Topband
[Top] [All Lists]

Re: Topband: Verifying integrity of 75 ohm coax.

To: "Gary@ka1j.com" <Gary@ka1j.com>, "Topband@contesting.com" <Topband@contesting.com>
Subject: Re: Topband: Verifying integrity of 75 ohm coax.
From: Bill Wichers <billw@waveform.net>
Date: Tue, 19 Nov 2013 20:37:48 +0000
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Just a suggestion: the T&B Snap'n'seal connectors also have "Seal nuts" which 
can be bought separately. They're intended to seal out water from the thread 
area on the F connector. They are basically a metal shell with some threads 
that captivates an O-ring such that tightening them against the connector seals 
the o-ring between the threads and the F-connector itself. They're intended to 
be a water seal, but they also make a pretty decent locknut for an F connector 
even if you don't care about the weather proofing function.

The newer CATV splitters, etc, have rubber boots that the male end seats into. 
Those also reduce the possibility of loosening but probably not as much as the 
seal nuts. If you have a problem with F connectors loosening over time the seal 
nuts used as lock nuts might be worth a try. Note that the seal nuts will 
require about 1/8" or so of extra threaded area on the female connector 
compared to using the F connector alone so they don't work with all female 
connectors. You need to make sure when using them that the mail connector still 
seats properly (i.e. the coax shouldn't rotate within the threaded ferrule of 
the male connector after it's been tightened).

  -Bill

> However, the cause of the majority of my problems were the F connectors
> being somewhat loose in the RX array. They were all connected to the coax
> properly, it was the connections to the many different chassis' involved; It's
> beyond me how so many of them were not tight and I have more than my
> share of OCD and leaving so many loose makes me wonder if I did close them
> tightly in the early winter last year but not tightly enough and perhaps with
> cooling/heating they loosened some more.
> 
> Yeah, that seems like a stretch but whatever it is, there has to be a reason
> they were all loose when I always crank down on outdoor connectors to
> keep water out. That looseness was the cause of most of my issues. I
> wonder if a diode/rectifier effect might have taken place and was creating a
> signal due to the proximity of Amtrak with it's catenary suspended 15KV
> power supply. I'm not enough of an engineer to figure that one out but
> regardless, tightening solidly all the F connectors and cleaning the grounds 
> to
> each antenna in the array made all the difference.
> Topband Reflector
_________________
Topband Reflector

<Prev in Thread] Current Thread [Next in Thread>