[TowerTalk] Hard Line Question
Eric - VE3GSI
ve3gsi at sympatico.ca
Wed Oct 17 17:09:27 EDT 2007
Kip,
I just went through almost what you are telling us. Here is what I found:
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> A friend of mine just gave me a bunch (guessing 200' - 400')
> of hardline in about 6-8 pieces. Some pieces with connectors
> some without. So I plan to use this on two VHF antennas, and
> on a separate UHF antenna.
I ended up with about 4 pieces (LDF4-50A) most of which had N-type fitting I
could salvage. One piece did have a UHF male and UHF female, which I choose
not to use for my current project. I only wanted 200 feet for my HF
installation on a 70 foot tower to a microHAM antenna switch. The rest of
the short run will be with LMR-400.
----------
> 1. How do you put connectors on this stuff?
Go to the Andrew web site and look for this file:
http://www.andrew.com/search/BN_237467.aspx
These instructions should make putting on connectors crystal clear.
---------
> 2. If it looks good, no cracks and the outside looks good, is
> it probably good? It has been sitting in a coil, outside,
> under and against a tree for a few years.
The cable must be checked - REGARDLESS of how it looks, but a good looking
cable without kinks is a very good start.
----
> 3. On the pieces that have no end, if I cut off 1' - 2' I
> should be able to use it because I doubt if any water can
> penetrate that far up. Correct?
If the cable has been flooded you will see it quite easily, the copper turns
black. Do make sure you check the inside of the shield as well as the
outside. I had one bad piece that was black on the inside of the shield for
a good three feet, maybe a bit more. Even though this cable was stored in a
dry place, I suspect it was taken out of service in a flooded condition.
--------
> 4. My MFJ-259A should tell me if it is not good, as it has a
> coax loss measurement. Correct? What is the best way to test it?
Test first with a Megger if you can find one. I suspect a good sensitive ohm
meter might work, but beg-borrow-or-steal a Megger if you possibly can. The
Megger will put about 500V on the cable and will show moister in the cable
in a matter of seconds. Reason to test this way first, you can only test the
cable with the analyzer with ends installed.
Once the cable test good with the megger and looks physically clean then
install the connectors and then test with the MFJ. Make sure you sweep the
analyzer up and down the band around the frequency you want. The MFJ-259A
has a bad habit of showing bad cable or misleading 'lumps' at lengths of
cables that resonate as various frequencies. If you then show a loss well
beyond the spec chart of your type of cable, then you simply cut you losses
and visit the scrap yard. I really suspect the cable will be good.
-------
> 5. Should I use UHF or N connectors? The pieces that have
> connectors have UHF.
You choice. Even for HF I am going with the N-type, simply because I have a
bunch of them. I am sure the rest of the gang can give you their preferences
here.
By the way Kip, I ended up making up a jig that helped me to do an in-line
hardline butt splice. It worked out well and tested out with my equipment to
my satisfaction. It saved me using up a couple of my surplus ends.
As for your project and findings, please let me (us?) know how your cable
tests out.
73 from Canada,
Eric - VE3GSI.
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