If the variable capacitor in question has ball bearings, it's probable that the bearing is
a bit tight and the races have indented. This gives the effect of a detent.
On 2011-12-19 01:17, Ed Palmer wrote:
I haven't seen a capacitor with detents. Could the fine adjustment be a
multi-turn pot?
I've seen detents with those. I looked at mine but couldn't tell. A pot would
mean voltage
control. Maybe we could build a GPSDC (GPS Disciplined Counter). Yes, I'm
kidding. I
think.....
Ed
On 12/18/2011 1:21 AM, Charles P. Steinmetz wrote:
It turns out that I unfairly maligned the 1992 (and the 9462 oscillator, option
04E)
when I accused it of poor oscillator "settability." I was inspired by the recent
discussions to have another crack at mine, and they can, in fact, be set very
accurately. One of mine has been reading "000.000000 E-3" for about 24 hours
now, hooked
to a Thunderbolt and using the 10-second gate. The other has been toggling
between
"999.999999 E-3" and "000.000000 E-3." (This is how mine are used ---
perpetually
reading the shop standards to give an independent reality check on their
condition.)
Walking the oscillators to 0 is tedious and time-consuming, but not difficult.
I think I
must not have been sufficiently patient in the past. The fine adjustment has
detents --
if you adjust it slowly, you can count the clicks. On both of mine, each click
adjusts
the oscillator frequency about 3 mHz (CW lowers the oscillator frequency/raises
the
displayed frequency). Interestingly, when you are close to zero and adjusting
the
oscillator only a few clicks at a time, it takes off in the opposite direction
and peaks
at a MUCH greater offset than the eventual increment, then returns and
overshoots in the
direction of the adjustment (again, quite a bit further than the eventual
increment),
and finally settles to its new value, with another cycle or two of smaller +/-
overshoots around the final value. It takes at least 1/2 hour to settle within
a count
or two of the eventual final value, and several hours before you can be
confident that
it has settled to its new value.
Best regards,
Charles
--
Cheers, Ken
vk7...@users.tasmanet.com.au
www.vk7krj.com
'It seems hard to sneak a look at God's cards. But that He plays dice and uses
"telepathic" methods .... is something that I cannot believe for a single
moment.' (Einstein's famous quote on Quantum theory)
---
avast! Antivirus: Outbound message clean.
Virus Database (VPS): 111218-1, 2011-12-19
Tested on: 2011-12-19 10:59:57
avast! - copyright (c) 1988-2011 AVAST Software.
http://www.avast.com
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
