Posted: 4/8/2015 3:22:41 PM EDT
| I have a Kenwood TM-281 with a Kenwood power supply and a 2M ringo antenna. In this same room I have a 42" LG LCD TV. Ever so often (like 45secs to a min) the radio will squelch, static whatever you want to call it. It only does it when the TV is on and it seems like it is happens more when the TV is displaying a light colored or completely white screen. It has gotten to the point I hate to even turn the 2M on. Any ideas on a fix. Short of getting rid of the TV. :-) |
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How's your coax routed?
How's your station ground? How well is the TV grounded? (I partially fixed my in laws Plasma TV by running a ground to it.) How close is the antenna to the TV? Can you tune to the same frequency as the 281 with an HT and get the same interference? Do you have an RTL-SDR dongle? |
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Try putting snap-on Rf chokes on the TV power cable. Some higher end surge protection units have RF filters in them. Relocating your antenna may help too. Adding an external bandpass filter may help too. Some radios with wide band receivers have less than perfect RF Image rejection.
I had similar issues with an Icom IC-2410H radio when I used it with a high gain external vertical antenna. I've tried grounding, RF chokes, external filters etc. Nothing seemed to help. I replaced it with Yaesu FT2800M and it fixed the problem. |
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Quoted:
How's your coax routed? How's your station ground? How well is the TV grounded? (I partially fixed my in laws Plasma TV by running a ground to it.) How close is the antenna to the TV? Can you tune to the same frequency as the 281 with an HT and get the same interference? Do you have an RTL-SDR dongle? The coax is routed under the house and up though the floor. Station is grounded with a braided strap into a 8 ground rod drove about 6' into the ground. TV is not grounded. The TV is in the middle of the house and the antenna is approximately 25' feet from the TV. It doesn't seem to be as much interference on the handheld but yes there is some. As far as the frequency goes. It doesn't matter. I keep the radio on scan most of the time and when it happens it doesn't matter where in the scan loop it is. No I don't have the RTL-SDR dongle. YET!! I have tried two different 281'S. This may give me an excuse to get a new 2M. You know for "experimental purposes" 
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My dad lives several miles from a powerful TV Broadcast tower (1,200 ft. tall, running 50 kW). He could never hear anyone on 2 meters when he turned his antenna towards the tower. I gave him several new radios made by Yaesu, Kenwood and Icom. The only radio that worked was an old Radio Shack HTX-212 single band mobile rig.
I'm not saying replacing the radio will be the cure for your problem but it may be worth borrowing one to try at your location. I would first try placing RF cokes on every cable that connects to your TV, including the power cable and cable TV coax. |
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Quoted:
My dad lives several miles from a powerful TV Broadcast tower (1,200 ft. tall, running 50 kW). He could never hear anyone on 2 meters when he turned his antenna towards the tower. I gave him several new radios made by Yaesu, Kenwood and Icom. The only radio that worked was an old Radio Shack HTX-212 single band mobile rig. I'm not saying replacing the radio will be the cure for your problem but it may be worth borrowing one to try at your location. I would first try placing RF cokes on every cable that connects to your TV, including the power cable and cable TV coax. The '212 (and the '202 HT) are interesting radios because they had built-in helical filters which rejected everything but the 2M band, so they'd work in really cluttered RF environments. Hence, my suggestion, putting a 2M-only narrow bandpass filter between the rig and the antenna. Most radios today have wide front ends (and in the case of some, no real front end filtering at all) so this may go a long way towards helping. ETA: Here's a quick BP filter using coax. I've done coax notch filters before and they work amazingly well. |