[TowerTalk] HyGain BN-86 Balun

[Jim Thomson]

Date: Mon, 9 Feb 2015 19:33:30 -0800
From: "Don " <w7wll at arrl.net>
To: "Towertalk" <towertalk at contesting.com>
Subject: [TowerTalk] HyGain BN-86 Balun

I sent MFJ/HyGain a set of photos a couple of months back of the balun which came from my TH7DX. The contact at the connector flange was totally corroded and the wire around the ferrite was burned/arced across 3-4 turns.  It was also the home for the central OR coast spider population. this is the response I received.

?This design is at least 30 years old. The current version uses an entirely different design. The BN-4000B is the same, but 4kw PEP or 2KW average.?

There was no further elaboration on what the current different design was. Someone know? I chose to replace it with a Balun Designs unit.

Don W7WLL

##  I burned 3 of those BN-86s  up... burnt between windings...back in the late 70s....and that was with a 1:1 swr on each band they were used on.   With 1.9 kw pep out ssb.  They  were junk back then, and still are.   If Hy-gain /mfj is still selling the
damn things,  they must think everyone is stupid as a brick.   The new BN-4000, as far as I know, consist of a string of type 77 beads on 213 coax.   The 1.125 inch long, x .505 inch ID x 1 inch OD  type 77 beads are still listed on fair rites site.
But they are the wrong bead for the job if beads are used.  the same size beads are still available from far rite, in type 43 and also type 31.   per fair rites specs, the type 31 has a higher Z tan the type 43...all the way up to 30 mhz and beyond. 

##  Don’t mess with a BN-4000, its not optimized either. Type 77 is low freq stuff, where Z peaks at 1 mhz, then goes downhill above 1 mhz.   Its another fubar design. 

Jim   VE7RF