[time-nuts] Input voltage for Zeeman on 5061A
John Ackermann N8UR
jra at febo.com
Sat Jan 22 16:55:05 EST 2005
Brooke wrote:
>>
>>I'm curious as to how close you get using the Zeeman method. Do you
>>have any data showing Zeeman frequency vs. Source frequency for HP
>>and/or FTS tubes?
>>
Based on my experience today, using the dinky built-in meter the closest
I could place the peak was within about plus or minus three minor
divisions. Based on a sensitivity of 8x10e-14 per minor division, that
would be about +/-2.5x10e-13. I'm now measuring against a Z3801A and
Loran-C to see how close I am; I need several hours more data before I
can draw any conclusions.
By the way -- following up on a posting from Poul-Henning a while ago,
I've been doing some reading about the Loran Modernization Project and
it looks like (a) Loran will be around for a while, and (b) it's
becoming a more useful frequency calibration tool. They've already
replaced the old Cs at all LORSTAs with three new 5071As, and there's
new time/frequency equipment being installed that improves the
performance in a number of ways, notably replacing the old 20ns step
adjustments with a more gradual slewing of time. And, the old
transmitters are being replaced with solid-state units that should
improve reliability.
Fortunately, the station nearest me, Dana, Indiana (8970-M) has the full
complement of new stuff installed. I hope to do some real-time
intercomparisons of Loran and GPS to see how the two stack up these days.
John
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