[TenTec] OT 75 Ohm twin feeder

Steve Hunt steve at karinya.net
Thu Jun 12 18:05:49 EDT 2008


Jerry,
> Two pieces of 75 ohm coax in parallel (corresponding conductors
> connected together at each end) gives 37.5 ohms. Two sets of those in
> push-pull gives 75 ohms shielded balanced. Or the same with 50 ohm coax
> gives 50 ohms balanced.
>   
That would work, but using four lengths of coax to replace one seems a 
bit OTT
> The jacket is the least consistent part of the coax and I believe it to
> be loaded with carbon to make it black and UV resistant. That would make
> it lossy (and slightly improve the shielding properties) to some extent.
>   
I've just ordered a short length of RG-400 to try in place of the 
RG-58.  It seemed to me the outer jacket  (FPE) would have better RF 
characteristics than the PVC.

Tried the RG-58 option on my Hexbeam today and it took the max I could 
throw at it - 400W.

Steve G3TXQ



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