Topband: Digiwave feedline

[Jim Brown]

On 8/10/2023 5:34 PM, Radio KH6O wrote:

> I purchased a 500 foot roll of Digiwave coax via Home Depot. It's
> double shielded (braid and foil) and is sweep tested up to 3.5 GHz.
> I'm unable to determine the country of origin.
> 
> Any comments on short runs of Digiwave feedline for HF or VHF?

What metal is the braid? What is the center -- copper or copper clad 
steel? If the braid is Al, it's most likely 75 ohms, designed for CATV, 
will require crimp-type connectors made to fit its dimensions. Most are 
type F, but I've seen BNCs. I use a high quality CATV coax for RX 
antennas. It's a type that has a gooey substance between the shield and 
outer jacket to make small penetrations of the jacket self-sealing. I 
like it because most varmints don't.

Since loss is virtually all resistive below UHF, the relevant spec is 
the combined resistance of the center and the shield at the frequency of 
interest, Al shields and CCS centers can be fairly lossy below VHF. CATV 
coax tends to be much cheaper than the coax designed for transmitting, 
thanks both the the lower cost construction and the extremely large 
market for it.

73, Jim K9YC