Are LightSquared still trying to get some value from their contributions?
Of course they are. Lightsquared (LS) bought low-valued spectrum
at fire-sale prices, speculating that with rule changes and waivers
they could use it for a terrestrial broadband network, in which case
its value
There is also a proposal to pay commercial TV stations to move together
as a cluster, then chop off part of the TV band for wireless. The
current market simply will never fill the allotted DTV spectrum.
[Cable/satellite/internet-streaming filled the void.] It is a bit
nauseating to pay the
And I will not pay telephone prices for wideband data service. Pfui.
Don
gary
There is also a proposal to pay commercial TV stations to move together
as a cluster, then chop off part of the TV band for wireless. The
current market simply will never fill the allotted DTV spectrum.
Hi
The OCXO probably isn't going to do very well with the outdoor temperature
swings…
Bob
On Oct 2, 2012, at 12:12 AM, Raj vu2...@gmail.com wrote:
Just saw this mentioned in Circuit Cellar, just wonding if it really
exists, how much they are asking, and if anyone has played with one
yet?
correction: HP53132A
timeok
Il 2012-10-02 13:29 Timeok ha scritto:
test using HP53123A:
The pink line is the noise floor using the TI mode
The blue line is the noise floor using the Frequency mode (gate 2
sec)
The other two line are the same oscillator, an HP105B tested with
both the modes.
Yes, I agree.
On Tue, Oct 2, 2012 at 1:29 PM, Bob Camp li...@rtty.us wrote:
Hi
The OCXO probably isn't going to do very well with the outdoor temperature
swings…
Bob
On Oct 2, 2012, at 12:12 AM, Raj vu2...@gmail.com wrote:
Just saw this mentioned in Circuit Cellar, just wonding if
Whilst considering the best settings for ADEV measurements, could I
ask for views regarding the venerable HP 5345A counter/timer? I like
this counter, particularly regarding its ability to operate up to
40GHz - with a suitable plug-in of course, and that I have two of
them!
Thanks Geoff
Hmm, the frequency mode sigma is the same as the TI mode sigma for 200*tau.
That is if I take the sigma at 200*tau from the TI mode I have the same
figure of the frequency mode. Maybe the frequency mode 2 seconds sample
time uses 100 averages per second.
On Tue, Oct 2, 2012 at 1:50 PM, Timeok
I'm also interested in this. I've got one of these and a 53131A and
am still learning the ins and outs of ADEV measurements with timelab.
I was not aware of the 5/10MHz shortcomings of the 53131A that were
discussed this weekend..
Brent
On Tue, Oct 2, 2012 at 8:11 AM, Geoff Blake
Luciano,
For TI mode, I have recommended the Wavecrest DTS time interval counters here
in the past.
Can be 1/2 price of an HP 53132A ($600 or so) on ebay, has 800 femtoseconds
resolution, and around 3ps SD typically. Goes to 800Mhz or twice that depending
on model. That blows the 53132A out
Searchin for the best clock characterization gear, the first parameter is
the ability to sense the smallest time movement beetween clock edges. When
you buy your top multimeter, you first decide about the resolution: 6 1/2
digits (for example) is better than 5 1/2. Here it is the same: the
Timeok schrieb:
test using HP53123A:
The pink line is the noise floor using the TI mode
The blue line is the noise floor using the Frequency mode (gate 2 sec)
The other two line are the same oscillator, an HP105B tested with both
the modes.
As you can see the range between 1 and 200 sec is
Then you need a stable clock as a reference, OK, but the first move is
towards the smallest one-shot resolution. It is the same as your
multimeter: it is useless to have 6 1/2 digits resolution and a voltage
reference that wipens out the last 2 digits. The HP5345A has a resolution
of 10E-10 (page
Wavecrest DTS for $600? Interesting...
On Tue, Oct 2, 2012 at 2:43 PM, Adrian rfn...@arcor.de wrote:
Timeok schrieb:
test using HP53123A:
The pink line is the noise floor using the TI mode
The blue line is the noise floor using the Frequency mode (gate 2 sec)
The other two line are the
No matter how much averaging takes place inside the counter, in TI mode
the output resolution is limited to +/- 200ps (53132A) or +/- 500ps
(53131A) which appears to translate directly into the measurement limit
/ noise floor.
Adrian
Azelio Boriani schrieb:
Hmm, the frequency mode sigma is
Yes, and why the 10 seconds frequency mode sigma is apparently better than
the 10 seconds TI mode sigma? Because between the two there are 200
averages taken by the frequency mode processing. This is possible also
because the input frequency in frequency mode is 10MHz or 5MHz and in TI
mode a 1Hz
Raj,
JLT just sent out a press release some days ago on the LC_XO sub 1 inch square
GPSDO that is smaller and higher performance than the RFX unit, runs from only
3.3V, and it can be soldered into a 100 mil standard breadboard, and consumes
only about 0.5W (RFX unit is probably 1W).
On 10/2/12 5:08 AM, Azelio Boriani wrote:
Yes, I agree.
On Tue, Oct 2, 2012 at 1:29 PM, Bob Camp li...@rtty.us wrote:
Hi
The OCXO probably isn't going to do very well with the outdoor temperature
swings…
Bob
Why not.. granted it's easier with large mass and large insulation, but
There are two on ebay now, $600 and $700... Buy it now..
I would ask the seller to connect the 100MHz ref output to both inputs one at a
time and to measure jitter to make sure they work before buying though..
Dts-2075 recommended due to higher performance.
On Oct 2, 2012, at 5:49, Azelio
Maybe a dumb question. Just got my new oscillator hooked up to my Fury board.
Using the z38xx program of Ulrichs. Can someone help me wrap my head around
the pps TI /s? It seems to be confusing me. May dovetail into the counter
thread.
Doc
KX0O
Sent from mobile
Hi Said,
I have bought the HP53132A from HP several years ago when WWW and ebay
was not invented! hi!
I agree with you about the wavecrest
luciano
Il 2012-10-02 14:40 Said Jackson ha scritto:
Luciano,
For TI mode, I have recommended the Wavecrest DTS time interval
counters here in the past.
Hi Adrian,
I had the Tracor and I say the instability is normal. Every decade
multiplication is affected by noise introduced by the circuit it self. I
think is a good, fast approach to evaluate the oscillators or adjust the
frequency but not so affordabe for precision measurements
Luciano
Il
Wonder what the cost is? Love the size and footprint. Something I can
solder to.
Regards
Paul
WB8TSL
On Tue, Oct 2, 2012 at 9:03 AM, Jim Lux jim...@earthlink.net wrote:
On 10/2/12 5:08 AM, Azelio Boriani wrote:
Yes, I agree.
On Tue, Oct 2, 2012 at 1:29 PM, Bob Camp li...@rtty.us wrote:
Don,
Check out the JLT GPSTCXO eval board, plug and play no pcb layout required,
very good performance if shielded from airflow, delivery from stock less than
1week, much lower power, gpstcxo itself w/o eval board is similar size.
Supports WAAS, Egnos and Msas too.
Supported by Ulrichs
Hi Luciano,
Have a bunch of 53132as too, nice and small and convenient for frequency
measurements.
In the absence of Johns' Timepod, or if you need to measure 30MHz then I think
the DTS are the best bang for the buck..
From there, its either 3048a or TSC5110... But those are $$$
Said
On
Azelio,
In frequency average mode the 53132A makes something like 200,000 measurements
per second, according to the manual. This is why the instrument does so well as
a smoothed frequency counter. The resolution gain is some fraction of
sqrt(20), subject to the normal caveats like the need
I'm also interested in this. I've got one of these and a 53131A and
am still learning the ins and outs of ADEV measurements with timelab.
I was not aware of the 5/10MHz shortcomings of the 53131A that were
discussed this weekend..
Brent
To be fair, HP/Agilent did not hide this fact, but I
The TI (time interval) is the measure of the stability/accuracy of your
clock: TI is always the same figure - clock is stable, TI is always 0 -
stable and accurate.
On Tue, Oct 2, 2012 at 3:12 PM, Bill Dailey docdai...@gmail.com wrote:
Maybe a dumb question. Just got my new oscillator hooked
OK, got the papers. I'm still trying to figure out if a minimum resolution
can be determined for the TI measurement OCXO_PPS/GPS_PPS. That is, if the
GPS has a 25nS random wondering, is it worth having 25pS measurement
resolution? At first yes, I can use the negative sawtooth but I'm not
Azelio,
Correct, all GPS timing receiver boards have jitter, sawtooth, or random
wandering of some sort, on the order of tens of nanoseconds. This is normal.
And so if you use a counter to compare the OCXO 1 Hz with the GPS 1PPS, a TIC
resolution of 1 ns or 500ps is sufficient. I would say 25
Hi
The rated temperature stability of the OCXO is not super good. You will
see more frequency shift on it than say the TBolt OCXO, far more than a
DOCXO.
That's not at all saying it's a bad part. For Time Nut duty, I would try to
keep it in a fairly benign ambient situation.
Bob
-Original
Hi
So to do things the same way, start your time measurement at something
less than 1 ms and do the math to get to 1 second and beyond. One advantage
over the frequency reading would be that you will know what math has been
done. The math *does* very much matter
Bob
-Original
OK, so my 2.5nS resolution is OK. Now I have to determine what level of
average is best for the combination MV201/M12M and LPFRS/M12M.
On Tue, Oct 2, 2012 at 6:33 PM, Bob Camp li...@rtty.us wrote:
Hi
So to do things the same way, start your time measurement at something
less than 1 ms and do
Hi
By far the easiest way to do it with the combinations you describe is to do
a single mixer approach. Offset one oscillator by a few Hz and run the
counter on the beat note. You will need a mixer and a limiter, but the total
cost should be well below $100. If you have a pile of parts sitting
Is there a list of GPS timing receivers that provide the sawtooth
correction message or implement sawtooth correction internally?
I assume there is a design compromise that prevents economically phase
locking the GPS receiver clock to the GPS signal to remove that
contribution to timing error.
Hi
Almost any receiver that's labeled timing receiver will put out some sort
of saw tooth correction. The saw tooth is a result of the math, so no
there's not a cheap way to get rid of it. By the time you do a receiver that
does the phase lock thing, you have pretty much built a GPSDO.
Bob
I also would love to get some hints/tips/secrets on ADEV measurement
with my Phillips PM6680 - Clocked by a Tbolt.
According to the Specs it should have :
250 ps single-shot time interval resolution
100 ps averaged time interval resolution
Does anyone know if it suffers from the same 5/10Mhz
In the case of just the sawtooth error, I thought it was caused by the
limited resolution of the counter generating the output pulse. If the
counter clock was 100 MHz and not phase locked to GPS time, then
depending on how far off it is in frequency, the output pulse would
wander an additional
Said
I was looking and did not see the eval kit on the sight???
Thanks
Paul
WB8TSL
On Tue, Oct 2, 2012 at 12:29 PM, Bob Camp li...@rtty.us wrote:
Hi
The rated temperature stability of the OCXO is not super good. You will
see more frequency shift on it than say the TBolt OCXO, far more than a
Are these easily calibrated? I contacted Wavecrest earlier today and they
want $750 for the annual calibration. Not exactly 'hobby' friendly :-)
jerry
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Said Jackson
Sent: Tuesday,
Yes, very easy:
1) calibrate the internal 100MHz vectron OCXO using a small screwdriver,
this is not really critical though as the unit does not really function as a
frequency counter.
2) Calibrate the power supplies for proper voltages if necessary with same
screwdriver, I found that is
Hi Mark,
When you operate the 5370A in that configuration you are essentially just
measuring the RMS sum of jitter of the 5087A output, 5370A input circuitry
(ZCD), interpolators, and reference clock. I haven't measured this myself but I
would expect jitter in the 5370A reference 10811 would
No, the Thunderbolt does it and it works beatutifully. The GPS receiver
clock is derived from the 10 MHz oscillator. Voila, no messy sawtooth
corrections to deal with.
The Thunderbolt is a VERY user/hacker friendly design. Even if I were silly
enough to build my own GPSDO, I'd still
On 10/02/2012 03:27 PM, Said Jackson wrote:
Hi Luciano,
Have a bunch of 53132as too, nice and small and convenient for frequency
measurements.
I have never got along very well with the 53132A. I just don't like it,
it seems. The user interface isn't directly what I like, and I have
never
Mark,
All GPSDO remove that contribution to timing error by virtue of the quartz
fly-wheel.
I think David was asking about GPS timing receivers, not full-blown GPSDO.
Yes, I agree the Thunderbolt is a very nice GPSDO.
/tvb
- Original Message -
From: Mark Sims hol...@hotmail.com
To:
Magnus,
Tell me more; I hope I can help.
I use 53132A all the time, including for my cesium time scale. A wonderful
instrument; totally reliable sub-nanosecond TIC; easy RS232/GPIB talk-only or
full SCPI control.
/tvb
I have never got along very well with the 53132A. I just don't like it,
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On 10/02/2012 10:04 PM, Tom Van Baak wrote:
Magnus,
Tell me more; I hope I can help.
I use 53132A all the time, including for my cesium time scale. A wonderful
instrument; totally reliable sub-nanosecond TIC; easy RS232/GPIB talk-only or
full SCPI control.
I'll try to rig it up again at
I am sorry if my question was not clear.
Why not phase lock the clock that the pulse per second output is
derived from to GPS time so that the pulse per second output does not
display sawtooth jitter.
I assume this is not done because it is cheaper to report the sawtooth
correction for those who
Take a look at the specs of this unit:
http://www.mobilephonejammer.com.au/covert-gps-jammer-portable-p-119.html
The Power Output is 0.5 Watts and it claims a jamming range of 1-10 Meters.
Anybody think there is something wrong?
-John
On 10/02/2012 10:45 PM, David wrote:
I am sorry if my question was not clear.
Why not phase lock the clock that the pulse per second output is
derived from to GPS time so that the pulse per second output does not
display sawtooth jitter.
I assume this is not done because it is cheaper to
It also says output power +10 dBm.
3 hour Li battery life.
Only for legal use :)
Much does not make sense with this.
Forward a copy to the commission?
Regards
- Original Message -
From: J. Forster j...@quikus.com
To: Discussion of precise time and frequency measurement
On 10/02/2012 10:43 PM, J. Forster wrote:
Take a look at the specs of this unit:
http://www.mobilephonejammer.com.au/covert-gps-jammer-portable-p-119.html
The Power Output is 0.5 Watts and it claims a jamming range of 1-10 Meters.
Anybody think there is something wrong?
For a 500 mW jammer
Hi
All the signals into the GPS are Doppler shifted. The satellites are all
moving and thus you get a variety of carrier frequencies. There is no one
carrier to lock to. Each one gets a separate mathematical solution relative
to the sampling clock.
Yes, you can steer the LO towards the center
The 0.5 W and + 10 dBm numbers in the specs don't work out. +10 dBm is 10 mW.
I suspect that the 1/2 watt is really the DC input power.
And, I'd agree about the range. +10 dBm into a dipole at 10 meters gets you
about -44 dBm at the receiver antenna in a free-space model. That's really
Said
I have to say I was looking through the list of modules that are available.
I guess a couple of things really jump out.
The low power consumption and what you get in terms of behaviors. It is
pretty amazing actually. Though I have my power sucking Tbolt and 3801.
But I could easily see for a
On Tue, 02 Oct 2012 23:01:45 +0200, Magnus Danielson
mag...@rubidium.dyndns.org wrote:
On 10/02/2012 10:43 PM, J. Forster wrote:
Take a look at the specs of this unit:
http://www.mobilephonejammer.com.au/covert-gps-jammer-portable-p-119.html
The Power Output is 0.5 Watts and it claims a
Well Said, it looks like you have been busy!
Congrats for an amazing product.
Didier
Sent from my Droid Razr 4G LTE wireless tracker.
-Original Message-
From: Said Jackson saidj...@aol.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Cc:
On 10/02/2012 11:05 PM, John Lofgren wrote:
The 0.5 W and + 10 dBm numbers in the specs don't work out. +10 dBm is 10 mW.
I suspect that the 1/2 watt is really the DC input power.
Now, that makes sense.
And, I'd agree about the range. +10 dBm into a dipole at 10 meters gets you
about
Thanks much Didier!
Those are kind words for the JLT team :)
bye,
Said
In a message dated 10/2/2012 14:28:13 Pacific Daylight Time,
shali...@gmail.com writes:
Well Said, it looks like you have been busy!
Congrats for an amazing product.
Didier
Sent from my Droid Razr 4G LTE
Hello Paul,
thanks much for the feedback!
Yes, we think we have identified a nice combination of oscillators, GPS,
and firmware that seems to work pretty well. The GPSTCXO units cannot be
compared to a lower cost $150 Thunderbolt in terms of phase noise or stability
of course, and they
No, I didn't modify either of the 5370B's. Now that you mention it I recall
seeing a reference to this mod in the past in the archives. I'm curious how
much of a difference did the mod make on yours ?
Regards
Mark S
On 10/02/2012 07:19 PM, Mark Spencer wrote:
On a somewhat related
The Power Output is 0.5 Watts and it claims a jamming range of 1-10 Meters.
Anybody think there is something wrong?
I'd expect a much greater range with a 0.5 W jammer. But note that
0.5 W is the total output power -- the transmit power is only 10
dBm (0.01 W). Whatever those terms mean.
HI
At least from here, the link no longer works.
Bob
On Oct 2, 2012, at 7:48 PM, Charles P. Steinmetz
charles_steinm...@lavabit.com wrote:
The Power Output is 0.5 Watts and it claims a jamming range of 1-10 Meters.
Anybody think there is something wrong?
I'd expect a much greater range
Shameless plug for JLT, but they helped me with a special application need in
my day-job and it worked like a charm!
One happy customer.
-Brian, WA1ZMS
(sent from my over-priced iPad3)
On Oct 2, 2012, at 5:36 PM, saidj...@aol.com wrote:
Hello Paul,
thanks much for the feedback!
Yes, we
In case anyone here hasn't seen this article:
http://www.wired.com/wiredenterprise/2012/09/google-spanner/all/
Google is using GPS and atomic time synchronization across its data
centers to ensure database consistency in innovative ways. Apparently
there's a paper out on the system now but I
Seems like a good reason to have LORAN-C or some other backup/sanity check.
-John
In case anyone here hasn't seen this article:
http://www.wired.com/wiredenterprise/2012/09/google-spanner/all/
Google is using GPS and atomic time synchronization across its data
centers to
John writes:
Seems like a good reason to have LORAN-C or some other backup/sanity check.
What LORAN? I thought the U.S. had shut down all LORAN transmissions
in order to enhance the vulnerability of navigation systems in the
U.S. (?).
--
Anthony
The US, foolishly IMO, has killed LORAN-C and is killing WWVB. Hence my
comment. Essentially, GPS is soon going to be the sole source of a
standard of time interval.
It is going to take a disaster of some kind to return sanity.
-John
===
John writes:
Seems like a good reason to
The Thunderbolt is a special case that does not provide sawtooth correction
because it does not need it.
It uses the OCXO as the clock for the processor while disciplining it to GPS so
there is no nominal timing error between where the 1PPS is versus where it
should be.
The processor is
On 10/2/12 3:39 PM, johncr...@aol.com wrote:
Hello All -
Here is a link that describes the GPS modulation. You do not need the
1 pps to lock the 10 MHz oscillator to the atomic clock in the satellites.
http://www.kowoma.de/en/gps/signals.htm
If you look at the block diagram you see PN code
On 10/2/12 4:48 PM, Charles P. Steinmetz wrote:
The Power Output is 0.5 Watts and it claims a jamming range of 1-10
Meters.
Anybody think there is something wrong?
I'd expect a much greater range with a 0.5 W jammer. But note that 0.5
W is the total output power -- the transmit power is
In considering the effect of a simple jammer on a GPS receiver, a
simple link analysis
is insufficient.
What must also be considered is the anti-jam capability of the receiver
which due to spread spectrum processing gain will reject any simple
jamming signal even though is it 10's of dB
On 10/2/12 7:00 PM, shali...@gmail.com wrote:
The Thunderbolt is a special case that does not provide sawtooth correction
because it does not need it.
It uses the OCXO as the clock for the processor while disciplining it to GPS so
there is no nominal timing error between where the 1PPS is
I am ok for awhile but how do you center the efc of an ocxo? I understand
there is something (screw) to adjust the ocxo so it is approximately on freq
with 2.5v efc.
Specific oscillator datum-c. I have he datasheet but doesn't say coarse
frequency adjust this screw or some such.
Doc
KX0O
On 10/2/12 7:33 PM, johncr...@aol.com wrote:
In considering the effect of a simple jammer on a GPS receiver, a simple
link analysis
is insufficient.
What must also be considered is the anti-jam capability of the receiver
which due to spread spectrum processing gain will reject any simple
And yes thank god we are cutting funding to those pesky satellites. Seems
we can't afford them anymore. But fortunately other countries are filling
our gap slow but surely.
There was an article this month in GNSS about the funding cuts.
Regards
Paul
WB8TSL
On Tue, Oct 2, 2012 at 9:11 PM, J.
We don't know that they modulate the jamming signal some what. I bet 10 mW
would do a good bit of harm to GPS systems even a block away.
- Original Message -
From: Jim Lux jim...@earthlink.net
To: time-nuts@febo.com
Sent: Tuesday, October 02, 2012 10:45 PM
Subject: Re: [time-nuts]
John,
Coherent reproduction of the spread PRN standard positioning signal (SPS)
signal gives ~30dB of A/J protection, the GPS signal level, as received at
the GPS receiver is on the order of -160 dBW (L1-CA). If the jammer outputs
half a Watt, and is anywhere nearby, the receiver will not maintain
I talked to the GPS jamming group at Nellis a few years ago. They use
broadband noise to jam GPSs. If somebody is going to the Nellis Aviation
Nation coming up in November, the jammer group always has a static
display. They have some Soviet jammer gear they acquired.
Hi Jim -
Thanks for the update on the modern GPS receivers. I was aware that the
modern ones
do not have a classical analog tracking loop, much less a bunch of them.
However it is a useful concept for purposes of explanation that you do
not need the 1 pps to
lock up the 10 MHz VCXO - which
On 10/02/2012 10:37 PM, Jim Lux wrote:
Intriguing.. Can it handle the Doppler, etc., for a cubesat in LEO?
(7km/s) The total Doppler isn't usually the issue (the GPS satellites
are moving faster, after all), but the receiver may not work for high
velocities, high altitudes?
GPS receivers that
Hi:
Other than a terrorist, who would want to jam GPS?
Ron
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Magnus Danielson
Sent: Tuesday, October 02, 2012 2:28 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPS Jammer
On 10/02/2012
Many folks.
The paranoid tinfoil hat crowd
Folks who are concerned that law enforcement has placed a GPS tracker on their
car.
Truckers avoiding log enforcement
Truckers who want to sleep rather than drive.
Ambulance drivers who want to sleep but claim to have been held up at hospital.
docdai...@gmail.com said:
I am ok for awhile but how do you center the efc of an ocxo? I understand
there is something (screw) to adjust the ocxo so it is approximately on freq
with 2.5v efc.
Specific oscillator datum-c. I have he datasheet but doesn't say coarse
frequency adjust this
Other than a terrorist, who would want to jam GPS?
Generic bad guys who don't want the FBI tracking them. The civil liberties
types are suing the FBI to make sure the get a court document before they
install GPS trackers on suspects cars.
Truckers who don't want their boss to know what they
Hi all:
Thanks for your response to my question.
I had no idea!
Ron
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Hal Murray
Sent: Tuesday, October 02, 2012 10:07 PM
To: Discussion of precise time and frequency measurement
Subject:
On 10/2/12 2:36 PM, saidj...@aol.com wrote:
Hello Paul,
thanks much for the feedback!
Yes, we think we have identified a nice combination of oscillators, GPS,
and firmware that seems to work pretty well. The GPSTCXO units cannot be
compared to a lower cost $150 Thunderbolt in terms of
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