----- Original Message -----
From: "Tom Rauch" <w8ji@contesting.com>
> That means losses in the earth would be reduced by as much
> as 50% if they were all due to ground current at the antenna
> base. That's a big change if the ground losses totally
> dominate the whole system and most of the transmitter power
> was being turned to heat. The ERP might go up around 3dB.
> With a typical mediocre ground the change would be much
> less. With a very good ground losses wouldn't any noticeable
> amount at all from the change in radiation resistance.
>
> It always helps to put the perspective change into real
> numbers, and we know it is less than 3dB from the change in
> radiation resistance in a current fed antenna.
>
> It's certainly possible if we use a bad loading design to do
> more than 3dB of damage. The GAP vertical is a good example
> of loss. They worked pretty hard to get the 10dB or more
> loss on the lowest bands (the Titan was measured about 16dB
> below a 1/4 wave vertical on 80 meters). Still, many people
> are happy with that kind of loss! 16 dB loss makes <3dB loss
> look unimportant.
>
> 73 Tom
>
I think the numbers you are citing above are spot on, but I
would argue that even even as little 1dB improvement in
EIRP is worth going after, especially if you are dealing with
a compromise system (as with a small radial field). In most
cases it won't make any difference, but I've had so many 160
QSOs that were just on the margin, I can't help but think
that 1dB shouldn't be neglected.
73, Mike W4EF...................
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