Topband: Another Antenna Question

Mike(W5UC) & Kathy(K5MWH) w5uc at suddenlink.net
Tue Aug 21 21:09:18 EDT 2007


While searching for information about RX antennas, I ran across 
K7TKR's page and ultimately his receive antenna comparison. 
http://www.k7tjr.com/rx1comparison.htm

Having to make the most of a small lot, only two antennas appear to 
be a choice; the K9AY array, and two verticals spaced fairly 
closely.(1/8 WL or less)  Per Lee's chart, the pair of verticals has 
a RDF of 9.03, and the K9AY antenna has a RDF of  7.2, a difference 
of 1.83. This brings my first question which is:  How much difference 
in performance will that variation in RDF make?

The second question comes from modeling a two vertical array in 
EZ-Nec.  By experimenting with EZ-Nec I have determined that I can 
vary the F/B of a two vertical array by varying the length of the 
delay line, and ange of radiation of the antenna. Additionally, if I 
understand the calculation of RDF, RDF can be manipulated by varying 
the F/B of the antenna.  Thus the second question;  How do I 
determine what reasonable and practical numbers are for calculating RDF?

This brings the 3rd and final question. Are my methods, as described 
above, flawed?

73,
Mike, W5UC




"age & treachery will overcome youth & skill"
http://www.suddenlink.net/pages/w5uc/ 



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