[TowerTalk] 5 db required to see?

[Tom Rauch]

Hi Brian,

> I lost the original e-mail.  However, I believe it was W8JI who stated one
> needed 5db type improvements to see much of a difference.

Depends on what the conditions of the test are. 

If signals are strong, and we are judging without a direct "A-B" test, 
we would be lucky to observe a 5 or 10 dB difference.

If signals are marginal, even one dB makes a world of difference! 
One dB can be the difference between a readable signal and a 
bust. 
 
> It appears at 2db one uncovers a whole new layer of people to work
> (especially during contests) and many additional contacts on a given
> band can be worked as a result.

On 160 or 80 meters, a few dB certainly can, under the right 
conditions, uncover a whole new layer of DX. That's why I have an 
extensive ground system, and many large antennas, for 160 
meters. Every dB counts when working someone who is right at 
noise floor.

I'm not so sure that is as true on the higher bands, as a general 
rule, because there is generally plenty of signal level to work 
with...and noise is much lower. For example, ERP is almost 
meaningless on ten meters once you are at the kilowatt level 
because you are almost certainly far above the noise if the band is 
open. 

Not having a null at the optimum wave angle is probably more of 
the problem, and a major reason for using a stack, than a few dB of 
gain on higher bands.


73, Tom W8JI
w8ji@contesting.com

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