[CQ-Contest] Re: 2 dB more?

[Tom Rauch]

> I have been using a KT-36XA in the last few contests.  Joke is that
> I've basically only worked 10M as I am really a DXer first and don't
> like getting a run going as I can't handle the mess.  However, it is
> nice to call into a pile and get in on the first call.  And then there
> are the weak stations that plead for a contact and they are in the QRN
> with syllables only.  A few dB more and?  Or would I just find another
> layer? 

The common myth is if you have more antenna "gain" the gain also 
improves reception. That isn't true, unless you have a relatively 
"insensitive" receiver.

The **directivity** of the antenna system determines the receiving 
ability, not the "gain". Directivity does NOT include losses, it is 
only a measure of the peak response in the direction of signals 
compared to noise or unwanted signal response from other 
directions. 

There is a little article about this on www.w8ji.com under receiving 
arrays, and while it deals mainly with 160 it also applies to other 
bands.

The only time gain, or reduction of loss, helps is when the your 
system is limited by noise in the feedline or receiver.

We need to compare pattern differences, rather than gain, for 
receiving. Odds are very good you won't see anywhere near the 
receiving S/N improvement that you see "gain" difference. many 
times a lower gain antenna system is a better receiving system 
than higher gain systems.

Transmitting is another story, and even one or two dB can be major 
in how a weak signal sounds. A couple dB is actually well over one 
"S" unit marking on the meters of almost all receivers when signals 
are weak. Most receiver meters are very non-linear low on the 
scale. 

When you are weak, that two dB will seem more like several dB. If 
your signal is anywhere near strong, it won't mean anything unless 
you are in a pileup with other equally strong stations.

Myself, I'd look at all options before changing the antenna!
73, Tom W8JI
W8JI at contesting.com 


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