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a couple questions about AM reception

B

bobdavcav

We lost power somewhere between noon and 1 yesterday and got it back about an hour and a half ago. I noticed 2 things,
1. My neighbor was running a generator, but other than that there shouldn't have been much power line noise if there usually is any. We have underground wiring as it is, so I'm not sure how much noise there is usually as opposed to how much there would be with no power. Is there a certain distance I'd need to be away from power lines to notice any am noise difference? A traffic light about a half mile away had power but that was the only thing within that distance to have power as far as I know, yet DX wasn't anything special.
2. I keep the G8 on a shelf with a bunch of other power chords and electronics, and I figured that it was the collection of those, even if they were unplugged, that caused the noise on the G8 when I had it there. However I had the radio in the same spot with the power out last night, there wasn't any noise there. Could this have something to do with the power chord on the clock radio I have plugged in on the shelf above?
 
It might have something to do with the clock radio itself, or anything else emitting RFI.

As far as noise levels, it's hard to tell much w/o a signal strength meter on the receiver.
I've noticed a similar thing to you, that DX was nothing special when the power was off.
But the noise floor was definitely lower. It still didn't really help daytime AM reception.
Night reception is fine regardless- it's all above the noise floor.
 
During widespread power outages such as the one in the Northeast in 2003, many stations, AM and FM, were off the air. The bigger stations in SE Michigan like WJR and WWJ continued to operate with generators. But you could get stations outside the power outage area. One example was getting WSAM 1400 about 80 miles away, just 15-20 miles from the area where the WDTK 1400 transmitter is located. It was fun until I started thinking about all the things that would happen if the outage lasted for days, and realized that I had to start filling water containers in preparation for a continued outage. It lasted about 20 hours in my location.
 
Unplugged power cords & electronics shouldn't cause any RFI. As for powerline noise, remember that the powerline wires themselves act like transmitting antennas so you can get decent AC hash from them even a couple blocks away. So if there are above ground powerlines a couple blocks away, and they are emitting hash, they could possibly be heard on your radio.

Re: your clock radio: the best way to check would be to unplug it momentarily while DXing and see if it indeed is causing your RFI. I have several clock radios -- none of them put out RFI. The best thing to do is take your G8 around the room or house and DF the RFI source.
 
Depends on what the clock radio is - my daughter had one of those 'iHome' things. The moment she plugged in her phone to charge - immediate strong RFI that goes many feet.
 
rbrucecarter5 said:
Depends on what the clock radio is - my daughter had one of those 'iHome' things. The moment she plugged in her phone to charge - immediate strong RFI that goes many feet.
Click to expand...

I hear ya. My clock radios are all 90's and late 80's vintage: Sony Dream Machines and a Panasonic (which, although it has a smallish loopstick, pulls in DX).

A lot of them now seem to have docking stations and the like. Probably RFI generators. :)
 
I'm not sure what brand mine is, but good luck trying to DX from it. I'm thinking I'm going to get the CC Witness sometime soon, which comes with a wire antenna. I think I'll plug that into the clock radio, which does have a spot for an antenna. I've never had my phone plugged into it while DXing, maybe I'll try that.
 
AM radio is susceptible to all types of electrical interference.The neighbor's heatolator in the fireplace across the street,running continually,created all type of electrical interference to my radio,and the neighbor up the street with a defective heating element in a fish tank was just as bad.Two separate incidents.I walked up and down the street with a small portable radio tuned to a weak AM station to find the Culprits !Fortunately the neighbors agreed to fix their issues.Troubleshoot my friend, just troubleshoot.
 
Another very odd thing happened last night. Our wireless router got unplugged for reasons I won't get into here, but I noticed on my clock radio that KOMO was buzzing semi-loudly. Mom plugged the router back in and just like that the buzzing was gone.
 
No idea why that would happen.

Here the router coats half the AM band with clucking hash if the cable to the computer is plugged in. Unplugged, there is much less noise. The switching power supply puts out a lot of AC-type hash, also, but thankfully it only goes about 15 feet from the source or so.
 
I have a washer/dryer that creates RFI on several frequencies, even if the power is off or disconnected. It's probably part of the "computer" in the machine.
I'm planning to add ferrites to the power cord, and possibly add a ground braid or two.
 
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