RG58 cable etc. How do you know?

cardiffrob · Post by **cardiffrob** » Thu Oct 23, 2008 3:25 pm

I've got a few sections of coax cale from old aircraft radios. How does one tell if it is RG58 C/U as specified in the installation manual?

cardiffrob · Post by **cardiffrob** » Thu Oct 23, 2008 3:29 pm

Thinking about it, does anyone have a lightweight antenna and at least 2 meteres of cable on it? Also, a couple of the TRS headset jack plug sockets?

Valcom 760 radio.

Cheers.

Rob Thomas
South Wales

PB · Post by PB » Thu Oct 23, 2008 7:34 pm

It will have RG58 printed on it at intervals....

tnowak · Post by **tnowak** » Fri Oct 24, 2008 8:30 am

Unless the cable is marked you cannot tell. So many coax cables look near identical but their characteristics are so different.
Tony Nowak

Rob Swain · Post by **Rob Swain** » Fri Oct 31, 2008 6:02 pm

Easiest way to know you have RG58 is to buy it new.

Doesn't cost much and the likes of Maplin sell it by the metre.

cardiffrob · Post by **cardiffrob** » Sat Nov 01, 2008 7:57 am

My radio manual specified RG58c/u cable but I couldn't find that EXACT reference at Maplins, RS or Farnell. I did, however, have a pile of old cables with connectors already fitted at each end. It would've been great to have saved the effort and used some of the garage clutter. In the end, a fine chap has made me a complete aerial 'kit' for not much more than the postage costs from Maplins! Nice shiny stainless lightweigh aerial wire thingy. No more wiggly amp confusion! Also, the aerial connector at the box end has to be a specific one and he had a pile of ex Navy connectors that fitted the quick-release radio tray.

Ian Melville · Post by **Ian Melville** » Sat Nov 01, 2008 8:18 am

The Maplin and RS stuff should be OK, in fact, a better bet than that you find kicking around. However if you really want RG58C/U
http://www.nevadaradio.co.uk/acatalog/c ... 58cu1.html

This one is mil spec

cardiffrob · Post by **cardiffrob** » Sat Nov 01, 2008 6:11 pm

Cheers.

A 100 metre (£39:95 plus postage and VAT) roll might come in handy when I have to fit a Mode S transponder a safe distance away!

Has anyone got an ideas as to what the difference is with RG58 and RG58c/u? Not too worried, now that my new £25-ish aerial kit is in the post, but it would be interesting to see what the 'radio Anorak' meant when he was writing the manual.

Why can't people keep it simple?

Ian Melville · Post by **Ian Melville** » Sat Nov 01, 2008 7:40 pm

For the cable types
http://www.belden.com.au/beldencatalogu ... ax/6.9.pdf
For the abbreviations
http://www.belden.com.au/beldencatalogu ... x/6.15.pdf

If you are looking at RG58 and it has a multicore inner that is tinned, Solid insulator, and a tinned braid outer, then it is very likely that it is RG58C/U

PS Maplin photo is wrong

cardiffrob · Post by **cardiffrob** » Sun Nov 02, 2008 8:45 am

Thanks for that, Ian.

Added to my list of handy links since it has a tech advice section.

Hey! Maybe that would be a good thing to add to the website? A 'sticky' list of handy websites with tech info like this that doesn't fit the usual mould?

Just a thought.

PS I'm not volunteering. I can't even program my wristwatch.

JonKil · Post by **JonKil** » Sat Nov 08, 2008 9:53 am

cardiffrob wrote: A 100 metre (£39:95 plus postage and VAT) roll might come in handy when I have to fit a Mode S transponder a safe distance away!

RG 58 or 58U not suitable for mode S. Frequencies too high. Cable for this installation has higher freq characteristics and is not so tolerant of mechanical stress. Check this out before you fit the transponder. Using wrong cable (or wrongly tuned antenna) can cause high SWR in the system resulting in reflected power being sent back through the cable and "blowing" the output amp. A lot of the installations I look at that are having problems can be traced back to poor installation of the antenna and wrong cable being used, the range and performance can be dramatically improved by having this feature properly installed. I have learned this from building antennas for amateur radio use over the years.

And by the way, that is a completely crazy price for RG58/U... 100% too expensive.
Check these guys out for the prices, £18.50 for the same 100 metre reel
http://cpc.farnell.com/CBBR0133/cable-w ... black-100m