can you rig a car radio to send a SOS for short distances or use a car battery to create radio signals?

Question

I am referring to the family lost in Oregon with their car in the snow. I wonder if there is anything that could be done to the car radio to produce a short range signal.

Answer 1

The last answer is correct, you can't use the radio to send an SOS. However, you could probably come up with something. If you cause a spike of current, it shows up as a "pop" on the radio. I would NOT recommend shorting out a car battery, but if you could short it though a resistance or a large coil of wire, it could be possible to send a short distance signal.

Do not short out the car battery, it will consume heavy current and possibly explode due to the hydrogen in it.

To simulate this "RF pop", try it on a small scale. Take one or two D cell batteries, and tap a wire on them to short them out. It works even better if you have a fairly long wire. Ensure you TAP the wire. Holding the wire on could cause you to burn your hand or cause a fire, and it does no good for the transmission. You will only detect a pop when you tap the wire.

The pop is detected on any radio, and usually only on the AM band (lower frequency is better). I tried this as a kid many years ago.

I'm assuming you are thinking of using this as a "distress call" if you needed one. While this "MacGuyvering" might work, I wouldn't count on it. Even if you did it correctly with a car battery, the signal would not travel very far, and most people wouldn't be listening or know where the noise was comming from. The chances of rescue would be slim.

A cell phone or satelite phone is a much better approch.

In any case heres a nify link regarding radio kits:
http://sci-toys.com/scitoys/scitoys/radio/radio.html

One other note - transmitting (ANYTHING) without a licence is usually a federal offence. Tapping a battery like this would be "broadband noise" and definetly illegal. The reason you can do it with a D cell is that the signal doesn't get very far. If you ever tried something like this with higher power, you would be in big trouble by the FCC if they found the transmission. Of course, if it was a matter of life and death, they might be more forgiving. Still, use a cell phone instead.

Answer 2

Sweet thought, but the problem is that a car radio is a receiver and what you need to send a signal is a transmitter. And they are as different as day and night. Forget MacGyver and Mr. Data, the stuff they do in movies doesn't work in real life!
What people (especially those with some lack of common sense) should have in their cars is a scaled down version of "On-Star", in the hope that there actually are still people out there who understand ...---... when they hear it, somewhere, well, on which frequency or band?!