biro@oracle.DEC (07/02/85)
I just saw the first review of the FRG9600 and though
it was time I added my two cents also.
YAESU FRG9600 VHF/UHF SWL RECEIVER:
AND THE MX5000 COMMENTS
I have had a Yaesu 9600 now for almost a month and these are
my observation and comments on this swl receiver. I also have
the RS232 interface and have been able to program it from my
computer. I have had the MX5000 for about 6 months that is the
only other receiver I can use for comparison.
Conclusion:
The FRG9600 is a great SWL receiver but is not really design
for a scanner. I have both the MX5000 and the FRG9600 and if
I could only have one I would pick the FRG9600 as most of my
receiving is listing to satellites and SWL like activities.
The unit is easy to use and to program from a computer.
The unit is in a shielded case and little intermod / birdies
have been found. I do a lot of monitoring of the 137 MHz
band and the MX5000 has problems with a local FM station but
the FRG9600 does not. This may be why the sensitivity of the
FRG9600 is not as good as the MX5000. I am glad to see that
the scanner are going towards SWL receivers, but where is
the cw filter, the agc selection, bandpass tuning etc.
- The sensitivity of the FRG9600 is not as good as the
MX5000 but it is not as susceptible to microprocessor noise
as the MX5000 is. I have not done any measurements but
by simple step attenuators test I would assume that there is
about 3 to 6 db of difference.
- The scanning routine is very bad, it stops on a channel
and then continues. There is no option to stop on scan.
It sure would have been nice to have the unit send out
the freq. on the RS232 line. I still wonder if that is
what they had in mind when they had it stop and blink one
digit at a time and then continue scanning.
- The programming of the unit from the keypad is very easy
and straight forward. All commands are done the same way
not like the MX5000 which requires a different sequence
depending on what scanning mode you are in and if the
squelch is open or closed. I found the rotary dial to be
easy to use an much like the two meter FM units, with the
variable rate tuning steps one can easily tune threw bands.
The only exception is in the ssb/cw mode where the step
is fixed and not adjustable.
- The RS232 interface is simple a RS232 level converter
to TTL levels (? 0 and 3 VDC and level inversion switching
to invert mark and space if needed ). The baud rate is 4800,
and there is restriction on the time for all 5 character
to be sent to the receiver. The odd part is the fact
that there is a requirement of two stops bits. I am not
sure why as the industry standard is 1 stop bit above
300 baud. This gave me some problem as my computer only
did one stop bit, at first I could not program the unit
because of this. After many hours of scopeing out the
signals I determine if I put in a delay between sending
characters to the FRG9600 I could fake out an extra
stop bit. I use about 1 ms as that is what my delay
loop first came out to be but any delay that is greater
the 1.5 bit time should be enough. After this I found
it very easy to program the mode and frequency of the
FRG9600. These are the only command one can program.
It would have been nice if you could program
the selection of the memory channels but you can not
and it would have been nice if you could use the step
size and stepping and features but you can not. It also
would have been nice if they had brought out the squelch
to the RS232 interface but they did not. I did bring
out the squelch line and tied it it data set ready of
the RS232 line.
- From the computer interface one can set any frequency
independent of the mode to 100 hz and it dose not snap
to the nearest mode dependent step size. This is a
very nice feature for odd frequency and in automating
doppler shift correction for monitoring satellites.
- There is a clock and timer on the unit but it is not
assessable to the RS232 interface. The clock is not
battery backup like the MX5000 but all the memory
channels are.
- Separate squelches are provide for AM/WBFM and NBFM.
It seems to work well except for AM.
- The ssb detector is very good, I was lucky to receive
the unit just before the VHF contest and copied may
ssb/cw station in the 144/220/432 MHZ bands. They
are easy to tune in.
- I have ordered the Video interface for it , but it
is not available yet.
- External connections allows one to get the following
signals, squelch, agc voltage, audio, if output and
more . Those are the one I remember as I do not have
my manual with me. The connector for the ant is a
standard PL259 type connector, it should have been
an N type connector.
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