I found the parameters for the X72's 1PPS input. The range of Tau is 5 -
10,000 seconds, or about 2 hrs, 45 min. at the longest setting. It
defaults to 400 seconds. However, mine doesn't have the firmware to enable
the 1PPS input, so it really doesn't matter.
Out of curiosity, does anyone
Charles Steinmetz wrote:
Dave wrote:
does anyone know of any Rb units that can be programmed to a 24 hr
(or longer) Tau, either by EFC or 1PPS input?
The SRS PRS10 has a very versatile PPS input that can discipline its
frequency with a truly comprehensive array of adjustments (to the
point
Dave wrote:
does anyone know of any Rb units that can be programmed to a 24 hr
(or longer) Tau, either by EFC or 1PPS input?
The SRS PRS10 has a very versatile PPS input that can discipline its
frequency with a truly comprehensive array of adjustments (to the
point of potential bafflement).
Hi
The only Rb’s I know of that go out to the 24 to 72 hour tau’s are full blown
GPSDO Rb’s.
Bob
On Aug 25, 2014, at 1:53 PM, Dave M dgmin...@mediacombb.net wrote:
I found the parameters for the X72's 1PPS input. The range of Tau is 5 -
10,000 seconds, or about 2 hrs, 45 min. at the
Charles
I agree with every thing you wrote and I am implementing many of your
recommendations. Forty years ago I bought a 15 foot Alu channel to make small
frequency counter housings, always small, and at the time I did have access
to a machine shop so I made end plates. Still have five
Hi Dave,
On 8/23/2014 3:51 PM, Dave M wrote:
Thanks for that suggestion, Ed. After a bit of reading in the X72
Reference Guide, it appears that the X72 does have a 1PPS input.
That would be considerably easier than trying to interface the Rb
into the GPSDO. Still trying to understand what
Charles
I use double bobble pack inside the Alu channel and I always start out by
monitoring the OCXO and make sure it is at least 10 C below the spec range.
The tbolt is center located and I use a combination of rubber mounts but
suspended that they sell for hard drives and squares of
Bert wrote:
As I said before am waiting for the small spheres and will see what happens.
Monitor carefully, as I suspect the spheres will pack too tightly
leaving too little airspace. You could easily burn down an OCXO if
this proves to be the case and the oven control loop goes
unstable.
Hi
Keep in mind that the OCXO is likely (if it’s a modern part) optimized for TC
at it’s normal thermal gain. The gain and set point are adjusted for a flat
curve. If you bump either the gain or the set point you rotate the curve.
Bob
On Aug 24, 2014, at 8:36 PM, ewkeh...@aol.com wrote:
Hi
Keep in mind that watching the OCXO in a fixed ambient may not tell the whole
story. Setting a PLL to 10,000 seconds on an OCXO and then ramping the
temperature 40 or 80C is likely to create issues…..
It’s very easy to fall into the “I only have a room that swings 0.2C” loop when
looking
Hi Charles,
I agree with your statement regarding the determination of the optimum
time constant, but, as Bob Camp mentioned, temperature change has a
significant impact on setting the value. My 'lab' is a
non-airconditioned bedroom. My Tbolt doesn't have any active
temperature control.
Ed wrote:
I don't think you're correct about the Miller GPSDO containing a
Shera controller.
Is there more than one Miller GPSDO? I was referring to this one,
by James Miller G3RUH, which uses a Shera controller and 10811 OCXO:
http://www.jrmiller.demon.co.uk/projects/freqstd/frqstd.htm
Now that I see it again, I think I knew about Miller's Shera version,
but I purged it from my brain in horror and disgust. He bought a
Z3801A, threw away the controller and added a Shera board. The Shera
board is good, but .
Ed
On 8/23/2014 1:40 PM, Charles Steinmetz wrote:
Ed wrote:
Ed wrote:
I agree with your statement regarding the determination of the
optimum time constant, but, as Bob Camp mentioned, temperature
change has a significant impact on setting the value. My 'lab' is a
non-airconditioned bedroom. My Tbolt doesn't have any active
temperature control. If
Does anyone have any info on the OXCO in the Nortel/Trimble NTBW50AA-17
GPSTM receiver? The OXCO is labeled as Trimble 34310-T. I see some Trimble
34310-T oscillators on Ebay with pinouts labeled, but no other info.
Specifically, I'd like to know the EFC characteristics for it. I'm thinking
From: Dave M dgmin...@mediacombb.net
To: FEBO Time Nuts time-nuts@febo.com
Sent: Friday, August 22, 2014 1:39 PM
Subject: [time-nuts] EFC info on Trimble 34310-T OXCO
Does anyone have any info on the OXCO in the Nortel/Trimble NTBW50AA-17
GPSTM receiver? The OXCO
Hi
All of the OCXO’s in the GPSDO’s pull 100’s (or more) times the pull of a Rb.
The firmware that they have on that board for the OCXO is going to need some
serious tweaks to get it to work properly with an Rb. The GPSTM is not as tweak
friendly (no filter changes allowed) as some of the
Have you checked your X72 to see if it has the 1 PPS discipline option?
That would be a lot easier (and probably better) than your proposed
transplant.
Ed
On 8/22/2014 12:39 PM, Dave M wrote:
Does anyone have any info on the OXCO in the Nortel/Trimble NTBW50AA-17
GPSTM receiver? The OXCO
Bob wrote:
The GPSTM is not as tweak friendly (no filter changes allowed) as
some of the other GPSDO's.
And that is a major problem. The correct filter settings for a Rb
local oscillator are very different from the settings for an OCXO,
which in turn are different from the correct settings
19 matches
Mail list logo
