I would expect problems with the SteppIR at only 5 feet separation. My
experience is that 10 feet is usually required to reduce mutual impedance to
a tolerable level.
73, Keith NM5G
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of K4SAV
Sent: Saturday, May 14, 2005 7:47 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Antenna interaction tests
I am getting ready to mount a 4 element SteppIR at 55 ft, and an XM240 on
the same mast only 5 feet above the SteppIR. I am concerned about degrading
the SteppIR. I don't think there will be a problem degrading the 40M
antenna because I can always retract the SteppIR elements.
Can any of you suggest some good tests to perform to see if the SteppIR is
being effected? Tests which don't require removal and replacing antennas on
the tower would be most useful. Is 15 meters likely to be the biggest
trouble frequency?
I am locked-in to a maximum of 5 feet seperation using the mast I have.
Ordered an HDX555 tower and mast from Texas Towers and ended up with an
M15 mast from US Towers. I called them up and asked for the mast strength
rating and was told "they range from about 35 KSI to 55 KSI". I was amazed.
That's about the same range as common water pipe (as I am told by people who
think they know, even though water pipe doesn't have a rating.) Anyway, with
70mph wind ratings around here, I think I can get only about 5 ft seperation
and have any safety margin.
Or do you think there is no chance and I should get another mast?
Turning the antennas 90 degrees may not be a solution, because the XM240 may
then be effected by the SteppIR boom.
Jerry
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
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