[TowerTalk] Any BN-86 Balun Replacement Suggestions?

[Pat Barthelow]

Eric, and group.

Amen to Jim's reply about 1.2:1 being quite acceptable, quite good actually, and in no need of extra effort to reduce.... 

Take a look at the bottom of the page of the LP 1017 data sheet below, to see the wide variation of (acceptable) SWRs over its design frequencies.  

Granted, one reason to seek extra low SWRs is due to the fold back protection circuits of ham gear, that sometimes trigger at SWRs far lower than those that would otherwise do perceptible harm to a signal, or damage a well designed transmission line system.   The LP 1017, while perfectly usable, and I can attest, puts very good sigs over the pole, and to other DX points,(65' in the clear with views to the Pacific helps) might present loading problems to some modern Ham gear, without antenna matchers.

Another consideration.... The BN-86 Balun over the decades shows up in actual use to have a fairly high failure rate when used at it's limit power ratings.  I have personally had 2 (out of 3)  fail in my ham career.    There is still a BN 86 at the end of the boom that I cant get at, to do a post mortem,  on the LP-1017  at N6IJ.  When it failed, we built a choke balun from coax, and left the dead BN-86 where it was at the end of the boom.

see: http://www.n6ij.org/images/n6ijsunlp.jpg
http://www.usantennaproducts.com/pdf/LP_1017_data_sheet.pdf


  There seems to be  enough anecdotal evidence/history to suggest that someone should look at the BN-86 to find if it truly  has a  design problem, or is optimistically  rated power wise, or if  its failures may be  due to  abuse by users.. perhaps High SWR can kill it when running High power. 
All the best,
Pat Barthelow    (916) 315-9271
aa6eg at hotmail.com
http://www.jamesburgdish.org


> From: ve3gsi at sympatico.ca
> To: TowerTalk at contesting.com
> Date: Tue, 8 Apr 2008 12:07:50 -0400
> Subject: [TowerTalk] Any BN-86 Balun Replacement Suggestions?
>
> TT Gang,
>
> It looks like my BN-86 Balun used on a TH7-DX beam is giving me grief. The
> antenna was assembled to use the DX or lower portions of the bands. 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. After doing some basic research and talking
> with a friend we have come to the conclusion the Balun may be causing my SWR
> problems. I am considering a new Balun for as a replacement from DX
> Engineering. DXE have several models to choose from so I will have to wade
> through the details, but several obvious questions come up.
>
> How do you mount these Baluns on a beam and is the ground strap still
> required for beam mounting or does one 'float' the Balun electrical ground?
>
> Which DXE Balun model works best on the THY antenna?
>
> Are there other Baluns I should consider for using with the TH7 antenna?
>
> Thanks gang,
> Eric - VE3GSI