Electromagnetic Waves

[ZLZPQX1]

The factory-installed radio in my car does not work. So I purchased from Radio Shack a palm size battery-operated radio. There is a favorite radio station which I like to listen to by keeping the radio on the passenger seat when I am driving the car alone. The problem is that when I tune in for that station, I get quite a bit of interference --hissing sound-- which more or less disappears (and I am able to listen to the station quite well) if I either hold the radio in my palm or even place my palm about six inches away from the radio. Needless to say that this solution is useless while I am driving the car.

 

As a possible alternative solution to improve the radio's selectivity in capturing the electromagnetic waves broadcast by my favorite radio station, I hooked up an 18" long metal wire to the antenna, but that solution does not work.

 

Ca you please suggest a solution to my problem?

 

Also, as a scientific curiosity, how does the vicinity of my palm near the radio or my holding the radio in my hand exactly improve the tuning selectivity?

 

Thank you!

 

Regards.

Edited March 20, 2012 by ZLZPQX1

[Klaynos]

So what's most likely the issue is that the body of the car is shielding the internal antenna. Connecting the external one in they way I think you describe won't work well as the cable from the areial to the radio needs to be a resitance matched transmission line. The right kind of cable with the right kind of connectors on the end.

 

I'm not sure what is happening with your hand (I've seen similar effects with TV antenna) but I suspect you are acting as a relfector/scattering centre.

 

The first thing I'd try is to get a bit of tin foil, stick it to some cardboard so it's ridged and try just moving that around the arial to see if it helps the signal. I suspect having it set up so you have the arial between the tin foil and the car windscreen will work best...

[Joatmon]

It is likely that most of the interference comes from the engine compartment. You could try placing the radio on the rear parcel shelf. This might give the aerial a better signal also.

[ZLZPQX1]

It is likely that most of the interference comes from the engine compartment. You could try placing the radio on the rear parcel shelf. This might give the aerial a better signal also.

 

 

Thank you, both Joatman and Klaynos, for taking time to provide responses to my query.

 

I tried the easier suggested solution of placing my portable radio on the rear parcel shelf in my car (and also alternatively on the back seat). Either place worked equally well and quite satisfactorily --like "magic"!

 

By definition, "magic" is something which "works" without a person's understanding the involved science or sciences. But both of you provided scientific explanations as to where the interference likely comes from and also, likely how the vicinity of my palm near the radio remarkably reduces the interference. So I thank you both for both suggesting solutions AND providing scientific explanations.

 

Diverse sciences and diverse applications of sciences --technologies-- both form sources of immense joy --intellectually and practically-- for us human beings.

 

Regards.