[time-nuts] Mercury Ion Clock

Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby at kirkbymicrowave.co.uk
Mon Nov 3 05:09:07 EST 2014

On 3 Nov 2014 02:59, "Bert Kehren via time-nuts" <time-nuts at febo.com> wrote:
> I respectfully disagree. Before getting totally submerged in time nuts
> issues I did extensive work on signal sources up to 40 GHz as a hobby. So
> have  since the early 90's sweeper, synthesizer, power meter, mixer for
the HP
> 70000  series, attenuates and most important frequency counter and non
> off the  cliff at 40 GHz. 40.5 is still doable the limiting factor is wave
> guide cut off  frequency. One of the reasons I still hold on to the 5345
> frequency counter the  best for high resolution frequency counting in that
> range. Yes it was not cheap  but more and more equipment and components
> available last year I helped a  friend sell eight HP mixers for
> above 50 GHz.
> The big question is phase noise and how much power and no it will not be $
> 200 but $ 2500 depending on power and phase noise.is attainable.
> Bert Kehren

I doubt that you could assemble either a spectrum analyzer or signal
generator at just over 40 GHz for $2500. A frequency counter one could
easily do.

I puchased a used 20 GHz sweeper in the UK last week for the US equivalent
of $900. I think that was particularly cheap and probably helped by the
fact that the seller had poor feedback and didn't do a good job of
describing it. But that was "only" at 20 GHz.

A US dealer, who is kindly going to give me a software code to enable a
step size of 1 Hz, rather than 1 kHz said it was worth more than that in
just parts.

Waveguide modes should not be a problem if you use either the right size
coax or waveguide.  In coax that means using 2.4 mm connectors,  as both
SMA and 3.5 mm can't work at 40 GHz. But anything in 2.4 mm is going to be
expensive. A simple female-female adapter is like to cost nearly $100.

I just looked quickly on eBay and could not see any working 40 GHz signal
or sweep generator for less than $15,000.  Neither could I find a non
working 40 GHz signal or sweep generator for $2500. As I wrote earlier,  40
GHz tends to be one of the frequencies that commercial gear stops at, so
getting to 41 GHz is likely to be substantially more expensive than 40 GHz.

There's now quite a bit of modestly Chinese test equipment up to a few GHz,
but I don't see anything modestly priced at 40 GHz. So I don't think $2500
is likely to buy you a lab of 40 GHz test equipment.

I am sure if one waits enough,  one will find a cheaper unit on eBay,  but
I think that one is still going to be paying serious amounts of money.


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