On 11/7/2012 9:20 PM, Missouri Guy wrote:
FWIW...I needed connectors for the 1/2 aluminum coax
quite a few years ago. I didn't think of K8RI's neat idea
of the brass fittings back then. What I did was to make
an adapter-sleeve with a ~1" length of 1/2" i.d. aluminum tubing.
The tubing fit over the standard PL-259 connector
and the coax.
I found a thick steel washer in the junk box
that is about the same size as the CUTTER WHEEL in a copper tubing
cutter.
I rounded off the edge of the washer and installed it in the
cutter. I then used the "cutter" to ROLL two indented rings
on each end of the aluminum tubing (4 rings total). That worked, but I
found that the aluminum coax was TOO SOFT to "fuse"
to the aluminum sleeve. I solved that problem by making
some hard plastic inserts that "just fit" inside the coax.
I removed the foam inside the coax with a homebrew
hollow "drill" made from a chunk of mild steel so the
inserts could slide in. It worked well and the connections
are still good many years later.
Yeah, you may have to use a small lathe to make the inserts, but I know
some of you have one in your shop. Those inserts may be needed
*IF* you find that the brass compression fittings that Roger used
are somewhat loose when compressed over the soft aluminum
coax.
I like your idea and I'm trying to picture it a bit better. It has a
certain elegance to it, but unfortunately takes a bit more work and I've
noticed a lot of us are not extremely gifted on ambition...at least I'm
not. OTOH I can't resist a challenge, particularly if it doesn't cost much.
I wonder if a swagging tool couldn't be built to fit the jacket tightly
onto the PL-259 Barrel? This would give a large area of contact and
might be strong enough to hold well. The problem with swagging onto the
barrel is the Aluminum tends to spring back. OTOH swagging to an ID
slightly undersize with a bit of a bell on the end of the jacket and
then pressing the PL-259 into the end of the coax jacket might work
well. Now some one just needs to make the tools to do this well. <:-)).
As in writing computer programs, there are usually far more than one way
to get the same result. My approach was neat and easy, but you are
correct in that using the compression fitting the coax is a bit small
for the fitting. It will tighten down fine, but it takes care to keep
things straight. Of course if you have a good lathe and a bit of skill,
you can build the equivalent of of a 7-16 DIN. With some brass rod of
the proper size you can also build the connectors used on Heliax. Those
are fairly simple, but it takes about a 4" rod and that brass rod is
kinda pricey!
73
Roger (K8RI)
73,
Charlie, N0TT
On Wed, 07 Nov 2012 18:01:07 -0500 K8RI <K8RI-on-TowerTalk@tm.net>
writes:
On 11/7/2012 5:32 PM, Tom KD8DEG wrote:
I use standard copper pipe compression fittings if the cable is
the
aluminum 75 ohm cabel tv line. They work great.
A couple ways of making adapters.
http://www.rogerhalstead.com/ham_files/conn.htm
73
Roger (K8RI)
Tom KD8DEG
----- Original Message ----- From: "Steve Maki"
<lists@oakcom.org>
To: "towertalk" <towertalk@contesting.com>
Sent: Wednesday, November 07, 2012 10:00 AM
Subject: Re: [TowerTalk] Fwd: Attach a PL-259 to a 1/2" hardline
Well, they do make female F connectors for anything up to .750,
but
normally it's terminated with pin connectors. The pin connectors
though are useful as a starting point to transition to UHF.
-Steve K8LX
On 11/7/2012 9:49 AM, Jim W7RY wrote:
Is this 75 Ohm CATV cable?
If so, there are NO standard adapters or connectors. The cable
TV
industry does not use "connectors" on this type of coax. The
cable
connects directly to the device through a hole in the side of
the
device.
73
Jim W7RY
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