[TenTec] OT: Question on Coax Cable

[Dr. Gerald N. Johnson]

On Sat, 2007-03-31 at 17:46 +0200, Rick, NJ0IP / DJ0IP wrote:
> Tnx Carl.
> 
> I just read the reports on eHam.
> The stuff looks very good.
> 
> For the outdoor piece, I want to buy various lengths with the connector
> already soldered and weatherproofed.
> 
> However, it looks like this stuff is pretty hefty.  For permanent use.
> 
> I just bought a Kelemen dipole (trap dipole for 80/40/20) which I will
> install immediately when I get to my mom's house.  Since it's a temporary
> installation and probably using a telescoping fiberglass pole, I need
> something light to feed it with.  It will be a short run, max 50 ft.  Here I
> was thinking about using the CNT-240 and wonder how it compares to RG-58.
> 
> 73
> Rick
> 

For use on 80/40/20 in a 50' run, you won't detect a significant power
loss in RG58 compared to these fancier coaxes. Their loss on HF is
insignificantly better than plain old RG58. You would prefer RG58A or
RG58C with a stranded center conductor. These fancy coaxes are more
important at VHF through microwave. Its important at all frequencies to
have good braid coverage which leaves out RS coax cables.

With UHF connectors, there no water proofing that can be applied to the
connector until its been connected to the mating connector. With N
connectors, most are inherently waterproofed by the gaskets in the cable
to connector assembly. And pretty much so with BNC.

All of this presumes you aren't going to run a PA which can warm if not
melt the RG58 sizes of coax. If you are going to run a PA, RG-213 is
good, RG8 is OK, I'm no fan of RG-8X for anything. But you still have to
look a the coax braid because the military specs that these RG numbers
came from are no longer in effect and coax makers approximate them
roughly, more roughly when price is a factor. With the high price of
copper these days, many a maker will leave out as much as possible. I'm
a fan of Belden products because they seem to no be taking short cuts.

The xx-240 and xx-400 products are products claimed to be competitive
with Times LMR coaxes with the same numbers. Some may be, some may be
poor approximations. 240 is the same size as RG-58, namely about a
quarter inch in diameter and 400 is close to RG-8 at .400" diameter or
10 mm.

-- 
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer