If you have an MFJ-259, or the likes, you could check the line with the
"distance to fault" mode, remembering to use the feedline velocity factor to
correct the answer.
Gene / W2LU
----- Original Message -----
From: "Jim Brown" <jim@audiosystemsgroup.com>
To: <towertalk@contesting.com>
Sent: Sunday, April 01, 2012 2:09 PM
Subject: Re: [TowerTalk] Stange SWR/AttenuationpProblems, goes away when the
sun comes up
> On 4/1/2012 8:01 AM, Richard Thorne wrote:
>> All coax, connectors etc are brand spanking new.
>
> This does, indeed, have flaky connection written all over it. What kind
> of connectors? Who installed them, and how? Soldered or crimped? If
> crimped, proper tool used?
>
> For troubleshooting -- first thing I would do is to stick an antenna
> analyzer on the coax at the shack at a time when the connection is bad
> and find all the impedance nulls. What you're doing is observing the
> behavior of that bad line as a stub. Go down as low in frequency as your
> analyzer will work, then stick those numbers in a spreadsheet to find
> possible lengths to the fault. Do the calculation both ways -- that is,
> assuming both a short and an open at the other end, although an open is
> the more likely possibility.
>
> This ought to get you within 5-10% of the cable length to the fault.
>
> Another point -- BEWARE OF JUNK CONNECTORS, BARRELS, AND OTHER
> ADAPTERS. I have had EXACTLY this sort of failure with junk
> connectors. Any connector other than an Amphenol should be viewed as
> junk.
>
> 73, Jim K9YC
> _______________________________________________
>
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