Nifty old GR OCXO?
eBay item 150082419799 (Genrad 475-C)--is this some kind of OCXO frequency
reference? From the description, it sounds like it might be used to
monitor a broadcast transmitter frequency. Be sure and scroll down and
check out the wood and foam oven box and the "quartz plate" resonator.
The '56 GR catalog at the bama site doesn't show a 475-C, but that's not
surprising as the 475-C looks quite a bit older.
--
newell N5TNL
eBay item 150082419799 (Genrad 475-C)--is this some kind of OCXO frequency
reference? From the description, it sounds like it might be used to
monitor a broadcast transmitter frequency. Be sure and scroll down and
check out the wood and foam oven box and the "quartz plate" resonator.
The '56 GR catalog at the bama site doesn't show a 475-C, but that's not
surprising as the 475-C looks quite a bit older.
Yes, that's a nice example of a mercury thermometer
regulated, ovenized quartz plate oscillator, complete
with balsa wood case and lots of asbestos (not foam)
insulation. I have a couple of these ovens -- though
with 100 kc xtals, not the special broadcast freq.
spkr_volume -- please send me email, OK?
For other old GR oscillator stuff see:
http://www.leapsecond.com/museum/gr1103a/
http://www.leapsecond.com/museum/gr1190a/
http://www.leapsecond.com/museum/gr676b-50kc/
http://www.leapsecond.com/pages/old-genrad/
Of special note, see the 4 patents I have there
on the web page, like this one:
http://www.leapsecond.com/museum/gr676b-50kc/US1967185.pdf
Would you believe that GR had double ovens all
figured out back in 1931? HP wasn't the first...
/tvb
Tom Van Baak (mobile) wrote:
eBay item 150082419799 (Genrad 475-C)--is this some kind of OCXO frequency
reference? From the description, it sounds like it might be used to
monitor a broadcast transmitter frequency. Be sure and scroll down and
check out the wood and foam oven box and the "quartz plate" resonator.
The '56 GR catalog at the bama site doesn't show a 475-C, but that's not
surprising as the 475-C looks quite a bit older.
Yes, that's a nice example of a mercury thermometer
regulated, ovenized quartz plate oscillator, complete
with balsa wood case and lots of asbestos (not foam)
insulation. I have a couple of these ovens -- though
with 100 kc xtals, not the special broadcast freq.
spkr_volume -- please send me email, OK?
For other old GR oscillator stuff see:
http://www.leapsecond.com/museum/gr1103a/
http://www.leapsecond.com/museum/gr1190a/
http://www.leapsecond.com/museum/gr676b-50kc/
http://www.leapsecond.com/pages/old-genrad/
Of special note, see the 4 patents I have there
on the web page, like this one:
http://www.leapsecond.com/museum/gr676b-50kc/US1967185.pdf
Would you believe that GR had double ovens all
figured out back in 1931? HP wasn't the first...
/tvb
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Tom
The mercury regulator evolved into the mercury toluene regulator used at
NBS (and elsewhere) in the 60's and earlier to control the temperature
of their standard cell oil baths.
NBs technical note 141 gives some details. Refinements such as
anticipator windings were employed to achieve temperature stabilities of
around 1mK or so.
Bruce
Since the topic has been raised- herewith a few pix of an equally old
(well, nearly!) OCXO using mercury-in-glass high and low set point
thermometers for temperature control.
http://homepages.ihug.co.nz/~tractorb/oven/
This came out of an early openwire carrier system-of UK
origin-probably immediately post WW2 manufacture. One of the original
glass xtals has been replaced with a much less interesting style
holder.
DaveB, NZ
----- Original Message -----
From: "Tom Van Baak (mobile)" tvb@LeapSecond.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Thursday, January 25, 2007 7:31 PM
Subject: Re: [time-nuts] Nifty old GR OCXO?
eBay item 150082419799 (Genrad 475-C)--is this some kind of OCXO
frequency
reference? From the description, it sounds like it might be used
to
monitor a broadcast transmitter frequency. Be sure and scroll down
and
check out the wood and foam oven box and the "quartz plate"
resonator.
The '56 GR catalog at the bama site doesn't show a 475-C, but
that's not
surprising as the 475-C looks quite a bit older.
Yes, that's a nice example of a mercury thermometer
regulated, ovenized quartz plate oscillator, complete
with balsa wood case and lots of asbestos (not foam)
insulation. I have a couple of these ovens -- though
with 100 kc xtals, not the special broadcast freq.
spkr_volume -- please send me email, OK?
For other old GR oscillator stuff see:
http://www.leapsecond.com/museum/gr1103a/
http://www.leapsecond.com/museum/gr1190a/
http://www.leapsecond.com/museum/gr676b-50kc/
http://www.leapsecond.com/pages/old-genrad/
Of special note, see the 4 patents I have there
on the web page, like this one:
http://www.leapsecond.com/museum/gr676b-50kc/US1967185.pdf
Would you believe that GR had double ovens all
figured out back in 1931? HP wasn't the first...
/tvb
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A GR system - as per the tvb web page - in operation at Makara (an
MF/HF receiving/monitoring site) near Wellington NZ-this came out of
service in 1955 and was replaced with the completely home-grown
frequency measuring system in the second photograph.
http://homepages.ihug.co.nz/~tractorb/GR%20freq%20measuring%20eqpt/
DaveB, NZ
Tom Van Baak (mobile) wrote:
For other old GR oscillator stuff see:
http://www.leapsecond.com/museum/gr1103a/
http://www.leapsecond.com/museum/gr1190a/
http://www.leapsecond.com/museum/gr676b-50kc/
http://www.leapsecond.com/pages/old-genrad/
Tom, if you have a working Genrad oscillator, you should run some
performance tests on it. It would be interesting to see how that
technology looks today...
John
While we're on the old GR subject...
I have a General Radio 693-A "syncro-clock and amplifiers" that contains
a GR model 611 syncro-clock module. I think the oscillator and power supply
are separate (and I don't have them). Does anyone have any information on
the 693-A?
(Copies of a manual would be great!)
I'd like to get it running within a decade, and given the number of
projects I have going at once, I should start soon.
Don't know if this helps, but there is a decal on that back that says:
THIS INSTRUMENT IS LICENSED UNDER
PATENTS OF THE AMERICAN TELEPHONE
AND TELEGRAPH COMPANY SOLEY FOR
UTILIZATION IN RESEARCH, INVESTIGA-
TION, MEASUREMENT, TESTING, INTRUC-
TION, AND DEVELOPMENT WORK IN PURE
AND APPLIED SCIENCE.
Stan
I have a 693-B which has a large dial, the internal 1kHz amplifier, and the
power supply. I also have a 1103-A which requires an external power supply.
They are slowly moving up my to do list. The only manuals I have are for
the 1103-A. I would be interested in a manual for the 693-B.
John
----- Original Message -----
From: "Stan Searing" stans@sycard.com
To: "'Discussion of precise time and frequency measurement'"
time-nuts@febo.com
Sent: Thursday, January 25, 2007 2:00 PM
Subject: Re: [time-nuts] Nifty old GR OCXO? (looking for information on693-A
SYNCRO-CLOCK)
While we're on the old GR subject...
I have a General Radio 693-A "syncro-clock and amplifiers" that contains
a GR model 611 syncro-clock module. I think the oscillator and power
supply
are separate (and I don't have them). Does anyone have any information on
the 693-A?
(Copies of a manual would be great!)
I'd like to get it running within a decade, and given the number of
projects I have going at once, I should start soon.
Don't know if this helps, but there is a decal on that back that says:
THIS INSTRUMENT IS LICENSED UNDER
PATENTS OF THE AMERICAN TELEPHONE
AND TELEGRAPH COMPANY SOLEY FOR
UTILIZATION IN RESEARCH, INVESTIGA-
TION, MEASUREMENT, TESTING, INTRUC-
TION, AND DEVELOPMENT WORK IN PURE
AND APPLIED SCIENCE.
Stan
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----- Original Message -----
From: "jmfranke" jmfranke@cox.net
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Friday, January 26, 2007 8:29 AM
Subject: Re: [time-nuts] Nifty old GR OCXO? (looking for information
on693-ASYNCRO-CLOCK)
I have a 693-B which has a large dial, the internal 1kHz amplifier,
and the
power supply. I also have a 1103-A which requires an external power
supply.
They are slowly moving up my to do list. The only manuals I have
are for
the 1103-A. I would be interested in a manual for the 693-B.
John
And I'm still looking for a manual for the GR 1123 synchronometer.
DaveB, NZ
I did find some information on the 693-A in a partial installation manual
for a C-21-H Standard Frequency Assembly. I can scan the one page that at
least shows the rack wiring harness if that would be of help. Or I could
loan you the partial manual so you could tell more about the high volyage,
oscillator,
etc.
John
----- Original Message -----
From: "Stan Searing" stans@sycard.com
To: "'Discussion of precise time and frequency measurement'"
time-nuts@febo.com
Sent: Thursday, January 25, 2007 2:00 PM
Subject: Re: [time-nuts] Nifty old GR OCXO? (looking for information on693-A
SYNCRO-CLOCK)
While we're on the old GR subject...
I have a General Radio 693-A "syncro-clock and amplifiers" that contains
a GR model 611 syncro-clock module. I think the oscillator and power
supply
are separate (and I don't have them). Does anyone have any information on
the 693-A?
(Copies of a manual would be great!)
I'd like to get it running within a decade, and given the number of
projects I have going at once, I should start soon.
Don't know if this helps, but there is a decal on that back that says:
THIS INSTRUMENT IS LICENSED UNDER
PATENTS OF THE AMERICAN TELEPHONE
AND TELEGRAPH COMPANY SOLEY FOR
UTILIZATION IN RESEARCH, INVESTIGA-
TION, MEASUREMENT, TESTING, INTRUC-
TION, AND DEVELOPMENT WORK IN PURE
AND APPLIED SCIENCE.
Stan
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