[time-nuts] Mercury Ion Clock
EWKehren at aol.com
EWKehren at aol.com
Mon Nov 3 12:58:43 UTC 2014
Do not want to get off list subject but again have to disagree. First I was
not referring to $ 2500 spectrum analyzer but a single frequency source.
As to equipment available some of the equipment on ebay is not visible to
offshore buyers. It also helps to know your sellers and I am not talking
actually have talked to them but understand their listing. Just checked my buys
and on July 1st 2012 I bought a Wiltron 6740B 40 GHz excellent condition
for $332 total cost. You could not have bid on it.
All I am saying that 40.5 GHz should not be hindrance to pursue Mercury Ion
there may be more challenging issues and if time nuts want to do something
I may be able to furnish that source. Like I said before I commit I would
have to better understand the requirements.
Bert Kehren
In a message dated 11/3/2014 5:09:08 A.M. Eastern Standard Time,
drkirkby at kirkbymicrowave.co.uk writes:
On 3 Nov 2014 02:59, "Bert Kehren via time-nuts" <_time-nuts at febo.com_
(mailto: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 I
> have since the early 90's sweeper, synthesizer, power meter, mixer for
the HP
> 70000 series, attenuates and most important frequency counter and non
fall
> 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
become
> available last year I helped a friend sell eight HP mixers for
frequencies
> 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_ (http://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.
Dave
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