[TowerTalk] balanced line loss on a mismatched antenna

Steve London n2icarrl at gmail.com
Wed Feb 29 06:34:12 PST 2012


KT0A said:

 > As far as reasons for trying the 8JK.... Mainly I want a 40M antenna that I can
 > put on the same mast with my hf tribander.  The 8jk is nice cause it has some
 > gain and I could also tune it for the WARC bands.  I like that its a
 > non-resonant antenna so I wouldn't worry as much about interaction with the
 > tribander (that's a whole nother thread... would a 40M yagi cause me problems
 > 6' away from my tribander).

It may be another thread, but some reality needs to go into your decision.

Just because a nearby antenna is non-resonant does not mean that it will not 
interact with other antennas.

Every ARRL Antenna Book written in the past 30 years has a figure showing 
"ungrounded guy wire lengths to avoid". It shows 26 feet to be a "magic" length 
for 10, 15 and 20 meters. Now take your favorite modeling software and put this 
"magic" length within a few feet of a 10, 15 or 20 meter yagi. Major pattern 
distortion.

73,
Steve, N2IC


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