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K7ITM · November 3rd 06, 10:52 PM posted to rec.radio.amateur.antenna

wrote:
.... How about Belden 9913? Of course, the construction of that line
is "different" enough that it would be hard to mistake it for something
else, and I assume ....

For those of us who never noticed -- or never recognized -- the
9913 differences in the first place, could you please explain....

The outside diameter of the cable, like .195, .240, .260, .405,... and the
gage of the center conductor, like #10, 14, 16, 18, stranded or solid.

I don't understand. Are you saying 9913 has been made in ALL
of those different sizes and with ALL of those different center-
conductor gauges?

Actually, the difference I was writing about in the original posting
has to do not with whether the center conductor is solid or stranded,
but rather with the form the dielectric takes. It's a polyethylene
tube with fairly thin wall that supports the outer conductor, and
inside that, a "thread" of polyethylene with a diameter half the
difference between the inner conductor diameter and the ID of the
polyethylene tube, which is formed in a spiral to support the inner
conductor coaxially with the outer conductor. The result is that much
of the dielectric space is air (or water, if you install it
incorrectly...or get a lot of condensation in it). It's a very obvious
differentiator from the usual solid or foam dielectrics. It's also low
enough effective relative dielectric constant that the inner conductor
is particularly large, for 50 ohm line of that OD.

Cheers,
Tom