Electromagnetic Interference

[Ultimate Noise Man]

As some of you guys know I'm pretty new here. I'm waiting on my system to arrive (any day now.) To get to the point, I was curious if have to worry about electromagnetic interference with a satellite system. I have a set of high tension power lines south of me. It occured to me today as I was standing near them listening to the crackle that they may cause interference. What do you guys think? I suppose I could move my dish south of them, but that would require quite a length of cable. As usual any info is greatly appreciated. Adios.

 

[qwert1515]

I am not sure what your system is going to be, but for Ku band it should not be much of a problem, if you do have a problem, you can always get a longer cable and move the dish far away from the lines, you can easily go 100 ft with out any problems.

 

[Anole]

Just off hand, I'd be shocked if you had any more trouble, than you already have with hum or noise in your TV or hi-fi system.

 

[Ultimate Noise Man]

Thanks guys, some of my OTA digital channels to the south aren't so good, and I suspect it may be due to the lines. Anyways, that's why I was curious. Only time will tell.

 

[bloomdog]

The location of the dish shouldn't matter so much as the electrical current running through the power lines is on the order of 60 Hz (see Electricity Around the World). The satellite signal is on the order of 10,000,000,000 Hz. (10 GHz or 10 billion Hz). The satellite signal will pass right through the eletrical field and corresponding magnetic field around the power lines without any appreciable effect. Once the signal leaves the LNB, it's still at too high a frequency to be noticeably effected. However, once the signal hits the receiver, you need to be creative at shielding because the power which runs the receiver is at 60 Hz. Check out some Hi -Fi websites. Hi Fi enthusiasts have been fighting this type of problem, usually represented by a hiss or a hum, for 50 yrs.

 

[tvropro]

Usually the very high tension wires tend to interfere less than the lower voltage wires on the pole near your house. EMI and TVI can be a pain on OTA low band channels I have been plagued for years with TVI on my low band VHF channels. Every so often I get the power company to clean them up somewhat. I only had problems once on my satellite system back in about 1992 with them. I had the power company come out and replace some bad tie wraps on the poles and the problem ceased. Never had trouble since on satellite at least.

To see if you are a candidate for possible trouble take and portable AM radio and tune it between stations and listen for a sound of buzzing or bacon frying. Take a walk with the radio and see if it increases as you get near the lines (real close some noise will show up) then walk back to your house and see if it more or less dissipates. If it's very low to none don't even worry since it will probably not be an issue.

 

[bloomdog]

I reiterate, it's the RECEIVER which picks up the interference, not the dish.

 

[tvropro]

I reiterate, it's the RECEIVER which picks up the interference, not the dish.

It is possible that your cables can act like an antenna and bring the noise into the receiver. I used to have an arial run for my ribbon feed. When I was getting that TVI back in 1992 I buried the cable, this helped somewhat.

You can always put the receiver in a lead lined box A good designed EMI RFI noise filter with full common and differential mode filtering on the AC line is a must.