On Dec 17, 4:08 pm, "William Sommerwerck"
wrote:
wrote in message

...

Seconding this, most high-end RC transmitters will transmit on a
variety of frequencies within a specific range, changed by crystal.

The difference in frequency is less than 5% -- probably less than 2%. That
is not a major difference in antenna length.

Inches, anyway. I do notice that when I trim the antenna "correctly",
I will get about another foot of depth before the "No-Signal" blow-
ballast (Sub-Saver) relay kicks in. There are several of us on our bit
of creek, so we are acutely sensitive to frequency and try to be
several steps apart, at least.

I had to change out the factory motor in the latest sub for one with
more torque and speed, which, in turn required a different propellor
(but same diameter) to reduce cavitation at the higher RPM. Going
downstream is no problem. Going upstream requires a bit more oomph
than is typical of a submarine operating at "scale" speeds. The creek
is about 40' wide and something around 6' deep in the channel directly
in front of our summer house, and crystal-clear so ideal for the
purpose - except for the current.