Hi Nigel,
I don't have any specific info on your oscillator. If I was doing it,
I'd investigate the oscillator and oven seperately.
Power just the oscillator and monitor the output while you slowly raise
the voltage from zero. Once the output appears, watch the amplitude as
you increase the supply voltage. In my experience, it will increase
until some point where a further increase in supply voltage has no
effect on output amplitude due to the action of an internal voltage
regulator. Now you know the minimum voltage for the oscillator. Add a
couple of volts for headroom on the voltage regulator.
It isn't as easy to determine the appropriate voltage for the oven.
Start with a low voltage and see if the current ever drops. If not,
raise the voltage in small increments until it does drop. You will
probably have to wait for many minutes after each increment to see if
the current will drop. Now you know the minimum oven voltage at room
temperature. Since it's probably rated for temperatures lower than room
temperature, the design voltage will be somewhat higher.
I've had good luck with this technique. YMMV.
Ed
On 6/23/2012 12:20 PM, [email protected] wrote:
I've recently bought a Vectron 229-9268 100MHz crystal oscillator via
Ebay with no information other than it was supposed to have been removed from
an item of Racal radio equipment several years ago.
It has an SMA RF connector and a 7 pin circular power connector, much in
the style of a B7G valve base, with several leads attached to that which
terminate at what appears to be a miniature version of a 9 pin D connector.
A search through the list archives, and online generally, has thrown up
two different connection options offered in response to previous requests for
information on 229-xxxx series oscillators, the first listed as being for a
CO-229 is as follows.......
Pin 1 No connection (NC)
Pin2 Case(0V)
Pin3 Case(0V)
Pin4 B+ 24VDC
Pin5 VCXO Supply For option V models only
Pin6 VCXO Input For option V models only
Pin7 VCXO Return/case For option V models only
The second is shown as being for a "VECTRON 229 osc with 7 pin Kovar feed
through in circle similar to a
tube base".......
1 B+ (Oven)
2 N/C
3 N/C
4 B+ (Osc)
5 VCXO Supply
6 VCXO Input
7 return (Case)
Mine looks to be a very close match to the second option, pins 2 and 3
aren't used, 7 is definitely ground, and there are small decoupling caps from
pins 1 and 6 to pin 7, although no decoupling on 4 and 5.
I've seen suggestions for the single power feed versions that the supply
options were either 12, 15, or 24 volts but have found nothing to indicate
whether or not the dual power feed versions would always use identical
supply voltages, or if they might also have been available requiring different
voltages for oven and oscillator.
I'm happy enough to play "suck it and see" with the oven voltage, and judge
that by current and case temperature, but would prefer not to fry the
oscillator as part of that process, bit self defeating really:-), so any
information would be very much appreciated.
regards
Nigel
GM8PZR
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