[time-nuts] Comparing 10 MHz Oscillators at 10 GHz

[wa1zms at att.net]

Bruce-

I can speak to the Freq West PLOs. They, like the others, use a  
sampling phase detector. In theory you could use any subharmonic of  
the actual L-band VCO frequecy to get the loop to lock. I have used  
freqs as low as 5MHz. But there are limitations. You must couple the  
signal directly to the sampler and must bypass the vhf xtal osc and  
amps since they are tuned for VHF.

The lock-in range will be impacted since now the VCO could lock to any  
freq with in 5 or 10MHz of the free running VCO.

I can give you more details off-list if you wish.


-Brian, WA1ZMS

On Jan 4, 2011, at 6:09 PM, Brucekareen at aol.com wrote:

> Luciano Paramithiotti's January 1 post about his 10-to-100 MHz  
> multiplier
> project reminded me of past musings about using two 10GHz, phase- 
> locked
> oscillators to compare the 10MHz outputs of my T-bolt and LPRO so I   
> could
> quickly adjust the latter by observing the mixed 10 GHz signals  
> with  a
> microammeter.  I am talking about the California Microwave,  
> Frequency  West, etc.,
> modules that were used as local oscillators in commercial microwave   
> systems.
>
> I was about to ask Luciano for more information on his coil forms,
> amplifiers, and RF chokes when it occurred to me that loop-noise in  
> the PLOs  might
> force a very narrow bandwidth and correspondingly long observation   
> time.
> Have members of the list been successful with this technique?
>
> While most common PLO modules require an input signal in the 100
> MHz-range, I have heard of versions that lock directly to a 10 MHz  
> input.   Is anyone
> familiar with these and how difficult it would be to modify   
> conventional
> oscillators to securely lock to 10 MHz?
>
> Bruce, KG6OJI
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