Topband: 1000 feet 5/8" hardline or 600ohm True Ladder line.

[Jim Brown]

On 4/29/2014 10:08 AM, Richard (Rick) Karlquist wrote:
> The ARRL Antenna Handbook shows about 0.4 dB for 420
> feet of 75 ohm 1/2 inch hardline.

I suspect they are talking about 75 ohm heliax, not the typical CATV 
hard line. The CATV hard line I've seen has an Al shield, so I would 
expect loss to be a bit greater than heliax, which has a much heavier 
copper shield.

> Paralleling two
> runs of line does not decrease the insertion loss. 

That depends. Given the same source and load Z as with the single run, 
it does decrease the loss, because the current divides between the two 
lines. The condition that does not reduce the loss is the use of two 
runs of coax wired in series to raise their impedance, so that the 
center conductors are parallel wire line.

73, Jim K9YC