D Peter Maus ) writes:
Rob Mills wrote:
"Lucky" wrote in message
...


So are you saying the GE Super Radio II {2} is the best one GE makes for
shortwave??

Can you please elaborate on why the radio impressed you so much? What are
the features that make this radio still talked about today?



I have the Super 1 (7-2880a) and it beat the socks off of my early (I
assume it's an early one since I have had it for about 10 yr) Super3. The
one pulls in MW stations that the three wasn't even getting. Never use it
for FM so can't evaluate the FM side
As near as I can tell there are only minor differences between the one and
two, the two has a tweeter which the one's do not. The very early one (mine)
does not have external antenna connections while the later ones and the two
do.
I also have Radio Shacks attempt to copy the GE Super and it isn't even in
the race, actually it sounds like a radio with a squelch that is set quite
deep, it's just another nice sounding portable that's good for local use
only. RM~





As I recall, GE SupeRadio is a superhet. RS's attempt is a TRF.
There will be substantial differences in DX performance.

I don't think this is true. While TRF, ie Tuned Radio Frequency, was
used to denote a receiver with a couple of tuned amplifier stages
going into a detector stage decades ago, I think the TRF in the Radio
Shack radio was a marketing thing. At least the term. I was always
under the impression that the TRF was indeed a superheterodyne design,
but unlike many/most portable radios, had a stage of tuned amplification
ahead of the mixer, and that Tuned RF stage is what the name refers to.

For that level of radio, it was something relatively unique. It wasn't
unique to receivers that were primarily shortwave receivers, and it
wasn't unique for car radios, but most lower end am receivers, certainly
portables and maybe even a lot of home base receivers (the famed All
American Five had not stage ahead of the mixer for isntance) did not
have that extra stage.

Done well, the extra stage would help reject images, and improve sensitivity.


About 30 years ago, Popular Electronics had an article about an AM
radio on a single chip. The chip is a ZN414 (three leads, power, common
and RF in), at the time available from Circuit Specialists, Tempe, AZ,
and with a tuning stage added, produced a very nice tuner/preamp for a
TRF receiver.

The point of the ZN414, and the later MK484, is that by having good AGC
there is vast improvement over a what one would expect for a single tuned
circuit receiver. In effect, turn down the gain when a decent signal
is there, and as long as adjacent signals were weaker to start off, they
are now way down.

I wonder how you used it as a preamp, given that the design doesn't really
make for using it for anything but a TRF receiver. Only three pins, so
the output comes after the detector stage.

Michael