Tv antennas
 

I have a Radio Shack roof top antenna, I bought about five years ago,
it still works great.

It's a long range antenna, model vu 210, the best one they made, but
they don't make it anymore.

I had a similar antenna about thirty years ago, it seemed to have a
longer range

I lived in rural upstate New York lots of mountains, but I could get
stations as far away as 141 miles, namely Ottawa and stations 75 miles
away like Montreal.

But here in the Chicago area flat terrain and the same hight, I get
Milwaukee very clear, but nowhere near the range I got years ago.

I have a theory, that it might be that the flat 300 ohm wire used in
those days had better reception, and I know a lot more interference.

Right now I am using rg6 quadshield cable and have a high end booster
connected.

Is my theory correct about the wire?

A few possible reasons;

- 300 ohm ribbon certainly has less loss than RG6 but given you have a
masthead preamp (booster) this is a mute point (The main idea of the
preamp being to overcome line losses)
- The propogation conditions (inversions and bending etc) may have been
better around NY than IL. Maybe the terrain helped too (eg knife edge) I
wouldnt know though cause I am on the other side of the world!
- The general noise floor in the TV band has no doubt risen over the
years with a lot more transmitters and general frequency use. In other
words your TV may be able to resolve a low signal but it is blanked out
by general band noise. We just did a test in the Melbourne CBD on the
noise floor on VHF pager freqs. -76dBm was quite normal. The pagers work
down to about -102dBm but with the noise that high are severely limited.

The noise floor problem is very hard to beat. You can point the antenna
to reduce the noise from a known direction, using it to null
interference rather than get max signal from the TV transmitter. Of
course if the noise is all around you you are kind of stuffed!

- Your masthead preamp maybe being overloaded by strong signals and
swamping the TV receiver. This will also serve to reduce the apparent
sensitivity.

Selecting a preamp with good dynamic range or tuning specific to the
station you want to watch may help. Realise though that these are
commercial devices priced accordingly. If it has the capability try
reducing the gain of the preamp and see if it improves things. You may
also be able to purpose build an antenna for a particular frequency
(tuned for gain and f/b etc) but this may not actually help. It all
depends on how important it is to you!

Cheers Bob VK2YQA


Archer wrote:
I have a Radio Shack roof top antenna, I bought about five years ago,
it still works great.

It's a long range antenna, model vu 210, the best one they made, but
they don't make it anymore.

I had a similar antenna about thirty years ago, it seemed to have a
longer range

I lived in rural upstate New York lots of mountains, but I could get
stations as far away as 141 miles, namely Ottawa and stations 75 miles
away like Montreal.

But here in the Chicago area flat terrain and the same hight, I get
Milwaukee very clear, but nowhere near the range I got years ago.

I have a theory, that it might be that the flat 300 ohm wire used in
those days had better reception, and I know a lot more interference.

Right now I am using rg6 quadshield cable and have a high end booster
connected.

Is my theory correct about the wire?

Archer wrote:
I have a Radio Shack roof top antenna, I bought about five years ago,
it still works great.

It's a long range antenna, model vu 210, the best one they made, but
they don't make it anymore.

I had a similar antenna about thirty years ago, it seemed to have a
longer range

I lived in rural upstate New York lots of mountains, but I could get
stations as far away as 141 miles, namely Ottawa and stations 75 miles
away like Montreal.


I also used to live in NNY, Potsdam, and did quite a bit of 2m and 6m
weak signal work, as well as the obligatory FM. The St Lawrence Valley
plus the ducting from all the moisture from Lake Ontario are most of
what you were seeing. You could often trip the Watertown W2WLR repeater
from Ottawa with a handheld in a modestly tall building, say 4 stories.
Ottawa (CHEZ ?) and Montreal (CHOM, as I remember) FM broadcast were
audible over all of St Lawrence County, and well into Jefferson County
most of the time on a car radio.

Tom
K0TAR

On 13 Feb 2005 23:22:19 -0800, "Archer"
wrote:
But here in the Chicago area flat terrain and the same hight, I get
Milwaukee very clear, but nowhere near the range I got years ago.

Hi OM,

Those transmitters in NY and Canada were also on mountains.

Is my theory correct about the wire?

Seems unlikely. If anything, the quality would have been worse in
"the good ol' days."

73's
Richard Clark, KB7QHC

remember) FM broadcast were
audible over all of St Lawrence County, and well into Jefferson County
most of the time on a car radio.

Yes that is true, I used to get great fm on rabbit ears now I live
outside
Chicago and use the above mentioned antenna for fm also,

Seems unlikely. If anything, the quality would have been worse in
"the good ol' days."

True it probably wasn't as good as I remember it, after all the picture
was black and white, and I settled for less back then.

Even now when I watch video tapes I recorded twenty years ago, before
cable. I could not believe I settled for that kind of reception.

But I do remember getting a strong signal from stations far away, the
only time I get that now is when there is a thunderstorm in the area.

I have had cable since 1990, Iove the technology of tv, not
necessarily the programming that is on it, that is why am messing
around with antennas and so on.

I primarily use it for fm and back up if cable goes off.