On Fri, 27 Jul 2012 10:12:54 -0400, micky
wrote:

On Ebay, I bought a cell phone with FM radio, that gets the radio from
local stations, not from cell phone data, and after I bought it, I
found the manual online, which says that the radio antenna is the wire
to the earphones.

Yep. I have one like that. Motorola Droid X. The receiver
sensitivity is horrible and it only works in strong signal areas.

But the phone didn't come with the factory earphones.

Mostly I want to listen to 88.1 Mhz FM, and if possile 88.5, and
90.1frequencies.

For antenna purposes and those frequencies, are there any differences
from one headset to another?

Somewhat. There are headsets (4 wires) and earphones (3 wires).
Either will work. The problem is that some of the headsets come with
shielded wires, which will cause reception problems. I've only seen
one like this, and it has an easily identified thick cable.

Does the thickness of the copper wire matter?

No. In theory, tiny wire may add some resistance or reduce the tuned
bandwidth. In reality, the receive is so bad, you probably won't see
any differences.

Factory headphones may be impossible to get. without buying a second
phone.

Baloney. Such headsets are all over eBay. It would be helpful if you
would kindly disclose the maker and model of your phone.

Should I try to find out how long the wire is on factory
earphones and get a headset with the same length?

No. While getting the length correct, the lack of a counterpoise
(other half of the dipole) is probably more important. In ham radio,
it's called a "tiger tail".
http://www.hamuniverse.com/htantennamod.html
http://pgh-net.com/ae3c/tiger-tail.html
I played with it on my Droid X. It certainly improved reception, but
it was still lousy. I'm thinking of an external RF amplifier, but
suspect that will increase the sensitivity to the point where it will
pickup computah noise from the processor (which is why the receiver is
nearly comatose). Good luck.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558