[time-nuts] Vremya-ch Hydrogen Masers

[Joseph M Gwinn]

time-nuts-bounces at febo.com wrote on 03/02/2010 04:51:15 PM:

> From:
> 
> "Bob Camp" <lists at rtty.us>
> 
> To:
> 
> "'Discussion of precise time and frequency measurement'" <time-
> nuts at febo.com>
> 
> Date:
> 
> 03/02/2010 04:55 PM
> 
> Subject:
> 
> Re: [time-nuts] Vremya-ch Hydrogen Masers
> 
> Sent by:
> 
> time-nuts-bounces at febo.com
> 
> Hi
> 
> Without doing a lot of digging, I doubt we'll find out just what they 
did
> (or didn't) find and fix. They certainly started with a "from scratch"
> design. They may have multiple points of departure from the US approach.
> 
> Then again, it may just be a better brand of coating they spray on the
> boards.

It does not take much moisture absorption in printed circuit boards and 
conformal coats to cause significant variation in electrical delay with 
variation in humidity, given that the dielectric constant of water is 
about 80.  The solution may be no more complex than use of only 
low-absorption materials surrounded by hermetic metal enclosures also 
containing a cloth bag of moisture absorbing chemical granules.

Joe


> Bob
> 
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Magnus Danielson
> Sent: Tuesday, March 02, 2010 3:05 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Vremya-ch Hydrogen Masers
> 
> Bob Camp wrote:
> > Hi
> > 
> > I hear that the US ones look better than the Russian ones when you 
have
> them
> > spinning around on a frozen pond. Nether one does a very good
> triple axle
> > jump though. At least that's what I read on the internet....
> > 
> > ---------------
> > 
> > There's always been a *lot* of debate about exactly what the source of
> > humidity impact on the US built masers is. It's been talked 
> about for at
> > least 30 years. It's not real surprising if somebody 
> somewhere has found
> the
> > answer and fixed it.
> 
> Rather, what did the Russians figure out and fixed?
> 
> Cheers,
> Magnus
> 
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