View Full Version : Is Preamp Overload Harmful?


SonicLogic
11-06-08, 11:52 PM
I've read a lot of information here concerning preamp overload with the CM-7777. However, if the TV picture and sound are good and you're receiving all the channels, what harm is caused by preamp overload?

Is there any actual harm caused to the TV tuner because of preamp overload? It seems to me that as long as you've got a good picture and sound with no distortion, then preamp overload is not a problem. So what if you have to aim your antenna a few degrees away from the transmitters to compensate for a strong signal? Am I missing something?

Digital Rules
11-07-08, 06:57 AM
You won't damage the tuner; but too much amplification can result in "fewer" received channels. Just for kicks, I hooked a 7777 to my system, and I lost all channels 40 or more miles away. They normally come in great with "no amp". The stronger signals(4 miles) were un-affected. I had bought the amp to use at a friends house in the fringes; and it worked wonders there.

If the antenna has to be pointed away from strong signals to compensate for overload; then a lower gain amp or no amp at all would be better.

"Why use a sledgehammer to put in a thumbtack"

SonicLogic
11-07-08, 04:49 PM
"Why use a sledgehammer to put in a thumbtack"

Because with the CM 7777 I can pick up all of my local stations (with some overload) and I can also pick up some far distant stations as well. Without the CM 7777, I can pick up most of the locals except for two stations. If the overloading condition does not cause any damage to the tuner, why should I get a preamp with less power and possibly jeopardize the reception of my fringe stations?

spwace
11-07-08, 08:21 PM
Because with the CM 7777 I can pick up all of my local stations (with some overload) and I can also pick up some far distant stations as well. Without the CM 7777, I can pick up most of the locals except for two stations. If the overloading condition does not cause any damage to the tuner, why should I get a preamp with less power and possibly jeopardize the reception of my fringe stations?

I'm curious why you think the amp is overloading. If you receive more channels with the amp in and you don't lose any of the channels you can receive without it, it is unlikely that it is overloading.

SonicLogic
11-07-08, 08:45 PM
I'm curious why you think the amp is overloading. If you receive more channels with the amp in and you don't lose any of the channels you can receive without it, it is unlikely that it is overloading.I have a 91XG and a YA-1713 with a CM-7777 and a rotator. When I point the antennas directly at the main cluster of TV transmitters (closest one being 38 miles away), the signal strength meter shows reduced signal.

When I point the antennas about 25º to either side of the main TV tower cluster, the signal strength increases on the meter. However, the picture and sound are perfect in all instances.

Digital Rules
11-07-08, 09:10 PM
At 38 miles; it's very unlikely you are overloading . Is your antenna pointed at any close by trees?

SonicLogic
11-07-08, 09:40 PM
Yes indeed. My neighbor has a large tree that is 50 or 60 feet away and in a direct line of sight between my antenna position and the TV towers. Lots of dense pine branches and it stays green all year here in Florida.

NightHawk
11-08-08, 09:13 AM
Is there any actual harm caused to the TV tuner because of preamp overload? It seems to me that as long as you've got a good picture and sound with no distortion, then preamp overload is not a problem. So what if you have to aim your antenna a few degrees away from the transmitters to compensate for a strong signal? Am I missing something?

To answer your question the overload causes no harm. and unlike you few people get the fact even if you do experience it, simply aiming the antenna off direct LOS can compensate. It sounds like you have a good workable setup.

SonicLogic
11-08-08, 09:01 PM
Thank you for that information NightHawk. I was unclear on whether or not preamp overload could cause damage to the tuner in any way. You have set my mind at ease. I understand the concern about preamp overload as it relates to signal degradation and/or losing signals entirely.