[time-nuts] Vectron Type 229 Crystal Oscillator

GandalfG8 at aol.com GandalfG8 at aol.com
Sat Jun 23 22:09:32 UTC 2012


Hi Ed
 
Thanks very much for your suggestions, it had occured to me that it should  
be possible to run the oscillator without the oven and if I don't find any  
specific information as to actual supply voltages I'll give your  
suggestion a try.
 
That's a great idea re the oven too, followed carefully I would expect that 
 to identify the minimum voltage quite accurately.
 
I've found comments for several Vectron oscillators that the maximum output 
 is limited to +7dB for frequencies over 100MHz. I can't be sure that  
automatically applies to this one too, nor that it might not be rated for less,  
but at least that's another bit of possibly useful information.
 
I've written to the seller in the hopes that he might be able  to better 
identify where it came from, with a bit of luck that  might help provide the 
answers I'm looking for.
 
Regards
 
Nigel
GM8PZR
 
 
 
In a message dated 23/06/2012 22:42:08 GMT Daylight Time,  
ed_palmer at sasktel.net writes:

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, GandalfG8 at aol.com  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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