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Old July 2nd 05, 01:28 AM
Stephan Grossklass
 
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m II schrieb:

How do these radios compare? They were both relatively modest relatives of the
expensive rigs being sold at the time.


Did you mean R-1000 and FRG-*7700*, by any chance? You can find some
measurements for those (along with the FRG-100) on the Sherwood
Engineering page:
http://www.sherweng.com/table.html
The Kenwood should be the better performing of the two overall. Note the
comparatively high phase noise of these semi-synthesized sets. I think
the Sony ICF-6800 employed a similar receiver concept. Not sure whether
it's as closely related to the Wadley concept as you think... I suggest
you get the R-1000 service manual off the web and read the functional
description.

Stephan
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Home: http://stephan.win31.de/
PC#6: i440BX, 2xP3-500E, 704 MiB, 250+80 GB, R9k AGP 64 MiB, 110W
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Old July 2nd 05, 01:51 AM
m II
 
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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
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Old July 2nd 05, 05:43 PM
Mark Zenier
 
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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

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Old July 4th 05, 10:57 PM
Stephan Grossklass
 
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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
--
Home: http://stephan.win31.de/
PC#6: i440BX, 2xP3-500E, 704 MiB, 250+80 GB, R9k AGP 64 MiB, 110W
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Old July 2nd 05, 10:24 AM
John Plimmer
 
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Stephan gave an extremely useful and comprehensive website for receiver
performance which I had not come across befo
http://www.sherweng.com/table.html
As a mediumwave DXer, Bob Sherwood ranks the various receiver performances
by:
"Sorted by Dynamic Range Narrow Spaced"
which I know to be the MOST important spec in a MW DX receiver.

Very informative and blows the lid on some very expensive receivers that
just don't cut the cake.
OTOH the AOR 7030 comes out smelling like roses just off the top of the
pick.

thanks for posting that Stephan

--
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
Icom IC-756 PRO III with MW mods
RX Drake R8B, SW8 & ERGO software
Sony 7600D GE SRIII
BW XCR 30, Braun T1000, Sangean 818 & 803A.
Hallicrafters SX-100, Eddystone 940
GE circa 50's radiogram
Antenna's RF Systems DX 1 Pro, Datong AD-270
Kiwa MW Loop
http://www.dxing.info/about/dxers/plimmer.dx

"Stephan Grossklass" wrote in message
...
m II schrieb:

How do these radios compare? They were both relatively modest relatives

of the
expensive rigs being sold at the time.


Did you mean R-1000 and FRG-*7700*, by any chance? You can find some
measurements for those (along with the FRG-100) on the Sherwood
Engineering page:
http://www.sherweng.com/table.html
The Kenwood should be the better performing of the two overall. Note the
comparatively high phase noise of these semi-synthesized sets. I think
the Sony ICF-6800 employed a similar receiver concept. Not sure whether
it's as closely related to the Wadley concept as you think... I suggest
you get the R-1000 service manual off the web and read the functional
description.

Stephan
--
Home: http://stephan.win31.de/
PC#6: i440BX, 2xP3-500E, 704 MiB, 250+80 GB, R9k AGP 64 MiB, 110W





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Old July 2nd 05, 03:47 PM
 
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Good point Stephan! I obviously took his post literally and responded.
If he did mean FRG-7700 then definitely go with the R-1000. The 7700
I had was an absolute dud. Poor sensitivity and input bandpass filter
performance. I got it new and even a re-alignment did nada.

Frank
K3YAZ
Tucson

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