[TowerTalk] Hy Gain Balun Substitute (fwd)

[Pat Barthelow]

Hi Folks,

We at N6IJ, have suffered a failure of our Hy-Gain LP 1017 Log periodic
antenna. :*(  It has gone high SWR intermittently for several months.
Careful
troubleshooting has eliminated as possible sources, all transmission line
fitting problems betweeen the shack and the final pigtail lead located at
the kingpost/Rotor.  Sweeping the coax pigtail shows infinite (nearly) SWR
through the entire range (6.2
to 30 MHZ.)  The antenna uses the Hygain BN-86 ferrite balun.  The
antenna is mounted on a standard ARMY MARS platform, trianglar, 18 ft
corner to corner.  The Balun, at the tip of the boom is 25 feet out from
the edge of the platform, so is difficult to access.  I need to locate a
cherry picker, or crane with Man-Bucket to look closely at the feedpoint.
	
Question: Can I/Should I replace the ferrite balun with a coil
balun, made of coax?  Or should I replace the BN 86 with a more rugged
Hygain ferrite Balun?  (I'm assuming the balun has failed internally, as I
have
been told that this particular model was subject to unreliablity when used
at high power levels.  We use up to 1200 watts out, but who knows what the
ARMY MARS OPS used when the ex MARS station at Ft. Ord was active.)  If I
fabricate a coil balun,  for 40 thru 10 meters, how many turns and
what diameter should I use for the RG-213 Coil?  

Tnx, de Pat, AA6EG/N6IJ;  aa6eg@tmx.com
The Contest Station from the Government

Marina Amateur Radio Contest Station
599 DX Drive
Marina CA 93933



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