"JB" wrote:

That is a complication but not if your antenna can just see across the roof
of the other building, then it can actually help. If the main signal source
is reduced, reflections will be more pronounced. The problem with digital,
all you have is a bar graph. Reception problems are totally masked. The
reception problems that degrade Analog still degrade Digital, you just can't
see it. I have seen situations where there is lots of signal on the bar
graph, but the picture still breaks up because of distortion of the signal.
So while Analog is still there, get your antenna aligned and locked down and
hope no one builds another building.

Well you have sure opened my eyes up to the importance
of a DIRECTIONAL antenna when it comes to DTV!! I'm
lucky in that all stations locally are broadcast from
same towers in same location..... so only one direction
to worry abt. Again my zip is 63401

Seems like the more directional the antenna the better
as it will be "blind" to multi-path. Yes?

Sometiimes pointing the antenna at a tall building or mountain will give a
better signal because all stations are bouncing from that building..

If you can stand on your roof with binocculars and see the broadcasting
site, and there are no 12-100 story buildings or mountains around, put your
antenna there and be done with it. Keep in mind that if you find yourself
running 75 feet of coax, it would be like putting up an $80 antenna just to
shorten the coax to 35 feet.

Well I cant see the towers but they are there

"JB" wrote:

While the 1080 UHF is fairly sharp with some potential gain, the VHF
elements seem to be little more than "rabbit ears" - In fact it is a swept
dipole, so will be bi-directional and easily pick up reflections from behind
and around you..

I'm a bit confused on your remark above.

Looks to me like the 1080 is perfectly flat antenna.
Where do you see any bending or sweeping of elements?

On Tue, 05 Aug 2008 18:15:50 -0500, wrote:

"JB" wrote:

While the 1080 UHF is fairly sharp with some potential gain, the VHF
elements seem to be little more than "rabbit ears" - In fact it is a swept
dipole, so will be bi-directional and easily pick up reflections from behind
and around you..

I'm a bit confused on your remark above.

Looks to me like the 1080 is perfectly flat antenna.
Where do you see any bending or sweeping of elements?

It would be even more informing if the "gain" attributed to it (not to
speak of lobe characteristics) were revealed through a link, as
certainly the vendor is wholly lacking in those substantives.

73's
Richard Clark, KB7QHC

wrote:
"JB" wrote:

That is a complication but not if your antenna can just see across the roof
of the other building, then it can actually help. If the main signal source
is reduced, reflections will be more pronounced. The problem with digital,
all you have is a bar graph. Reception problems are totally masked. The
reception problems that degrade Analog still degrade Digital, you just can't
see it. I have seen situations where there is lots of signal on the bar
graph, but the picture still breaks up because of distortion of the signal.
So while Analog is still there, get your antenna aligned and locked down and
hope no one builds another building.

Well you have sure opened my eyes up to the importance
of a DIRECTIONAL antenna when it comes to DTV!! I'm
lucky in that all stations locally are broadcast from
same towers in same location..... so only one direction
to worry abt. Again my zip is 63401

Seems like the more directional the antenna the better
as it will be "blind" to multi-path. Yes?


Except that some receivers actually use the multipath signals to enhance
the overall SNR, by essentially delaying and recombining them in an
adaptive equalizer. So directivity, if it comes at the expense of gain,
might not be what you want.

I am looking at a 1080. It is being used in the computer room. All of the
elements are in two, parallel planes that are each normal to earth. In
other words, flat. On high-VHF (channel 12, here) there is little F/B
ratio, but that has not been a problem. The chances of needing to reject a
high-VHF station (at 180 degrees) on the same frequency is slim. The
antenna is a stout, little, two-bay broadside array with reflector mostly
effective on UHF.

I provided a detailed set of measurements in another message. 73, Mac
N8TT

--
J. McLaughlin; Michigan, USA
Home:
wrote in message
news
"JB" wrote:

While the 1080 UHF is fairly sharp with some potential gain, the VHF
elements seem to be little more than "rabbit ears" - In fact it is a swept
dipole, so will be bi-directional and easily pick up reflections from
behind
and around you..

I'm a bit confused on your remark above.

Looks to me like the 1080 is perfectly flat antenna.
Where do you see any bending or sweeping of elements?

OOPS! I guess I got them backwards. I must be up past my bedtime.
wrote in message
news
"JB" wrote:

While the 1080 UHF is fairly sharp with some potential gain, the VHF
elements seem to be little more than "rabbit ears" - In fact it is a
swept
dipole, so will be bi-directional and easily pick up reflections from
behind
and around you..

I'm a bit confused on your remark above.

Looks to me like the 1080 is perfectly flat antenna.
Where do you see any bending or sweeping of elements?

Sorry about that. I did get them mixed up not having the photos in front of
me when writing. Roy is also correct. All that is in the ARRL Antenna
Handbook. I believe impedance is lowered though at the dipole elements
apex. to some extent. The dipole vs. Inverted V comes to mind, but the
feedpoint impedance of a LPDA is really about the spacing of the feeders and
matching system. .

I'll shut up now

"J. Mc Laughlin" wrote in message
.. .
I am looking at a 1080. It is being used in the computer room. All of
the
elements are in two, parallel planes that are each normal to earth. In
other words, flat. On high-VHF (channel 12, here) there is little F/B
ratio, but that has not been a problem. The chances of needing to reject
a
high-VHF station (at 180 degrees) on the same frequency is slim. The
antenna is a stout, little, two-bay broadside array with reflector mostly
effective on UHF.

I provided a detailed set of measurements in another message. 73, Mac
N8TT

--
J. McLaughlin; Michigan, USA
Home:
wrote in message
news
"JB" wrote:

While the 1080 UHF is fairly sharp with some potential gain, the VHF
elements seem to be little more than "rabbit ears" - In fact it is a
swept
dipole, so will be bi-directional and easily pick up reflections from
behind
and around you..

I'm a bit confused on your remark above.

Looks to me like the 1080 is perfectly flat antenna.
Where do you see any bending or sweeping of elements?

Dear JB (no call sign): The objective was in no way intended to stifle,
only to describe.

Here is the essence of my message about the 1080 of about a month ago:

It is deceptive to put numbers on the size. The reflector consists of five
doublets each with a tip-to-top length of 26.5 inches and a total height of
a little over 16 inches. The twin "driven" elements are spaced about 6.6
inches in front of the reflectors (obviously the reflectors are only
effective for UHF). The tip-to-tip length of the driven elements is about
34.5 inches (giving a predicted 0.5 WL resonance towards the bottom of the
higher VHF TV band). Each driven element is coaxial with a fan dipole that
should have a resonance somewhere in the UHF band. Thus one expects a small
gain with a small F/B in the higher VHF band and fair gain with good F/B in
the UHF band.

Regards, Mac N8TT

--
J. McLaughlin; Michigan, USA
Home:
"JB" wrote in message
news:F7vnk.521$EL2.235@trnddc01...
Sorry about that. I did get them mixed up not having the photos in front
of
me when writing. Roy is also correct. All that is in the ARRL Antenna
Handbook. I believe impedance is lowered though at the dipole elements
apex. to some extent. The dipole vs. Inverted V comes to mind, but the
feedpoint impedance of a LPDA is really about the spacing of the feeders
and
matching system. .

I'll shut up now

"J. Mc Laughlin" wrote in message
.. .
I am looking at a 1080. It is being used in the computer room. All of
the
elements are in two, parallel planes that are each normal to earth. In
other words, flat. On high-VHF (channel 12, here) there is little F/B
ratio, but that has not been a problem. The chances of needing to reject
a
high-VHF station (at 180 degrees) on the same frequency is slim. The
antenna is a stout, little, two-bay broadside array with reflector mostly
effective on UHF.

I provided a detailed set of measurements in another message. 73, Mac
N8TT

--
J. McLaughlin; Michigan, USA
Home:
wrote in message
news
"JB" wrote:

While the 1080 UHF is fairly sharp with some potential gain, the VHF
elements seem to be little more than "rabbit ears" - In fact it is a
swept
dipole, so will be bi-directional and easily pick up reflections from
behind
and around you..

I'm a bit confused on your remark above.

Looks to me like the 1080 is perfectly flat antenna.
Where do you see any bending or sweeping of elements?