"Joe" wrote in message
k.net...


Hi John,

That's what I have been doing. Just using a piece of 20 ga wire for an
antenna, it is about 15cm in length (a vertical antenna). On the
transmitter, I was using a loop, a piece of 20 ga wire with a 1 pf cap
between the hot end of the antenna and the transmitter pin, other end
grounded.

Last nite after I read all the responses, I went to the Handbook and
looked
at page 10.10. There is a graph at the bottom of the page that shows
inductances of a straight piece of wire at that frequency. Anyway, I
rigged
up a 0.9" piece of 20ga wire between two 8pf ( I did not have 8.2pf) caps
and the reception increased dramatically. My test method was: Receiver in
my
house on a bench. TX outside about 80 feet away. In the old configuration,
the receiver would sometimes receive the TX pulses. Once I put the TX
inside
my tool shed (about) the same distance away, the receiver would not pick
up
the signal. So after I rigged up my "almost" 18nH inductor and the 2 8pf
caps, I repeated the experiment and the receiver was able to reliably
receive the transmissions in both places. So I definitely saw an
improvement.

As far as FCC goes, this frequency is supposed to be for ISM, and you can
use it unlicensed subject to part 15, that's why my first attempt was to
work on the receiver, not the TX, but I may experiment on the TX now also.

Joe
KB1KVI


Good work, Joe. Keep experimenting. It pays off.

John