[time-nuts] need recomendation for a portable 10mhz reference oscilator

[David Forbes]

At 11:38 AM -0800 12/11/07, Eric Fort wrote:
>I'm looking for a fairly basic, relatively simple 10 Mhz PORTABLE
>reference (probably quartz based) with enough stability over a period
>of a week of outdoor temp extremes to keep a 47Ghz transmitter locked
>within 100hz  while mountaintop contesting.  Suggestions are
>appreciated.  something that is small and ran off 12 volts dc (car
>battery) would be a definite plus.
>
>Thanks,
>
>Eric

Eric,

It's interesting to see all the suggestions. There are many ways to 
achieve this goal.

It is always a good plan to use the existing environment to your 
advantage. However, the environment on a mountaintop is not exactly 
conducive to maintaining stability of an OCXO, so you have to look at 
the environment that *you* are living in.

I assume that you will be on this mountaintop all week, and that you 
will have a source of warmth and fuel and electricity, and that you 
will be near the radio when doing your transmissions. Since your body 
will maintain its internal temperature at 37C, why not take advantage 
of that to keep your OCXO warm?

I am thinking of an HP hockey puck oscillator, the E1938A or whatever 
it was that Rick Karlquist designed. It's apparently a very good 
oscillator.  You could slip it into a pocket you would sew in your 
long johns in the armpit or groin area. That should keep it 
toasty-warm at all times.

You can power it with a Li-ion battery pack kept in another pocket in 
not quite such a private area. You'd want to have about three of 
these battery packs on hand, one charging, one ready to go, and one 
in use. You'd also want the oscillator to have two power pack plugs 
with steering diodes built in, so you could do a hot swap of 
batteries.

The result of all this is that the oscillator's temperature and power 
supply voltage would be nearly constant. Those are conducive to 
stability. The only unstable part of the environment is physical 
motion. Just sit still when you're transmitting!

-- 

--David Forbes, Tucson, AZ
http://www.cathodecorner.com/