In article , Leo Szumel
writes:

Hi Jim,

Hello Leo

N2EY wrote:
I think there's a problem with using a code that is not publicly available.
ID
is not enough; if the message cannot be read by a suitably-equipped
monitoring
station (read: FCC) what you have is a form of encryption.

Amateurs are not allowed to intentionally encrypt or otherwise conceal
transmission meaning or content, with one exception: remote control
commands.
So the "turn off" command would be OK to encrypt, but not the data coming
from
the remote sensors.

I see your point. How about this, though:

97.217:

"Telemetry transmitted by an amateur station on or within 50 km of the
Earth's surface is not considered to be codes or ciphers intended to
obscure the meaning of communications."

97.3(45):
"Telemetry. A one-way transmission of measurements at a distance from
the measuring instrument."

Also, 97.309(b) indicates that unspecified codes can be used so long as
the purpose is not to obscure the meaning of a communication.

Good point!

As I interpret it, what this means is that the telemetry message doesn;t have
to be self-explanatory. For example, a remote sensor might report "534A0" as a
telemetry message in, say, ASCII, which is a "specified code", but there's no
need to have the remote sensor indicate what the symbols mean.

Thanks for your input,

You're welcome!

73 de Jim, N2EY