[TowerTalk] Any BN-86 Balun Replacement Suggestions? - - - - continued..

[Eric - VE3GSI]

Thanks Jim,

Did not notice the type-o in the SWR ratio that should have been 2.1:1.

I actually have two Hy-Gain beams, a TH6 and a TH7, both with the same balun
and both with a higher then expected SWR at the lower end of 10 and 15
meters. I don't have a long run on either tower and even the longest run of
100' is fed with hardline so loss is not the problem. The SWR is just high
enough that the rig's fold-back protection kicks in. 

What I wish to do is put a pair of bandpass filters on the antenna feed
lines and the manufacture strongly suggests a low SWR to prevent problems in
the filters.

Overkill? Probably - but research is telling me I can potentially have a
more efficient antenna and as a bonus reduce any potential RF on the coax. 

As always, information from people in-the-know is welcome.

Thanks again Jim,

de Eric.


> -----Original Message-----
> From: Jim Brown
> Sent: April 8, 2008 12:45 PM
> To: Towertalk e-Goups
> Subject: Re: [TowerTalk] Any BN-86 Balun Replacement Suggestions?
> 
> 
> On Tue, 8 Apr 2008 12:07:50 -0400, Eric - VE3GSI wrote:
> 
> >The SWR measurements are good on 20 meters, but on 15 and 10 meters
> >the SWR is 1.2:1 on the CW portion of the band. 
> 
> Unless you're measuring at the end of a long line that is swamping a 
> much higher SWR at the antenna, your definition of "an SWR 
> problem" is 
> quite different from mine. I'm thrilled if the SWR at the 
> feedpoint of 
> one of my antennas is less than 2:1 over the bandwidth that I want to 
> operate it. Graphs (and equations) in the ARRL Antenna Book make it 
> clear that losses due to SWR are negligible below 2:1 unless 
> a line is 
> VERY long.
> 
> 73,
> 
> Jim Brown K9YC