I live about 8 miles from 4 local tv stations, and 25 miles from a much
desired UHF station. Luckily, they are all in the same general direction.

I plan to buy a medium size vhf/uhf antenna. My coax run will be 50 feet.

Although I don't really need "gain" for the vhf stations, I do need it for
the uhf station. "Some" extra gain will be ok for the vhf stations.
Whatever the setup, I want to use the lowest-loss RG6 that I can buy.

Here are my questions:

1. Where (online or else) can I find the very best, lowest loss RG6 coax ?

2. Assuming that I need a pre-amp, if I only have a 50 ft run of low-loss
coax, will my system work well if I mount the preamp at the tv end of the
50 ft coax, as compared to putting it at the antenna? I realize the
advantage of mounting at the antenna, yet I would like the convenience of
having the pre-amp inside. I am considering an adjustable pre-amp, and that
would be more usuable if I had it at the tv instead of at the antenna.

3. Will a brick chimney (with no steel liner or inserts) about 20 feet from
the antenna, but in-line with the desired stations, attenuate the signals
??

4. Are the Radio Shack pre-amps decent ??

------------------------------

My thoughts: Perhaps I will get a pre-amp that will produce about 20 db
of gain. I will mount it inside. The 50 ft of coax will have a loss of
perhaps 5 db, so I have a net of 15 db gain at the tv. This will be more
than enough for the vhf stations that are pretty close, but I am not sure
about the uhf station 25 miles away. It would seem to be good enough for
that as well.

What do you think ?? Thanks for any advice !!


--james--

"James" wrote in message
...


I live about 8 miles from 4 local tv stations, and 25 miles from a much
desired UHF station. Luckily, they are all in the same general
direction.

I plan to buy a medium size vhf/uhf antenna. My coax run will be 50
feet.

Although I don't really need "gain" for the vhf stations, I do need it
for
the uhf station. "Some" extra gain will be ok for the vhf stations.
Whatever the setup, I want to use the lowest-loss RG6 that I can buy.

Here are my questions:

1. Where (online or else) can I find the very best, lowest loss RG6 coax
?

2. Assuming that I need a pre-amp, if I only have a 50 ft run of low-loss
coax, will my system work well if I mount the preamp at the tv end of the
50 ft coax, as compared to putting it at the antenna? I realize the
advantage of mounting at the antenna, yet I would like the convenience of
having the pre-amp inside. I am considering an adjustable pre-amp, and
that
would be more usuable if I had it at the tv instead of at the antenna.

3. Will a brick chimney (with no steel liner or inserts) about 20 feet
from
the antenna, but in-line with the desired stations, attenuate the
signals
??

4. Are the Radio Shack pre-amps decent ??

------------------------------

My thoughts: Perhaps I will get a pre-amp that will produce about 20
db
of gain. I will mount it inside. The 50 ft of coax will have a loss of
perhaps 5 db, so I have a net of 15 db gain at the tv. This will be
more
than enough for the vhf stations that are pretty close, but I am not sure
about the uhf station 25 miles away. It would seem to be good enough for
that as well.

What do you think ?? Thanks for any advice !!


1_ there is very little differance in the loss of the coax if name brands
are used. Get some that has a braid and foil shield. Forget about all the
stuff that is quad shielded and other things unless you get it at a good
price. Look for Belden if you can find it .

2- with the station only 25 miles away and only 50 feet of coax you should
not need a preamp. With the VHF stations that close you might even get too
much signal and the stations will overlaod the preamp and the reception
goes all to pot. (simple explination)

3- probably not so much that you could tell it.

4= almost nothing from Radio Shack is worth it.

"James" wrote in message
...


I live about 8 miles from 4 local tv stations, and 25 miles from a much
desired UHF station. Luckily, they are all in the same general
direction.

I plan to buy a medium size vhf/uhf antenna. My coax run will be 50
feet.

Although I don't really need "gain" for the vhf stations, I do need it
for
the uhf station. "Some" extra gain will be ok for the vhf stations.
Whatever the setup, I want to use the lowest-loss RG6 that I can buy.

Here are my questions:

1. Where (online or else) can I find the very best, lowest loss RG6 coax
?

You want quad shielded. They're all pretty much the same. Any electric
supply house would have it. You didn't say where you are. A thousand foot
spool costs $110 at http://www.smarthome.com/8527.html

2. Assuming that I need a pre-amp, if I only have a 50 ft run of low-loss
coax, will my system work well if I mount the preamp at the tv end of the
50 ft coax, as compared to putting it at the antenna? I realize the
advantage of mounting at the antenna, yet I would like the convenience of
having the pre-amp inside. I am considering an adjustable pre-amp, and
that
would be more usuable if I had it at the tv instead of at the antenna.

No real need for a pre-amp if you are 8 to 25 miles away. I would just get
the next size up antenna (or one with just a better UHF element) if you are
worried about a weak signal.

-al sung
Rapid Realm Technology, Inc.
Hopkinton, MA

James wrote:

I live about 8 miles from 4 local tv stations, and 25 miles from a much
desired UHF station. Luckily, they are all in the same general direction.

I plan to buy a medium size vhf/uhf antenna. My coax run will be 50 feet.

Although I don't really need "gain" for the vhf stations, I do need it for
the uhf station. "Some" extra gain will be ok for the vhf stations.
Whatever the setup, I want to use the lowest-loss RG6 that I can buy.

Here are my questions:

1. Where (online or else) can I find the very best, lowest loss RG6 coax ?

2. Assuming that I need a pre-amp, if I only have a 50 ft run of low-loss
coax, will my system work well if I mount the preamp at the tv end of the
50 ft coax, as compared to putting it at the antenna? I realize the
advantage of mounting at the antenna, yet I would like the convenience of
having the pre-amp inside. I am considering an adjustable pre-amp, and that
would be more usuable if I had it at the tv instead of at the antenna.

3. Will a brick chimney (with no steel liner or inserts) about 20 feet from
the antenna, but in-line with the desired stations, attenuate the signals
??

4. Are the Radio Shack pre-amps decent ??

------------------------------

My thoughts: Perhaps I will get a pre-amp that will produce about 20 db
of gain. I will mount it inside. The 50 ft of coax will have a loss of
perhaps 5 db, so I have a net of 15 db gain at the tv. This will be more
than enough for the vhf stations that are pretty close, but I am not sure
about the uhf station 25 miles away. It would seem to be good enough for
that as well.

Use RG-6/U. It definitely has lower loss than the cheap stuff with the
foil shield. And don't use the twist-on connectors. Get good
connectors and a crucher to install them. Most problems are caused by
poorly installed connectors.

Amplifiers introduce noise and decrease signal-to-noise ration. Don't
use an amplifier if you don't need it. If you do need one, avoid the
Radio Shack models. I tried one and it caused lots of problems.

James wrote:
I live about 8 miles from 4 local tv stations, and 25 miles from a
much desired UHF station. Luckily, they are all in the same general
direction.

I plan to buy a medium size vhf/uhf antenna. My coax run will be
50 feet.

Use two separate antennas, one for the local stations and one (yagi or
corner reflector with gain) cut for the 25 mile distant station. Join
them together with a coupler at the antenna. No preamp should be
needed.

1. Where (online or else) can I find the very best, lowest loss RG6
coax ?

Any name brand double-shielded coax (Belden) will be fine.

2. Assuming that I need a pre-amp, if I only have a 50 ft run of
low-loss coax, will my system work well if I mount the preamp at the
tv end of the 50 ft coax, as compared to putting it at the antenna?

Don't use a preamp unless you install it at the antenna. Preamps
amplify noise as well as signal. One exception is where you are using a
preamp for distribuiton purposes -- assuming that you have a good signal
at the house end of the coax you can add a preamp to boost the signal
prior to distribution via a multi-set splitter. But if you have a good
antenna you won't need a preamp for a single set installation.

3. Will a brick chimney (with no steel liner or inserts) about 20
feet from the antenna, but in-line with the desired stations,
attenuate the signals ?

It should not be a problem for stations 8 miles away, but for the 25
mile distant UHF station it could be. If you use the two antenna
configuration will the UHF antenna be pointed far enough away from the
chimney to miss it? If not, consider mounting the entire antenna
assembly on the chimney with a chimney mount.

4. Are the Radio Shack pre-amps decent ??

I'm not a fan of RS products, but their distribution amplifiers work OK.

Travis Jordan wrote:


Don't use a preamp unless you install it at the antenna. Preamps
amplify noise as well as signal.
...
Right advice, wrong reason. If the noise and signal are both
amplified, the signal-to-noise ratio will be unchanged. The problem is
amplifiers add noise, lowering the SNR.

William W. Plummer wrote:
Right advice, wrong reason. If the noise and signal are both
amplified, the signal-to-noise ratio will be unchanged. The problem
is amplifiers add noise, lowering the SNR.

Well, yes, of course. I just thought a discussion of the merits of
low-noise amplifiers might be beyond the scope of comprehension for the
OP.

I do thank all persons for the helpful replies !! I am busily making notes
!!

Thanks again !!

--James--

use a remote line powered preamp near the antenna. Put it in the attic
if you want to be able to serivce it. You can use RG6 or even low
loss RG59 is you use a preamp near the antenna.

since yo uneed it for UHF only, try to find one that has only a little
gain at VHF.

The key to a good signal to noise is to have a minimum loss BEFORE the
fist amplifier. Putting the amplifier after the coax is NOT as good as
putting the amplifer before the coax.

But a few feet won't hurt so mounting it in the attic where you can get
to it easilly is a good compromise.

Mark

On 10 Mar 2005 19:50:06 -0800, "Mark" wrote:

use a remote line powered preamp near the antenna. Put it in the attic
if you want to be able to serivce it. You can use RG6 or even low
loss RG59 is you use a preamp near the antenna.

since yo uneed it for UHF only, try to find one that has only a little
gain at VHF.

The key to a good signal to noise is to have a minimum loss BEFORE the
fist amplifier. Putting the amplifier after the coax is NOT as good as
putting the amplifer before the coax.

But a few feet won't hurt so mounting it in the attic where you can get
to it easilly is a good compromise.

Mark


As a video pro, I recommend the higher quality RG-6/U with braided
shield.

Low quality RG-6 with a foil shield will both radiate and absorb
signals on similar channels (say... same channel cable and off-air
signals). If cable tv is not an issue, maybe the cheaper stuff will
work, but you can still have problems if, for example, there is a
channel 3 or 4 in your area and you use a VCR that re-radiates at that
channel.

I got tired of the ghosts, threw away all of the cheap RG6 with the
pre-molded connecters and put my own connectors on the best RG-6/U
that I could buy.

No more ghosts... and the best signals I've ever seen... These were
the results.

Beachcomber

James wrote:


My thoughts: Perhaps I will get a pre-amp that will produce about
20 db
of gain. I will mount it inside. The 50 ft of coax will have a
loss of
perhaps 5 db, so I have a net of 15 db gain at the tv. This will
be more
than enough for the vhf stations that are pretty close, but I am not
sure
about the uhf station 25 miles away. It would seem to be good
enough for
that as well.

What do you think ?? Thanks for any advice !!


--james--

As others have stated, you probably won't need a preamp for signal
gain. However, I use a low gain preamp as lightning protection for the
tv's input circuitry. I figure it's better to replace a $20 preamp than
to replace a $500 tv.
Bob

Many people forget their primary school science. They
assume destructive transients enter as if ocean waves.
Crashing and damaging only that one location. Reality: it is
electricity. Electricity first flows through everything in
the circuit. Only then does something (or many things) in
that circuit fail. The poster 'feels' that the pre-amp will
stop or block what 3 miles of sky could not? How silly.

Sacrificial protection is the classic myth. One more
reason why. It would take milliseconds or longer for the
pre-amp to become an open circuit. A destructive transient
does damage in microseconds. Even the fastest 'sacrificial'
protector - a fast blow fuse - takes tens of milliseconds to
blow. Where is protection provided by a pre-amp? Mythical
once we apply numbers.

"Bob S." wrote:
As others have stated, you probably won't need a preamp for signal
gain. However, I use a low gain preamp as lightning protection for
the tv's input circuitry. I figure it's better to replace a $20
preamp than to replace a $500 tv.
Bob

"w_tom" wrote in message
...
Many people forget their primary school science. They
assume destructive transients enter as if ocean waves.
Crashing and damaging only that one location. Reality: it is
electricity. Electricity first flows through everything in
the circuit. Only then does something (or many things) in
that circuit fail. The poster 'feels' that the pre-amp will
stop or block what 3 miles of sky could not? How silly.

Sacrificial protection is the classic myth. One more
reason why. It would take milliseconds or longer for the
pre-amp to become an open circuit. A destructive transient
does damage in microseconds. Even the fastest 'sacrificial'
protector - a fast blow fuse - takes tens of milliseconds to
blow. Where is protection provided by a pre-amp? Mythical
once we apply numbers.


While it will not protect from a direct hit it may help from the spikes
produced by near by flashes. I have a radio repeater on top of a mountain
and the phone line connected to it is my biggset problem . I installed a
couple of very low amp fuses and a couple of coils after them. The fuses
blow often after a thunder storm but they do protect the other equipment.
No doubt that a direct hit would take out everything.

Lightning will find a path to earth ground with or without
that in-line pre-amp. It is nonsense to wish something will
stop, block, absorb, or filter such transients. Anything that
is going to accomplish that protection is already inside the
TV tuner.

Either it suffers a direct hit or it suffers nothing. And
that means everything in that path suffers the same current
equally. If nearby strikes were so destructive as implied,
that we routinely see cell phones and car radios damaged by
nearby lightning. Too often the 'so called' nearby strike is
really a direct strike. But that is beyond the scope of this
discussion and is already explained (using a horse as example)
in the newsgroup microsoft.public.windowsxp.basics on 11 Mar
2005 entitled "Power surge safety".

The preamp does nothing to provide transistor safety. For
transistor safety, earth ground defines that. Some inductance
in the coax can assist IF the earthing system exists. But no
earthing system means inline impedance (the pre-amp) provides
nothing.

Richard Harrison discusses this often in the newsgroup
red.radio.antenna.amateur. He posted this on 12 Dec 2003
entitled "Lightning Arrester":
A folded VHF monopole fed by coax and well grounded at the
tower top is nearly immune to lightning.

Coax, inside, rejects common-mode propagation of lightning
energy. Coax, outside, needs good grounding to make a good
path around (bypass for) protected equipment.

The equipment needs direct low-impedance grounding so that
most surge energy is dropped across the coax, not the
equipment. Coils of extra coax may be used to raise the
impedance of the outside of the coax.

In this and most every post from experienced industry
professionals, there is nothing stopping lightning damage.
Either it is given a non-destructive path to earth, or it goes
right on through that pre-amp and TV tuner, as necessary, to
find earth ground. For those blessed with basic electrical
knowledge, the transient is a current source. That means
voltage will increase as necessary to overwhelm everything in
that path. That also means everything in that path sees the
same current. Current passes destructively down that wire
EXCEPT if the human provides the transient with a better path
to earth. Earthing is the protection; not some suicidal
pre-amp or fuse.

If fuses blew, well now you know how much protection is
already inside that tuner. The fuses quit long after the
tuner had protected itself and long after the transient had
completely finished. That pre-amp provides no protection.

Ralph Mowery wrote:
While it will not protect from a direct hit it may help from the
spikes produced by near by flashes. I have a radio repeater on
top of a mountain and the phone line connected to it is my biggset
problem . I installed a couple of very low amp fuses and a couple
of coils after them. The fuses blow often after a thunder storm
but they do protect the other equipment. No doubt that a direct
hit would take out everything.