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Old May 5th 06, 01:08 PM posted to rec.radio.amateur.homebrew
Doug Goncz
 
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Default FME "paper clip" antenna

Hello, my new group.

Let me know if I am on topic for this group, please. It seems like rrah
has had some cellular posts. There didn't seem to be a NG for cell
hacks. Homebrew is the thing.

My Cingular / Seimens SX66 ( HTC Blue Angel ) has an FME RF port on the
back. I couldn't find an accesory antenna without a cable at Wilson,
or anywhere else. I usually lay it down on its face to protect the
touch screen while I am using it with the headphones. When it's in the
sun, this keeps the screen from overheating.

It seems natural to insert the _right length_ of suitable gage piano
wire into the FME port but somebody could get an RF burn that way. I
got one off my Motorola Star TAC long ago. God, what a clunker.

I guess whatever surface the 'phone was lying on would be a ground
plane. I wonder if a metal surface would produce better results than a
wood surface. I think it would.

What length and gage of piano wire would work? That is, the gage would
be a pin to fit the FME center conductor socket and the length would be
determined by an equation involving the speed of light and a factor
applicable to the particular antenna design.

First off, is this a port for the cell antenna or for the WiFi?

What's the shortest wire I can use? A quarter wave in the 1800-1980
MHz band would be shortest, wouldn't it?

Could I just dip the wire in some grip compound, the kind you would dip
plier handles in?

Would it help to heat-shrink this thin wire?

Would heat shrink and grip dip be enough protection for a reasonable
level of safety?

Looking forward to more bars and bits per second more often. (I use it
as a wireless modem, too) Might be some fun.

The smallest antenna I found was a Wilson mini that magnet mounts to
the roof of a car. Not so good since I don't drive, and travel very
light on my bicycle and by bus.

I can see a bus driver coming back to my seat and saying "Would you
please take your antenna off the side of my bus? Somebody's gonna get
their eye poked out!"

Doug Goncz
Replikon Research
Falls Church, VA 22044-0394