[time-nuts] Don't use cheap cables -- a cautionary tale

Volker Esper ailer2 at t-online.de
Sun Mar 3 13:49:17 EST 2013

Yes, we all have to learn that lesson...

At the time I use bedea RG-223 and Belden H155 with soldered and crimped 
Telegaertner BNC connectors as general purpose cable (up to 2 GHz). 
Above that frequency I wouldn't use BNC. If you simply connect your 
tracking generator with the spectrum analyzer by using such a BNC cable 
there's not one that is absolutely stable when stressing the connector. 
I tried several manufacturers, HP, Suhner, Radiall, Rosenberger, it's 
always the same.

To make precise measurements I prefer screwed connectors like N or SMA.


Am 03.03.2013 17:30, schrieb Jim Lux:
> On 3/3/13 8:00 AM, Kevin Rosenberg wrote:
>> On Mar 3, 2013, at 7:59 AM, John Ackermann <jra at febo.com> wrote:
>>> Lesson learned -- use only double-shielded cable in the oscillator 
>>> rack (and in any RF measurement path) from now on.
>> I've learned that lesson as well. John Miles said that RG-58 is 
>> occasionally referred to as 'soaker hose'.
> RG-58 (which by the way, is a spec that officially no longer exists as 
> part of MIL-C17-28, ditto for RG-8, RG-213, etc. The military 
> apparently doesn't use PVC insulated wire any more.) comes in myriad 
> forms all of which bear a passing resemblance to each other.  (leaving 
> aside the RG-58A, RG-58, RG-58C differences).
> The term seems to be used for any 50 ohm single shield coax that's 
> about 0.20 inch in diameter with solid polyethylene insulation. You 
> really need to look at the specific model number to know what the 
> shielding looks like. It could be anything from a  very loose weave of 
> thin copper strands to something nice and dense.
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