Hi
Since the magnetic “response” of the field around the physics package is
non-linear, reversing the field on a package with magnetized mu metal
*should* produce a delta frequency.
More or less:
C field at 4 ma is +0.10 gauss ( no it’s not, but you need a number
here …)
Mag o
Rheostats are not necessarily stable because the current is 1st-order
dependent
on the contact resistance.
I had missed the part about the nearby lightning strike. Could it be that
the mu-metal
shielding got partly magnetized by the high current pulse of the
lightning? If so, there
ought to be s
I found a datasheet for the Bourns "Knobpot" type pots I have. Specs are
not all that great. No info about the innards.
https://www.bourns.com/pdfs/3600_obsolete.pdf
Ed
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Hi,
I scanned and uoploaded the R20 and 304D manuals to ko4bb a couple of
years ago. Have a 304D which sort of works, but the meter was open
circuit and had to replace with a similar sized edgwise meter, and
an op amp to correct the range. Still have the original manual somewher,
but the scans
If some one wants to make a breakout board or Saw tooth get with me off list
Bert Kehren
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Paul S. wrote
"The pots on the digital counter and its actually quite small. The 3
leads all fit into an area about the size of a pencil eraser."
Yeah, I know what you mean. I had assumed the pot in question was one of
the more modern, fairly compact ten-turn helipots, that are about an
inch
Hi
The existing c field winding is *inside* the magnetic shield on the physics
package.
Simply getting a second winding inside that package involves some (scary to
most
of us) tearing apart (an re-assembly) of the physics package.
Next up, the mag field needs to be reasonably uniform. That m
Dana Whitlow writes:
> Would it be feasible to add a smaller winding around the outside of
> the existing C-field winding, and drive it from something other than
> the crude rheostat circuit?
That would be on the outside of the mu-metal screen and therefore a
really bad idea.
--
Poul-
Unfortunately the cfield is deep in the tube. So that would require taking
the shields and such apart. The cfield isn't just a pot its actually tied
to a feedback loops and diff amp that changes the slope to match the tube.
There are quite a few ways to improve on it. Poul wrote up a whole page on
Paul,
Would it be feasible to add a smaller winding around the outside of
the existing C-field winding, and drive it from something other than
the crude rheostat circuit? Then you could make finer adjustments
than the existing driver permits, and would rely only on the existing
driver to provide o
Ed
Like you I don't like dangling pots either. But since I had the system open
I took a look to see how hard that would be to accomplish. The pots on the
digital counter and its actually quite small. The 3 leads all fit into an
area about the size of a pencil eraser. To work on it requires removing
Agree
But considering you mentioned it, thats very attractive. Considering a
couple just to play with.
Regards
Paul
On Mon, Dec 7, 2020 at 10:33 AM ew wrote:
> Normally such a price would be suspicious but cut outs from Huawai reduces
> the risk.
>
>
> In a message dated 12/7/2020 10:26:52 AM Ea
Normally such a price would be suspicious but cut outs from Huawai reduces the
risk. In a
message dated 12/7/2020 10:26:52 AM Eastern Standard Time, paulsw...@gmail.com
writes:
OK I was wondering how to handle that.Thank you.R
OK I was wondering how to handle that.
Thank you.
Regards
Paul.
On Mon, Dec 7, 2020 at 10:22 AM ew wrote:
> We will remove them with a heat source and use them on designs we already
> have and tested with 5T and 6T like GPSDO and a Saw tooth correction board
> using the DS 1023- 25 for delay
>
We will remove them with a heat source and use them on designs we already have
and tested with 5T and 6T like GPSDO and a Saw tooth correction board using the
DS 1023- 25 for delay
Bert Kehren
OK, I see now what the circuit looks like, in the manual. The pot is
used in rheostat mode, so the specific value is needed, and it would
take some more modification of the circuit to increase the setting
resolution.
I would recommend making a simple change to the existing pot hookup
though,
Bert Very attractive price. They appear to be on a cut out circuit board.
How are you connecting to them please?
Regards
Paul.
WB8TSL
On Mon, Dec 7, 2020 at 9:14 AM ew via time-nuts
wrote:
> With not much happening on Ublox 9T I went back looking at 8T in support
> for Jim Harnan's next generati
With not much happening on Ublox 9T I went back looking at 8T in support for
Jim Harnan's next generation GPSDO.. Shopping on ebay I ran across this super
deal. No financial interest but we have bought from him repeatedly no problem.
There is a reason he has 100%.. We have offered $ 15 for three
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