[time-nuts] Re: What's the best HP OCXO for frequency counter reference?

[Bob kb8tq]

Hi

All HP 10811’s came off the same line and with the exception of the “weird” one used
in the original HP GPSDO, they all had the same parts / same optimizations in them. The
only thing that was done to make this or that dash number was to screen the finished 
units. Once “enough” of this or that spec came out of screening, they stopped looking. 
The “next one in line” might have well beat any of the ones in the batch … they simply 
had no time ( = funds ) to screen everything. 

Since this screening was done a *long* time ago, there is no way to know if the OCXO 
you have still is a “good one”. Stuff happens over time …. subtle changes rarely get 
noticed. 

Bob

> On Jun 28, 2022, at 12:03 PM, Dr. David Kirkby <drkirkby at kirkbymicrowave.co.uk> wrote:
> 
> On Tue, 28 Jun 2022 at 20:04, Bob kb8tq via time-nuts <time-nuts at lists.febo.com <mailto:time-nuts at lists.febo.com>> wrote:
> Hi
> 
> The “typical” 10811 struggles when shut down for a while. Once the oven
> is turned off, the boards are just sitting there in whatever environment your
> lab provides. Do they soak up humidity or is it something else? We could 
> (and have) debated that quite a bit. 
> 
> Part of my problem is that if I ever wanted to sell this, I'd like to sell it with an oven that was designed to meet the specifications given in the frequency counter manual for option 010, which are better than the 10811A. 
> 
> Another quite practical issue is setting the blinking frequency, as the pot on the oscillator seems too touchy. I set a signal generator to 20 GHz, which was fed from a GPS frequency reference. The output of the signal generator was then fed into the counter. Getting the counter to read within 100 Hz is extremely difficult, as the tuning control is too coarse. As I write the frequency counter is reading 83 Hz higher than 20 GHz. 
> 
> To be honest, that's "good enough" for what I am practically going to need. But I would like to do better if possible. 
> 
> Dave