Moderate humidity changes caused frequency shifts on the
order of parts in 10^9. With the environmental chamber
on full throttle, I saw parts in 10^8.
The E1938A has an unmeasurable humidity coefficient, even
unsealed.
Rick Karlquist N6RK
Jim Lux wrote:
Some mention has been made recently of
Hello,
Does anyone have a copy of a schematic or service manual for the down-converter
for the Hameg HM8125
GPS frequency/time receiver?
The receiver and display seems to be working fine, but the separate
down-converter appears to have been modified with a capacitor blocking the DC
power feed
The Thunderbolt arrived today. Thanks again to all involved.
However, it looks like my PSU is faulty.
I carefully cut the outer on the cable, splayed out the coloured inner
connectors, so as to avoid short circuits, and noticed that colours of
the insulation on the cable cores did not match
Hi Ian I dont know whether it works for that unit, but try the Hameg site.
http://www.hameg.com/66.0.html
There are almost complete manuals for all the units (well certainly the
scopes!) You may find that there are no schematics in the English
versionsdownload the German versions (which you
Hi Alan,
Tried that, and downloaded the operating manual a while back.
Tried your tip and looked at the German version, but no luck either.
Thanks for the suggestion though.
Cheers,
Ian.
- Original Message -
From: Alan Melia [EMAIL PROTECTED]
To: Discussion of precise time and
Simply put, stability is a measure of how much something varies from a
constant value.
A stable value doesn't mean an accurate value; accuracy is a measure of
how close to some standard value a device emits (in this case) or
measures, for a meter.
So, you could have something that's perfectly
Bill
A very big thank you for what must be a near perfect (accurate) answer to a
question that most of us without Degrees have pondered from time to time. I
shall paste this into my book of many answers
Regards
Roy Phillips.
- Original Message -
From: wje [EMAIL PROTECTED]
To:
You might try the UK agent who has been quite helpful on scope spares.
[EMAIL PROTECTED]
I can't remember the fellow's name now, but I bought several control knobs
to refurb an HM1005 scope. He was very helpful though this adress is not the
one on the back of the manuals!
Alan G3NYK
-
Hi José,
before trying to fix the antenna, please check if it's still working.
Connect it through a bias Tee (for feeding 5 V into the antenna cable,
and for decoupling DC from the analyzer) to a spectrum analyzer and use
a signal generator with a short wire inserted into the output jack. Set
I have been reading this thread with interest since I enjoy resurrecting
'dead' instruments. Two questions though:
1. Since I have been out of the loop for many years, what is an 'MMIC'?
2. The picture suggests some corrosion or oxidation near the coax cable
connection. Has this been cleaned
At 05:49 AM 7/22/2008, David Ackrill wrote...
On plugging in a lead there was a slight 'buzz' and, on checking the
outputs, no DC volts. Checking the lead showed no AC volts. So, I
opened the plug and checked the fuse, a 3 Amp type - too big for the
unit output really, but shouldn't have
MMIC = Monolithic Microwave Integrated Circuit
Bill Ezell
--
They said 'Windows or better'
so I used Linux.
J. L. Trantham wrote:
I have been reading this thread with interest since I enjoy resurrecting
'dead' instruments. Two questions though:
1. Since I have been out of the
J. L. Trantham wrote:
I have been reading this thread with interest since I enjoy resurrecting
'dead' instruments. Two questions though:
1. Since I have been out of the loop for many years, what is an 'MMIC'?
Monolithic Microwave Integrated Circuit.
2. The picture suggests some
Mike S wrote:
Most switching supplies require a minimum load to operate correctly. If
the output is just open, and you don't see any voltage, it doesn't
necessarily indicate a problem.
No, the unit is dead...
I managed to get another one locally, a place called JPG in Chesterfield.
Almost
Oh, for anyone else who has the same PSU as I received, the colours of
the output, from the markings I can see on the PCB, are as follows.
Brown = Ground (Yes, honestly! The brown wire is soldered to the case
in my unit)
Black = 12 Volts (I presume nevative)
Red = +12 Volts
Green = +5 Volts
David Ackrill wrote:
Oh, for anyone else who has the same PSU as I received, the colours of
the output, from the markings I can see on the PCB, are as follows.
Brown = Ground (Yes, honestly! The brown wire is soldered to the case
in my unit)
Black = 12 Volts (I presume nevative)
Red =
My 2100 timing receiver (no suffix) has started to give me problems with
what looks like bounce from the keypad switches, with a lot of numbers
repeating without being asked. Is this a known problem with these
units, and is there a known fix? I don't think the guts of the pad are
accessible
Bill Janssen wrote:
On my unit White is Common for the other voltage leads and blue is not used.
Yes Bill,
Now I've had a bit of a poke round, the white is common, it's connected
to the ground plane on the main PCB, and the blue wire is cut off just
behind the grommet.
My Thunderbolt lives!
On Tue, Jul 22, 2008 at 2:49 AM, David Ackrill [EMAIL PROTECTED] wrote:
Also, I see that the antenna socket on the Thunderbolt is an F-type.
Someone has thoughtfully provided an F-Type to BNC adapter. However,
the plug on the Motorola GPS antenna is an SMA type. Ah well, I can
make a lead
Well, setting up the Trimble software was quite straight forward, and
I've got nearly all Green on the alarms.
The only two yellowed are Self Survey Activity and Stored Possition.
I'll do some reading of the manual before I go messing with any of the
settings.
Next thing to do is save up
Bruce wrote:
Circuit is exactly that to be expected with a discrete pHEMT or similar
device.
It looks to me as if the bias flows through the trace on the BR
and then through a couple of 001 R's before the bias
setting 221 R.
Nonsense they are 100 ohm resistors text is upside down.
The self survey will go green after it has completed the survey as will the
stored position.
Dave
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of David Ackrill
Sent: 22 July 2008 17:47
To: Discussion of precise time and frequency measurement
Subject:
David C. Partridge wrote:
The self survey will go green after it has completed the survey as will the
stored position.
Thanks for the advice Dave,
Yes, I can see that it's only 73% through the self survey, so I'll leave
it whilst I do the dinner, and see if it's finished by then.
Did I
It's been a year or so since I shopped for any, but eBay yielded quite a
few for me, searching on rack ears.
John
J. L. Trantham said the following on 07/21/2008 07:19 AM:
I, too, have been looking for rack mount ears for similar units (5334B,
3325A, 3335A, 8657A, 5087A, 105B, 8130A,
I have what I believe to be a rubidium frequency reference made by
Efratom. Research with Google has not helped me find info on using it.
The unit is a cube about 2x3x4 marked ASSY 100334-004. The unit has
a connector that looks identical to the Stanford PRS10. I have the
pinout for that.
Can
John, Sounds to me like you have a FRS-C. Same pin out as the PRS-10
for the most part. See the FRS-C manual at my TF site www.to-way.com
Hadley
At 12:51 PM 7/22/2008, you wrote:
I have what I believe to be a rubidium frequency reference made by
Efratom. Research with Google has not helped
John,
I don't have mine at hands to cross-check if I'm right, but you probably
have a Ball Efratom / Symmetricom FRS.
Adrian
John Simmons schrieb:
I have what I believe to be a rubidium frequency reference made by
Efratom. Research with Google has not helped me find info on using it.
The
In looking into extremely low phase noise synthesizers, I have come
across the new HMC700LP4 chip from hittite, which seems to have the
best figure of merit I have found, -227 dBm/Hz. That gives you
-107dBc/Hz at 20 kHz offset at 6 GHz according to the datasheets.
That sounds amazingly good, but
Thank you very much Bruce and all who replied my previous message,
According to measurements made with multimeter I think the MMIC is damaged,
because it´s consuming more than 10mA, when its maximum specified current,
at 3V, is 8mA, and the typical 6mA; maybe some of its internal transistors
Matt Ettus wrote:
In looking into extremely low phase noise synthesizers, I have come
across the new HMC700LP4 chip from hittite, which seems to have the
best figure of merit I have found, -227 dBm/Hz. That gives you
-107dBc/Hz at 20 kHz offset at 6 GHz according to the datasheets.
That
David C. Partridge wrote:
The self survey will go green after it has completed the survey as will the
stored position.
The Self Survey has gone green as Self-Survey Progress is at 100% now,
and the Thunderbolt is seeing 7 out of the 8 satellites at the moment.
However, Stored Position is
José,
14 mA seems a bit high... but you may check the other pin voltages, too.
The UPC2749TB is available here:
http://www.mouser.com/
http://search.digikey.com/
Digikey has a sales office in Germany, so you might save on shipping.
It's probably easier to ask NEC for 2...3 samples than to order
Only 3 sats visible and the Thunderbolt has un-locked. I guess I need
to get an external antenna up ouside and clear of as many obstructions
as I can make it.
Dave (G0DJA)
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In this case the Stored Position will never go green since 1) the Self survey
has not been configured to store the surveyed position and 2) you have not
manually stored a position.
You have two choices: 1) Click on Setup, select Position..., fill in an
appropriate
position and click Save
Bill Beam wrote:
The unit was shipped configured not to save position after a self-survey.
This
assures a Self-Survey after power cycle.
Thanks Bill,
Someone else pointed out my mistake as well.
So, I've now set the self-survey up again after doing as you suggested.
Thanks - Dave (G0DJA)
Sorry to be a bore, but like any kid with a new toy I'm facinated by the
changing values on the display...
What do the values under SV and AMU mean?
Maybe I should recognise them from other GPS satellite days, but they
don't seem to be values that I remember.
I'm sure it all means that they
On Tue, Jul 22, 2008 at 4:14 PM, David Ackrill [EMAIL PROTECTED] wrote:
Sorry to be a bore, but like any kid with a new toy I'm facinated by the
changing values on the display...
What do the values under SV and AMU mean?
SV = space vehicle. mostly irrelevant, unless you care about the
serial
I've played with the Hittite chips before and obtained PN results in the
same ballpark (see http://www.ke5fx.com/hpll.htm ), but at 8 GHz rather than
6 GHz. To save further head-scratching, the figure of merit on these chips
works like this:
In-band phase noise in dBc/Hz = FOM + 10*log(Fcomp) +
Oh well then, I guess everyone is asleep.
So, GN all.
Dave (G0DJA)
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and follow the instructions there.
In a message dated 23/07/2008 00:15:51 GMT Daylight Time,
[EMAIL PROTECTED] writes:
The 10MHz output seems, as far as my old Multifunction Counter is
concerned, to be to 10.0MHz within +/-0.1 MHz.
The display showing 10.3 to 10.4 MHz all evening.
So, my guess is that my
Chris Kuethe wrote:
What do the values under SV and AMU mean?
SV = space vehicle. mostly irrelevant, unless you care about the
serial number of the bit of metal up there. Usually people mean to say
PRN, or Pseudo-Random Noise code number - one of the 32 codes
transmitted by the satellite.
At 07:14 PM 7/22/2008, David Ackrill wrote...
So, my guess is that my poor old counter is +/- 10Hz out, but that may
be due to the age and non-calibration of my frequency counter over the
years.
Or... The Thunderbolt 10MHz output is moving up and down by 0.1
MHz
within a 10MHz band.
Variation of +/- one count in the last digit is normal for any counter. It
is caused by a slight shift between the counter gate and the input signal.
The longer the time between digit changes, the more stable the phase between
the unknown and the counter gate.
John WA4WDL
- Original
http://www.ko4bb.com/dokuwiki/doku.php?id=precision_timing:store_position_on
_trimble_thunderbolt
Thank to John Miles for that one...
Didier KO4BB
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of David Ackrill
Sent: Tuesday, July 22, 2008 11:47 AM
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