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Author Topic: TV Antenna problem
Mike Fitzgerald
Expert Film Handler

Posts: 224
From: Castle Hayne, NC, USA
Registered: Jun 2002


 - posted 09-21-2002 09:39 PM      Profile for Mike Fitzgerald   Email Mike Fitzgerald   Send New Private Message       Edit/Delete Post 
I am trying to help out the local cinema grill with a reception problem. They show Survivor on Thursdays and the Picture needs improvement. Last year when they did it the local CBS station gave them all the equipment they needed. This year however CBS decided to go with a local bar leaving them in the cold. The bar paid a lot of money to get it. They do not have cable in the theatre and the local time warner is not planning on running it to them. So they are left with a old fashioned antenna for now. They are looking for thoughts on preamps and amps that will improve the picture for them. Any thoughts

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Fitz

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Paul Mayer
Oh get out of it Melvin, before it pulls you under!

Posts: 3835
From: Albuquerque, NM
Registered: Feb 2000


 - posted 09-21-2002 10:37 PM      Profile for Paul Mayer   Author's Homepage   Email Paul Mayer   Send New Private Message       Edit/Delete Post 
Need some details. What's the situation? Is this a multipath problem (lots of tall buildings or trees between the grill and the transmitter)? A signal strength problem (fringe area)? How far is it line-of-sight to the transmitter? What's the cable distance from the antenna to the receiver? UHF or VHF? NTSC or ATSC?

Surveying these things will narrow the choices of antenna type, mast height, transmission line type, and any additional amplifier gain needed.

Regards,

Paul


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Michael Gonzalez
Jedi Master Film Handler

Posts: 789
From: Grand Island , NE USA
Registered: Sep 2000


 - posted 09-21-2002 10:47 PM      Profile for Michael Gonzalez   Email Michael Gonzalez   Send New Private Message       Edit/Delete Post 
You could always go the Satallite Dish route. The Dish Network offers local channels at most places as oppose to Direct TV which has a more limited local access.

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Mike Fitzgerald
Expert Film Handler

Posts: 224
From: Castle Hayne, NC, USA
Registered: Jun 2002


 - posted 09-22-2002 12:06 AM      Profile for Mike Fitzgerald   Email Mike Fitzgerald   Send New Private Message       Edit/Delete Post 
I think it is more of a signal problem. The CBS station here is only a year old and is mainly on cable. There is no buildings or trees in the way that I am aware of. The Cinema grill is in a old shopping center free standing. The antenna was just replaced with a radio shack VU-190XR which is supposed to have a range of up to 100 mile which is way more than they need. I added a High Gain signel amp tonight after the show with a built in FM trap. The FM trap says it has 25db at 95mhz. gain of 30db. The other 2 stations in area come in fine with this antenna. The basic problem seems to be the horizontal black lines showing up in the picture and from time to time and some picture fading. Last year when the station did the atennna they used a channel master antenna which was so so and they had something in the line I think they called it a diffuser. Is it just the weakness of the signel causing these problems. Do we need a diffuser to boost the signal more
Thanks

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Fitz

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16112
From: Bountiful, Utah
Registered: Jun 99


 - posted 09-22-2002 05:22 AM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
I used to do master antenna systems back in the late 70's. Wiengard made a huge beast of an antenna I think it was a CH8200 or something like that. The boom on it was over 15 feet long assembled! On one school I did in suburban Chicago(30 miles straight west) I installed one of these beasts on a rotator. After installation and checkout we swung it around to see what we could get and low and behold we were able to get a bit over 200 microvolts from an Indianapolis TV station! Also Rockford, Ill, and Peoria were at watchable signal strengths as well. Pretty amazing tenna to say the least. If you need amplifiers use Jerrold equipment if they are still around. They made some of the best stuff available back then. Not cheap though....
(Added) I checked the Winegard site and they still make the beast. The boom is 14.75 feet long! See it here... http://www.signalelectronics.com/winegard%20chromstar.htm
Mark @ Claco


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Steve Kraus
Film God

Posts: 4051
From: Chicago, IL, USA
Registered: May 2000


 - posted 09-22-2002 11:56 AM      Profile for Steve Kraus     Send New Private Message       Edit/Delete Post 
If possible try to get an antenna designed for the specific channel rather than one which is compromised to receive a range of frequencies. I used to be a TV DX-er and my first summer home from college I decided to build an antenna to pull in the college town's Ch. 3 from about 120 miles away. I used part of an old VHF-only antenna consisting of a single folded dipole and reflector. I mounted it to a wood beam and put a number of director elements in front of it (old curtain rods!!) that were specifically cut to the right length for that freq.

Even though it was not mounted very high up it worked quite well although the front/back ratio was not steep enough and as a result I had a lot of co-channel interference from Ch. 3's a similar distance off in the opposite directions. However, there were occasions when the ionosphere and skip conditions were just right and I pulled in stations from (mind you I am near Chicago) Texas, New Mexico, Florida, and the capper was Halifax, Nova Scotia. Several of these including the latter were confirmed in writing by letter or QSL card.

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