Towertalk
[Top] [All Lists]

[TowerTalk] TH-11DX and 40/30m dipole

To: towertalk reflector <towertalk@contesting.com>
Subject: [TowerTalk] TH-11DX and 40/30m dipole
From: N1BUG <paul@n1bug.com>
Date: Tue, 10 May 2016 08:40:06 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
I am sure this subject has been beaten to death many times but I am not finding all of the wisdom I seek either on the bookshelf or in the archives of this list.

I have a TH-11DX at 100 feet. I plan to build a 40/30 meter rotatable dipole which I want to put above the TH-11. I assume (uh-oh) that with the close frequency spacing of 20-17-15-12-10m it will be difficult or impossible to get resonances of the 40-30m antenna far enough away from all of those bands to get away with putting the elements in the same plane. This assumption however leads to two questions:

1) I'm not sure this can be answered in general terms, but: How far removed from a band does a resonance have to be in order to not cause significant problems? I don't mind a little distortion of pattern or a dB loss of gain but significant SWR changes are not to be tolerated.

2) Is there a simple way to measure said resonances of the 40/30 meter dipole that will be good enough for this purpose? I have an MFJ antenna analyzer at my disposal.

Assuming putting the 40/30 dipole in the same plane as the TH-11 elements is out brings me to my next question.

3) If mounted in the same plane Will the boom of the TH-11 cause problems for the 40-30 meter dipole? How far above the boom should I be trying to mount it for good performance? Four feet could be done very easily but I worry that may be too close. I could get a few feet more with extra work and expense. Anything beyond 8 feet is probably not possible in this instance.

I would appreciate any comments or advice I can get before I get too deep into this project.

Thanks,
Paul N1BUG
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>