[Ciesel]

Back in the "Old Days" when you drove under a bridge you would have a momentary loss of signal on the ol AM radio.

On my 06 Wing the signal gets louder. WTHell ! :?

 

[Mark Rowell]

Understanding radio wave propogation is 1 part techno jargon and 8 parts magic. The remaining part is BS. I am a ham (KC6BPH) and should know this stuff, but if I am not reading it out of a book, antenna construction is lost on me.
:roll:

 

[Ciesel]

Understanding radio wave propogation is 1 part techno jargon and 8 parts magic. The remaining part is BS. I am a ham (KC6BPH) and should know this stuff, but if I am not reading it out of a book, antenna construction is lost on me.
:roll:

Roger that ,amateur operator Extra Class AD5MG

 

[Guest]

Back in the "Old Days" when you drove under a bridge you would have a momentary loss of signal on the ol AM radio.

On my 06 Wing the signal gets louder. WTHell ! :?

Imported steel...........LOL

 

[Arn Butt Bill]

One of the pan-handlers that lives under the bridge is broadcasting.

 

[Jan Kokochak]

Well, if you really want to know, it could be what is known as "re-radiation." The bridge sturcture receives radio waves and resonates on the same (or exact multiple) freqency and sends the signal to your antenna. I guess one could say it's almost like the bridge is a mirror in the right place to reflect the sun into yours eyes as you pass under. It is likely it would not happen under the next bridge, or the next one or the next. Really, more like sonar or radar, where the signal hits the metal object and bounces back.

The only way for this to be corrected, is for you to set up a booth at the offending bridge, stop all traffic, have everybody sign a petition, then hire a lawyer and submit the complaint to the FCC. Then the FCC will investigate and if the offending reradiation is found to be causing interference, the state will be forced to detune the bridge. That is, if the radio station was there before the bridge. If the bridge was there first, then the station will have to take steps to detune itself slightly.

Aren't you glad to asked. BTW, I'm glad you were on your goldwing when this happend so that the "off topic" police won't chase us.

 

[PoleCat]

You sure know how to lobe a grenade into a room Jan.

 

[ziggystyles]

AM radio....hmm...I remember my grandpa telling me about that. :lol:

 

[Daver]

Yep, My Dad works for a TV station and He said they used to only have AM Radio when they were kids... and NO TV... So I asked him "what did you listened to after school?" He looked at me puzzled for a moment, laughed and said "the victrola".

 

[Dave]

AM Radio thats the one that plays American Music right...FM plays Foriegn Music

 

[KA7W]

OK, I see a lot of answers but will give the correct one here.

Jan Kokochak had it pretty close, re-radiation. What he left out was phase angles. When the re-radiation is in phase with the originating signal, they add and the field strength goes up. I have used bridges many times to make a long distance contact. Move around until the signal increases.

Its like a Yagi antenna.. ( a multi-element beam antenna) It has areas of high signal strength and areas of low signal strength and even a few nulls.

When I was working in the antenna field and manufacturing antennas, I had a saying " Antennas are an exact science with a infinite number of variables "

Still looks confusing !! 8)