Bob E wrote:
And another thousand points for answering the question--which was about the
cable's specs, NOT ABOUT ITS APPROPRIATENESS FOR A SPECIFIC APPLICATION.

Your posting appeared on usenet different from your own intention.

From your posting:

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

That clearly is a question about appropriateness for a specific application.

You did not ask about the loss, you asked about the performance. So
that means "they may be loss, but does it affect the results". The
answer clearly is: it depends on further details, like what margin you
have on the signal.

Shouting does not help you, just face the facts.

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.

In message , Rob
writes
Bob E wrote:
And another thousand points for answering the question--which was about the
cable's specs, NOT ABOUT ITS APPROPRIATENESS FOR A SPECIFIC APPLICATION.

Your posting appeared on usenet different from your own intention.

From your posting:

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

That clearly is a question about appropriateness for a specific application.

You did not ask about the loss, you asked about the performance. So
that means "they may be loss, but does it affect the results". The
answer clearly is: it depends on further details, like what margin you
have on the signal.

Shouting does not help you, just face the facts.

OK, Bob E - it appears that the ball is in your court. In the interests
of peace and harmony, and to prevent confusion, please could you please
tell us exactly (and I mean EXACTLY) which RG-6 vs RG-6Q parameters you
are concerned about?
--
Ian

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

OK, Bob E - it appears that the ball is in your court. In the interests
of peace and harmony, and to prevent confusion, please could you please
tell us exactly (and I mean EXACTLY) which RG-6 vs RG-6Q parameters you
are concerned about?
Ian

OK, thanks for the discussions.

I have a VHF/UHF omnidirectional antenna with integral amplifier for TV
reception:

http://www.amazon.com/Antennacraft-5...mplified-HDTV-
Antenna/dp/B007Z7YOKS

Several broadcast towers surround me, from 40 to 50 miles:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d5b9405cba93e1 5

Terrain is pretty flat.

The antenna is currently connected to RG6 located indoors, up high in a
1-story cathedral-ceiling home. Signal reception is marginal, gauged by the
HDTV's (relative) Signal Strength display; dropouts occur regularly on some
channels.

I plan to mount the antenna outdoors on the peak of the roof. I was planning
to use RG6 quad-shield, but wanted to check whether it is truly a better
solution or not.

Cable run indoors now is about 50 ft. From the roof location this will
increase to 75 or 100, depending on the route I choose, hence my question.

Thanks.

Bob E wrote:
OK, Bob E - it appears that the ball is in your court. In the interests
of peace and harmony, and to prevent confusion, please could you please
tell us exactly (and I mean EXACTLY) which RG-6 vs RG-6Q parameters you
are concerned about?
Ian

OK, thanks for the discussions.

I have a VHF/UHF omnidirectional antenna with integral amplifier for TV
reception:

http://www.amazon.com/Antennacraft-5...mplified-HDTV-
Antenna/dp/B007Z7YOKS

Several broadcast towers surround me, from 40 to 50 miles:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d5b9405cba93e1 5

Terrain is pretty flat.

The antenna is currently connected to RG6 located indoors, up high in a
1-story cathedral-ceiling home. Signal reception is marginal, gauged by the
HDTV's (relative) Signal Strength display; dropouts occur regularly on some
channels.

I plan to mount the antenna outdoors on the peak of the roof. I was planning
to use RG6 quad-shield, but wanted to check whether it is truly a better
solution or not.

Cable run indoors now is about 50 ft. From the roof location this will
increase to 75 or 100, depending on the route I choose, hence my question.

Thanks.

When you have an antenna with integrated amplifier, the loss of the
cable normally will not be a prime concern. Of course this only holds
true when the antenna+amplifier is well designed. I don't know the
situation in the USA, but here in Europe there are only very few good
manufacturers and all the rest sell crap and snake-oil. Don't know what
category your antenna is in.

With a bare antenna (without amplifier), loss is very important as the
signal from the antenna is attenuated and the noise at the input of
the receiver is constant, so your signal/noise ratio worsens.

However, with an amplifier near the antenna, the signal should be raised
sufficiently to be above the noise at the receiver, and the signal/noise
ratio at the input of the amplifier becomes the predominant factor.

In this case, the loss from your coax should not matter too much.
The good-quality shielding is often more important.

Note that in digital TV, the occurrence of dropouts is not only determined
by signal strength, but also by signal quality. This will improve
dramatically when you put the antenna on the roof, especially when this
results in a more or less clear view of the transmitter. What you
receive now is probably a jumble of reflections. While digital TV is
more tolerant to that than old analog TV, it still eats from the margin
that you need for dropout-free reception.

In message , Rob
writes
Bob E wrote:
OK, Bob E - it appears that the ball is in your court. In the interests
of peace and harmony, and to prevent confusion, please could you please
tell us exactly (and I mean EXACTLY) which RG-6 vs RG-6Q parameters you
are concerned about?
Ian

OK, thanks for the discussions.

I have a VHF/UHF omnidirectional antenna with integral amplifier for TV
reception:

http://www.amazon.com/Antennacraft-5...mplified-HDTV-
Antenna/dp/B007Z7YOKS

Several broadcast towers surround me, from 40 to 50 miles:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d5b9405cba93e1 5

Terrain is pretty flat.

The antenna is currently connected to RG6 located indoors, up high in a
1-story cathedral-ceiling home. Signal reception is marginal, gauged by the
HDTV's (relative) Signal Strength display; dropouts occur regularly on some
channels.

I plan to mount the antenna outdoors on the peak of the roof. I was planning
to use RG6 quad-shield, but wanted to check whether it is truly a better
solution or not.

Cable run indoors now is about 50 ft. From the roof location this will
increase to 75 or 100, depending on the route I choose, hence my question.

Thanks.

When you have an antenna with integrated amplifier, the loss of the
cable normally will not be a prime concern. Of course this only holds
true when the antenna+amplifier is well designed. I don't know the
situation in the USA, but here in Europe there are only very few good
manufacturers and all the rest sell crap and snake-oil. Don't know what
category your antenna is in.

I would say that all omnidirectional TV antennas (amplified or not) tend
to be in the snake-oil category, and should not be used unless there is
not a more-sanitary alternative. The antenna itself has low gain (at
least 3dB down on a halfwave dipole - so analogue pictures could be
noisy), and offers no protection to the effects of multipath reception
(analogue picture could have lots of ghosts). That said, an
omnidirectional does have its uses - provided it works well enough for
what you want. The advent of digital TV has meant that - up to a point -
reception is much more tolerant of the impairments that often gave you
poor analogue reception.

With a bare antenna (without amplifier), loss is very important as the
signal from the antenna is attenuated and the noise at the input of
the receiver is constant, so your signal/noise ratio worsens.

However, with an amplifier near the antenna, the signal should be raised
sufficiently to be above the noise at the receiver, and the signal/noise
ratio at the input of the amplifier becomes the predominant factor.

Indeed. If you need an amplifier, it should be located at or near the
antenna. This gives you the best signal-to-noise ratio (whatever the
length of the drop cable is).

In this case, the loss from your coax should not matter too much.
The good-quality shielding is often more important.

Note that in digital TV, the occurrence of dropouts is not only determined
by signal strength, but also by signal quality. This will improve
dramatically when you put the antenna on the roof, especially when this
results in a more or less clear view of the transmitter. What you
receive now is probably a jumble of reflections.

Quite.

While digital TV is
more tolerant to that than old analog TV, it still eats from the margin
that you need for dropout-free reception.

In the UK, I don't think that many homes use installed omnidirectional
antennas. You see some on caravans and mobile homes, and on boats, but
never on houses. Those living close to the transmitter might use
'rabbit's ears' set-top antennas (or some fancy variant) - especially
now that all TV is UHF (small antenna) and 'you can get away with
murder' digital - but you don't see any proper installations.

One big difference between the UK and many other countries (and in
particular the USA) is that we have generally received all our TV
signals from one direction (initially from closely-located transmitter
masts, and latterly from a single mast). It is only in outlying 'fringe'
areas where you used to see homes with two (or more) antennas pointing
in different directions - and as the TV signals were weak, these were
always high-gain yagis.

Regarding the original question, on looking at the specs for RG-6, it
appears that Mr Heinz and his '57 varieties' is left standing. 'RG-6'
seems to be a generic number for many types of coax. Various parameters
differ - including the loss (typically 6 to 7.5dB per 100' at 1000MHz)
and - in the case of RG-6Q - the outside diameter could be 1mm more (in
which case the diameter of the dielectric is probably the same as
ordinary RG-6).

One caveat sometimes mentioned is the relative high loop resistance
(because the inner is steel, copper plated, and not all copper), and
this can cause problems if you're line powering up the drop cable. It's
unlikely to affect the working of (say) a straightforward, relatively
low current antenna preamplifier, but with a satellite LNB the voltage
drop could confuse the band-switching operation.

In the OP's situation, it's pretty obvious that the addition of another
50' RG-6 will drop the signal at the TV set by (at the most) around 3dB
- and (with luck) this will probably be more-than-be-made-up-for by
mounting the antenna outside, higher, and in-the-clear. [Depending on
the roofing material that the TV signal is presently having to pass
through to reach the antenna, the received signal could be a lot
stronger.] All the OP can really do is try it, and see what happens. If
that doesn't provide satisfactory reception, the best advice might be to
consider an antenna with inherent gain - possibly with a rotator to
enable him to get all the transmissions.
--
Ian

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

Ian Jackson wrote:
In the UK, I don't think that many homes use installed omnidirectional
antennas. You see some on caravans and mobile homes, and on boats, but
never on houses. Those living close to the transmitter might use
'rabbit's ears' set-top antennas (or some fancy variant) - especially
now that all TV is UHF (small antenna) and 'you can get away with
murder' digital - but you don't see any proper installations.

One big difference between the UK and many other countries (and in
particular the USA) is that we have generally received all our TV
signals from one direction (initially from closely-located transmitter
masts, and latterly from a single mast). It is only in outlying 'fringe'
areas where you used to see homes with two (or more) antennas pointing
in different directions - and as the TV signals were weak, these were
always high-gain yagis.

Here in the Netherlands, the original state TV programs were transmitted
from about 8 high towers spread around our (small, flat) country, and yagis
were used by everyone. Closeby for the required directivity to avoid
ghost pictures, further away for the additional gain.

In the seventies and early eighties, all cities got cable TV.
Commercial TV and programmes from other countries were introduced only
on cable TV and later on direct-to-home satellite, they were not
transmitted on the analog network. Yagis disappeared from the rooftops.

Later a digital terrestrial TV network was deployed in the most densely
populated areas of the country and it includes both state and commercial
TV, but it operates using a dense network of lower powered and lower
height transmitters (usually on tall buildings) so the nearby transmitter
is often at most 10km away.
This means users can often employ small nondirective antennas typically
placed on the windowsill near the TV. It often does not work completely
satisfactorily, but the digital terrestrial TV network is inferior
in quality and channel repertoire to cable and satellite anyway, and
mainly used by those with low quality requirements and by mobile users.

When the analog network was shut down, the existing towers were fitted
with transmitters for the digital terrestrial network, to act as coverage
for less populated areas. People there would have to use yagis, but
they are seldomly seen as most had installed satellite dishes by then.

The programming and distribution companies are separate, so there is no
issue with receiving different programmes from different directions.
(all transmitters transmit all TV programmes available on the system)
This is probably the same as in the UK.

"Rob" wrote in message
...
Ian Jackson wrote:
In the UK, I don't think that many homes use installed omnidirectional
antennas. You see some on caravans and mobile homes, and on boats, but
never on houses. Those living close to the transmitter might use
'rabbit's ears' set-top antennas (or some fancy variant) - especially
now that all TV is UHF (small antenna) and 'you can get away with
murder' digital - but you don't see any proper installations.

One big difference between the UK and many other countries (and in
particular the USA) is that we have generally received all our TV
signals from one direction (initially from closely-located transmitter
masts, and latterly from a single mast). It is only in outlying 'fringe'
areas where you used to see homes with two (or more) antennas pointing
in different directions - and as the TV signals were weak, these were
always high-gain yagis.

Here in the Netherlands, the original state TV programs were transmitted
from about 8 high towers spread around our (small, flat) country, and
yagis
were used by everyone. Closeby for the required directivity to avoid
ghost pictures, further away for the additional gain.

In the seventies and early eighties, all cities got cable TV.
Commercial TV and programmes from other countries were introduced only
on cable TV and later on direct-to-home satellite, they were not
transmitted on the analog network. Yagis disappeared from the rooftops.

Later a digital terrestrial TV network was deployed in the most densely
populated areas of the country and it includes both state and commercial
TV, but it operates using a dense network of lower powered and lower
height transmitters (usually on tall buildings) so the nearby transmitter
is often at most 10km away.
This means users can often employ small nondirective antennas typically
placed on the windowsill near the TV. It often does not work completely
satisfactorily, but the digital terrestrial TV network is inferior
in quality and channel repertoire to cable and satellite anyway, and
mainly used by those with low quality requirements and by mobile users.

When the analog network was shut down, the existing towers were fitted
with transmitters for the digital terrestrial network, to act as coverage
for less populated areas. People there would have to use yagis, but
they are seldomly seen as most had installed satellite dishes by then.

The programming and distribution companies are separate, so there is no
issue with receiving different programmes from different directions.
(all transmitters transmit all TV programmes available on the system)
This is probably the same as in the UK.

With the exception of regional "opt-outs", this is true.
--
;-)
..
73 de Frank Turner-Smith G3VKI - mine's a pint.
..
http://turner-smith.co.uk

The programming and distribution companies are separate, so there is no
issue with receiving different programmes from different directions.
(all transmitters transmit all TV programmes available on the system)
This is probably the same as in the UK.

With the exception of regional "opt-outs", this is true.

Not really, many of the low powered relays do not carry the full set of
programmes, they only carry the 3 public service multiplexes not the
full set.

See
:http://stakeholders.ofcom.org.uk/binaries/research/tv-research/no3factsheet.pdf

Jeff

On 3/15/2014 8:45 PM, Bob E. wrote:
OK, Bob E - it appears that the ball is in your court. In the interests
of peace and harmony, and to prevent confusion, please could you please
tell us exactly (and I mean EXACTLY) which RG-6 vs RG-6Q parameters you
are concerned about?
Ian

OK, thanks for the discussions.

I have a VHF/UHF omnidirectional antenna with integral amplifier for TV
reception:

http://www.amazon.com/Antennacraft-5...mplified-HDTV-
Antenna/dp/B007Z7YOKS

Several broadcast towers surround me, from 40 to 50 miles:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d5b9405cba93e1 5

Terrain is pretty flat.

The antenna is currently connected to RG6 located indoors, up high in a
1-story cathedral-ceiling home. Signal reception is marginal, gauged by the
HDTV's (relative) Signal Strength display; dropouts occur regularly on some
channels.

I plan to mount the antenna outdoors on the peak of the roof. I was planning
to use RG6 quad-shield, but wanted to check whether it is truly a better
solution or not.

Cable run indoors now is about 50 ft. From the roof location this will
increase to 75 or 100, depending on the route I choose, hence my question.

Thanks.


Bob,

You have two problems here. The first one is the antenna is located
inside of the house. This results in significant signal loss. Your
second problem is you're using an omnidirectional antenna. I agree with
Rob - there isn't a decent omnidirectional antenna around.

HDTV requires a stronger signal than the old NTSC. If you're looking at
40-50 miles, even if it is flat terrain, you're going to have a weak
signal on an omnidirectional antenna. The preamp will help - but it's
not going to be a good solution. And whether you use RG-6 or RG-6 quad
will make no noticeable difference (as long as both are good quality -
there are good brands and bad brands in coax, also).

Putting the antenna outside will, of course, help. It might even be
satisfactory if you're willing to put up with some pixilation and
dropout. But if you want a good signal, get a directional antenna and
rotor. It will make a huge difference.

BTW - we only use RG6-quad in our installations. The extra shielding
means less signal leakage - both into and out of the cable. The loss
difference is negligible.

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

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