[TowerTalk] Strange HV-18T HyTower issue

[Wayne Kline]

Bruce
 
 I do not have an answer to you problem, BUT I have trouble shot issues in antenna systems as you described. 
 If it a break down under Power. You friend is a High powered dummy load.  start at one end ( makes no difference which) at  trace my way back or out from the FIRST connection. I have   (4) Hy-Gain  Hi Towers an a 4 sq on 75/80 mtrs. Not sure of the DX engineering base plate But my Homebrew aluminum  is where I connect the coax to and feed the tower  from that connection.  How are you feeding the center conductor to the tower base ? This is the FIRST place I would look at. If it is breaking down you MY see carbon trace ! But this connection to the HOT feed must be SOLID . I use 1/4" SS bolts with internal toothed  washers and the seal that area ( i use  DUM DUM . comes off easy and cleans up with Brake clean )and then attach the feed from the ground plate connector with soldered eyelets and another set of washers nuts ,. I use striped RG213  ( no ground /no shield ) as the jumper.
  
YMMV
 
 Wayne W3EA

 

> Date: Thu, 6 Oct 2011 07:59:30 -0400
> From: n8de at thepoint.net
> To: brucebeard at gmail.com
> CC: towertalk at contesting.com
> Subject: Re: [TowerTalk] Strange HV-18T HyTower issue
> 
> Sounds like a cold solder joint where the wire comes from the SO-239 
> at the base of the HyTower and goes to the radiator. Make certain 
> there is NO corrosion anywhere from that connector to the center 
> 'pole' of the antenna.
> 73
> Don
> N8DE
> 
> Quoting Bruce Beard <brucebeard at gmail.com>:
> 
> > The Antenna
> > 3 year old Hy Gain Hy Tower. Optional MK-17, 17M stub installed, 
> > MK160A,160M long wire installed .
> > DX Engineering radial plate.
> > Fed with Andrew Heliax hardline.
> > 4000+ feet of radials.
> >
> > The Installation:
> > Mounted in concrete. Located in heavily wooded area. lots of 
> > leaves and debris, constantly cleaning stuff from base of antenna, 
> > never seems to make any difference.
> >
> > The problem:
> > First noticed that while working on 75M and 160M, after 
> > transmitting, the antenna would go quiet. It is as if the attenuator 
> > is coming on or the antenna is being disconnected. If I put just a 
> > small amount of RF into the antenna system it "wakes up". This 
> > condition is more apparent on 160M than 75M.
> > SWR is fine under power; however, I have noticed that SWR 
> > (indicated on my LP 100A) sometimes begins rising, in ssb while 
> > keyed but without drive (i.e. keyed but not speaking). Speaking and 
> > thus putting power into the system brings SWR back down.
> >
> > Now I believe I am getting a flashover somewhere. Plate voltage will 
> > spike on the amp after transmitting with power thus shutting off 
> > the amp. My OCF dipole is fine with the same radio/amp/tuner 
> > combination. My Yagi is fine with no symptoms although I don't use 
> > the tuner for the Yagi.
> >
> > Replaced coax last year with no apparent change. Dropped antenna 
> > for visual inspection and saw nothing that looked unusual.
> >
> > I am at a bit of a loss here and I need suggestions as to where my 
> > problem might be or how to diagnose this (these) issue (s).
> >
> > 73,
> > Bruce Beard
> > AB1KC
> > ab1kc at arrl.net
> >
> > _______________________________________________
> >
> >
> >
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> >
> 
> 
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