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

[Jim Brown]

On 4/29/2014 8:00 AM, Kenneth Silverman wrote:
> We lost the data but I seem to remember the total loss on 80/160 with 1000' of line was negligible.  Maybe in the 2 dB range on 10m with 1000' of ladder line.

I suspect few here would consider 2dB negligible. i don't. N6BT says 2dB 
is a lot.

On 4/29/2014 8:32 AM, Shoppa, Tim wrote:
> Really, for decades I did not understand why ladder line had so much less loss than comparable-copper coax.
>
> It's because ladder line is used at 450 or 600 ohm impedance, so it of course has one tenth the resistive losses of 50 ohm coax built with similar amount of copper.

Exactly right -- it's because the current is much smaller for the same 
power.

On 4/29/2014 8:49 AM, Milt -- N5IA wrote:
> For my 160 Meter, 1/4 WL vertical, which is more than 400 feet from my 
> operating position, I use 1/2" CATV hardline X 2.
>
> Since the feed point impedance of the vertical measures ~ 39 Ohms, I 
> parallel two of the 75 Ohm cables for a near perfect match to the 
> antenna.
>
> The 420 foot long run of paralleled cables dampens the slight mismatch 
> between the presented impedance of 37.5 Ohms and the desired 50 Ohms 
> for the amplifier such that the Alpha does not light a single 
> reflected power segment from 1.800 to 1.880. 

Exactlly right again.

Many of the "best" solutions for antenna problems depend on which of 
them are readily available to us.  If you have that CATV hard line, it's 
a great solution once you know how to use it.

Another great way to use 75 ohm cable in a 50 ohm system is to use some 
multiple of half waves of it, coiling up any excess, or using 50 ohm 
coax to add length.

None of these solutions are "new" or particularly innovative. All have 
been used since the earliest days of radio.

73, Jim K9YC