Dish acting like AM antenna

[KAB]

Anybody ever encounter this? On intermittant basis (every few days or so) I am getting audio bleed from an AM radio station. I am running my TV's audio out through a receiver, which makes it more noticable. When I remove the coax input, no bleed, so definately from the dish side. Any ideas/suggestions as to how to get rid of it. BTW, the station antenna is about 5 mi away, and often varies in intensity with the weather. But most of the time, it is quiet.

 

[Spin]

You have a ground loop. If the dish box has a 3 prong plug get a ground lift adapter. This is usually the main problem.

If it does not, then your ground loop is in grounding of the dish. You would then have to lift the ground out of the line. I don't know if there are coax adapters. But try removing the grounding blocks and see what happens. If that makes it disappear you will need to run your ground to another place to remove the loop.

 

[KAB]

Well, I isolated the problem to the TV since I have a 625 and it is TV2. I used a ground lift adapter...it got rid of the station, but now I get a hum. Anything else?

 

[Spin]

Do you get a hum on TV1? or just TV2 with the ground lift. Second did you only get the radio station on TV2?

If the hum is only on TV2 right now make sure your TV does not have a ground plug also. The whole thing has to be lifted to remove the loop.

 

[KAB]

Thanks for the reply. It is and has always been only on TV2. No hum currently on TV1. Since last post, I realized the ground prong was not touching the plate mount screw. Buzz is now gone, but as said above, still hear the station, albeit quieter. When you say "the whole thing needs to be lifted, are you referring to the ground rod?
Thanks!!!

 

[Spin]

I'm referring to the line. All plugs will need to be lifted, Dish, TV etc. You remove the ground you get rid of the loop. If it still remains the loop is being formed in the grounding of the dish. I'm not an expert in grounding dishes so I can't help you there. I actually don't have mine grounded. Oh well it's a risk I'm willing to take.

Additon.

By reconnecting the ground you have reformed a loop. That is why the buzz is gone and the station has returned. Is your TV2 3 prong?

 

[KAB]

Please bear with me here Spin. When you say the plugs need to be lifted, please clarify. Are you saying remove the ground wire from the plug itself?

 

[Spin]

The ground lift adapter turns a three prong plug into a two prong plug. This removes (lifts) the ground, as long as you don't connect the adapter to the screw.

 

[KAB]

OK, we're square. But that's when I get the Hum. The only thing I have plug in at TV2 location is the TV. So, how to get rid of hum?
Also, this house wiring is from 1950, and there was no three wire/gound wiring in this part of the house.

 

[Spin]

You still haven't answered if you have the TV2 connected to a ground. If it is not grounded you will need someone to fix the grounding of the dish. Im a sound engineer so dish grounding is not my specialty. If there is no ground connected on the TV or Reciever and you still get a hum I would reconnect the ground on the dish until someone can help you with dish grounding.

 

[KAB]

Tv2 is connected to the ground block, if that is what you are asking.
Even when I disconnet the ground wire from the block, same story.

 

[Spin]

Sounds like a dish grounding problem. Not an electrical grounding problem then. I can't help you there. Maybe someone else has an idea other than removing the grounding from the dish.

Crazy question,

TV 2 is connected using new RG6 cable correct?

 

[KAB]

Thanks, Spin!

And, yes it is.

 

[KKlare]

Since you have a house from the 1950's, check the following:
Do you have aluminum wiring? Very bad.

Have you used a wiring fault tester? 3 neon lights across hot, neutral, and ground. Hot and each of the others should light yellow. Neutral to ground must not light red. If it does then the white (neutral, wide prong) and black (hot, narrow prong) wires are reversed on that plug or the whole house. You can check with a VOM but the 3-wire checker is a lot faster and about $3.

Lifting the ground may be a good test but is NOT by code and real problem should be solved to prevent shocks and worse.

Wiring to other rooms may require checking the 3-prong wiring there. I had 1/2 of my outlets wrong for 13 years and did not know why I sometimes got tingles due to a Sony TV with no transformer. I check and re-did it all.

-Ken

 

[SimpleSimon]

Lifting the ground may be a good test but is NOT by code and real problem should be solved to prevent shocks and worse.

CORRECT!

I doubt this is actually a ground LOOP issue, but that the coax itself is acting as an antenna due to a very powerful AM station. Many people near 850 KOA radio's 1000' 50KW tower in Parker, Colo. hear the station via their phones and dang near anything else with a straight wire that has a connection to ground.

Maybe a local retailer has encountered this and can help - or contact the station, and speak NICELY to the station engineer asking them if they have any solutions. One thing to remember - they are within their rights to transmit (unless they are exceeding their authorized power - unlikely). Consumer equipment has to accept interference, and it is the consumer that has the responsibility to cure thier problem.

As Parker, Colo. developed, and people started building all around the tower, everybody started yapping. Those that screamed at KOA were told to F-Off, while those that asked nicely were given several simple and cheap fixes for their various problems.

 

[inwo]

Correct! If it is just over powering something there may not be an easy fix. Quad shield may not even help if it's being picked up on the shield.

Oxidized connections can demodulate AM. Specific cable lengths can be resonant and cause large standing waves on any conductor.

Try dif routing and cable lengths maybe.