That is good. I like that receiver quite a bit. I also did a full bypass on
the emitters of the 455kHz I.F. amplifiers. Yaesu uses a partially bypassed
emitter to give some negative feedback, probably for stability. I haven't
had any negative effects from doing the full bypass, except for the increase
in I.F. gain that I was looking for.
When I mentioned the MW attenuator mod, I forgot to mention that you reroute
the MW input signal to the unused MW input termimal on the preselector range
switch.
That has to be one of my alltime favorite receivers. Right now, I am working
on a redesign of my R-388. I am going to convert it to a solid state unit. I
have enought dual-gate MOSFETs laying around, at least to complete the
modifications. There is just something about analog receivers, when you
think about all of the mechanical design that was done in order to make it
happen. Synthesized units are much cheaper to manufacture.

Pete

" wrote in message
...
On Dec 12, 2:46 am, "Pete KE9OA" wrote:
I didn't change the function of mine. Is your responding too slowly or
too
quickly? On another note, that MW attenuator can be bypassed by
rerouting
the RF path of the MW input filter to the 50 Ohm input. This eliminates
the
1k resistor and the other components that are in the series string. There
is
a Yaesu users group on Yahoo. They do mention that S-Meter mod, and they
do
have documentation for this mod. You can also find the schematic and the
owner's manual on this site. The nice thing about this schematic is that
it
is a complete scan, instead of the partial multiple scans.

Pete

" wrote in message

...

Pete - I'm pretty sure you have an FRG-7. If so what circuit mod have
you done to fix the horrible S-meter circuit action?

Thanks,

Frank
K3YAZ
Tucson (where it has been raining for 5 days!)

Thanks Pete. Mine just has a very compressed range. If you adjust it
so the background level with no signal is about S-1, few signals are
above S-9. Conversely, if you calibrate it on a known S-9 signal, the
"noise floor" is typically S-4 to S-5, very inaccurate. From the
existing circuit design it appears that some type of adjustable gain
meter amp is needed with the set-point pots.

Best FRG-7 I've had otherwise. Looks and performs like it came right
off the assembly line. Even the 6 kHz ceramic IF filter is good with
very steep skirts and good audio. Quite unlike the previous 2 FRG-7s
I had. This is one Marty was not watching!!

Frank
K3YAZ