Hi Rick,
> to think I need a preamp. I am wondering if the 10 foot Beverage was
> working more as a long wire close to the ground?
On 40 meters, I seem to find low height Beverages are better. My
ten foot high wires give me the impression they are not nearly as
good on 40 as my six foot high antennas. On 80, I seem to see
less of a difference.
On 160, I can not notice a difference.
> I also did some BCB tests for rejection off the side on 1510, 1520, and
> 1530 kHz. The 2 foot Beverage was perhaps an S-unit better in this
> respect.
That doesn't surprise me. The velocity factor of the Beverage drops
like a rock at low heights. That makes the same length antenna
"look longer". If the lower height makes it look an electrical full
wave long, it will have maximum null along the ground at right
angles to the antenna.
> I have seen various discussions here about putting Beverages at heights
> determined by convenience rather than performance (e.g. one posting
> suggested the correct height was 1.1 times the height of a deer). Now I
> am wondering if height is more critical than generally believed.
The key would be the difference in signal-to-noise ratio in a location
free of local noise. That would indicate the directivity improved, but
you'd have to make sure it wasn't from "fooling" the antenna into
thinking it was longer.
There is a risk in forming a conclusion without fully understanding
why a change occurs. The risk is the conclusion will not repeat, or
hold true in other cases.
Is the change because the all Beverages will work better when
lower, or is the change because the antenna improved for you
because it became electrically longer and that lowering it steered
some nulls to a useful direction for your exact situation?
If an antenna the same electrical length is compared, does it work
better or worse than the lower height antenna?
It could be that as the antenna is made physically longer, it needs
to be higher. It could also be that a higher and longer antenna will
work better than a shorter and lower antenna.
73, Tom W8JI
w8ji@contesting.com
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