[time-nuts] My Racal-Dana 1992

Larry McDavid lmcdavid at lmceng.com
Fri Dec 16 12:31:00 EST 2011


Chuck, I have a Racal 1992 with exactly the same government label on its 
side as in your picture, except that my ink-stamped warranty date is a 
few days later than the date on your counter/timer. These must have come 
from a large government contract order.

However, while counting the 10 MHz from my HP Z3801A and displaying 0.01 
Hz resolution on my 1992, I can rap very smartly indeed with my knuckles 
on the outside of the counter case (anywhere) and not change the 
displayed count. Further, my counter seem insensitive to orientation or 
motion. Of course, I can see only to 0.01 Hz resolution at 10 MHz.

I just recently got this 1992 and have not yet tried to adjust its 
Option 04E ocxo (the Racal 9462) so I don't know if my unit exhibits the 
same cat-herding issue as yours. Judging from the condition of my 1992, 
I doubt it was used much. Mine looks new; it had plastic caps on all the 
BNC connectors and those connectors are all bright and shiny. My unit 
had a calibration-due date of 9/26/2011; it may not have been used since 
that calibration just over a year ago. At present, I'm letting it run to 
see if there will be short term drift or room temperature sensitivity of 
its ocxo. Later, I'll do what you have done to evaluate long-term drift 
more critically.

I also have a Racal 1999 10-digit counter that counts to over 3 GHz. I 
like these compact counters! I'm using a TADD-1 to distribute the 10 MHz 
from the Z3801A to five devices so the ocxo performance is important 
only if I use them portable.

How many TimeNuts have the Racal 1992 and what is your experience? Yes, 
I've heard of push button switch issues but so far I've not encountered 
any myself.

Larry W6FUB


On 12/16/2011 3:19 AM, Chuck Forsberg WA7KGX N2469R wrote:
> Has a 9462 oscillator module in it.
> I've been fooling with little C hacks to make freq and phase
> measurements via GPIB.
>
> In my desire to super-tweek the timebase I discovered that small
> adjustments take
> many minutes to settle down. It's like herding cats.
>
> I noticed that physical shocks would randomize the frequency over a 10
> Hz range
> at 10 MHz. What's more, the new frequency didn't seem to take 10 minutes to
> settle down. So I tapped on the oven with the screwdriver until it
> landed right on frequency.
> The resulting plot is attached.
>
> Come to think of it, I could use the counter to measure the time between
> 1pps and WWVB
> zero crossing as an ultimate frequency reference as well as detecting
> changes in the ionosphere.


-- 
Best wishes,

Larry McDavid W6FUB
Anaheim, CA  (20 miles southeast of Los Angeles, near Disneyland)




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