Speaking of Ham
I listen to 560 AM when I’m in the car every day. I get a LOT of interference. The Van gets almost none of this interference. If this were the other way around, if my 2m/440 radio was getting some interference, I’d know how to high pass/low pass it, but I don’t know what I’d do with an AM radio. A notch filter? Maybe around 60 hz? And how would I hook it in?
Anyone out there who is uber geek enough (Yes, Roberta, I’m talking to YOU, and Grumpy Old Ham, Too!) maybe you could point me in some meaningful direction.
12 comments Og | Uncategorized
What kind of interference? Impulse noise? (pop-pop-pop, related to engine revs). Whining at higher speeds that varies with road speed?
Lots of sources of broadband noise in a car (or van)! Check the ignition wiring and components for age and tightness, bonding straps between various components (engine-body, boot and bonnet hatches. Check that the antenna and antenna cable are all tight, too.
The noise seems to be power related. I used to have a whine that associated with the blower motor, so I replaced the motor. The antenna is properly grounded. The cap that shields from ignition noise has been replaced, and there was never a whine/engine speed corellation. The noise is worst when around high tension lines, and the radio is perfectly static free at 890 am, just close to 600 and 1200 it’s nasty. Checked ground straps. More noise/whine associated with plugging in cellphone adapter. Antenna recently replaced, and properly grounded to a rust-free area ofthe frame, bare metal to bare metal, protected with conductive grease.
The station in question is 560 AM- close enough to the worst spot (600) to get a lot of carryover noise. Hence I was thinking a notch filter.
Sounds like way too much work for me. Switch to FM and deal :). Hey, does it mean I’m turning into a geek since I’m reading and commenting from my new Blackberry?
“the radio is perfectly static free at 890 am”
How does it sound in the evening?
Y’know, I think listening to AM radio is a sign of impending geezerdom.
I noticed a couple years ago I stopped listening to music on FM, & started with the talk radio thing (around here it’s 680).
I too have the AC/RF interference when near power lines or “heavy use†areas. Didn’t have that when the truck was new(er). That might be a clue I suppose…
Hope you find the answer to the problem so I can fix mine as well.
Good luck!
Roberta X covered most of the bases, and it sounds like you’ve hit the usual trouble spots. If you’re not getting ignition pops or alternator whine, there’s no point in wasting money on expensive shielding and bypass capacitors for those areas.
A notch filter in the antenna feed would cut down the noise. Since Radio Shack has long since stopped carrying a meaningful line of actual electronic components, you might try DigiKey or a similar outfit. Specialty auto sound places (not WorstBuy or the like) might be of use, or perhaps Crutchfield. It really sounds like the receiver sensitivity peaks around those two freqs; do you have a substitute receiver you could (temporarily) install for an A-B comparison?
Oh, and Weet? I’m a kick your ass for that.
Just givin’ you static.
LOL! Nicely done.
Still have to kick you. Nothing personal. If I let you get asway with it soon EVERYONE will be a smartass.
I like GOH’s suggestion of trying a different radio. Like you, I listen to AM radio when I’m in a vehicle; the one in my Dodge truck is great, the VW radio, not so much. The problem with the latter might be the antenna, as they use a shorty (about a foot long) amplified job instead of the old-fashioned kind that the truck has.
Point is, if you can’t lower the noise, increase the signal, it’ll do the same thing for you, increase the S/N ratio and make it listenable.
If you can’t afford the $250-400 for a new receiver (and get a EU model, they still use shortwave over there and it will have those bands), then take the cheap but best route and get a GE Superradio 3 and throw it up on the top of the dash. It has the best AM receiver for the least money in it. They come in at $50 on sale, watch for them.
Grundig now markets most of their stuff here made in China under the name Eton, and I have an Eton 360 that is the equal of the Superradio 3, but has digital tuning, AND a choice of batteries (AA or D) to run it on, AND it will charge NiMH batteries in the radio with the included A/C adapter AND it has a decent shortwave (digital) section with RF-Gain. It will take an external antenna, but I’ve never had to use one, even on ultra fringe area AM stations. I routinely pull in AM stations running at 500 watts in neighboring states (400-600 miles away). It cost me about twice what the GE radio would have, but it is at least twice as versatile.
I may very well try that, Dog. I been wanting to get a little portable SW rig.