Stephan Grossklass wrote:

Not sure whether
it's as closely related to the Wadley concept as you think...



Sorry about that.. I should have been more explicit. I meant to compare the
r-1000 tuning to the Barlow-Wadley setup in the FRG-7. That Yaesu has the
similar thirty band, 1 Mhz step switch along with the khz spread dial. Very
similar, except for the digital readout.




mike

In article Iylxe.102809$9A2.52247@edtnps89, m II wrote:
Stephan Grossklass wrote:
Sorry about that.. I should have been more explicit. I meant to compare the
r-1000 tuning to the Barlow-Wadley setup in the FRG-7. That Yaesu has the
similar thirty band, 1 Mhz step switch along with the khz spread dial. Very
similar, except for the digital readout.

Having played with a FRG-7 at a shop a few times, the R-1000 is way
better. You just turn the switch. And the digital readout tells you
which MHz you've got. For the FRG-7, you have to tune around until you
get the lock light to come one.

Next, the R-1000 has only one local oscillator that matters. Which drives
the first mixer which then feeds the 45.something MHz (fairly narrow)
"roofing filter" for the first IF. So, no images. (For a reasonably
wide definition of "no"). The minus side is that the actual oscillator
(actually, one of a bank of them, selected from ranges of the 1 MHz
switch) is part of a phase locked loop running at 45-75 MHz so is going
to squiggle around a bit and allow the reciever to pick up adjacent
signals as noise.

I don't know the exact details of the FRG-7, but Barlow-Wadley receivers
usually convert an entire 1 MHz wide block to their first IF and second
IF, which is then tuned with using a VFO to the narrowband third IF,
so there's plenty room for intermod, spurs and such.

Mark Zenier Washington State resident

m II schrieb:

Sorry about that.. I should have been more explicit. I meant to compare the
r-1000 tuning to the Barlow-Wadley setup in the FRG-7. That Yaesu has the
similar thirty band, 1 Mhz step switch along with the khz spread dial. Very
similar, except for the digital readout.

The FRG-7 is a true Wadley Loop design, three IFs and all. These are a
bit problematic because of their very wide 1st IF (remember, 1 MHz
spread) and thus plenty of potential for intermod. (The Sony analogs
with the "dual conversion light" concept using 10.7 MHz / 455 kHz are a
good example. My ICF-7601, while being fairly sensitive, regularly drove
me nuts when the respective band got a bit more crowded. At least the
FRG-7 uses a mixer based on a dual gate MOSFET.) The R-1000 is a fairly
conventional dual conversion rig with a high 1st IF, only the frequency
synthesis is a bit funky. (I'll have to look at it again one day, didn't
really get the hang of it last time. Not too surprisingly, given my
level or rather lack of experience in these things.) This generation of
receivers - to which, as I mentioned, the FRG-7700 belonged as well -
came out a few years after the venerable FRG-7.

Stephan
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