75-ohm RG-6 coax: quad shield differs from "standard" RG-6 in that the
dielectric is reduced in diameter to accomodate the extra shielding.

How does this affect the performance? I'm looking at 1 GHz (HDTV use).

Thanks.

On 3/14/2014 6:51 PM, Bob E. wrote:
75-ohm RG-6 coax: quad shield differs from "standard" RG-6 in that the
dielectric is reduced in diameter to accomodate the extra shielding.

How does this affect the performance? I'm looking at 1 GHz (HDTV use).

Thanks.


How are you going to use it for HDTV? HDTV is a TV signal protocol, not
a communications method.

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Jerry, AI0K

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How are you going to use it for HDTV? HDTV is a TV signal protocol, not
a communications method.

Not to be rude, but it's a simple question asked. The answer doesn't involve
the use to which it will be put.

Just trying to keep replies on-topic...

Bob E wrote:
How are you going to use it for HDTV? HDTV is a TV signal protocol, not
a communications method.

Not to be rude, but it's a simple question asked. The answer doesn't involve
the use to which it will be put.

But sure that does matter. Especially the signal frequency at which
you will use it, and the tolerable losses in the run of cable.

"HDTV" by itself does not tell enough. It could be terristrial broadcast,
cable TV, satellite TV.

Each of them has different characteristics w.r.t. frequencies in use
and losses that are tolerable.

On 3/15/2014 1:29 AM, Bob E. wrote:
How are you going to use it for HDTV? HDTV is a TV signal protocol, not
a communications method.

Not to be rude, but it's a simple question asked. The answer doesn't involve
the use to which it will be put.

Just trying to keep replies on-topic...


Yes, it does. The question was completely on topic. How you use it
will determine if RG6-quad is usable of your needs or not.


--
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Remove the "x" from my email address
Jerry Stuckle

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75 ohm cable with a loss of ~6db/30m at 1GHz

In message ,
Bob E. writes
75-ohm RG-6 coax: quad shield differs from "standard" RG-6 in that the
dielectric is reduced in diameter to accomodate the extra shielding.

How does this affect the performance? I'm looking at 1 GHz (HDTV use).

Thanks.

I note that there have been a some replies, but none seem to make much
attempt at answering your question.

RG6Q is used extensively in the UK cable TV industry as 'drop' cable -
ie from the taps in the street cabinet to the home. It is used to
provide a high degree of immunity from ingress of interfering signals -
especially those at the lower frequencies (in the reverse path part of
the spectrum - typically between 5 and 65MHz). RG6 is not a particularly
low-loss cable, and for long drop runs, RG11 is sometimes used.

As for the attenuation differences between RG6 and RG6Q, I've done a bit
of Googling, and I can't see anything which is immediately pointed out.
Even on this site
http://www.ehow.com/list_7605813_difference-between-rg6-rg6q.html
all it says is that "RG-6 and RG-6Q share nearly the exact same outer
dimensions and have similar flexibility. RG-6Q is slightly stiffer due
to the increased amount of inner shielding".

I suspect that even if the diameter of the RG6Q dielectric is slightly
less (something which I've never really noticed) - requiring a slightly
thinner inner conductor in order to preserve the Zo - the increase of
attenuation won't be very much. However, I'm sure that a bit more
intensive Googling on RG6 physical and electrical specs will reveal the
true answer!
--
Ian

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On 3/15/2014 9:18 AM, Ian Jackson wrote:
In message ,
Bob E. writes
75-ohm RG-6 coax: quad shield differs from "standard" RG-6 in that the
dielectric is reduced in diameter to accomodate the extra shielding.

How does this affect the performance? I'm looking at 1 GHz (HDTV use).

Thanks.

I note that there have been a some replies, but none seem to make much
attempt at answering your question.

RG6Q is used extensively in the UK cable TV industry as 'drop' cable -
ie from the taps in the street cabinet to the home. It is used to
provide a high degree of immunity from ingress of interfering signals -
especially those at the lower frequencies (in the reverse path part of
the spectrum - typically between 5 and 65MHz). RG6 is not a particularly
low-loss cable, and for long drop runs, RG11 is sometimes used.

As for the attenuation differences between RG6 and RG6Q, I've done a bit
of Googling, and I can't see anything which is immediately pointed out.
Even on this site
http://www.ehow.com/list_7605813_difference-between-rg6-rg6q.html
all it says is that "RG-6 and RG-6Q share nearly the exact same outer
dimensions and have similar flexibility. RG-6Q is slightly stiffer due
to the increased amount of inner shielding".

I suspect that even if the diameter of the RG6Q dielectric is slightly
less (something which I've never really noticed) - requiring a slightly
thinner inner conductor in order to preserve the Zo - the increase of
attenuation won't be very much. However, I'm sure that a bit more
intensive Googling on RG6 physical and electrical specs will reveal the
true answer!

No one has answered his question because the information is insufficient.

FYI - my company (a home automation company) installs thousands of feet
of coax every year (even more twisted pair). But we never specify what
to use until we know how it is being used.

Additionally, it depends if he needs to send send power over the coax
also, and if so, how much.

For instance, the new specs for HDTV (Ultra-hi-def, 3D at 240
frames/sec) require bandwidths of up to 18Ghz. It's something we have
to take into consideration on ANY installation.

Just saying it's going to be used for HDTV is not sufficient.

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

In message , Jerry Stuckle
writes
On 3/15/2014 9:18 AM, Ian Jackson wrote:
In message ,
Bob E. writes
75-ohm RG-6 coax: quad shield differs from "standard" RG-6 in that the
dielectric is reduced in diameter to accomodate the extra shielding.

How does this affect the performance? I'm looking at 1 GHz (HDTV use).

Thanks.

I note that there have been a some replies, but none seem to make much
attempt at answering your question.

RG6Q is used extensively in the UK cable TV industry as 'drop' cable -
ie from the taps in the street cabinet to the home. It is used to
provide a high degree of immunity from ingress of interfering signals -
especially those at the lower frequencies (in the reverse path part of
the spectrum - typically between 5 and 65MHz). RG6 is not a particularly
low-loss cable, and for long drop runs, RG11 is sometimes used.

As for the attenuation differences between RG6 and RG6Q, I've done a bit
of Googling, and I can't see anything which is immediately pointed out.
Even on this site
http://www.ehow.com/list_7605813_difference-between-rg6-rg6q.html
all it says is that "RG-6 and RG-6Q share nearly the exact same outer
dimensions and have similar flexibility. RG-6Q is slightly stiffer due
to the increased amount of inner shielding".

I suspect that even if the diameter of the RG6Q dielectric is slightly
less (something which I've never really noticed) - requiring a slightly
thinner inner conductor in order to preserve the Zo - the increase of
attenuation won't be very much. However, I'm sure that a bit more
intensive Googling on RG6 physical and electrical specs will reveal the
true answer!

No one has answered his question because the information is insufficient.

FYI - my company (a home automation company) installs thousands of feet
of coax every year (even more twisted pair). But we never specify what
to use until we know how it is being used.

Additionally, it depends if he needs to send send power over the coax
also, and if so, how much.

For instance, the new specs for HDTV (Ultra-hi-def, 3D at 240
frames/sec) require bandwidths of up to 18Ghz. It's something we have
to take into consideration on ANY installation.

Just saying it's going to be used for HDTV is not sufficient.

My immediate lateral-thinking guess is that the OP has acquired some
RG6Q, and is wondering whether he can use it as antenna drop cable for
UHF TV (which, in the UK, includes HD). He has specifically said that
it's for use at less than 1GHz. His main concern is probably that
quad-shield might be a more lossy than RG6 (which indeed it could be as
a smaller diameter dielectric would require a smaller diameter inner in
order to maintain a Zo of 75 ohms, and this would increase the
attenuation). Of course, he could also be concerned about some of the
many other parameters - but I suspect not. If it's not attenuation
that's concerning him, I'm sure he will tell us.
--
Ian

--- news://freenews.netfront.net/ - complaints: ---

Ian Jackson wrote:
My immediate lateral-thinking guess is that the OP has acquired some
RG6Q, and is wondering whether he can use it as antenna drop cable for
UHF TV (which, in the UK, includes HD). He has specifically said that
it's for use at less than 1GHz. His main concern is probably that
quad-shield might be a more lossy than RG6 (which indeed it could be as
a smaller diameter dielectric would require a smaller diameter inner in
order to maintain a Zo of 75 ohms, and this would increase the
attenuation). Of course, he could also be concerned about some of the
many other parameters - but I suspect not. If it's not attenuation
that's concerning him, I'm sure he will tell us.

This was my understanding as well. But he reverted to shouting and
indicated that we have all misunderstood him.

He asked about the performance. As he was pointing to loss, I would
guess he would like to know the performance w.r.t. loss. But as he
also indicated a use case, I think he wants (or needs) to know if the
loss is not too high for the use case he has.

That cannot be determined given the info there is. We need to know
what margin he has on the signal and how long his cable run is.
The margin is determined by the type of signal (terrestrial, cable,
satellite, we can rule out satellite because he said 1GHz). When
terrestrial, we need to know how close he is to the transmitter.

Even with all such general information, it probably is not possible
to close in enough on the calculation to know if a couple of dB or
so of extra loss per 100m is going to affect the performance of the
system.