Unless you're really crazy about climbing why not start out by opening
things up where the feedline goes up the tower and look up the tower with
the analyzer. If you're lucky and it looks good then there's a pretty good
chance the problem is on the ground. Put a 50 ohm load on the station side
of the feed, at the base of the tower and look at it from the station and
just start working your way towards the tower until you find the problem, or
just work your way from the tower base back towards the station. However,
I'd bet on the bad tower coax scenario, then it's time to start climbing.
You could put the 50 ohm load on the anenna side of the base end of tower
coax, climb up to the antenna, open the coax and look down the coax and/or
into the antenna.
If you have an MFJ analyzer, or possibly one of the others, and there is
enough of a short or open circuit you might be able to locat it's
approximate location by using the "TDR" mode.
Gene / W2LU
----- Original Message -----
From: "EZ Rhino" <EZRhino@fastmovers.biz>
To: "TowerTalk construction topics." <towertalk@contesting.com>
Sent: Thursday, February 16, 2012 7:11 PM
Subject: Re: [TowerTalk] TowerTalk Digest, Vol 110, Issue 42
>I just replaced the feedline on my T6 from the feed point to the top of the
>tower (water ingress, similar high SWR). I would start by looking at the
>feed point and how the coax was weatherproofed. Also do what Steve sez,
>put an ant. analyzer on at that point and then go backwards. Also you can
>use a dummy load on the coax (once separated from the antenna) to see if it
>is indeed bad. Either way you gotta pull the antenna off or tilt it so you
>can get to the feed point, a big pain I know.
>
> Chris
> KF7P
>
>
>
>
>
> On Feb 16, 2012, at 16:14 , K7LXC@aol.com wrote:
>
>> I have a Cushcraft ASL2010, 8 element Log up at 80 feet. All of a
> sudden
> the SWR went up well over 5:1 on all 5 bands the antenna covers (20-10
> meters).
>
> What you need do is start at the antenna and work your way back.
> Measure the SWR at the feedpoint and then go back thru the balun,
> feedline,
> switches, etc. Something'll pop out.
>
> It's been my experience that most SWR problems are feedline related.
>
> Cheers,
> Steve K7LXC
> TOWER TECH -
> Professional tower services for hams
> Cell: 206-890-4188
> _______________________________________________
>
>
>
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