Hi,
I'm interested in doing some ionospheric research, but I don't
want to break
the bank with an $8,000 USD GPS disciplined Rubidium clock.
Anyone have some ideas on cheaper alternatives?
Suggest getting one of these, or another one like it:
Hi
Are you interested in 24 hour stability or something longer than that?
Bob
On Sep 22, 2010, at 1:42 AM, Lester Veenstra wrote:
From: q...@yahoogroups.com [mailto:q...@yahoogroups.com] On Behalf Of David
Sent: Tuesday, September 21, 2010 10:55 PM
To: q...@yahoogroups.com
Lester Veenstra wrote:
From: q...@yahoogroups.com [mailto:q...@yahoogroups.com] On Behalf Of David
Sent: Tuesday, September 21, 2010 10:55 PM
To: q...@yahoogroups.com
Subject: [qs1r] Looking for good, cheap, external reference
Hi,
I'm interested in doing some ionospheric
Hello Lester,
To expand on Bob's message a little, do you need medium to
long-term accuracy (for a frequency counter reference for example), or
something that is both accurate AND has low phase noise, suitable for
multiplying up to GigaHertz, say, for communications? Particularly if
the
I don't think the firmware on the Tbolt makes much difference in performance.
(The older firmware even has a couple more features in it).
Units with the 3.0 firmware are newer and have a much greater chance of having
the poor temperature sensor which definitely has a bad effect on
Hi
Not so simple decoder ring:
0 to 24 hours = use an auction site double oven OCXO ($50).
1 hour to a few days = use an auction site LPRO (or similar) rubidium ($50).
1 hour to forever = use a TBolt (or similar) made after 2001, but before
2005($100).
The gotcha with any of the GPS devices is
Hi
The 3.0 firmware is one way to make sure you don't get one of the early
ocxo's. The later designs certainly worked better.
I haven't seen any of the original red label ocxo's show up for quite a
while, so they all may be gone by now.
Bob
-Original Message-
From:
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Peter Vince
Sent: Wednesday, September 22, 2010 2:27 PM
To: les...@veenstras.com; Discussion of precise time and frequency
measurement
Subject: Re: [time-nuts] [qs1r] Looking for good,
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bob Camp
Sent: Wednesday, September 22, 2010 5:06 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] [qs1r] Looking for good, cheap, external reference
John, unless I am going mad, the ADEV plots for both auctions you
mentioned look the same - maybe the bad one has been replaced since
you posted your message?
The black-and-white plot that everybody uses is from the original
Thunderbolt data sheet, which was way conservative even for the
Would a newer unit with the 3.00 firmware, the trimble branded OCXO and the
older temperature sensor be one of the better (or perhaps best ?) TBOLT
combinations ?
- Original Message
From: John Miles jmi...@pop.net
To: les...@veenstras.com; Discussion of precise time and frequency
Hi
That's my feeling. The firmware isn't the issue. The OCXO and the temp sensor
are the important points. The firmware is just an easy way to get the right
OCXO.
Bob
On Sep 22, 2010, at 7:00 PM, Mark Spencer mspencer12...@yahoo.ca wrote:
Would a newer unit with the 3.00 firmware, the
And if you buy a newer unit with the better oscillator, new firmware,
and newer (but brain-dead) temperature sensor, it's trivial to replace
the sensor. It took me longer to take the unit apart than to change the
chip and I don't have a lot of experience with surface mount.
Ed
Bob Camp
Is there anyway to tell without opening the box if you have:
1) better oscillator (=Trimble labeled) Anything visible from SW
(Tboltmon or LH)? Any behavior fingerprint?
2) newer firmware (=rev 3.00)Does show up in SW.
3) newer brain dead temp sensor (=?).
HI
Opening the box to be sure there's not a dead spider in there is always a good
idea...
The old oscillators all went out before firmware 3.0. Manufacturing dates past
end of 2000 should all have a better oscillator. You could test it for phase
noise and short term stability, but pulling the
Hi
The black box TBolt is the real version. The one with the chromate box is the
upside down version. It's pretty obvious which is which looking at things
like the 9 pin D connector. Rumor has it that a very large customer designed
their box backwards and the upside down part came into being
Hi All,
I recently purchased a Wenzel 245MHz OCXO from ebay. It appears to work
very well and shows good stability after 2 weeks on the bench.
I would like to use it as the primary reference for a DDS 1st Lo in my
homebrew HF transceiver. I have come to the conclusion the unit requires
a
On Sep 22, 2010, at 5:57 PM, Bob Camp wrote:
The temp sensor is the one that moves in real small steps. The bad one moves
in (1/2 degree???) big steps.
All of that (and much more) is visible if you bring up Lady Heather and see
what's going on.
My TBolt has the 3.0 firmware and the
I am not able to measure Phase Noise as per spec, I am looking for
assistance from this group on the best method for measuring phase noise
and stability using what equipment I do have in my Lab. I have a
TDS2022B with FFT, HP 53131 and Tek492BP. My standard's reference is
one of Tom's
Robert,
Many apologies for giving you the big snip (!) - replying to TN postings when
receiving via Digest mode leaves room for such mishaps.
I'm not familiar with 5/32 dowels or how well they fit in WG mounting holes.
One major problem is European IEC US-MIL spec'd flanges have varying size
WG flanges are brass or aluminum. Dowel pins are case hardened steel. For
all practical purposes, they do not wear.
-John
Robert,
Many apologies for giving you the big snip (!) - replying to TN postings
when receiving via Digest mode leaves room for such mishaps.
I'm
Does the temperature move around a little or is it a flat, straight
line? If it never moves, it's probably the bad one. As Bob mentions
below, the temperature only changes in large steps with the bad
sensor. The good one has steps in the millidegree range. I got my
chips from
Using 4 surplus Lucent rubidiums compared to a Lucnet GPS receiver I find a
consistent error of between 110 and 860 pico-seconds using a HP 5370B after
running them for about two weeks. By measuring the weekly drift one could
calculate the drift. I measure the offset at about 20 milli-Hz.
To
On Sep 22, 2010, at 7:50 PM, Ed Palmer wrote:
Does the temperature move around a little or is it a flat, straight
line? If it never moves, it's probably the bad one. As Bob mentions
below, the temperature only changes in large steps with the bad
sensor. The good one has steps in
Youâd probably want to inhibit the circuit during the two periods between
dawn and dusk to avoid what I believe is called the diurineal (sp) shift.
In that small amount of time the Rb oscillator shouldnât drift out of spec.
diurnal
I think it's more complicated than that. The problem
Hi John,
Actually he had 10+ for sale at $25 each free postage. Later that same
day with a sudden spike in sales, the silly seller put them up to $80
and went back on several sales at $25. Now he has swapped them out with
Vetron at $49 each and the excuse was the other Wenzel failed his
If I remember aright, every flange should mate to a choke. that's how to
keep the joints from giving bad stuff...
Don
- Original Message -
From: Kit Scally ksca...@bytecan.com.au
To: time-nuts@febo.com
Sent: Wednesday, September 22, 2010 8:34 PM
Subject: [time-nuts] WG mounting h/w (3)
27 matches
Mail list logo
