Jim,
most if not all fitting strategies make use of an assumption concerning the
underlying model.
For those who are not sure what the underlying model is this one
http://creativemachines.cornell.edu/eureqa
is the hottest tool that I have ever seen. Give it a try.
Best regards
Ulrich
Hi
Anything that will receive up there should be able to tell you when a jammer
comes by. The issue is that not a lot of gear is made for that band (other than
GPS receivers). The easy approach would be to use a modern GPS module that puts
out noise level / jamming information.
Bob
On Oct
On 10/6/13 9:59 PM, Hal Murray wrote:
The recent discussion of solar flares screwing up GPS timing was interesting.
I just watched Todd Humphreys TED talk again. He's focused on location, but
does mention time in terms of stock exchanges.
Todd Humphreys: How to fool a GPS
very cool
Am 07.10.2013 09:46, schrieb Ulrich Bangert:
Jim,
most if not all fitting strategies make use of an assumption concerning the
underlying model.
For those who are not sure what the underlying model is this one
http://creativemachines.cornell.edu/eureqa
is the hottest tool that
Proposing a random fitting with various curves without an underlying
physical (e.g. Eureqa) model seems... odd. That's more voodoo
engineering/science than anything real. It doesn't surprise me that
computer scientists would propose that as an approach to data, making it
even more inappropriate.
On 10/7/13 6:03 AM, Tim Shoppa wrote:
Proposing a random fitting with various curves without an underlying
physical (e.g. Eureqa) model seems... odd. That's more voodoo
engineering/science than anything real. It doesn't surprise me that
computer scientists would propose that as an approach to
Many scanners now go to that frequency e.g AOR AR-8600. (100kHz to 2GHz )
They are hardly state-of-the-art receivers but should be capable of
detecting jammers driving past. However a new unit is quite pricey $1000
equivalent in the UK as little as $300 for a used version. Also the AMSAT
FCD
I agree a fit to an equation that has no physical meaning is a bit spurious.
You can fit almost anything to a polynomial, but it doesnt mean that the
coefficients mean anything or that an interpolation between data points is
even sensible!! I have been the victim of a clever maths graduate
Many scanners now go to that frequency e.g AOR AR-8600. (100kHz to 2GHz )
They are hardly state-of-the-art receivers but should be capable of
detecting jammers driving past. However a new unit is quite pricey $1000
equivalent in the UK as little as $300 for a used version. Also the AMSAT
FCD Pro+
Indeed, the inexpensive DVB-T dongles are showing up in many places including
as David noted, decoding GPS.
For some details:
This gets you to the start of their web site:
http://gnss-sdr.org/
This is an interesting document they have published on their project:
From: Collins, Graham
[]
I wonder if the Fun Cube Dongle will be likewise changed (perhaps it already
has).
Cheers, Graham ve3gtc
=
Yes, Graham, it already has been updated:
http://www.funcubedongle.com/?page_id=1073
Adds more filtering and HF
On 10/7/13 7:46 AM, Collins, Graham wrote:
Indeed, the inexpensive DVB-T dongles are showing up in many places
including as David noted, decoding GPS.
The AMSAT Fun Cube Dongle is a very capable and interesting device.
Interestingly it uses the same Elonics E4000 front end chip that many
of
On 10/7/13 8:01 AM, David J Taylor wrote:
From: Collins, Graham
[]
I wonder if the Fun Cube Dongle will be likewise changed (perhaps it
already has).
Cheers, Graham ve3gtc
=
Yes, Graham, it already has been updated:
I think that when a GPS chip reports that there are no satellites found then
you got a jammer or a tunnel!
At 07-10-2013, you wrote:
Hi
Anything that will receive up there should be able to tell you when a jammer
comes by. The issue is that not a lot of gear is made for that band (other
than
We make sell the jammer detectors as a part of our contraband cell phone
detector products. The jammers are so common now flooding in that we have a
stealth GPS tracker so that drivers of company trucks that have radios in
them aren't aware of the fact that they are being monitored BUT if they
Hi Hal:
Yes you can detect jammers driving by.
There was a prior case of unintentional GPS jamming around Moss Landing harbor, Monterey Bay, California caused by a
faulty (oscillating) active TV antenna on a boat that was powered 24/7.
Military GPS receivers, like the DAGR or PLGR-II,
On spacecraft hardware, even though something is a bit old, it does make
sense to use it.
Space qualifying a piece of hardware is very, very expensive, because it
requires a lot of shake and bake plus thermal vaccuum and other things.
Furthermore, there are always unknowns.
Do YOU really want
OK so let's say you have a receiver and detect a certain about of power at
the right frequency. How do you determine which of three cases you have
(1) an actual GPS signal from a satellite. (2) a spoofer (who tries hard to
look like #1) or (3) a jammer.
You can't just go by the amount of power
Yes, there is equipment out there today that can be used: UBlox offers jamming
detection and level. We incorporated that into the later JLT products, and even
made a special board for a customer that displays the GPS spectrum in real time
showing the jammers in the frequency domain.
Bye,
Said
From: Jim Lux
Yes, Graham, it already has been updated:
http://www.funcubedongle.com/?page_id=1073
Adds more filtering and HF coverage, but also has a dead zone between
~240 and 420 MHz.
So much for receiving signals from Transit at 400 MHz (grin) or from
Mars (The rovers relay through
Paul,
try the Jackson Labs GPSTCXO eval kit. Comes with GPS antenna, USB
comm/power cable, and board.
You can get a Hammond enclosure for it for less than $20, and have a
complete desktop system for less than $400 new. Probably the lowest-cost new
way to go other than Ebay-used or
Hi Everyone,
My GPSDO has been running for about a month now and the last frequency
adjustments are:
09/24/2013 15:48:37
1301186
Freq
1.0484E-13
09/25/2013 15:53:26
1387875
Freq
4.7980E-13
09/30/2013 16:17:26
1821315
Freq
-2.2965E-13
10/04/2013 16:36:38
2168067
Freq
Which reminds me, there is a nifty tool called fityk that I tend to use
just to view graphs, but has a rather nice set of routines to do various
fits to various curves.
Cheers,
Magnus
On 10/07/2013 09:46 AM, Ulrich Bangert wrote:
Jim,
most if not all fitting strategies make use of an
Paul,
I can speak for a few of us over in the OpenHPSDR group that are also
'time-nuts' - We have the GPSTCXO eval kit that Said is speaking of and we
have been very satisfied.
It is a great fit for what we're doing. We are working on a new board now
that is near completion that can either have
On Mon, Oct 7, 2013 at 2:52 PM, saidj...@aol.com wrote:
Paul,
try the Jackson Labs GPSTCXO eval kit.
On Mon, Oct 7, 2013 at 5:59 PM, John C. Westmoreland, P.E.
j...@westmorelandengineering.com wrote:
We have the GPSTCXO eval kit that Said is speaking of and we
have been very satisfied.
I
On Sun, Oct 06, 2013 at 09:59:50PM -0700, Hal Murray wrote:
Suppose I lived near a major highway. Could I build a receiver that would
count jammers driving by? Could I track them (at least somewhat) with a
directional antenna on a rotator?
I would think this would be a natural
What did it cost? When I inquired, the price was horrendous.
Jim
wb4...@amsat.org
On 10/7/2013 7:28 PM, Paul wrote:
On Mon, Oct 7, 2013 at 2:52 PM, saidj...@aol.com wrote:
Paul,
try the_Jackson Labs GPSTCXO eval kit_.
On Mon, Oct 7, 2013 at 5:59 PM, John C. Westmoreland, P.E.
Paul,
I don't want to speak too soon or appear to be tooting the HPSDR horn - but
the Khronos board (Khronos is the name of the board that I mentioned in the
previous e-mail) has that.
I didn't realize the issue here was the BNC connector and your dislike of
the MMCX style connector that is
On 10/7/13 2:44 PM, Magnus Danielson wrote:
Which reminds me, there is a nifty tool called fityk that I tend to use
just to view graphs, but has a rather nice set of routines to do various
fits to various curves.
gnuplot's not bad, either..
you define a function f(x) and the free parameters,
On 10/7/13 10:44 AM, David J Taylor wrote:
From: Jim Lux
Yes, Graham, it already has been updated:
http://www.funcubedongle.com/?page_id=1073
Adds more filtering and HF coverage, but also has a dead zone between
~240 and 420 MHz.
So much for receiving signals from Transit at 400 MHz
On 10/7/13 8:31 AM, Chris Albertson wrote:
OK so let's say you have a receiver and detect a certain about of power at
the right frequency. How do you determine which of three cases you have
(1) an actual GPS signal from a satellite. (2) a spoofer (who tries hard to
look like #1) or (3) a
On 10/7/13 4:51 PM, David I. Emery wrote:
On Sun, Oct 06, 2013 at 09:59:50PM -0700, Hal Murray wrote:
Suppose I lived near a major highway. Could I build a receiver that would
count jammers driving by? Could I track them (at least somewhat) with a
directional antenna on a rotator?
Bob,
I think what you have pointed out is interesting - I have even given it
more than a passing thought on how to design what is on the CellBusted site.
I am working on a design of my own on how to detect low-power RF signals
using a wide-band method of detection.
73's,
John Westmoreland
AJ6BC
On Mon, Oct 7, 2013 at 7:53 PM, Jim Sanford wb4...@wb4gcs.org wrote:
What did it cost?
There's a hobbyist price. It was less than $400.
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To unsubscribe, go to
On 10/7/13 6:49 PM, John C. Westmoreland, P.E. wrote:
Bob,
I think what you have pointed out is interesting - I have even given it
more than a passing thought on how to design what is on the CellBusted site.
I am working on a design of my own on how to detect low-power RF signals
using a
On Mon, Oct 7, 2013 at 8:01 PM, John C. Westmoreland, P.E.
j...@westmorelandengineering.com wrote:
I didn't realize the issue here was the BNC connector and your dislike of
the MMCX style connector that is pretty much a standard for passive GPS
antennas (I guess any GPS antenna).
SMA is fine,
On Mon, Oct 07, 2013 at 08:02:13AM -0700, Jim Lux wrote:
On 10/7/13 7:46 AM, Collins, Graham wrote:
The AMSAT Fun Cube Dongle is a very capable and interesting device.
Interestingly it uses the same Elonics E4000 front end chip that many
of the inexpensive DVB-T devices do. Apparently Elonics
Paul,
OK - that is good information. I have mature vision too - got these
bifocal contact lenses that take some getting adjusted to.
But I am blind without my Pro's Kit MA-016 head-gear which has become a
required piece of equipment when I work these days.
Best Regards,
John
On Mon, Oct 7,
Yes, these specific jammers do, but someone asked the general question how
to detect a jammer and a sophisticated jammer will use no more power than
is requires so as to avoid detection. Could it be that there are such
devices and they are successful at avoiding detection?Likely not as at
In general, we expect a jammer to be involved in criminal activity.
What about a wilderness guide whose reputation is built on finding
the best spots to view Nature's wonders. Should he or she be happy
to let people in the guided group save the coordinates of those
spots in order to compete with
On 10/7/13 9:30 PM, Bill Hawkins wrote:
In general, we expect a jammer to be involved in criminal activity.
What about a wilderness guide whose reputation is built on finding
the best spots to view Nature's wonders. Should he or she be happy
to let people in the guided group save the
On Mon, Oct 07, 2013 at 11:30:57PM -0500, Bill Hawkins wrote:
In general, we expect a jammer to be involved in criminal activity.
What about a wilderness guide whose reputation is built on finding
the best spots to view Nature's wonders. Should he or she be happy
to let people in the guided
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