Does it matter if the tv antenna points one way, or 180^ the other?

You guys, especially Dave, have convinced me that I need a better (and
thus bigger) antenna more than I need an amplified antenna. Does it
matter if I point an antenna with several elements of different
lengths to the station, or if I point it the exact opposite direction?
In my attic, it would be more convenient to do the latter. (I'm too
old and at least now, too fat to go on the roof.)


Also, I thought 50 miles was the longest range on level ground for a
transmitting tower of typical height and an antenna on the roof of a
two-story house.

So what about a claim that a Wineguard antenna has a range of 75 to 80
miles????
http://estore.websitepros.com/112973...00U/Detail.bok
This antenna is rated for low-band VHF and I don't need that, I've
learned, but it's the mileage claim I am asking about.

Even this one says: Up to 60 mile VHF range; 45 mile UHF range Don't
they get that by mounting it on a 100 foot tower or something?
http://www.radioshack.com/product/in...ductId=3739594
And isn't the info obsolete because digital transmitters are working
at lower power than analog did?

Thanks a lot.

And isn't the info obsolete because digital transmitters are working
at lower power than analog did?

Thanks a lot.

MM

Depends on the Front to Back ratio. FWIW the antenna should probably
point to the origin of the signal with the shorter elements being the
pointing end. And if you are looking at great distances from the
source you will probably have to tune the antenna by rotating it while
someone observes the picture/TV set.

Bob AZ

"Bob AZ" wrote in message
...
And isn't the info obsolete because digital transmitters are working
at lower power than analog did?

Thanks a lot.

MM

Depends on the Front to Back ratio. FWIW the antenna should probably
point to the origin of the signal with the shorter elements being the
pointing end. And if you are looking at great distances from the
source you will probably have to tune the antenna by rotating it while
someone observes the picture/TV set.

Bob AZ


Many if not most late model digital format TV receivers have a signal
strength indicator available via the menus. This would be very useful, I
would think.

Mark Z.

On Tue, 01 Dec 2009 00:29:31 -0500, mm
wrote:

Does it matter if the tv antenna points one way, or 180^ the other?

You guys, especially Dave, have convinced me that I need a better (and
thus bigger) antenna more than I need an amplified antenna. Does it
matter if I point an antenna with several elements of different
lengths to the station, or if I point it the exact opposite direction?
In my attic, it would be more convenient to do the latter. (I'm too
old and at least now, too fat to go on the roof.)


Also, I thought 50 miles was the longest range on level ground for a
transmitting tower of typical height and an antenna on the roof of a
two-story house.

So what about a claim that a Wineguard antenna has a range of 75 to 80
miles????
http://estore.websitepros.com/112973...00U/Detail.bok
This antenna is rated for low-band VHF and I don't need that, I've
learned, but it's the mileage claim I am asking about.

Even this one says: Up to 60 mile VHF range; 45 mile UHF range Don't
they get that by mounting it on a 100 foot tower or something?
http://www.radioshack.com/product/in...ductId=3739594
And isn't the info obsolete because digital transmitters are working
at lower power than analog did?

Thanks a lot.
I have to say you are going about this the wrong way. You are
choosing to mount the antenna in the attic because it's easier. An
indoor mount also has the advantage of reducing exposure to the
weather. While this is easier, it has several major disadvantages.
You have already mentioned one - difficulty in orienting it properly.
There is another - signal attenuation, particularly at higher
frequencies.

Have you considered the possibility you are focusing on convenience
and ignoring performance?

As far as antenna range, my parents lived over 60 miles from the
transmitter and received good signal levels with an antenna that was
mounted less than 15 feet above ground level.

PlainBill

In article ,
mm wrote:

Does it matter if the tv antenna points one way, or 180^ the other?

That depends on the antenna.

Typical log-periodic rooftop TV antennas are moderately directional.
They have the greatest gain when the small end is pointing towards the
transmitter. Directly off of the back, they're usually around 10 dB
worse (i.e. one-tenth the power sensitivity). There are some
directions around the side which are going to be *extremely*
insensitive (very deep nulls).

Other sorts of antennas are bidirectional.

You'll probably get the best reception from a directional antenna,
aimed towards the transmitter (or, sometimes, aimed off at an angle
which minimizes the antenna's pickup of reflections from nearby
buildings and trees).

You guys, especially Dave, have convinced me that I need a better (and
thus bigger) antenna more than I need an amplified antenna.

That's often the case. If your signal level at the TV is low, it's
usually better to try to improve it by adding antenna gain, than it is
to use an amplifier. An amplifier will boost incoming noise by just
as much as it will boost the desired signal.

Does it
matter if I point an antenna with several elements of different
lengths to the station, or if I point it the exact opposite direction?
In my attic, it would be more convenient to do the latter. (I'm too
old and at least now, too fat to go on the roof.)

You'll lose a significant amount of sensitivity if you point a
traditional log-periodic antenna directly away from the TV station.
With a 10 dB front-to-back ratio (typical for a log-periodic) you
could cut the antenna range to about a third of what it would be at
its best.

Let me toss out another idea for you. If you've got attic space which
runs long-wise towards, and away from the TV towers, you could install
a rhombic antenna. This is simply a diamond-shaped pattern of two
wires, with the long axis of the diamond pointing towards / away from
the transmitter. The feedline to the TV attaches at one end. At the
other end, you can either "terminate" the rhombic with a resistor, or
leave the two ends of the wires unconnected.

If you terminate the antenna with a resistor, it becomes a
unidirectional antenna... the resistor is at the end pointed towards
the transmitter, and the feedline attaches at the other end.

If you leave the wires at the far end open (unconnected) the rhombic
is essentially bidirectional... it can receive signals from stations
located off of either end.

Rhombics are fairly wide-band antennas. Their impedance is such that
yu can probably use a standard 4:1 balun transformer to match them to
a 75-ohm coax.

They do take up a fair bit of space - each "arm" of the diamond needs
to be at least one wavelength long at the lowest frequency you want to
receive. The longer, the better (as far as gain goes).

A big advantage to them is that they're inexpensive... all you need is
wire, a termination resistor (450-to-600-ohm carbon composition will
do), and a balun transformer.

http://en.wikipedia.org/wiki/Rhombic_antenna has an overview.

Also, I thought 50 miles was the longest range on level ground for a
transmitting tower of typical height and an antenna on the roof of a
two-story house.

So what about a claim that a Wineguard antenna has a range of 75 to 80
miles????
http://estore.websitepros.com/112973...00U/Detail.bok

It depends very much on how high your rooftop is, and how high your
mast is, and on the nature of the terrain between you and the
transmitter. You can count on some amount of diffraction, which
can actually let your antenna "see" a TV transmitter which is below
the optical horizon.

This antenna is rated for low-band VHF and I don't need that, I've
learned, but it's the mileage claim I am asking about.

Even this one says: Up to 60 mile VHF range; 45 mile UHF range Don't
they get that by mounting it on a 100 foot tower or something?
http://www.radioshack.com/product/in...ductId=3739594

"Up to" distance numbers are probably subject to the same sort
of marketing inflation, and selective-circumstances picking that
affect fuel-economy figures for cars. I'd guess that the upper
limits of the "up to" ranges may assume a TV transmitter on top of
Mount Wilson (or a similar-sized molehill), an antenna mounted on a
tall mast on top of a multi-story apartment building, clear terrain,
and perhaps a bit of atmospheric ducting under favorable weather
conditions. "We saw a picture once, for 30 seconds, at 80 miles, so
the range is up to 80 miles!"

And isn't the info obsolete because digital transmitters are working
at lower power than analog did?

"Assumes facts not in evidence."

A lot of TV stations had to run their "transition" digital
transmitters at lower power than their analog transmitters, for any of
a number of technical and legal reasons. Many of them (perhaps most)
either boosted their digital transmission power on The Big Day (when
the analog transmitters were turned off) or are in the process of
doing so as time goes by.

TV stations *really* don't like losing area-coverage, since this
reduces the number of viewers they can claim, and reduces the value of
the commercial-ad time they have available to sell. Stations will tend
to want to push up their transmitter power as far as they can afford
and/or as far as the FCC will let them.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

In article ,
mm wrote:

Does it matter if the tv antenna points one way, or 180^ the other?

That depends on the antenna.

Typical log-periodic rooftop TV antennas are moderately directional.
They have the greatest gain when the small end is pointing towards the
transmitter. Directly off of the back, they're usually around 10 dB
worse (i.e. one-tenth the power sensitivity). There are some
directions around the side which are going to be *extremely*
insensitive (very deep nulls).

Other sorts of antennas are bidirectional.

You'll probably get the best reception from a directional antenna,
aimed towards the transmitter (or, sometimes, aimed off at an angle
which minimizes the antenna's pickup of reflections from nearby
buildings and trees).

You guys, especially Dave, have convinced me that I need a better (and
thus bigger) antenna more than I need an amplified antenna.

That's often the case. If your signal level at the TV is low, it's
usually better to try to improve it by adding antenna gain, than it is
to use an amplifier. An amplifier will boost incoming noise by just
as much as it will boost the desired signal.

Does it
matter if I point an antenna with several elements of different
lengths to the station, or if I point it the exact opposite direction?
In my attic, it would be more convenient to do the latter. (I'm too
old and at least now, too fat to go on the roof.)

You'll lose a significant amount of sensitivity if you point a
traditional log-periodic antenna directly away from the TV station.
With a 10 dB front-to-back ratio (typical for a log-periodic) you
could cut the antenna range to about a third of what it would be at
its best.

Let me toss out another idea for you. If you've got attic space which
runs long-wise towards, and away from the TV towers, you could install
a rhombic antenna. This is simply a diamond-shaped pattern of two
wires, with the long axis of the diamond pointing towards / away from
the transmitter. The feedline to the TV attaches at one end. At the
other end, you can either "terminate" the rhombic with a resistor, or
leave the two ends of the wires unconnected.

If you terminate the antenna with a resistor, it becomes a
unidirectional antenna... the resistor is at the end pointed towards
the transmitter, and the feedline attaches at the other end.

If you leave the wires at the far end open (unconnected) the rhombic
is essentially bidirectional... it can receive signals from stations
located off of either end.

Rhombics are fairly wide-band antennas. Their impedance is such that
yu can probably use a standard 4:1 balun transformer to match them to
a 75-ohm coax.

They do take up a fair bit of space - each "arm" of the diamond needs
to be at least one wavelength long at the lowest frequency you want to
receive. The longer, the better (as far as gain goes).

A big advantage to them is that they're inexpensive... all you need is
wire, a termination resistor (450-to-600-ohm carbon composition will
do), and a balun transformer.

http://en.wikipedia.org/wiki/Rhombic_antenna has an overview.

Also, I thought 50 miles was the longest range on level ground for a
transmitting tower of typical height and an antenna on the roof of a
two-story house.

So what about a claim that a Wineguard antenna has a range of 75 to 80
miles????
http://estore.websitepros.com/112973...00U/Detail.bok

It depends very much on how high your rooftop is, and how high your
mast is, and on the nature of the terrain between you and the
transmitter. You can count on some amount of diffraction, which
can actually let your antenna "see" a TV transmitter which is below
the optical horizon.

This antenna is rated for low-band VHF and I don't need that, I've
learned, but it's the mileage claim I am asking about.

Even this one says: Up to 60 mile VHF range; 45 mile UHF range Don't
they get that by mounting it on a 100 foot tower or something?
http://www.radioshack.com/product/in...ductId=3739594

"Up to" distance numbers are probably subject to the same sort
of marketing inflation, and selective-circumstances picking that
affect fuel-economy figures for cars. I'd guess that the upper
limits of the "up to" ranges may assume a TV transmitter on top of
Mount Wilson (or a similar-sized molehill), an antenna mounted on a
tall mast on top of a multi-story apartment building, clear terrain,
and perhaps a bit of atmospheric ducting under favorable weather
conditions. "We saw a picture once, for 30 seconds, at 80 miles, so
the range is up to 80 miles!"

And isn't the info obsolete because digital transmitters are working
at lower power than analog did?

"Assumes facts not in evidence."

A lot of TV stations had to run their "transition" digital
transmitters at lower power than their analog transmitters, for any of
a number of technical and legal reasons. Many of them (perhaps most)
either boosted their digital transmission power on The Big Day (when
the analog transmitters were turned off) or are in the process of
doing so as time goes by.

TV stations *really* don't like losing area-coverage, since this
reduces the number of viewers they can claim, and reduces the value of
the commercial-ad time they have available to sell. Stations will tend
to want to push up their transmitter power as far as they can afford
and/or as far as the FCC will let them.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Tue, 1 Dec 2009 13:48:07 -0800, (Dave Platt)
wrote:

Let me toss out another idea for you. If you've got attic space which
runs long-wise towards, and away from the TV towers, you could install
a rhombic antenna.

Been there, tried that. It works well but is rather sensitive to
nearby metal objects. It will probably work in the attic.
http://www.tvtechnology.com/article/11412
The problem is that it's rather big.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Tue, 1 Dec 2009 13:48:07 -0800, (Dave Platt)
wrote:

Let me toss out another idea for you. If you've got attic space which
runs long-wise towards, and away from the TV towers, you could install
a rhombic antenna.

Been there, tried that. It works well but is rather sensitive to
nearby metal objects. It will probably work in the attic.
http://www.tvtechnology.com/article/11412
The problem is that it's rather big.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Inscribed thus:

On Tue, 01 Dec 2009 00:29:31 -0500, mm
wrote:

Does it matter if the tv antenna points one way, or 180^ the other?

You guys, especially Dave, have convinced me that I need a better (and
thus bigger) antenna more than I need an amplified antenna. Does it
matter if I point an antenna with several elements of different
lengths to the station, or if I point it the exact opposite direction?
In my attic, it would be more convenient to do the latter. (I'm too
old and at least now, too fat to go on the roof.)


Also, I thought 50 miles was the longest range on level ground for a
transmitting tower of typical height and an antenna on the roof of a
two-story house.

So what about a claim that a Wineguard antenna has a range of 75 to 80
miles????
http://estore.websitepros.com/112973...00U/Detail.bok
This antenna is rated for low-band VHF and I don't need that, I've
learned, but it's the mileage claim I am asking about.

Even this one says: Up to 60 mile VHF range; 45 mile UHF range Don't
they get that by mounting it on a 100 foot tower or something?
http://www.radioshack.com/product/in...ductId=3739594
And isn't the info obsolete because digital transmitters are working
at lower power than analog did?

Thanks a lot.
I have to say you are going about this the wrong way. You are
choosing to mount the antenna in the attic because it's easier. An
indoor mount also has the advantage of reducing exposure to the
weather. While this is easier, it has several major disadvantages.
You have already mentioned one - difficulty in orienting it properly.
There is another - signal attenuation, particularly at higher
frequencies.

Have you considered the possibility you are focusing on convenience
and ignoring performance?

As far as antenna range, my parents lived over 60 miles from the
transmitter and received good signal levels with an antenna that was
mounted less than 15 feet above ground level.

PlainBill

With all due respect to Bill, what works in one place doesn't always
work in another.

An example, Rhonda Valley. Two identical Tv's antenna and cables but a
common chimney stack. Really good signal reception on one side of the
stack and next to none on the other. Antenna less than 6 ot 7 feet
apart at the same hight.

Solution split the feed from the high signal antenna and feed both sets
from the single antenna. Which also had the effect of reducing the
signal improving the picture on both Tv's.

--
Best Regards:
Baron.

In article , mm wrote:
Does it matter if the tv antenna points one way, or 180^ the other?

You guys, especially Dave, have convinced me that I need a better (and
thus bigger) antenna more than I need an amplified antenna. Does it
matter if I point an antenna with several elements of different
lengths to the station, or if I point it the exact opposite direction?
In my attic, it would be more convenient to do the latter. (I'm too
old and at least now, too fat to go on the roof.)


Also, I thought 50 miles was the longest range on level ground for a
transmitting tower of typical height and an antenna on the roof of a
two-story house.

So what about a claim that a Wineguard antenna has a range of 75 to 80
miles????
http://estore.websitepros.com/112973...00U/Detail.bok
This antenna is rated for low-band VHF and I don't need that, I've
learned, but it's the mileage claim I am asking about.

Even this one says: Up to 60 mile VHF range; 45 mile UHF range Don't
they get that by mounting it on a 100 foot tower or something?
http://www.radioshack.com/product/in...ductId=3739594
And isn't the info obsolete because digital transmitters are working
at lower power than analog did?


You certainly don't need VHF low, but do you really need VHF high ?
I only have one station here on ch 13.

You could also use two separate antennas with a combiner.
Concentrate on the UHF.

Milages is highly dependant on height and terrain.
Height means nothing if there is a mountain in between.
Its surprsing though, there are some big hills around here, and people
got by from 30 mi away with hilly terrain on the old TV's.
Getting rid of shadows on the old TV was the main problem.
Digital has no shadows but must have a minimum signal to decode.

greg

"baron" wrote in message
...
Inscribed thus:

On Tue, 01 Dec 2009 00:29:31 -0500, mm
wrote:

Does it matter if the tv antenna points one way, or 180^ the other?

You guys, especially Dave, have convinced me that I need a better (and
thus bigger) antenna more than I need an amplified antenna. Does it
matter if I point an antenna with several elements of different
lengths to the station, or if I point it the exact opposite direction?
In my attic, it would be more convenient to do the latter. (I'm too
old and at least now, too fat to go on the roof.)


Also, I thought 50 miles was the longest range on level ground for a
transmitting tower of typical height and an antenna on the roof of a
two-story house.

So what about a claim that a Wineguard antenna has a range of 75 to 80
miles????
http://estore.websitepros.com/112973...00U/Detail.bok
This antenna is rated for low-band VHF and I don't need that, I've
learned, but it's the mileage claim I am asking about.

Even this one says: Up to 60 mile VHF range; 45 mile UHF range Don't
they get that by mounting it on a 100 foot tower or something?
http://www.radioshack.com/product/in...ductId=3739594
And isn't the info obsolete because digital transmitters are working
at lower power than analog did?

Thanks a lot.
I have to say you are going about this the wrong way. You are
choosing to mount the antenna in the attic because it's easier. An
indoor mount also has the advantage of reducing exposure to the
weather. While this is easier, it has several major disadvantages.
You have already mentioned one - difficulty in orienting it properly.
There is another - signal attenuation, particularly at higher
frequencies.

Have you considered the possibility you are focusing on convenience
and ignoring performance?

As far as antenna range, my parents lived over 60 miles from the
transmitter and received good signal levels with an antenna that was
mounted less than 15 feet above ground level.

PlainBill

With all due respect to Bill, what works in one place doesn't always
work in another.

An example, Rhonda Valley. Two identical Tv's antenna and cables but a
common chimney stack. Really good signal reception on one side of the
stack and next to none on the other. Antenna less than 6 ot 7 feet
apart at the same hight.

Solution split the feed from the high signal antenna and feed both sets
from the single antenna. Which also had the effect of reducing the
signal improving the picture on both Tv's.

--
Best Regards:
Baron.

I too have seen this. I clearly remember installing an early CTV in a
village that had generally poor UHF reception. Several members of the same
family all lived in this tiny village, and all rented CTVs from the company
that I worked for. One of the sons moved into a cottage in the same row as
one of his brothers, who had good enough signals to receive colour without
any preamping. We turned up at the same time as the antenna rigger, and then
spent most of the rest of the day there, trying to get useable signals, just
100 feet from his brother. I remember watching the rigger (with my heart in
my mouth - winter, frosty, slippy!) walking back and forth along the roof
ridge, holding a bloody great pole with a phased pair of long Yagis on the
top, trying to see if there was any point where we could get an acceptable
signal from any transmitter, with a view to then moving back to the chimney,
to see if we could figure a way to get the same signal from there.

As I recall, we ended up with something like a 15ft pole, with a double
chimney lashing kit, and a phased pair of long Yagis *and* a preamp. House
same height as his brother's one, no visible obstructions or hills as far as
the eye could see across open countryside. Sometimes, there's just no rhyme
or reason to TV reception.

As to receivable distance for an antenna, this depends a lot on the
frequency involved. At UHF, there is little 'bending' effect of the basic
radiated signal, so reception can be considered as pretty much 'line of
sight'. There are effects that can extend this, but nothing that you could
rely on. However, at VHF, wavefront tilt becomes more significant, and the
signal will try to follow the curvature of the earth more or less, due to
the wavefront 'digging in' and being 'pulled over'. This can give a
significantly greater 'range' to a signal. When I was a kid, we used to
watch really strong TV signals from a transmitter some sixty miles away. The
antenna was a double 4 ele with a shared loop 'dipole' and delta match. This
was a very common antenna type in my neck of the woods, at the time

Arfa