about 45 deg. H
> beam goes down to about 40 deg. So for one, they have to be "aimed" more
> cerefully (bevare of skewed path) and when the low angle propagation is
> happening (not too often). So casual tests might not show up the
> advantage, but when low angles happen, the difference is very pronounced.

That is very interesting, and certainly something to watch out for.
I will keep this in mind if I manage to set up beverages in a low
conductivity location.

The skew issue has discouraged me from trying to set up a "killer"
European beverage, because out here on the left coast, Eu is often
skewed.

I have measured the propagation loss of current as I walk down the
length of my beverage, and it is simply too high to be any use
at lengths of 2000 ft.  I don't think this is just a casual test.

> It is important to use decent gauge wire to minimize the ohmic losses.

My 1300 ft beverage used 17 gauge aluminum wire.  That should
amount to something like 40 ohms on 160m.   Doesn't seem like that should
matter a lot in a system with ~450 ohms characteristic impedance.
It certainly doesn't explain the attenuation I'm seeing.

> First time I used 1600 ft down hill Beverages, I concluded that they were
> "useless" too. Having the long ones during contests with low angle prop,
> they played, when most stations complained about "lousy" propagation.
>
> 73 Yuri, K3BU
>

Rick N6RK