The oldest coax

[W4RON]

OK guys here's a question for you.
What's the oldest coax you've got.
I found a piece today in the shop that a friend,
KN4R had given me years ago and I had forgotten about.
It's Amphenol RG8/U and it's dated June 1944.
That's pretty old for coax. I'll have to go
to some of my old ARRL handbooks and see when
the first ads for coax showed up.
Has anyone else seen any coax older than this?
Does anyone know when it was first introduced?

73, W4RON
http://radioheaven.homestead.com/W4RON-hamshack.html

[Steve - WB3HUZ]

Wow! That's some old cable. Would be interesting to see how it has aged by doing some attenuation tests on it.

Heaviside patented coaxial cable in the late 1800s in England. I recall seeing ads for coax in late 30's QSTs.

[W4RON]

Wow! That's some old cable. Would be interesting to see how it has aged by doing some attenuation tests on it.

It not but about 3 feet long, don't think it'll show much attenuation
even at 63 years old. Can we measure it by the inch?

W4RON

[WA1GFZ]

How does it look? cracked , brown?? the oldest coax I have is in my V2 and is is pretty brown.

[W4RON]

How does it look? cracked , brown?? the oldest coax I have is in my V2 and is is pretty brown.

It looks great, nice and black not hard or cracked at all.

W4RON

[Ed-VA3ES]

The oldest coax I have is 38 years old.  I use it for interconnects between equipment. It still looks good and is  still flexible.

[WU2D]

The coax that came with the wireless set 19 was 1942 vintage shocked me - it was very good quality and RG-8 sized. It has a solid center conductor silver over copper, PVC insulation very similar to that seen today but darker and greenish, a fine braid pure copper shield and a see thru PVC jacket. You would think that it came off a roll yesterday. The connectors are interesting too, I will send a picture. Obviously coax was figured out by then - the crap coax came later...

Mike WU2D

[WD8BIL]

I replaced 2 - 30 meter runs of RG8C/U here in the lab a few years back. Some of the data was getting a bit wierd. Attenuation check showed it was acceptable up to about 22 mhz. After that it skyrocketed to the point where it had tripled by the time you got to 500 Mhz. That coax was 18 years old. The center conductor insulation was a piss yellow color. Yup........ yeeeelllllooooeeee !!

In jumpers like 3 feet and such the only thing I'd be concerned with is voltage breakdown as the center insulation dries out and cracks.

[W9GT]

I have some RG-8 around here that is over 40 years old...the dielectric is brownish green.  I'm sure losses above 30 MHz are excessive.  What happens is...the copper migrates between the center conductor and the shield and the dielectric becomes contaminated.  Losses go way up, especially at VHF.  I do, however, have some 7/8" Heliax (hard line) that I have been using for over 30 years and it was possibly 10 years old when I got it.  It still works fine and losses have not increased measurably, even at 2 meters!  It has also been in a damp environment in an underground conduit.  I guess the foam dielectric material that is in that line does not break down or contaminate as easily as the polyethylene stuff in RG-8U.

Somewhere around here I also have some WWII vintage coax that has a brown/semi transparent jacket material.  The dielectric is deteriorated severely and has turned green and is crumbly.

73,  Jack, W9GT

[Todd, KA1KAQ]

Also have some WWII-era RG-8 sized stuff around here, never looked inside. IIRC, that's the timeframe for the introduction of coax cable? The jumpers on back of the KW-1 are original as well (1952 vint.), but very short. Oldest stuff I've used is now rolled up somewhere, some RG-8/U foam I got in the 70s from an old blind guy ("Looks good to me, Jody!")* which was 'new' as in unused at the time, but no idea how old. I've had it 30+ years, had some of that nassy discoloration going on in the foam dielectric when I rolled it up a few years back. Blue lettering on the outside.

The NOS Mil surplus RG-9 we used on the new dipole recently is also old stuff (35-40 yrs +), but it looked like it was made yesterday - inside and out.

* Ernie Thompson (SK), an old blind musician and radio buff. Loved to say things like "I'll be seein' ya" or "I'll keep my eyes open for ya" and was forever calling me Jody for some unknown reason. Traded a Les Paul knockoff and Traynor amp to him for my first big pile of radio gear back in the 70s. Also the first/last time I had 'shine. No wonder he was blind! 

[WA1GFZ]

I have a run of RG - 214 going up the tower since '77 looked good the last time i checked. Bud, we have a lot of problems with shield leakage on single shielded cable. We try to avoid it.

[WU2D]

Here is a chunk of the coax and the end connector for a Wireless set 19 marked 1942. This coax connector is similar to modern push on connectors with no thread but it has a strap that keeps it mated. The strap assy rotates so the coax can come off the radio at any angle. Pretty clever design.

The outer jacket of the coax is reddish plastic and as you can see the braid is copper.

Mike WU2D