[TowerTalk] Coax specifications, etc.

[Jim Lux]

At 07:00 PM 4/28/2004 -0400, Tom Rauch wrote:
> > Interestingly, there is no such thing as Mil-Spec RG-213
>or RG-58, since
> > the "slash sheet" for that coax has been invalidated since
>the early
> > 90's(although it's available for reference).  The military
>no longer buys
> > PVC jacketed coax, so there's no need for a procurement
>spec.  MIL-C-17/74C
> > for RG-213, -17/28C for RG-58
>
>Not to whip a dead horse, but there is no standard testing
>spec used in cables that are NOT intended to be sold under
>mil spec.
>
>My point is we shouldn't compare ratings offered by
>different vendors unless we know with certainty the vendors
>test and rate using the same standards.
>
>73 Tom

Tom raises a good point.  When a manufacturer advertises a cables as being:
"manufactured to meet" or "similar", then they might not meet the specs, 
and certainly there's no requirement that they actually test.  For things 
that don't have some sort of formal certification, one has to rely on "the 
brand is the guarantee of quality".

However, most manufacturers do specify, somewhere, what test procedures 
they use, since that would be required by most commercial customers, along 
with some sort of certification that it meets the spec or was tested, 
etc.  If you're a cable TV company buying tens of thousands of feet of 
coax, odds are you expect to get a cert with the shipment.

Even if you go down to the hardware store and buy zipcord, if it's got the 
RU or other similar mark on it (which it almost all does), then someone 
along the line had to test it, and provide a cert to the buyer.  Whether 
Home Depot is willing to give you a cert is another question, but then, 
consumers always get the short end of the stick on this sort of thing.

If you bought your zip cord (or coax) at a store catering to "the trade", 
then you would get a cert.  Likewise fasteners.  Likewise coax from major 
retailers (i.e. Newark, Mouser, etc.).

An interesting question: Do retailers to the amateur radio market (HRO, 
AES), provide certs on request, when buying bulk components (connectors, 
coax)? Or, do they sell by brand name, and you trust that the brand lives 
up to their advertising.  I haven't looked at the fine print on the back of 
the receipt or packing slip recently.

Jim, W6RMK