"Boozo" wrote in message
ups.com...
Have a 100 foot roll(approx) of used coax cable which has no markings
printed on it.
Can anyone tell me how I can work out what it might be ? e.g. 75 ohm or
50 ohm or ?
Going by the size it looks similar to 50 ohm but I'm not sure.

Any suggestions would be appreciated.


If it has a solid center conductor, it is almost certainly 75 Ohm. The only
exception I can think of is some weird version of RG58.

Tam

Tam/WB2TT wrote:
"Boozo" wrote in message
ups.com...
Have a 100 foot roll(approx) of used coax cable which has no markings
printed on it.
Can anyone tell me how I can work out what it might be ? e.g. 75 ohm or
50 ohm or ?
Going by the size it looks similar to 50 ohm but I'm not sure.

Any suggestions would be appreciated.


If it has a solid center conductor, it is almost certainly 75 Ohm. The only
exception I can think of is some weird version of RG58.

Tam

I do have a bunch of older RG-58 with solid center conductor, and
pretty much all the HP BNC patch cables I've seen the insides of have a
solid center. I believe the various semi-official versions (RG-58/U,
RG-58A/U, RG-58B/U and RG-58C/U) tell whether the center is supposed to
be solid or stranded, but that seems to have become *******ized. A
quick Google search for RG58A yields cables with both solid and
stranded centers. 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 the poster would have mentioned the
strange construction. Also, you're likely to find a solid center in
higher impedance line like RG62/U, and you're likely to find stranded
center on 75 ohm line (like RG-11/U, and others). And of course for
some surplus custom line, all bets are off about both stranding and
impedance!

Cheers,
Tom

If it has a solid center conductor, it is almost certainly 75 Ohm. The
only
exception I can think of is some weird version of RG58.

Tam

I do have a bunch of older RG-58 with solid center conductor, and
pretty much all the HP BNC patch cables I've seen the insides of have a
solid center. I believe the various semi-official versions (RG-58/U,
RG-58A/U, RG-58B/U and RG-58C/U) tell whether the center is supposed to
be solid or stranded, but that seems to have become *******ized. A
quick Google search for RG58A yields cables with both solid and
stranded centers. 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 the poster would have mentioned the
strange construction. Also, you're likely to find a solid center in
higher impedance line like RG62/U, and you're likely to find stranded
center on 75 ohm line (like RG-11/U, and others). And of course for
some surplus custom line, all bets are off about both stranding and
impedance!

Cheers,
Tom

Well, I was going to avoid this, but when you chimed in Tom, couldn't help
myself. In turn, I have a large helping of a Times Wire and Cable RG-8 size
50 Ohm coax with a solid inner conductor. Don't remember their nomenclature
for it but it's a real bear getting "N" connectors onto it..

W4ZCB

"Harold E. Johnson" wrote in message
news:A1N1h.261969$1i1.61365@attbi_s72...

If it has a solid center conductor, it is almost certainly 75 Ohm. The
only
exception I can think of is some weird version of RG58.

Tam

I do have a bunch of older RG-58 with solid center conductor, and
pretty much all the HP BNC patch cables I've seen the insides of have a
solid center. I believe the various semi-official versions (RG-58/U,
RG-58A/U, RG-58B/U and RG-58C/U) tell whether the center is supposed to
be solid or stranded, but that seems to have become *******ized. A
quick Google search for RG58A yields cables with both solid and
stranded centers. 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 the poster would have mentioned the
strange construction. Also, you're likely to find a solid center in
higher impedance line like RG62/U, and you're likely to find stranded
center on 75 ohm line (like RG-11/U, and others). And of course for
some surplus custom line, all bets are off about both stranding and
impedance!

Cheers,
Tom

Well, I was going to avoid this, but when you chimed in Tom, couldn't help
myself. In turn, I have a large helping of a Times Wire and Cable RG-8
size 50 Ohm coax with a solid inner conductor. Don't remember their
nomenclature for it but it's a real bear getting "N" connectors onto it..

W4ZCB


Solid could be 92 ohms too.

Have a 100 foot roll(approx) of used coax cable which has no markings....
I do have a bunch of older RG-58 with solid center conductor, and

....[snip]....

.... 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
difference in the first place, could you please explain what I
should have recognized?

--Myron
--
--Myron A. Calhoun.
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
NRA Life Member and Rifle, Pistol, & Home Firearm Safety Certified Instructor
Certified Instructor for the Kansas Concealed-Carry Handgun license

wrote in message ...
Have a 100 foot roll(approx) of used coax cable which has no
markings....
I do have a bunch of older RG-58 with solid center conductor, and

....[snip]....

.... 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
difference in the first place, could you please explain what I
should have recognized?

--Myron
--

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.

Tam
--Myron A. Calhoun.
Five boxes preserve our freedoms: soap, ballot, witness, jury, and
cartridge
NRA Life Member and Rifle, Pistol, & Home Firearm Safety Certified
Instructor
Certified Instructor for the Kansas Concealed-Carry Handgun license

.... 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?

--
--Myron A. Calhoun.
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
NRA Life Member and Rifle, Pistol, & Home Firearm Safety Certified Instructor
Certified Instructor for the Kansas Concealed-Carry Handgun license

wrote in message ...
.... 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?

Sorry, I thought you were talking about the original question. The base 9913
is #10 solid. 9913 Flex is stranded.

Tam
--
--Myron A. Calhoun.
Five boxes preserve our freedoms: soap, ballot, witness, jury, and
cartridge
NRA Life Member and Rifle, Pistol, & Home Firearm Safety Certified
Instructor
Certified Instructor for the Kansas Concealed-Carry Handgun license

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

On 3 Nov 2006 14:52:12 -0800, K7ITM wrote:
.......
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.

That sounds like RG-62 (93 ohm).
Video terminal cable -- 3270 and that ilk.

But, since none of the mind readers in this ng have yet to post the
dimensions, it's only a data point so far.

Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
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