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Old July 1st 05, 06:30 PM
Mark Zenier
 
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In article L%2xe.116550$on1.73955@clgrps13, m II wrote:
How do these radios compare? They were both relatively modest relatives of the
expensive rigs being sold at the time. Anyone with experiences in comparing the
two? The tuning seems identical to the FRG-7's Barlow-Wadley system, with the
addition of the digital display, of course.


It think the FRG-100 is newer than the R-1000. Even the FRG-8800(?)
was newer. Contemporary with the R-5000.

The R-1000 is a late 1970s design, judging from the guts. (I got
mine on a closeout in the early '80s). It's not a Barlow-Wadley.
It's synthesized for 1 MHz, and then has a 1 MHz wide analog tuning with
the VFO.

It's pre-microprocessor. The synthesizer is an amazing pile of 74Sxx TTL
and a bunch of balanced mixers combining the VFO and the synthesized xtal
oscillators, feeding a bank of phase locked oscillators to clean the LO
up and feed the mixer (High side of a 45 MHz first IF), and a seperate
output to feed the frequency counter (455 kHz above signal freq), which
uses a stock OKI frequency display/clock chip, (and seems like a last
minute add on). Display reads the center frequency of the bandpass,
to 1 kHz.

The signal path is a couple of built in 500 ohm matching transformers,
always used below 2 MHz, and optional for the HF antenna input. Then a
big bank of diode switched bandpass filters. The mixers are balanced
double gate MOSFETS. They must not have been too sure of it's overload
performance, there's a gain spoiler circuit that lowers the sensitivity
to 50 microvolts below 2 MHz. IF bandwidths are 12(!), 6 and 2.1 kHz,
with the front panel buttons reconfigurable with an internal plug/jumper
so that "wide" and "narrow" AM can be either 12/6 or 6/2.1 kHz.

Audio is OK, much better out of the "record" jack. (The tone control
does affect the record jack output).

You can't make the front panel much simpler. The only trap is the
damn antenna switch on the back.

But the quirks are that it's not stable enough for RTTY or probably CW
listening. (probably why it doesn't have a narrowband filter). And the
Medium Wave sensitivity is deliberatly stomped. And every couple of
years you have to hit the MHz switch with tuner-lube, and resolder the
power supply circuit board.

Some day I'm going to download the repair manual for the R-600.
Despite the lower number, it's a newer receiver that simplified a lot
of the circuitry and cost a bit less. But the Yen went from 300 to the
dollar to 100 to the dollar back then, so I've not seen that many.

Mark Zenier Washington State resident