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Steve Sampson

Well Known Member
Expecting RG58 I have received Belden URM43. I am frustrated because I cant decide what the difference is. I have chased around the net and am still at a loss, hence this mail. I guess my questions are:

Is it just fine for radio and xpdr antenna leads?

and of lesser importance

What is the difference?

Thanks.
 
Good for comm....

Steve Sampson said:
Expecting RG58 I have received Belden URM43. I am frustrated because I cant decide what the difference is. I have chased around the net and am still at a loss, hence this mail. I guess my questions are:

Is it just fine for radio and xpdr antenna leads?

and of lesser importance

What is the difference?

Thanks.
Click to expand...

Steve... definitely fine for the VHF comm.

It's legal for a Microair transponder... see page 8 of this document...

http://www.microair.com.au/admin/uploads/documents/T2000SFLInstallationManual01R6.pdf

.... but in the US, the transponder system needs to be a TSO'd system, and to meet this the co-ax should meet the requirements in the manufacturer's approved Installation Manual (in spite of what the "build on" crowd claims...:)...)

A Garmin transponder has different specifications, and needs RG-400 or better.

Looks like you got shipped a Euro specification for the equivalent of a variant of RG-58.... The URM 43 does not seem to be a US Belden product.

http://www.batt.co.uk/images/pics/2056urmcoax.pdf

See what happens when you guys abandon long standing specifications for your own harmonized ones....:D

You need to check your transponder installation manual to see what is approved for your specific transponder...

gil A

UPDATE...Here's the problem... you guys sold out and went metric...:)

The caution to follow is to make sure the BNC connectors you use are also metric - which should be no problem if they come from the same UK source.

The URM (Uni Radio-Metric) cables listed cover the majority of high frequency data and signal transmission requirements. Other types can be supplied on request as can armoured, duct grade or versions with alternative sheath colours.

The URM 70 is widely used for security applications connecting CCTV equipment where the stranded conductor centre is less likely to break than the RG59 type. This may be important if the camera is likely to pan and tilt frequently. Other URM cables are available to order.

URM Cables are manufactured generally to BS 2316 part 3.

UPDATE #2

The URM 43 specifications are here (in a brief form, from a UK company). The problem you might find is if the local PFA inspector does not like PVC jacketed cables. The Canadians are running into this based on previous postings.

http://www.fscables.com/coax-urm.php
 
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Gil, thanks for that. The Fscable link was a great help. Comparing the two cables they are almost identical, the URM slightly smaller and therefore lighter. I also noted the Microair credited it with very slightly less loss.

I am sure I wont have an approval problem. The major test of transponder installations over here appears to be a practical one wrt an ATC unit. I suspect I am using the cable specd by Filser anyway, though they define it as a made up cable with ends attached. I need to thread it.

Thanks for the help, Steve.

PS Us Europeans going our own ways. Its just not right! Look at that A380. It shouldnt be allowed. :)
 
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