On Aug 31, 4:15 am, RHF wrote:
QUESTION FOR ONE AND ALL :

Coax Cable - What's Between Your Antenna and Radio ?http://groups.yahoo.com/group/Shortw.../message/14610

Low Loss type Coax Cable ?

RG58 Coax Cable ?

RG8 Coax Cable?

RG6 Quad-Shield Coax Cable ?

WHY - Cost ? Performance ? Value ?

hope this helps - iane ~ RHF
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At the risk of starting yet another pointless flame war, I have tried
many different types of coax
over the decades. And unless one is close enough to a transmitter so
that any coax leakage
is an issue, it simply DOES NOT MATTER. Caps for emphasis.

Transfer Impedance, do a group search for my prior comments, may be a
cause of concern to
a very small number of radio listeners.

Most noise either comes from within the home and reaches the antenna
via common mode
conduction up the outside of the braid and is coupled to the antenna
where it becomes a noise
source, or comes from "nearby" sources and reaches the antenna
directly.

"50" or "72" ohm coax might matter IF our receivers presented anything
like a constant impedance
across the bands. With very few notable exceptions, receivers have
anything but a 50 Ohm
impedance at more then a few chance spots. Most receivers have
significantly higher imput
impedances so one might argue that a higher impedance coax should be
used.

I have used "50", "72" and "93" coax cable with no discernable
difference between either
50 or 72. 93 ohm coax works but is a PITA to put fittings on.

I my home was destroyed and all my stocks of coax were destroyed, and
I no longer worked
where I can get 100 foot runs of good Belden coax from the trash, I
would go with quad sheild
Belden from one of the big Home Cheapo stores. In a pinch I would use
any high quality quad
shield coax such as is sold for DBS. I would strip back the jacket to
insure that all 4 layers were
neat and tight.

I haven't checked, so I don't know what type "F" fittings and
strippers/crimpers they sell.
The "F" fitting can be a very good connector up into the GHz range IF
good connectors and
tools are used, and care is taken to install them correctly.

I have been able to introduce a signal through the coax shield, but
the conditions are very unlikley
to occur in the wild. A 10' wire is positioned 1" from the test coax.
The coax is terminated with
the correct load with a properly installed connector. Then I run 10mW
through a set of of 4 16:1
transformers to give a final step down 64:1. Then and only then can I
receive the test signal at
1MHz. I had 300' of coax between the test jig an my receiver. And the
recovered signal was low
enough that when I connect a 30' piece of wire to a another section of
300' coax the noise
from the real world swamped my noise source.

Perhaps is you lived in Grayland or some other extremely RF quiet
location TI might be an issue.
And perhaps, just perhaps in such a mythical location you could detect
any difference between
50 and 72 ohm coax.

I tend to put "" around 50 and 72 because there are coaxes listed as
50 or 72 that might be a little off.

Do not use Rat Shack, You got questions and we haven't a clue, coax.
Aside from the marginal
braid coverage it is also often not wound symmetrical and the outer
jacket tends to crack in a very
few years.

For a friend we use RG174, small mini coax, that wouldn't have been my
first choice, but because
she lives in a home on the historic registry she didn't want to drill
any holes through the thick wall,
and because the home gets more then it's share of visitors interested
in such historic places she
wanted her antenna to keep a very low profile. There was a very small
hole just large enough for
the RF174 to pass through. We used white RG174 and you have to know
where to look and get
real close, bring a long ladder!, to find it. Not my favorite
installation but it works very well. The bird
feeder in the back yard doubles as a Lankford "15' relay tuned
antenna". She lives out in the country,
with no nearby MW stations and has fantastic reception. We ran about
50' or RG174 then at the soil
line converted it to quad shielded direct burial 100' 75 ohm Belden.
And we didn't bother with any matching.

For any transmitter operations this is a big no no. And for anyone
using a true dipole, cut for
one band and not used harmonically, and if a proper balun is used, and
if the dipole is at least
1/4 wavelength in height, proper (IE 72 ohm) coax it might just
matter. From years of messing with feedlines I must say might because
when putting up some dipoles for dedicated single frequency
reception, think WWV, I could not tell any difference.

Terry