[time-nuts] EFOS2 Maser acting up :(

[Tom Van Baak]

Corby,

Nice detective work. Keep us posted. I had a case some years ago where my IF level was sputtering around. It turned out to be the dissociator. It was a pretty easy fix after a fax / email or two from Russia.

If you suspect the L.O. you can always free-run it for a week and see if similar symptoms occur. That would eliminate 99% of the complexity of the maser as the source of the problem.

/tvb

----- Original Message ----- 
From: <cdelect at juno.com>
To: <time-nuts at lists.febo.com>
Sent: Monday, August 13, 2018 1:07 PM
Subject: [time-nuts] EFOS2 Maser acting up :(


> Hi,
> 
> The EFOS2 Maser is having an "issue", the I.F.level is intermittently
> fluctuating and sometimes drops all the way to zero. I've always wanted
> to see the "raw" output from the cavity so now was my chance! Installed
> two SMA cables  bringing the output of the circulator and the input to
> the LNA out to where I can get at them. Managed to catch it at zero and
> hooked a Spec-A to the output of the circulator. Hooray, The Maser cavity
> output is good, so the problem lies downstream. Installed a directional
> coupler between the two lines looking back into the LNA. Can see a
> healthy 1440 Mhz L.O. leakage and logged a reference level. Now just
> waiting for it to drop again and see if it's the L.O. If not I'll have to
> dive in again and move my monitor SMAs to look at the 19.6...Mhz I.F.
> signal. Pix shows the cavity signal on the spec-A.
> 
> Cheers,
> 
> Corby


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