To answer which North, it is True North, not Magnetic. Orbits,
including GPS, are specified relative to the geographic pole. Magnetic
North moves noticeably over time and place. True North moves somewhat
over time but only very slightly.
David
On 12/15/14 9:05 PM, Jim Lux wrote:
On
I compared results from many different timing receiver surveys (VP,
UT+,Resolution-T,SMT, Jupiter , that of LH for my T-Bolt, Ublox-6T) with the
Google Earth position and with the exception of the Ublox receiver they are all
within the bounds of the GE uncertainty which is around 2m from the
I have a couple of Rb sources bought from China or Hong Kong a year or
two ago. I'd like to fix these up. Initially in a box where I can
adjust them to frequency manually, but perhaps later lock them to GPS.
Looking around the web, there are countless options on these things,
and different
Hi
On Dec 15, 2014, at 11:20 PM, Dave M dgmin...@mediacombb.net wrote:
Jim Lux wrote:
On 12/15/14, 5:46 PM, Dave M wrote:
With all the discussion about surveys position accuracy, I have a
question about my choke ring antenna. There is an arrow marked N
on the underside of the rings. How
Hi
On Dec 15, 2014, at 9:39 PM, Paul tic-...@bodosom.net wrote:
On Mon, Dec 15, 2014 at 8:35 PM, Bob Camp kb...@n1k.org wrote:
So the question - If they are not going to be equal, which one do you pick?
The better one. If the math is sound the presumably the better position
results
Hi
One fairly important issue - the unit needs to be on a heat sink. If you run it
without cooling of some sort, it will not run for very many years.
Bob
On Dec 16, 2014, at 5:22 AM, Dr. David Kirkby (Kirkby Microwave Ltd)
drkir...@kirkbymicrowave.co.uk wrote:
I have a couple of Rb
On 16 December 2014 at 12:16, Bob Camp kb...@n1k.org wrote:
Hi
One fairly important issue - the unit needs to be on a heat sink. If you run
it without cooling of some sort, it will not run for very many years.
Bob
I do realize that, but how big? Normally the bigger the better is
not an
Hi
You are dumping about 15W into the heat sink (or cooling system). You would
like to keep the baseplate at 40C if possible. In a 25C room, that works out
to a 1 C/W heat sink. If you are using a fan, that’s a pretty small gizmo. If
you are building a metal case and putting other stuff in
On 12/15/14, 8:10 PM, Tom Van Baak wrote:
But to prove us wrong, put the antenna on a 17 hour turn-table, collect data
for 6 months, and then see if you see any 17h peaks in the FFT!
Clever idea, but..
Most rotary joints have more phase and amplitude variability than the
antenna.
So
I suggest you go to http://www.febo.com/pipermail/time-nuts/ back a couple
of years and you will find every thing you ever want to know about the FE
5680A. Similar to the recent Lucent activity
Bert Kehren
In a message dated 12/16/2014 7:21:02 A.M. Eastern Standard Time,
On 16 December 2014 at 13:18, Bert Kehren via time-nuts
time-nuts@febo.com wrote:
I suggest you go to http://www.febo.com/pipermail/time-nuts/ back a couple
of years and you will find every thing you ever want to know about the FE
5680A. Similar to the recent Lucent activity
Bert Kehren
I
Clever idea, but..
Most rotary joints have more phase and amplitude variability than the
antenna.
So you're stuck with rotating back and forth with a cable that's flexing
and now you get to measure the phase variability of the coax.
I was thinking of some sort of non-contact RF bridge
Dave wrote:
I suggest you go to http://www.febo.com/pipermail/time-nuts/ back a couple
of years and you will find every thing you ever want to know about the FE
5680A. Similar to the recent Lucent activity
I did do that, and found various comments about various options, and
people note
On 12/16/14, 5:59 AM, Tom Van Baak wrote:
Clever idea, but..
Most rotary joints have more phase and amplitude variability than
the antenna.
So you're stuck with rotating back and forth with a cable that's
flexing and now you get to measure the phase variability of the
coax.
I was thinking of
Dan wrote:
My gut feeling is you are right about the GPS time base being
sensitive. It would be fun to hack into this and try clocking it off
the OCXO, but I'm not there yet! :)
One interesting way would be to use the disciplined OCXO output to
drive a DDS synthesizer set to the GPS unit's
Some time ago, I said I'd post a description and schematic of an
excellent frequency doubler using a quadrature hybrid directional
coupler to drive a diode DBM. It is now available on ko4bb.com
following Didier's recent work on the site (Thank you, Didier, for
this wonderful resource):
Hello,
I've mounted both my LPRO-101 and FE-5680 in Hammond 1590-type cast
aluminum boxes, bolting the rubidium unit to the lid of said box, and
found the heat sinking of the entire arrangement to be entirely
adequate. In each case there is a (well filtered!) switching regulator
present
Every so often, the subject of logging the zero-crossings of the AC
mains comes up. There are any number of ways to couple the AC mains
to logic circuitry (coupling with very high value resistors,
capacitor coupling, and optical isolation have been mentioned). A
simple AC mains ZCD that is
Hi Dave,
The ones I have use the following pin out
1 - 15 v
2 - ground
4 - 5 v
5 - ground
7 - 10 mhz
The pot on the side does nothing.
Look in the archives for my and other folks addition of an adjustment pot.
You can also adjust fx via software. Pot is easier.
73,
Bill
I have a
All,
It's interesting, but I've actually found the FE-5680 I have will power up, and
lock, from just 12v. Sure, takes a bit longer, but it eliminates the need for
the 7812 in the box, etc. I know the 5680 FAQ on ko4bb
Due to a bulk purchase, I have two used 53131A counters to sell.
Preferably a UK buyer, looking for about £200 + postage. Standard
reference (not medium or high stability), calibration expired.
Please contact me off-list for full details.
-adrian
___
Fellow time-nuts,
We have now 15 L2C signals and 8 L5 signals in the air.
An L2C only receiver start to become useful in it's own right.
L1 C/A, L2C and L5 would allow for tripple frequency receiver. Things is
starting to be interesting, if you have the receiver for it. With a
Apologies to Jean Louis, I obviously missed that part... :)
On Wed, Dec 10, 2014 at 3:47 PM, Jean-Louis Oneto jl.on...@free.fr wrote:
I just uploaded the file to K04BB. com.
Best regards,
Jean-Louis
On 10/12/2014 19:10, Charles Steinmetz wrote:
Jeaen-Luis wrote:
The size of the file
Magnus exciting. Now which ublox receiver is that on ebay? :-)
Regards
Paul
WB8TSL
On Tue, Dec 16, 2014 at 4:09 PM, Magnus Danielson
mag...@rubidium.dyndns.org wrote:
Fellow time-nuts,
We have now 15 L2C signals and 8 L5 signals in the air.
An L2C only receiver start to become useful in
Hi
What ever you do, take the extra step of checking the baseplate temperature
once you have things up and running. The Rb’s will *work* over a wide
temperature range. The region over which they will last a long time is a bit
more narrow. I seem to have spent a lot of time demonstrating that.
On 16 Dec 2014 23:06, Bob Camp kb...@n1k.org wrote:
Hi
What ever you do, take the extra step of checking the baseplate
temperature once you have things up and running. The Rb’s will *work* over
a wide temperature range. The region over which they will last a long time
is a bit more narrow. I
Paul,
That is indeed the question. Considering that the signal is better
supported, I hope the light goes on somewhere. The signals is all
1,023 Mchips/s, just a thad different. Should be possible to pull off if
people want to do dual frequency without going full bandwidth.
Then again, if
On 12/16/14, 3:36 PM, Magnus Danielson wrote:
Paul,
That is indeed the question. Considering that the signal is better
supported, I hope the light goes on somewhere. The signals is all
1,023 Mchips/s, just a thad different. Should be possible to pull off if
people want to do dual frequency
Hi
On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote:
On 12/16/14, 3:36 PM, Magnus Danielson wrote:
Paul,
That is indeed the question. Considering that the signal is better
supported, I hope the light goes on somewhere. The signals is all
1,023 Mchips/s, just a thad
Jim, Bob,
On 12/17/2014 01:06 AM, Bob Camp wrote:
Hi
On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote:
On 12/16/14, 3:36 PM, Magnus Danielson wrote:
Paul,
That is indeed the question. Considering that the signal is better
supported, I hope the light goes on somewhere. The
On 12/16/14, 4:06 PM, Bob Camp wrote:
Hi
On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote:
On 12/16/14, 3:36 PM, Magnus Danielson wrote:
Paul,
That is indeed the question. Considering that the signal is better
supported, I hope the light goes on somewhere. The signals is all
On 12/16/14, 4:29 PM, Magnus Danielson wrote:
Jim, Bob,
On 12/17/2014 01:06 AM, Bob Camp wrote:
Hi
On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote:
On 12/16/14, 3:36 PM, Magnus Danielson wrote:
Paul,
That is indeed the question. Considering that the signal is better
Hi
On Dec 16, 2014, at 7:29 PM, Magnus Danielson mag...@rubidium.dyndns.org
wrote:
Jim, Bob,
On 12/17/2014 01:06 AM, Bob Camp wrote:
Hi
On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote:
On 12/16/14, 3:36 PM, Magnus Danielson wrote:
Paul,
That is indeed the
Jim,
On 12/17/2014 01:46 AM, Jim Lux wrote:
On 12/16/14, 4:29 PM, Magnus Danielson wrote:
Jim, Bob,
There is a fair amount of work along the full path.
LNA with some L2 and L5 filters is pretty easy.
I think you still want to have a correlator baseband processing in say
an FPGA.
well,
The Swift Navigation Piksi project may be of interest:
http://swiftnav.com/piksi.html
It has an FPGA for correlation with an ARM Cortex-M3 for tracking
loops and navigation. The hardware and ARM firmware is open source,
but the FPGA design is closed-source at the moment. However, I don't
see
I just power mine off an old 19vdc laptop supply dropped with a linear
regulator (and filtered) to provide ~17vdc No 5vdc supply required for
mine. I recall reading that some have an internal 5v regulator. I believe
the way to check is if the lock pin signals and PPS is present without
external
On Wed, Dec 17, 2014 at 12:01 AM, Jim Lux jim...@earthlink.net wrote:
On 12/16/14, 3:36 PM, Magnus Danielson wrote:
what about one of the software receivers? I would think that making L2 and
L5 filters isn't that tough, so all you need is the back end.
I'm pretty sure GNSS-SDRLIB supports
HI
On Dec 16, 2014, at 8:14 PM, Gregory Maxwell gmaxw...@gmail.com wrote:
On Wed, Dec 17, 2014 at 12:01 AM, Jim Lux jim...@earthlink.net wrote:
On 12/16/14, 3:36 PM, Magnus Danielson wrote:
what about one of the software receivers? I would think that making L2 and
L5 filters isn't that
Hi
On Dec 16, 2014, at 4:36 PM, Brian M brayn...@gmail.com wrote:
I just power mine off an old 19vdc laptop supply dropped with a linear
regulator (and filtered) to provide ~17vdc
I think that keeping the internal regulators running is a good idea. The more
stages of stabilization and
Charles Steinmetz wrote:
Every so often, the subject of logging the zero-crossings of the AC
mains comes up. There are any number of ways to couple the AC mains
to logic circuitry (coupling with very high value resistors,
capacitor coupling, and optical isolation have been mentioned). A
simple
Since version 3.1 Lady Heather should be able to find a 9600,8,ODD,1 device.
This was added for the Resolution T timing receiver. It may take it a minute
or so for it to figure out. If the program does not see a valid receiver
version message within 30 seconds or so it toggles the parity
Jim Lux wrote:
On 12/16/14, 5:59 AM, Tom Van Baak wrote:
Clever idea, but..
Most rotary joints have more phase and amplitude variability than
the antenna.
So you're stuck with rotating back and forth with a cable that's
flexing and now you get to measure the phase variability of the
coax.
I
Hi
Indeed looking at the AC line is a Time Nut sort of thing to do. It was one of
the first things I did with an old Beckman counter back in the 1960’s. Yes I
realize that the AC line is a very noisy signal and that this may not be needed:
The same limiter / noise shaper stuff that works for a
Hi
On Dec 16, 2014, at 9:15 PM, Dave M dgmin...@mediacombb.net wrote:
Jim Lux wrote:
On 12/16/14, 5:59 AM, Tom Van Baak wrote:
Clever idea, but..
Most rotary joints have more phase and amplitude variability than
the antenna.
So you're stuck with rotating back and forth with a cable
Inquiring minds surely are in high gear!! And to think, all I
wanted to know was how close I needed to to point to north!!
The need to point north is a legitimate question. There is a chance
that they designed some magic into it to deliberately shape the response.
Having taken a few
Of *course* you can sync to better than a millisecond on the LAN. There's
not a machine worldwide at my employer more than 600 micros off from each
other, and the machines at my house are within 50.
You wanna start talking the sync-e+1588 test I'm doing? We're speaking in
nanos then.
My LTE
Bob wrote:
The Collins paper on hard limiters does indeed apply here. You
*could* make a 60 Hz chain that got down into 1 us sort of resolution.
I don't know how much less than 1uS you mean by , but I was
seeing less than 1uS jitter with the circuit described.
Best regards,
Charles
Thanks Mark!
I figured that there had to be a way, especially given that
Trimble's former TSIP standard was 9600,8,ODD,1.
Now, if I could figure out why LH thinks it needs something
newer than windows 95... which is what is on the old 486
laptop that I would like to use for that purpose...
I would venture that the extent of the magic was to note the physical
center of the array, and call that the phase center.
As long as you always orient the antenna in the same direction, any
errors that might exist in the real phase center will be consistent,
and could be corrected for by noting
Dave wrote:
I'm not trying to downplay the circuit in the link above, but I want
to offer another possible solution to Zero-Crossing needs.
Here's an Idea For Design from EDN magazine that I've used a couple
times in non-time-nut circuits, and I must say that it works
beautifully. I have
Of *course* you can sync to better than a millisecond on the LAN. There's
not a machine worldwide at my employer more than 600 micros off from each
other, and the machines at my house are within 50.
You wanna start talking the sync-e+1588 test I'm doing? We're speaking in
nanos then.
My LTE
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