Heavy Interference on AM Radio

[priusbob]

Does anyone else out there have a problem with heavy static on AM radio when passing under electric wires, under over passes, and in parking structures? It seems to me that I may have lost a filter or something, that in the past when the car was newer, I did not hear such heavy static when in these locations just silence until the signal was picked up again.

I'm not 100% sure, but this problem only happens on some of the radio stations. I listen a lot to a local News Radio station here in Los Angeles, it's one of the most powerful stations in Southern California, so I know the problem is not signal strength. When I listen to other AM radio stations, such as a sports station, the heavy static is not present.

Thanks,

Bob

[Smoke]

I have that problem, but had it in the last non-Prius vehicle as well. In case it matters, I did not invest in the upgraded sound system.

[walt]

<div class='quotetop'>QUOTE(priusbob @ Nov 9 2006, 01:53 PM) [snapback]346386[/snapback]</div>

Does anyone else out there have a problem with heavy static on AM radio when passing under electric wires, under over passes, and in parking structures?
[/b]

Yep, you just "discovered" what it was about FM radio that spelled the death of AM radio as a music provider in the 1970s. Static, interference, fading - or the lack of same. The AM signal is blocked by structures with a lot of steel in them. High voltage electrical transmission lines have lots of noise - and AM radio is VERY noise susceptible. It all depends on time of day (or night), distance from the AM transmitter, weather, direction, etc.

Nothing much you can do about it - you didn't lose a filter. And you are right, that 20-30 year old car your parents drove when you were a kid with the cheap AM only radio DID sound better than the souped up JBL system you have in your Prius. Today, car radios, even the upper level equipment, have a very cheap AM radio system. And, unfortunately, the better the amp and speakers, the worse AM sounds, since all the hiss, pop, crackle and hum gets amplified better and louder, then gets sent to new and improved speakers that can reproduce all those noises, since they think it is music! Back then, the radio amplifier and speakers didn't have bass response or high frequency response, so the hum and static never made it out of the radio, and what little did, never made it out of the speaker due to its roll-off at the low and high ends.

[stanleyjohn]

PriusBob! I have the same problems with my am.Also the fm sounds good!but i do have more fading than previous cars.My other car had the slide in antenna on the side!This is my first car with the prius type antenna.Maybe these antennas are not as good as the other types or the toyota stock radio is a bit weak in reception and noise reduction.I may look into some kind of a signal booster amp and noise filter.

[dreichla]

I've also noticed the interference with weak signals also is affected by the various functions of the car's electrical components. I can often eliminate the static for a few seconds by letting off the gas pedal and deadbanding.

I thought I read somewhere that the optimum antenna is of a certain length to match the wavelength of the signal. Could the length of the Prius antenna be too short for optimum reception?

[wb9tyj]

welcome to the world of RF...With so much RF floating around the atmosphere, it's a wonder the AM even works at all... Power lines, Cable lines, Telephone lines, street lighting, touch lamps in peoples houses, scanners, computers, and the new BPL over power lines have pretty much destroyed the AM broadcast band as well as HF as well. BTW, just food for thought, all aircraft still communicate with Air traffic control on AM...thanks to the short sightness of the FAA...scary when it can be interfered with and act just like your AM radio,in your car, in the aircraft....