Topband: Beverage upgrade question

[John Kaufmann]

Even in a quiet rural location, the limiting noise on 160 will be external atmospheric noise.  Improving RDF will generally improve your signal/noise ratio against the atmospheric noise.  There are exceptions when there is a source of high noise, like thunderstorms, in the same direction as the signals you are receiving.  In that case, improving RDF may not help so much.

I have a couple antennas whose RDF's differ by about 4 dB.  That's a pretty significant difference.  When I switch back and forth between the two with both antennas aimed at the direction of signal arrival, the improvement in S/N with the higher RDF antenna is very obvious to my ears, especially when the received signals are weak.  From that I would surmise that even a 1 dB difference in RDF would be discernable when signals are weak, although the difference won't be dramatic.

One thing to keep in mind is that increasing the RDF of an antenna system causes an unavoidable narrowing of the beam pattern.  This means the RDF advantage is realized only in an increasingly narrow range of angles.  This means that the S/N will drop off more sharply for signals off the peak of the antenna's main lobe.

73, John W1FV  

-----Original Message-----
From: Topband [mailto:topband-bounces+john.kaufmann=verizon.net at contesting.com] On Behalf Of Kenny Silverman
Sent: Tuesday, August 23, 2022 4:07 PM
To: topband
Subject: Topband: Beverage upgrade question

In a rural area with no significant man made noise, if you redesign a beverage for better RDF when do you start to notice a difference?

I’m considering upgrading my single EU beverage at 625’ (190m) to a pair in echelon where will each be 550’ (168m) with 20’ (6m)  spacing . The increase in RDF is 0.8 dB - will it be noticeable?

I realize if there’s noise in a direction where you reduce the energy you will better hear the difference , but my EU beverage is quiet.   Though the F/B change will help with thunder storms off the back. 

Overall I tend to receive better than I transmit to EU.  

73 , Kenny K2KW 
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