On Sat, 25 Dec 2004 22:17:42 -0600, "Kafir" wrote:


wrote in message
.. .
hi,

I am thinking about homebrewing a little digital packet transmitter
for 233.6MHz to telemeter some data back from a model aircraft (no not
radio control). It looks like thats a good freq for packet and it
seems to be very quite on my scanner.

I was looking at VHF versus .. say 900MHz to save power and keep the
batteries small. Perhaps a half a watt output max.

Do I understand correctly that since 233 is a quarter of 900MHz, it
appears the rf loss will be about 12db less (simple free space) than
if I went to 900, and thus it would take 16 times as much power at
900MHz to achieve the same distance?

I know that the higher freq would take more power but 1/2 watt versus
8 watts seems like a big difference.

Thanks in advance for the brain check. A


antenna size, efficiency, enters into the problem.
I would use the 233 for longer range, VHF is nice.


Thanks for the response, I was figuring a simple 1/4w whip in both
cases. A