[Yaesu] FM Receive on FT-757GX

[Glen Zook]

What is legal, and what is present convention are much
different.  Since most of the satellites are a linear
transponder, the signal would be repeated as FM if the
satellite was receiving in the 10 meter band.  Granted
that the use of FM on the satellites is "frowned upon"
by AMSAT, etc., since it uses a continuous carrier. 
The same thing is true for "normal" AM (double
sideband plus carrier - although SSB is an AM mode).

According to CFR 47 part 97, it is definitely LEGAL to
run FM anywhere that phone operation is allowed.  The
deviation of an FM signal below 29.0 MHz is reduced
from that above 29.0 MHz.

Now, as a matter of "band plans", etc., it is
definitely suggested to keep the +/- 5 KHz deviation
above 29.5 MHz.  However, this is voluntary.  Also, it
is definitely legal to run NBFM (usually +/- 2 to 3
KHz deviation) anywhere that you can run phone.  The
exception being that Noivce and Technician+ licensees
are restricted to using only SSB in the 28.3 - 28.5
MHz range.  This again per CFR 47 part 97.

There were some experiments during the 1950s and 1960s
using very narrow band FM (like +/- 200 Hz deviation).
 If there was sufficient audio recovery in the
receiver, along with a narrow bandwidth filter, the
signal was quite readible.  However, on receivers that
were not equipped to receive the very narrow band FM,
the signal sounded like a continuous carrier with a
slight "buzz"!

Anyway, again it is legal to run FM in the 29.0 to
29.7 range.  However, in those frequencies where space
communications are taking place, it is frowned upon!

Glen, K9STH
AMSAT 239 / LM 463
(member of AMSAT since its second month of operation)

--- Pres Waterman <presw@112motors.com> wrote:

This advice implies it is OK to run FM below 29.5
which it is NOT. That area has a lot of satellite
operation in it. They can not move.


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