Corby,
Power Basic certainly does the job. However, there's a fairly big learning
curve. I use Just Basic, which is a FREE cut-down version of Liberty Basic.
While there are a few limitations, and some things you need to do aren't
entirely intuitive, it works very well and the serial comms
Ulrich is right about the use of MTI 260 use in GPSDOs. I have a Korean-made
Z3815A clone (it's labelled Agilent) which has a little daughter board with
a 5MHz MTI 260 DOCXO in place of the original E1938A used in these models. I
understand that there were production and reliability issues with
Disassemblers are hardly rocket science. They are only a parser with a pile
of memory to remember labels. Why not write your own? I've written them in
the past (a long way in the past, and I've written cross-assemblers too), so
I don't see anything difficult about writing one for the 8051.
Keenan,
You can see my GPSDO source code for a mere $50. It comes with manual and
executables. The executables alone are $20.
See http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm
While this design does not use a Kalmann filter, it has pretty good
holdover, and you can see how the phase
My mistake was inferring that my GPSDO software was open source. It's
absolutely not. It is proprietary to me and written in AVR assembler. There
is no reference anywhere in it to any libraries from any other source.
So don't get too excited. You can still see what's inside it for $50, but
As Bill suggests, the best way to achieve any-frequency performance with the
newer FE-56xx devices is to pull out the Rb reference frequency and run an
external DDS off it.
I found that the Rb loop frequency in the one I played with was exactly
60MHz, rather than the 50.255MHz of the older
.
Regards,
Murray Greenman
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Warren,
I take the point that you are testing the SAME oscillator as a means of
adding some consistency to the test. However, leaving aside this
consistency and issues relating to the disciplining device (your TBOLT),
I suggest your test of double vs single oven OCXO may be unfair to the
single
Gerard,
By now you've no doubt had more offers to assist than you need, and in
particular from far more local enthusiasts than me.
However, if I can help answer any particular points, I would be pleased
to do so. My reason for suggesting this is that I have available a
Pendulum CNT-90 counter,
Probably hot air...
Murray
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of time-nuts-requ...@febo.com
Sent: Monday, 1 March 2010 2:56 p.m.
To: time-nuts@febo.com
Subject: time-nuts Digest, Vol 68, Issue 3
Send time-nuts mailing list
of the
currently known commands, a collection of modification information, and
also a PC program to download, which controls the FE-5650A and FE-5680A
in an easy to use manner, where you dial in the frequency in Hz.
These are great little units!
Regards,
Murray Greenman ZL1BPU
the 2nd order model.
Regards,
Murray Greenman
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf
Of time-nuts-requ...@febo.com
Sent: Thursday, 27 May 2010 5:31 p.m.
To: time-nuts@febo.com
Subject: time-nuts Digest, Vol 70, Issue 75
Send time
different but externally identical. Software
includes a monitor program with multiple windows and a rather cool retro
and very realistic Nixie Clock.
Regards,
Murray Greenman
--
Message: 4
Date: Thu, 10 Jun 2010 09:41:00 +0200
From: Magnus Danielson mag
I can't share the code (belongs to my employer), the idea is
simple enough and I could share the schematic.
Eight of these units have been built. I used the excellent Rakon
STP2402E OCXO.
Regards,
Murray Greenman ZL1BPU
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Jim,
Would an inexpensive Rubidium unit do what you want? I know it won't be
closer than a few ppb, but in my experience (LPR101, FE-5650A, FE-5680A)
they are stable inside about four minutes. The big advantage is they
don't need GPS at all.
Regards,
Murray ZL1BPU
Message: 1
Date: Wed, 14 Jul
You guys are trying to crack a nut with a sledgehammer!
For a start, as Didier says, you can't possibly read the frequency of a
sky-wave signal to 0.01Hz in any short time frame since the Doppler on
the signal can be as much as 1ppm (i.e. 10Hz at 10MHz). You can only
infer it closer than that by
I designed and built a similar thing a while back, which emulated the
full VNG time code (which could be decoded by 'Radio Clock' and other
clock software).
My unit was GPS locked, using two microcontrollers, but it wouldn't need
to be that complex for setting clocks/watches. It generated all the
I know this is a bit off-topic, but I wonder if any of you guys have
available the manual for the old (1970s) Drake DSR-2 receiver?
I've you are able to send me a PDF copy, I'd be most grateful.
73,
Murray ZL1BPU
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Nigel,
Thanks very much! I'm not able to download it from here at work (the IT
Police policies block so much the internet isn't fun any more!), but
will as soon as I'm home.
I have the receiver going quite well, and it certainly looks impressive
with its Nixie display. It's no great performer by
Hi,
I've just acquired a Trimble (Nortel) NTGS50AA GPSTM (another flavour of
GPSDO), and it supports the Trimble TSIP protocol, as used by the
Thunderbolt. Apart from one message, it works fine with the TBOLTMON
software.
TBOLTMONWorks fine, can post-process using the log, no
There is no easy way to divide directly from 10MHz to 32768Hz.
On my web site at www.qsl.net/zl1bpu/MICRO there are several signal
generator projects which would do the job of generating 32768Hz from
10MHz for you.
With any of these (single chip micro approach, using 24-bit Direct
Digital
What Rick says is completely correct.
I took the general approach (so you can generate any frequency) and by
using a binary counting scheme, the number of clock cycles required is
reduced to 9 (for 24-bit) or 10 (for 32-bit), provided you use an AVR
processor.
The advantage then is that you have
Phil,
It is very likely that the program WILL work with the 58534A. However,
there are several steps to take before you can be sure whether it will
or won't.
First, you must ensure that your RS422 to RS232 adaptor is working
correctly. The TX output should sit idle at -9V (or thereabouts), and
My present plan is to generate from a 5V micro two 0.5Hz outputs, 50ms
width (as TVB has shown), and to drive the coil via a resistor in each
output. The resistors serve a further function of protecting the micro
outputs from ESD to some extent.
Murray ZL1BPU
I've obtained a faulty HP 8640B signal generator, and have determined
that the fault is in one of the dividers. (The unit has output only on
the top two ranges). Other than that, the generator seems to be in fine
fettle.
Since the chance of finding a replacement gold-plated HP-numbered ECL
chip
Ulrich,
Living where you do, I'd suggest checking out the U-BLOX range of
modules. The model you need is the LEA-5T. The LEA-5 family is
state-of-the-art, and I believe uses an ATMEL DSP software baseband
engine (with reportedly one million correlators!)
I have two of their modules (LEA-5H and
Steve,
The suggestion of using the mains frequency as a reference is not
practical. There will be no certainty, even after counting for a week
that the mains frequency will give you a reliable reference. You said it
yourself - the instantaneous frequency of the mains is not always spot
on.
The
Hal and others,
I am sure that if one could accumulate mains cycles long enough, a
reasonable level of accuracy could be obtained, but you need to ask
yourself (1) to what standard is this 'reference' traceable, and (2)
what happens if there is a power failure?
On this latter point, let's say
Skip,
How about sending me some photos of the unit? I know the Z3815A and
E1938A well, and if it's the same in different packaging, I'll be able
to tell.
73,
Murray ZL1BPU
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Magnus,
I can't help you with the manual, but I agree, it will be useful for TF
applications. I have a newer model X-Y display (the one with storage,
forget the model) which I intend to use for TF.
By the way, for anyone who is wondering, a conventional TV Vectorscope
works great as a phase
Personally, I'd just leave the TBOLT to get on with the job.
It's probably a good idea to exclude draughts, but adding further
insulation will probably not help matters and may hinder them. I'm
thinking specifically of what happens to the ambient compensation of
OCXOs when the insulation thermal
You might as well forget using an indoor antenna for GPSDO use. For best
performance, you need an antenna which sees the top of the sky (say down to 30°
elevation) really clearly, and ideally you want an antenna designed for timing
applications, which favours high angle satellites.
This is
Down here in NZ, a common form of TV antenna mount is the 'hockey
stick', which is a J-shaped pole with a plate for barge-board or gable
mount (on a vertical surface) and a vertical pipe about 1m long and 20mm
diameter. A typical pipe-mount GPS antenna is easy to mount on this,
either directly
My Samsung GPSDO is a very good and fairly new unit, but I've just
spotted that the date it is reporting is incorrect!
It should be 1 March, but it is reporting 29 Feb, and there isn't one
this year. The GPS module I'm also running at present (u-BLOX Antaris)
does report the date correctly.
73,
Geoff,
I'm not in a position to check at present, but have also noticed
discrepancies in the time pips in the past. I'd not use a GPS receiver
for this, as they can easily indicate a second or so out. I use a GPS
Disciplined Receiver (HP Z3801A or Trimble NTGS50AA) for the job.
I suggest you talk
Leigh,
I agree with Chuck. I have both an FE-5650A and an FE-5680A. With the
former I was concerned about the heat, and so ran it only for short
periods, until I understood what was going on. I had the impression from
the data sheet that there were different heatsink options for different
I think we've all learned from this. Good info about the Efratom unit,
and sounds as though we should aim for around 38C with the FEI units as
well. The FE-5680 looks to be easier to deal with than the FE-5650, so
I'll look into that first.
Murray ZL1BPU
Hi,
Has anyone made further progress in understanding the PFORTH commands?
I find with my Z3815A (with an E1938A hockey puck oscillator installed) that
the command 'puck' returns:
a= -6.305066e-13 b= 0.00e00 a/d = 1.60e+01
puck communication is alive
puck warm= 1
puck EFC ADC err= 0
questions about the project, just send me an email.
By the way, if you're looking for a good homebrew GPS Reference (VNG in a
Box is a lot more than that), try my Simple GPSDO:
http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm
73,
Murray Greenman ZL1BPU
Mark,
I agree with you. I've been using an NTGS50AA here for some time, and it is
an excellent unit with none of the thermal problems of the Tbolt. Easily as
good as the old Z3801A, and much lower power consumption. I use the NTGS50AA
with the Thunderbolt software in TSIP mode, although not
John,
Good stuff. Excellent news.
You will be very impressed with the performance of the NTGS50AA.
If you have any questions, or need real Trimble software to test it with,
let me know. I did some spying on the comms using the Trimble software, but
it was very difficult. TSIP is not a
Kevin,
No, I've not found a 1PPS output. Not that I've looked, and I don't have the
official pinouts for the big connector on the back. It would be easy enough
to synthesize one, for example using a divider on one of the other products,
resetting it if necessary with the 1PPS2 (2 sec) pulse.
it running on an old
P1 Tosh laptop.
73,
Murray Greenman ZL1BPU
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Bjorn,
I don't know of an RS422 connection at the back of the NTGS50AA. There is a
'CMOS' level serial output (essentailly a monitor point) on the top pin, 7th
row along from the end the power is applied. There are also 10MHz PECL
outputs at the other end of the connector.
I use either
Bjorn,
Sorry, I have no further info re the RS422. Perhaps you could try tracing it
from the processor or at least the 422 interface chip, if you can find it.
Nobody so far has come up with a definitove pinout for the rear connector.
About the only thing GPS Monitor does that's different is
Ulrich,
I think this is a bit like discussing one's favourite wine or favourite
stereo! Especially since many of the participants here will not have the
capability to compare GPSDO performance reliably.
I have a few GPSDOs, and it's my impression that of them all the Agilent
Z3815A with
John/Mark,
I don't own a Thunderbolt, but I do have a very nice Trimble NTGS50AA
GPSDO which works very well, and it also operates very nicely with
TBOLTMON, in both TSIP and SCPI modes.
However, I've just fired up Lady Heather V2.0 for the first time, and
although the program starts, nothing
at a range of 8000km, and for my own 80uW EIRP
transmission on 181kHz to be detected 500km away. See
http://www.qsl.net/zl1bpu/ZL2AFP/CLICK/click.htm for more information
and Clicklock software by Con Wassilief ZL2AFP.
73,
Murray Greenman ZL1BPU
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time
phase
and power plots which are achieved by maths from the I and Q followed by
'leaky integrators'. That bit was my contribution. The whole idea
originated with Peter G3PLX, the source of many good ideas.
Give it a try - it's quite a tricky bit of software to drive.
Regards,
Murray Greenman ZL1BPU
Here's an idea which actually works (I tried it). Rather than lock at
10MHz, you lock directly to 1pps.
You can lock an XO to 1/3 Hz steps by locking to 1pps and ignoring two
out of three results from the TIC. I did it at 7.333MHz, using an
AT90S2313 micro, and you could just as easily do it at
Rick is right.
The effect you see when turning your GPSDO upside down will be
predominantly the direct gravitational effect on the OCXO crystal and
its mountings. You see this with any OCXO, and the good ones will have a
'2G turnover' or other G rating quoted.
For example, the well known HP
Mark,
How do you KNOW your position to such accuracy? Is it in fact possible
to survey your position to that accuracy by any independent means?
If, for example, you use official survey marks to determine your
position by direct measurement, are the survey marks really that
accurate?
Murray
I have an MV89, and it draws about 320mA steady state. No cycling of the
current at all once warmed up. The surface temperature is warm, but you
can leave your hand on it.
Performance wise, the MV89 is very good. The ageing is particularly low
- after only a week from power-up it's running at
,
Murray Greenman
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Someone asked what the Time-Nuts way of calibrating a Rb source would
be. I'm no expert, but here's my 2c worth:
I don't like making adjustments, as they can lead to lowered
reliability, lowered understanding of the processes of ageing, and are
also more work. As someone else pointed out,
I've not found this to be a problem. I simply turn mine on 5 minutes
before I need it. If it was necessary to run it for weeks, I'd find a
way to use an OCXO or GPSDO instead.
It's a bit different with the old-style Rb References such as the HP
5065A, which take longer to get going. Mine has
Ray,
There are several of us down here on the list. I can think of several in
AU and at least three or four in NZ. If they don't identify themselves
to you, let me know.
We also know the whereabouts of some nice gear.
Regards,
Murray Greenman ZL1BPU
www.qsl.net/zl1bpu
Think about it... no it doesn't. Just takes a while to get used to the
sun being on the wrong side and the moon being upside down (think about
that one!). And yes, the water goes down the plug hole the other way,
and hurricanes rotate the other way.
However, here in New Zealand we are currently
John,
Yes, the temperature and current are completely normal. I have my MV89
running on the bench here, and it's drawing 300mA and too hot to hold.
Don't think about lagging it to keep it warm, or adding cooling, as
you'll mess up the internal thermal profile, and then the calibration
and
dedicated unit for 2.048MHz. Bob Mokia
(NHBBob on Ebay) has the 1pps versions for sale, and these are easily
converted to remote frequency programming, as described in the links
above.
Regards,
Murray Greenman
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EROS is an abbreviation used by the Electronic Research Company. They
used to be in Overland Park, KS, USA. They made OCXOs for government and
space applications. I have some of their 5MHz devices which were widely
used in Transit (pre-GPS) satellite navigation receivers. These OCXOs
were fixed
Alberto,
The Z3815A is certainly less common - except down here in VK/ZL. I have
one, and can try to answer your questions. The oscillator used in the
Z3815A is generally the HP E1938A, although mine is a more recent
Symmetricom version with a Milliren 260 OCXO adaptation. Power supply is
20 -
Steve,
No, I've not seen a Z3805A at all. Not that I know all there is to know
about the Z3815A either.
73,
Murray ZL1BPU
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Steve,
There are at least 20 Z3815A units in ZL Amateur hands that I know of,
and many more in VK. They were 'rescued' by a friend in VK, and have
been distributed with firmware and manual that we've worked out for
them. As far as I can make out, they were not used in cellular systems
here.
Frank,
My suggestion would be to try injection locking, rather than a PLL. No
change is made to the 22MHz and 42MHz oscillators, except to find a way
to inject enough reference power to force them to lock to it. Injection
locking works well with modest harmonic relationships, and gives good
noise
-Original Message-
From: Murray Greenman
Sent: Wednesday, 3 February 2010 9:00 a.m.
To: 'time-nuts@febo.com'
Subject: Injection locking
Frank,
Bruce's collection would be a good place to start. Thanks Bruce. Most of
the examples relate to microwave applications, where often
Frank,
As Bruce suggests, you can in theory lock any rational number ratio,
including 11/5 and 21/5. However, the locking gain drops off as the
ratio becomes more extreme, and thus the lock range and potential
stability are degraded.
Yes, you could certainly use a regenerative divider to
Now I realize I'm known as an injection locking fan, but here's my 2
cents worth:
Divide 10MHz by 5 to 2MHz using a Johnson ring counter (74HC4017). Use
that to injection lock a 64MHz XO. A low noise solution and no PLLs
required.
I'd not be surprised if you could injection lock directly with
Bill,
One method I've found convenient is to use a DDS Development kit such as
the AD9852 one and drive that from a Rubidium or GPSDO source. I have a
60MHz FEI-5680B driving mine and easily get 0 - 200MHz out. No, it won't
give all the range you want, but there are few alternatives that will,
are very good - any frequency I want with microHz
resolution.
Regards,
Murray Greenman
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reference
in the OCXO, resulting in very good thermal performance. The design is
described in some detail at
http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm.
Regards,
Murray Greenman
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dial.
Ideally I'd like a schematic or manual so I can fix the receiver, but
I'd be grateful for any crumbs, such as suggestions about who might know
more about the receiver.
I can send photos if anyone is interested. Contact me direct if you are.
Regards,
Murray Greenman ZL1BPU
My thanks to those who suggested I join the vintage radio forum
www.vintage-radio.net. I have joined, and it certainly looks like a very
helpful group.
73,
Murray ZL1BPU
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There are of course many levels of performance in OCXOs, but in general the
ageing slows down with time, and veteran OCXOs can be very good. I recently
tested the OCXO in an old HP5245L counter (circa 1970), last calibrated in
1985, and it was still within 100ppb of 10MHz after 24 hours warmup!
Paul,
Whenever you make changes to the physical setup you will cause mechanical
disturbance to the OCXO which it is likely to take some time to recover
from. A couple of days continuous operating should suffice. Add to that an
hour for every day it's been switched off.
Even tipping the unit
Bob,
Many OCXOs, and definitely the CMAC (now RAKON) STP2145A, use ambient
compensation technology. It is not possible to place the heater, the crystal
and the temperature sensor in exactly the same place, and consequently there
will be a thermal profile within the OCXO which depends on the
Folk looking for alternatives to dunking things in oil might consider trying
a variant of the following technique which I have used with success:
The thermal stability of TCXOs and XOs can be improved considerably for
experimental purposes by slowing down the thermal time constant between the
It's my experience (and I have two FE-5680A and an FE-5680B, plus a couple
of FE-5650As) that you don't need a +5V supply with the FE-5680x devices,
just a +15V supply.
Now of course the model number has little to do with what we find inside -
there seem to be many variants - so I recommend
Bert,
Your comment about the AD9832 being a 25MHz part made me think, and I too
wonder how it might all work. The data sheet calls it a 25MHz part, and I agree
with you that it might be expected that some extra division occurred between
the ~60MHz Rb loop and the synthesizer MCLK.
That's not
As noted by others, the internal Rb locked signals of some FEI units are not
especially nice sine waves.
One way to profitably use them is to operate an external DDS generator. The
phase noise of the source will afffect the result, but not the harmonics. I
have an FE-5680B which has an
Bert,
There's a very nice way to separate diurnal thermal sensitivity from long
term ageing. It applies equally well to Rb sources as to OCXOs, which is
where I've used it.
What you do is set up to make frequency observations against a more stable
reference (of course in this case a GPSDO or
Hi,
I can think of at least one excellent use for the unwanted 63.8976MHz OCXO
that comes free with some of the recently offered FE-5680A units.
It would make a great reference for a DDS synthesizer, such as an
AD9852/AD9854. These chips have a 4x reference multiplier capability, and
thus would
Two thoughts re Simple GPSDOs:
1. For a conventional 1pps approach, see 'A Simple GPS Disciplined
Reference http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm, by yours
truly. It uses a high performance 10MHz OCXO and gently disciplines it.
Despite not having a Kalmann filter, the holdover
Marco,
I have had an HBG-controlled clock for some years. Not that it ever received
HBG at this range! The clock is an 'Irox HB13P' projection clock, and has
the logo 'Official Swiss Time' on the front, which you can clearly see at
http://www.irox.com/Web/en/Products/Archive/HB13P.htm.
The
distribution.
Since we need to purchase several of these, can anyone suggest a unit
with similar performance and quality that would be lower cost than the
Symmetricom 4036B?
Regards,
Murray Greenman
RAKON Ltd
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Navigators used chronometers to determine their longitude. If they were
stopped in one place long enough, they could work out longitude by a
complicated process of star and lunar observations; however, when they
left an established port, they usually took with them a time standard
based on local
I could tell you but...
There's a lot of interesting IP in these little guys!
Regards,
Murray Greenman
RAKON
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John,
The Z3801A 1pps is based on the mean UTC/GPS time, but regenerated from
the local (very stable) 10MHz reference, so has little jitter.
The UBLOX GPS module 1pps output is more or less instantaneous, so has
jitter resulting from each individual position solution. If you provide
it with a
Rick,
Maybe the French had a point... we all know NTSC stands for 'Never Twice
Same Colour'!
Regards,
Murray Greenman
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Bud,
I have a couple of these units going nicely, but I agree with Bob, you
are best to sort the pinouts for yourself since they vary.
Take the lid off (it's fairly simple, screws on the base, on the side
and by the connector) and identify the 5V regulator input, then use an
Ohmmeter to find
John,
I've had quite a bit of experience doing what you want to do, and have tried
several methods. TV used to be a good way, but now that everything's gone
digital that method is out.
Despite advice to the contrary, comparing with WWV or similar on HF is NOT
reliable to 1ppm. This is because
Hi,
You may recall we discussed here some time back about how time was
disseminated in days gone past, and mentioned Time Balls at various
locations from Greenwich onward.
I'd forgotten that there was (and still is) one at Lyttleton, NZ, right
at the epicentre of the big earthquake. This
Many older GPS units sending NMEA at 4800 baud will in effect indicate
one second slow, either all the time or some of the time, if there are
too many GPS sentences turned on. There's too much data in the queue.
Either drop the number of sentences enabled, or increase the baud rate,
or both.
Don,
You haven't explained how much you want to pull the oscillator, but assuming
it's less than 1ppm, what you suggest is quite viable. Replace one of the caps
in the Pierce oscillator PI network (preferably the output one) with an NPO one
of slightly smaller value and add across it a
Robert,
I've attached the data sheet for the STP2145A. The device is 12V
operated, and has an internal 8V reference which you can use to supply
the EFC circuit.
Have a look at http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm,
where I describe a simple home-brew GPS Disciplined Reference based
Dan,
Yes, you are right. There are so many variants of the FE-56xx devices
that I'm sure even FEI don't have a clue which is which!
The FE-5680 family are invariably single supply, although the connectors
vary. Pull the lid off and with an Ohm-meter trace the input to the
regulators back to the
I've also observed that JJY40 is now off the air. It has been excellent
reception down here in New Zealand for many years, generally better than
the JJY signal on 60kHz, where of course it competes with other signals.
JJY40 was typically strong enough to hear by ear during the day as well
as at
Why not just put a bigger battery in your UPS? I have a couple of old
ones, and they run just fine with an old car battery, and thus give me
many hours of backup for my Trimble/Nortel GPSDO.
Just be careful though - in some UPS units the battery is live to the
mains! The APC ones seem to be OK.
Joe,
I have several of the FEI units. You pay more for these, because
(assuming you get the right one) they have a DDS synthesizer included,
which (with suitable modification) allows them to operate from about
1kHz to 15MHz in 10mHz steps. Some models require +15V and +5V, others
just +15V. My
Jerry has described the situation fairly well. You take pot luck, and
the Chinese supplier does not know which are which.
Out of four units I have, two are remote controllable, one is fixed at
(reasonably close to) 10MHz, while the fourth had no output at all. I've
since discovered that this last
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