On Apr 5, 9:50 pm, Paul Franklin
wrote:
On Thu, 05 Apr 2007 17:43:47 -0500, clifto wrote:
szilagyic wrote:
I am just trying to get an updated list of the top brands of RG-6 quad
shield coax cable. I have seen posts from a few years back mentioning
Belden, Carol, and Commscope, but I just wanted to get an updated
list. I have seen Carol and Zenith brands at local stores recently,
are these any good? Mainly going to use this cable for running feeds
from HDTV & analog TV antennas in the walls of a house.

My experience with a few Carol Cable products (including coax) has been
good. I would consider that the Zenith brand name appears to be rented
out to the best bidder these days (peruse a.h.r for recent stories about
Heath/Zenith products) and expect that the manufacturer spent most of the
cost of making that coax on the marketing of that coax.

Belden, Alpha and Carol are all good. As important as the cable are
the connectors. The compression type are the way to go, IMO. Invest
in a good QS stripper and a compression tool. Don't bother with crimp
tools and don't even think about twist-on.

HTH,

Paul

What are the common issues with the crimp-on connectors? I've been
using them here and there mainly because they are cheap. So far I
haven't really noticed any problems, but maybe it's because I haven't
used anything else to see an improvement. Thanks!!

--
Chris

wrote in message
oups.com...

What are the common issues with the crimp-on connectors? I've been
using them here and there mainly because they are cheap. So far I
haven't really noticed any problems, but maybe it's because I haven't
used anything else to see an improvement. Thanks!!

it not that they are so bad it just that the compression fittings are the
way to go.

Hex-crimp fittings have 6 points where the connector is pinched into the
cable creating small impedance mismatches. Impedance mismatch creates
reflection. If the reflection(s) is(are) severe enough, whatever is at
that(those) frequency (frequencies) may not work. Plus, their return loss
is a fair amount lower than that of compression connectors (~18dB as
compared to 30dB).

I've replaced hex-crimp fittings on DirecTV systems because of hex-crimp
fittings which were causing some channels to not work.

Go to http://www.cencom94.com/Download.html and check out DBS Tutorial.
Pages 12 & 13 illustrates why you don't want to use hex-crimp fittings.

--

CIAO!

Ed N.


wrote in message
oups.com...
On Apr 5, 9:50 pm, Paul Franklin
wrote:
On Thu, 05 Apr 2007 17:43:47 -0500, clifto wrote:
szilagyic wrote:
I am just trying to get an updated list of the top brands of RG-6 quad
shield coax cable. I have seen posts from a few years back mentioning
Belden, Carol, and Commscope, but I just wanted to get an updated
list. I have seen Carol and Zenith brands at local stores recently,
are these any good? Mainly going to use this cable for running feeds
from HDTV & analog TV antennas in the walls of a house.

My experience with a few Carol Cable products (including coax) has been
good. I would consider that the Zenith brand name appears to be rented
out to the best bidder these days (peruse a.h.r for recent stories about
Heath/Zenith products) and expect that the manufacturer spent most of
the
cost of making that coax on the marketing of that coax.

Belden, Alpha and Carol are all good. As important as the cable are
the connectors. The compression type are the way to go, IMO. Invest
in a good QS stripper and a compression tool. Don't bother with crimp
tools and don't even think about twist-on.

HTH,

Paul

What are the common issues with the crimp-on connectors? I've been
using them here and there mainly because they are cheap. So far I
haven't really noticed any problems, but maybe it's because I haven't
used anything else to see an improvement. Thanks!!

--
Chris

"Ed Nielsen" wrote in message
. ..
Hex-crimp fittings have 6 points where the connector is pinched into the
cable creating small impedance mismatches. Impedance mismatch creates
reflection. If the reflection(s) is(are) severe enough, whatever is at
that(those) frequency (frequencies) may not work. Plus, their return loss
is a fair amount lower than that of compression connectors (~18dB as
compared to 30dB).

I've replaced hex-crimp fittings on DirecTV systems because of hex-crimp
fittings which were causing some channels to not work.



Funny how it works where a bad connector will blank out just a couple of
cable chanels. First time this hapened to me about 20 years ago the cable
guy came out and said it was a bad connection. Almost laughed at him,but he
replaced the connector at the outside of the house and it cleared right up.

On Apr 6, 2:27 pm, "Ralph Mowery" wrote:
"Ed Nielsen" wrote in message

. ..

Hex-crimp fittings have 6 points where the connector is pinched into the
cable creating small impedance mismatches. Impedance mismatch creates
reflection. If the reflection(s) is(are) severe enough, whatever is at
that(those) frequency (frequencies) may not work. Plus, their return loss
is a fair amount lower than that of compression connectors (~18dB as
compared to 30dB).

I've replaced hex-crimp fittings on DirecTV systems because of hex-crimp
fittings which were causing some channels to not work.

Funny how it works where a bad connector will blank out just a couple of
cable chanels. First time this hapened to me about 20 years ago the cable
guy came out and said it was a bad connection. Almost laughed at him,but he
replaced the connector at the outside of the house and it cleared right up.


Very good info. The interesting thing is since my original post I
went and bought a 500 ft roll of Carol Brand RG-6 QS from Home Depot,
and made some cables with the crimp-on connectors I already had. When
I swapped these new RG-6 QS cables with ones I made a while back with
regular RG-6 with the same crimp-on connectors, I got surprisingly
horrible results. A couple of analog channels don't come in at all
(ch 28 and 56), where they used to come in with a fairly good picture.
Yet other channels on lower frequencies, such as VHF appear to be the
same. I inspected the connectors and they appear to be OK, but I am
guessing there must be an issue with these connectors and the RG-6 QS,
where it's causing the issues that were described above with loss. Is
this possible?? It seems to be affecting various UHF channels (ch.
28, 56, 62).

Thank you very much for the help.

--
Chris

In message .com,
writes
On Apr 6, 2:27 pm, "Ralph Mowery" wrote:
"Ed Nielsen" wrote in message

. ..

Hex-crimp fittings have 6 points where the connector is pinched into the
cable creating small impedance mismatches. Impedance mismatch creates
reflection. If the reflection(s) is(are) severe enough, whatever is at
that(those) frequency (frequencies) may not work. Plus, their return loss
is a fair amount lower than that of compression connectors (~18dB as
compared to 30dB).

I've replaced hex-crimp fittings on DirecTV systems because of hex-crimp
fittings which were causing some channels to not work.

Funny how it works where a bad connector will blank out just a couple of
cable chanels. First time this hapened to me about 20 years ago the cable
guy came out and said it was a bad connection. Almost laughed at him,but he
replaced the connector at the outside of the house and it cleared right up.


Very good info. The interesting thing is since my original post I
went and bought a 500 ft roll of Carol Brand RG-6 QS from Home Depot,
and made some cables with the crimp-on connectors I already had. When
I swapped these new RG-6 QS cables with ones I made a while back with
regular RG-6 with the same crimp-on connectors, I got surprisingly
horrible results. A couple of analog channels don't come in at all
(ch 28 and 56), where they used to come in with a fairly good picture.
Yet other channels on lower frequencies, such as VHF appear to be the
same. I inspected the connectors and they appear to be OK, but I am
guessing there must be an issue with these connectors and the RG-6 QS,
where it's causing the issues that were described above with loss. Is
this possible?? It seems to be affecting various UHF channels (ch.
28, 56, 62).

Thank you very much for the help.

--
Chris


I've worked in the cable TV industry for nearly 44 years, and have NEVER
found that a certain type of male F-connector is, in itself, responsible
for 'horrible results' in terms of RF throughput. Provided that (a) the
shell makes good contact with a few strands of the braid, (b) you
haven't managed to wind a strand of the braid around the inner
conductor, and (c) you haven't left a thin film of the dielectric on the
surface of the inner conductor (yes, I've done all of these!), the
connector WILL appear to work normally. All that suffers is the
screening effectiveness and mechanical reliability.

Regarding whether some male connectors create a significant mismatch due
to crushing of the dielectric, even if this does happen, is not going to
be significant in normal use (up to at least 2GHz) until the outer
conductor is almost touching the inner. You can easily prove this for
yourself by looking at the RF throughput of a piece of coax, while
progressively crushing it with a large pair of pliers.

The thing which causes the most noticeable impedance mismatch is
normally the female part of the connection. Connectors with a
'duck-bill' inner (two parallel fingers) tend to be more capacitive than
those with a 'tulip' (three or four fingers). They are also likely to
make a less reliable ohmic contact.

Don't get me wrong. I do not advocate sloppy practices when fitting
connectors. In the UK, the compression and 'snap-and-seal' types are the
de facto standard. However, I would not hesitate to use crimp or
screw-on types for home use, provided you know how to fit them properly.
And I do.

Ian.
--

At a trade show several years ago, a vendor demonstrated the effects
stapling cables could have on signal transmission. He took a VCR, a ch. 3
modulator and a piece of drop cable and attached the cable to a piece of
wood utilizing a regular staple gun that you buy at any home improvement
store. Used the gun as most people would, and inspection of the cable
showed it to be fine (undamaged). By the seventeenth staple, ch. 3 was
completely gone..

It doesn't take major crushing to create mismatch, and as to whether it is
significant sort of depends on what happens to be trying to get through at
the particular point where the mismatch occurs.


At http://www.cencom94.com/gpage.html9.html, there is a picture of a sweep
trace of some cable with hex-crimp connectors (gotta scroll down a little).
--

CIAO!

Ed N.


"Ian Jackson" wrote in message
...
Regarding whether some male connectors create a significant mismatch due
to crushing of the dielectric, even if this does happen, is not going to
be significant in normal use (up to at least 2GHz) until the outer
conductor is almost touching the inner. You can easily prove this for
yourself by looking at the RF throughput of a piece of coax, while
progressively crushing it with a large pair of pliers.

Ian.
--

Ed Nielsen wrote:
At a trade show several years ago, a vendor demonstrated the effects
stapling cables could have on signal transmission. He took a VCR, a ch.
3 modulator and a piece of drop cable and attached the cable to a piece
of wood utilizing a regular staple gun that you buy at any home
improvement store. Used the gun as most people would, and inspection of
the cable showed it to be fine (undamaged). By the seventeenth staple,
ch. 3 was completely gone..

It doesn't take major crushing to create mismatch, and as to whether it
is significant sort of depends on what happens to be trying to get
through at the particular point where the mismatch occurs.

A periodically repeating mismatch, such as the one produced by the
staple demonstration, can cause extreme effects as the demonstration
showed. This is a very much worse case than a single mismatch.

Roy Lewallen, W7EL

"Ed Nielsen" writes:

It doesn't take major crushing to create mismatch, and as to whether it is
significant sort of depends on what happens to be trying to get through at
the particular point where the mismatch occurs.

At http://www.cencom94.com/gpage.html9.html, there is a picture of a sweep
trace of some cable with hex-crimp connectors (gotta scroll down a little).

That particular sweep seems to be from a highrise building which had hex
crimp connectors every 25 feet all the way up the building. A single
hex crimp, or a bunch of hex crimps spaced irregularly, would have far
less effect. So whether this matters partly depends on whether you're
wiring an apartment building or just a house.

Dave