Interference from multiple sources on FM stereo.


Old 03-11-15, 05:41 PM
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Interference from multiple sources on FM stereo.

Have an old (like from 1995, it even has a cassette player in it) little mini component system, JVC UX-A3, that I used outside on my porch for the last 7 years. Never had a problem other than the cassette doesn't work and the CD probably needs a good cleaning.

I bring it to this place and put it on the shelf with a good external (indoors) antenna and I get all sorts of interference. More on the lower FM bands like PBS (89.3)...but up around 106, not nearly as bad, even though they are both on repeaters placed on the same mountain about 10 miles away.

Previously I was using my little Ryobi jobsite radio and it had an annoying hiss and sometimes a Well I discovered that was because of the Ryobi battery charger 6 ft away. Hissed when not charging, when charging. Simple fix. Move the charger or unplug when not in use.

The mini system has the same issue, but it also has static when the garage lights (CFLs) are on, or I use the microwave which is a good 15 ft away behind 2 walls and a metal door. I can tell when my food is done because the pulsing crackle goes away.

I used the mini on a ship with radars, high power transmitters, all sorts of electronics and it never did this.

Is it just because it's old, or is there some sort of filter I could use? Maybe somehow actually locate the antenna outside? I mean, I live in a Faraday cage (stucco house with metal lath), and the radio signal does get a bit better when the garage door is open, but the interference is still there.

I don't like listening in the dark and being hungry just to hear clearly.
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Old 03-12-15, 03:49 AM
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Have you tried attaching a remote antenna? I have similar issues with my shop radio [an ancient radio shack receiver] I prefer some of the AM stations but it will not pick them up consistently out there and I had to install the remnants of an old TV antenna to get good reception with FM. The fluorescent lights don't seem to affect my radio
Old 03-12-15, 08:15 AM
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Yeah, I never had an issue with the tube shop lights at the other house, it's just the CFLs. Of course I normally run 6 at a time. I'm not spending almost $100 to light the garage by buying LED. I may try putting the antenna outside just to see what happens.
Old 03-12-15, 07:19 PM
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If the receiver has an FM antenna jack, get a piece of coaxial cable with the appropriate connector on it and run the cable outside and preferably up high. You can run it up to your attic also but it would seem that from your garage .... outside would be better. Keep in mind that FM is line of sight from the source antenna and has a max range of about 60/70 miles. (curvature of the earth, hills and valleys, large buildings, water towers etc. all can have an effect. Just like TV signals.) leave some of the center core wire exposed (a couple of feet.) but try to position the wire or seal the end where the braided shield is so that water doesn't get in and wick down the braid. It will eventually corrode the braid. The exposed couple of feet of the center core wire is your antenna. If you were a ham operator you could find out what the wave length of your favorite station is and cut the exposed wire to that length.

If you still don't get good reception, make sure that you leave some excess wire for the outside run as you may have to move it to a few different locations until you get an acceptable signal. Try to keep open space between your FM signal source and the antenna wire. Ie. don't put where your house is in the way.

If that doesn't work then you'll have to get an FM Antenna but you'll already have run the cable so more that half the work is done. FM antennas have various size elements on them like the old TV antennas did only they are cut to the length of the wave length of the commercial FM bands.

That's about the extent of my knowledge on the subject. Ham radio operators are the guys who know all about this stuff.

By the way, if you think about it, since you live in a "Faraday Cage" ..... as good as they are in keeping RF signals from getting in ..... they also don't allow RF signals (ie interference) that originate from inside of the cage to get out. You just may be living in an RF world of your own making. Technically ...... a microwave oven when all your stuff is running. :-> You may want to invest in a RF dose meter. Hell, you might even be able to put all the food on the dinner table uncooked, turn every thing on and leave. Come back in a few hours to a fully cooked dinner.

Don't forget about the cat .... though ..... or not.
Old 03-12-15, 07:30 PM
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That's right.... the cat likes FM radio too.
Old 03-12-15, 08:53 PM
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Thx Jimmiee. Yeah, I've thought about this stuff. Like I said (or implied I guess) I worked electronics for 24 yrs in the Navy. Of course we didn't have CFLs or apparently VERY leaky microwaves. My higher quality MW at the old house never caused this trouble. Got a appliance guy coming in a few days, maybe he'll be a Pro and have a meter.

As to running the coax, yeah, that would be a royal PITA. I haven't even been in the attic, but it doesn't look inviting and I'm not even sure what kind of vents I have. Have to look at that tomorrow. It's connected to a TERK amplified antenna (not powered ATT) and it picks up very well as long as all the static sources are off. Very odd though, moving it a matter of inches can change the problem, and just me walking near or away from it affects it. I may just drill a hole close to the unit and feed coax outside. I can always patch it later.

No worries about a cat...SHE kept them.
Old 03-13-15, 03:27 AM
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At least you have an FM signal. In our valley there is little to be had. I just insert an Ipod into my Ridgid jobsite radio and let it rip for hours at a time. The one station we can pick up is talk radio, and all the "talkers" are monotone and boring.
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