Bob the VLF guys in Europe can receive the 60Hz signal over here! so you
probably needed a test site on the far side of the Moon :-))
Alan
G3NYK
----- Original Message -----
From: "Bob Camp" <kb...@n1k.org>
To: "Discussion of precise time and frequency measurement"
<time-nuts@febo.com>
Sent: Tuesday, July 12, 2016 10:53 PM
Subject: Re: [time-nuts] OXCO Spurious Output at Line Frequencies
Hi
The “practical” solution often is to ship it to an office of the same
company that happens
to have 60 Hz power. The spur moves to 60 / 120 / 180 and they move on
with their
evaluation.
I have also played the “let’s do it with batteries" approach. Screen rooms
were of little benefit.
Simply running test gear on batteries did not do the job. Ultimately we
wound up in the
middle of an Illinois corn field with a bunch of gear modified to run
purely on batteries. The
spur did go down, but it never fully went away. It’s been 40 years since
that adventure so I
really could not say just how far down we got it ….
Anything past -120 db at line frequency is in the “don’t bother” category.
Bob
On Jul 12, 2016, at 6:44 AM, Martyn Smith <mar...@ptsyst.com> wrote:
Hello,
I have a customer who is measuring the phase noise of my 10 MHz ultra-low
phase noise frequency standard.
He is seeing spurious signals at line frequencies (50 and 100 Hz as we
are in Europe) at a level around -130 dBc.
My opinion is that it's impossible to get much better than that. Even
running on batteries make little difference, since the equipment is in a
test rack with AC signals everywhere.
Even the £50k R&S test set he is using only quotes a spurious spec of -90
dBc.
What experience does anyone have here?
Best Regards
Martyn
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