I am having a problem with my HAM bands. There is quite a bit of RFI coming from my house. To begin with, there is a lot of noise on all bands below 30 meters. I managed to isolate that, it is coming from the LCD television in the living room. When the TV is turned off, the noise is gone. This means that I can only work the 40 and 80 meter bands when no one in the house is watching TV in the living room. I can live with that.
In the 20m band, it is showing up as an S8 on the signal meter most of the time, and this hash covers up all but the strongest stations. Here is the pattern:
– turning off the circuit breakers to everything but the shack, it disappears and I get an S0-1.
– turning off one breaker at a time doesn’t get rid of it.
– Turning on all of the breakers doesn’t always make it return.
– When it DOES return, it starts at S3, and builds to an S8 over about a 30 second period
– The limits of the hash are from 10.6 MHz through 15.4 MHz.
This is driving me crazy. I think it is more than one piece of equipment.
SiGraybeard · June 21, 2013 at 6:50 pm
Those things can drive anyone crazy.
Random ideas: you might be able to get rid of it with better antenna placement, or a different antenna. I think you're using a loop around the house at about roof height? If possible, cut out the section closest to the TV or other expected sources. Possibly raise the wire – got a tree you can get it into? A weird aspect is that EMI can drop off a lot as the wire is raised. Guys with big towers, like over 50 or 60' often will tell you the biggest improvement is getting out of the noisy area close to the ground.
In a lot of cases I've seen, a clamp on ferrite bead on the power line can reduce noise at the source MPJA has these for example. Surplus dealers like Skycraft Surplus over in Orlando will often have them, too. These can work to protect the TV or stereo from your transmitter, too.
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