[Lowfer] RG-58 as TX loop conductor

[Bill Ashlock]

>I have been pleased with the improvement in switching the TAG loop from #8
>stranded to that old RG-8 last winter. But I recall that we always tried to
>use solid copper strap instead of braid for tuning network jumpers in the
>broadcast band.  In high current circuits, you could feel the temperature
>difference (after power was removed!). Possibly the braid is less efficient
>at higher frequencies.

Oh boy, looks like we have another confugualty. Thanks for the input. Was 
this at 630k (or is that 620)?

I just measured the Rac for the RG-58 loop away from the transmitter and it 
comes to about 1.1 ohms. This agrees with the readings when connected to the 
transmitter. Eric, that's not even 2db - even without re-adjusting the turns 
ratio for 1w, which knocks it down to not much more than a 1db improvement.

The DC resistance for the shield measured close to the 0.8 ohms tonight, so 
that agrees with the spec on this cable. The calculations work out if I 
assume the center conductor adds nothing to the conductivity of the cable. 
This isn't good news, especially for the RG-8 or 9 users, because I we were 
figuring for some help from the #13 center conductor. Kind of figures, 
though, because it seems like the same eddy current flow that causes the 
skin effect in a homogeneous conductor could also squeeze the current right 
out of that center conductor.

Back to the books.

Bill A

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