Posted: 5/6/2013 8:18:47 PM EDT
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I just took delivery of a new Yaesu FT-2900 and a Samlex 1223 power supply today. I hooked everything up and now I'm having intermittent interference problems. The radio will pick up intermittent bursts of static for 1/2 to 1 second long randomly. I'd say every couple minutes. It will do this regardless of where I have the squelch set.
The radio will do this attached to either of my home antennas, one is an externally mounted GP-9 and the other is an attic mount GP-6. It actually seems to be worse with the attic mount GP-6. My FT-8800 and my FT-60 will not do this attached to either antenna and on the same channels. Is this most likely a radio problem or is it possible it is the power supply? I haven't tried an alternate source of power but I plan to give that a shot tomorrow. Any advice would be appreciated. I'd at least like to narrow the problem down to the component before contacting either company. |
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Eliminate the supply as being the problem by running if from batteries for a while. Does the problem repeat?
Or it could simply be a strong signal of unknown origin. We have such a signal just as you describe that is directly on the frequency of our local repeater. We have not been able to track it down. It can be heard on all radios tuned to that frequency. |
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I would suspect that some other type of switching power supply is the issue. Most "wall warts" are notorious RFI generators. I also had a computer that had a bad switching power supply. It made my HF radio unusable until I turned off the PC.
I know that LED lighting fixtures will also cause extreme interference too. A friend recently installed some lighting fixtures that zapped his receive. Killing the mains to your house fuse panel and then hooking your radio to a 12 volt battery will give you a clear indication if its something hooked on house power grid. Samlex is good stuff and mine does not cause any RFI. Good luck in your search. |
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Does the noise occur with no antenna or feedline connected? I've been listening for about 15 minutes with no antenna attached and I haven't heard anything, so I'm going to say no. In the 5 minutes before I disconnected the antenna I heard the interference 3 times. I just brought my FT-8800 up from the basement to hook up in an attempt to replicate everything with a different radio and see what happens. I've already tried it hooked to the same antenna (I have a patch running from the basement upstairs so I can use the antennas in both locations) and it received no interference but I want to try the same physical location just to be sure. |
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Ok, I brought my FT-8800 up from the basement and tried it with the same antenna and cable and no interference. That radio is in my EMCOMM box and is run on battery power so I pulled it from my EMCOMM box and put it on top of the FT-2900. I used the power supply and the antenna so that everything was the same (position, power source, antenna) and I did pick up the interference, though much less frequently than with the FT-2900. Perhaps a better filter on the FT-8800? It is 2.5 times the price.
Now I'm going to rig up the FT-2900 to run off the battery and turn of the power supply to see what happens. |
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Playing around with several radios I've been able to replicate the interference with my FT-8800 in the EMCOMM box as well as out of it, and not with my HT attached to the large antenna and, rarely, using the small HT antenna. This source must be new, as I've run these radios on these antennas before without a problem.
I've pinned down that the source is almost constant on 144.585. I was noticing the interference sporadically on 144.500. I guess I'll just have to pick an alternate frequency as I've disconnected everything around the house I can think of and it is still a problem. |
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Quoted: Playing around with several radios I've been able to replicate the interference with my FT-8800 in the EMCOMM box as well as out of it, and not with my HT attached to the large antenna and, rarely, using the small HT antenna. This source must be new, as I've run these radios on these antennas before without a problem. I've pinned down that the source is almost constant on 144.585. I was noticing the interference sporadically on 144.500. I guess I'll just have to pick an alternate frequency as I've disconnected everything around the house I can think of and it is still a problem. Sounds like a little fox hunting ought to be in your future. You can tune slightly off frequency from the interference and use your handie as a direction finder. A tape measure yagi works very well also and are cheap & easy to make. http://www.open-circuit.co.uk/tape.php Find the source...and kill it.  |
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Start walking around the block with your HT and see if you can close in on the source. If you have a handheld yagi you can connect to it, direction finding will be much easier. That's the thing, there is no around the block here. I'm sitting in the middle of a field with the nearest house 1/4 mile away. I've unplugged everything I can think of. If suppose I could kill the house main and see if it goes away just to make sure it isn't from within the house. |
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Kill the mains to the house. If noise is still there, it may be intermod from another transmitter. Are there any commercial towers nearby? There is a cell tower a couple miles east of me but nothing else. When I can I'll try killing the main and see what happens. |
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Well, I took my HT outside and didn't get any interference on 144.585 so I killed the house main breaker. The interference on 144.585 went away, but I still got the intermittent interference on 144.500 on the FT-2900 (being run on batteries from my EMCOMM box).
This is frustrating. |
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Well, I took my HT outside and didn't get any interference on 144.585 so I killed the house main breaker. The interference on 144.585 went away, but I still got the intermittent interference on 144.500 on the FT-2900 (being run on batteries from my EMCOMM box). This is frustrating. May want to try and at least track the 144.585 interference to an individual circuit on the house... turn off each one individually and see which one/ones it happens with then figure out what on that circuit is causing it. As for the interference that doesnt go away on 144.500... I know that can be frustrating, I get some from my neighbors, and I verified my HF interference is from my neighbors pool pump, and still have 2 meter interference from the east that i cannot track down... |
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Well, I took my HT outside and didn't get any interference on 144.585 so I killed the house main breaker. The interference on 144.585 went away, but I still got the intermittent interference on 144.500 on the FT-2900 (being run on batteries from my EMCOMM box). This is frustrating. Take EMCOMM box mobile towards the cell tower and see if the noise gets louder. If it does, the cell company may have an issue with it's transmitter or are now using a combination of frequencies that are generating the intermod. ETA -- Can you hear this noise on an AM radio? AM usually is more sensitive to noise. ETA -2 Is there anything battery powered in your house, like a laptop? |
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Well, I took my HT outside and didn't get any interference on 144.585 so I killed the house main breaker. The interference on 144.585 went away, but I still got the intermittent interference on 144.500 on the FT-2900 (being run on batteries from my EMCOMM box). This is frustrating. Take EMCOMM box mobile towards the cell tower and see if the noise gets louder. If it does, the cell company may have an issue with it's transmitter or are now using a combination of frequencies that are generating the intermod. ETA -- Can you hear this noise on an AM radio? AM usually is more sensitive to noise. ETA -2 Is there anything battery powered in your house, like a laptop? I'll try that frequency range on my mobile near the tower and see what happens. This is a channel my mobile radio (also an FT-8800) scans and I've never had any interference break through but I'll try it. I can only replicate it using the other radios with the squelch turned down below half, if it is up above half they filter it out and don't break squelch. I'm still wondering if it may be a problem with the 2900, which will still pick it up even with the squelch all the way up. I have a laptop (using it now) but it was one of the things I turned off to test. Had no effect. I can't think of anything else that is capable of battery operation other than cell phones and an iPad (also turned off). How would I look for the noise using an AM radio? |
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Even turned off, the laptop will probably generate noise. Remove battery to truly power down the laptop. An AM radio (even an HF rig set on AM or SSB) is alot more sensitive to noise due to the nature of AM/SSB reception.
With an AM radio, the closer you get to the noise, the stronger the noise will be. Like playing hide and seek with RF. |
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I can't think of anything else that is capable of battery operation other than cell phones and an iPad (also turned off). Security system? Mine has a battery backed cell transceiver. I have a security system that is on battery backup, hadn't thought of that. I would still find it unlikely, since this interference has never popped up before, but I'll see if that might be involved. I work the next few days so I won't be able to mess with it much until the weekend. I did contact Ham Radio Outlet, where I ordered it, and they asked me to contact Yaesu to see if they have any suggestions. If not, they will exchange the radio. |