ourse in map reading and the inclusion of maps
in the vehicle.
Steve
> Didier
>
>> -Original Message-
>> From: time-nuts-boun...@febo.com
>> [mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus Danielson
>> Sent: Sunday, November 15, 2009 7:03 PM
>> To: Discuss
Lux, Jim (337C) wrote:
A *much* more effective and cheap strategy is a repeater jammer.. Receive
the signal and retransmit it: two antennas and an amplifier. The victim sees
the delayed retransmitted signal at a higher level than the direct one. It's
sort of like creating fake multipath interfere
Just a data point about timing applications and jamming
The HP 8935A CDMA base station test set when first released covered
0-1.0 Ghz and 1.7-2.0 Ghz on the spectrum analyzer function.
It was expanded to 1.4-2.0 Ghz on the upper range expressly for doing
GPS noise surveys of sites, to locat
>From a friend and GPS expert:
> A *much* more effective and cheap strategy is a repeater jammer..
> Receive
> the signal and retransmit it: two antennas and an amplifier. The
> victim sees
> the delayed retransmitted signal at a higher level than the direct
> one. It's
> sort of like creati
: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator
accuracy)
Considering that the GPS antenna in aircrafts is mounted on top of fuselage,
and that its radiation pattern is upward, it seems that a ground jammer will
have an uphill battle.
-Original Message-
From: time
Various not so random notes:
The power needed to jam GPS depends a lot on receiver state, during
TTFF it takes virtually nothing.
Therefore most "real" jammers will periodically blast at high power,
to "dislodge" any locked receivers and then continue at low power
to keep them off the signal. T
On Sun, Nov 15, 2009 at 10:33:07PM -0500, David I. Emery wrote:
>
> LORAN C represents a viable (albeit not often deployed) backup
> to time and frequency control and could be implemented in modern
> hardware as a backup location service at reasonably low cost for those
> applications where
> Bruce,
>
> I agree with your calculation and conclusion, as far as commercial
> consumer
> GPS receivers are concerned.
>
> A data sheet that was linked in a previous post for an aviation-grade
> commercial GPS receiver indicated resistance to signals -30dBm at the
> receiver input. That is quite
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] The Demise of LORAN (was Re:
>> Reference oscillator accuracy)
>>
>> > Jamming Range : Average 40 meters radius Output Power :
>> Total 6.5
>> > Watt
>>
>&
ssion of precise time and frequency measurement
> Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator
> accuracy)
>
> Francesco Ledda wrote:
>> Considering that the GPS antenna in aircrafts is mounted on top of
> fuselage,
>> and that its radiation
A *much* more effective and cheap strategy is a repeater jammer.. Receive
the signal and retransmit it: two antennas and an amplifier. The victim sees
the delayed retransmitted signal at a higher level than the direct one. It's
sort of like creating fake multipath interference. No need for PN
gener
In fact, GPS has performed so well, it has become "part of the furniture"
and it is really hard now to assess the full impact its loss would have.
Another overlooked aspect would be the perceived impact of a number of
failures. Just look at the hoohaws over lead in toys, defective cribs,
tainted b
On Sun, Nov 15, 2009 at 07:17:37PM -0800, J. Forster wrote:
> There were, of course, no map or chart displays. Imagine what 20+ years of
> development would have brought.
E Loran could supply the same basic position information as input
to charting and mapping software as GPS does... most
On Sun, Nov 15, 2009 at 08:56:36PM -0600, Didier Juges wrote:
>
> I don't disagree that it would be fairly easy to disrupt the consumer
> devices, but other than a few missed appointments and frustrated gadget
> freaks, and the occasional emergency vehicle not finding its way to the
> scene of an
My first contact with LORAN was at the bankrupcy of a local company that
supplied tracking and location services for trucking companies. The trucks
had a receiver that sent data back to home base via two-way radio and home
pbase computed positions. I was only nteresteed in buying their mimis.
In t
s
> > email with his GSM smart phone) during approach than a
> jammer on the ground.
> >
> > Didier
> >
> >
> >> -Original Message-
> >> From: time-nuts-boun...@febo.com
> >> [mailto:time-nuts-boun...@febo.com] On Behalf
On Sun, Nov 15, 2009 at 08:22:50PM -0600, Didier Juges wrote:
> I think the problem with the Monterey Bay jammer was that he was jamming the
> DGPS correction signal, not the GPS signal itself. The DGPS correction
> signal is sent over the UHF band. Most marine GPS are DGPS because they need
> the
al Murray
> Sent: Sunday, November 15, 2009 6:30 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] The Demise of LORAN (was Re:
> Reference oscillator accuracy)
>
> > Jamming Range : Average 40 meters radius Output Power :
> Total 6.5
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] The Demise of LORAN (was Re:
Reference oscillator accuracy)
Even 10 KM is pretty useful. If the thing were solar powered
with a supercap "battery" it could easly transmit for say 2
minutes per hour w/ s
age-
> From: time-nuts-boun...@febo.com
> [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster
> Sent: Sunday, November 15, 2009 6:38 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] The Demise of LORAN (was Re:
> Reference oscillator a
Mike,
Mike Monett wrote:
I said nothing about the type of modulation. The equipment I listed is
designed specifically to disrupt GPS. Presumably they use whatever
modulation method that gives the best results.
However, GPS is spread-spectrum, so it inherently rejects noise that is
not correlat
gt; > [mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus Danielson
> > Sent: Sunday, November 15, 2009 7:03 PM
> > To: Discussion of precise time and frequency measurement
> > Subject: Re: [time-nuts] The Demise of LORAN (was Re:
> > Reference oscillator accuracy
Hal Murray wrote:
cfhar...@erols.com said:
What makes you think it needs to be CW, and cannot be pulsed and
chirped?
All it has to do is confuse the receiver enough so that you can't
trust its readings.
Why is pulse or chirp likely to be more confusing per W of jamming powe
and frequency measurement
> Subject: Re: [time-nuts] The Demise of LORAN (was Re:
> Reference oscillator accuracy)
>
> Francesco Ledda wrote:
> > Considering that the GPS antenna in aircrafts is mounted on top of
> > fuselage, and that its radiation pattern is upward, it se
l Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of Magnus Danielson
> Sent: Sunday, November 15, 2009 7:03 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] The Demise of LORAN (was Re: Referen
Magnus Danielson wrote:
Well, then you have to consider what the potential gain would be from
such an attack. I fail to see the upside of that particular scenario. It
would draw the attention over to them and in a field I think they rather
stay calm about. Their ability to pull it off as such
The one the counts ARE! ;)
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Magnus Danielson
Sent: Sunday, November 15, 2009 7:03 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] The Demise of LORAN
recise time and frequency measurement
> Subject: Re: [time-nuts] The Demise of LORAN (was Re:
> Reference oscillator accuracy)
>
> See my earlier post. Briefly:
>
> Antennas do not have an infinite front-to-back ratio. (<40 dB)
>
> The path loss from a surface jammer to a plan
Mike,
A defective TV antenna preamp (oscillating in an uncontrolled manner),
on board a boat in California wiped out GPS for several kilometers!
Because it only wiped it out when the owner was watching TV, the
interferrence went on for months. This is well documented. Do a
google search and you
Francesco Ledda wrote:
Considering that the GPS antenna in aircrafts is mounted on top of fuselage,
and that its radiation pattern is upward, it seems that a ground jammer will
have an uphill battle.
Not all GPS receivers is sitting on flying airplanes. Far from it.
Cheers,
Magnus
___
J. Forster wrote:
Or even into MP3 players, iPods, laptops, or cell phones. Then they'd
wander all over the place too. With the latter two hosts, they could even
be controlled remotely and even be fairly powerful. Would you notice
having to recharge your battery a bit more often?
There is one r
Hal Murray wrote:
cfhar...@erols.com said:
What makes you think it needs to be CW, and cannot be pulsed and
chirped?
All it has to do is confuse the receiver enough so that you can't
trust its readings.
Why is pulse or chirp likely to be more confusing per W of jamming power?
I thought t
t: Sunday, November 15, 2009 6:28 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference
> oscillator accuracy)
>
>
> Or even into MP3 players, iPods, laptops, or cell phones. Then they'd
> wander all
Chuck Harris wrote:
>
>What makes you think it needs to be CW, and cannot be pulsed and
>chirped?
>
>All it has to do is confuse the receiver enough so that you can't
>trust its readings.
>
>-Chuck
I said nothing about the type of modulation. The equipment I listed is
designed specifically to dis
Even 10 KM is pretty useful. If the thing were solar powered with a
supercap "battery" it could easly transmit for say 2 minutes per hour w/
significant power. It'd be hard to find if the on times were generated by
a multiple fedback CMOS shift register.
-John
> Mike
>
> Instea
Chuck Harris wrote:
Magnus Danielson wrote:
Chuck,
Chuck Harris wrote:
What makes you think it needs to be CW, and cannot be pulsed and
chirped?
May I roll in a noise jammer into the debate?
Absolutely! They can be extremely power efficient. Raise the noise
floor in the vicinity of the r
Sent: Sunday, November 15, 2009 6:28 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference
oscillator accuracy)
Or even into MP3 players, iPods, laptops, or cell phones. Then they'd
wander all over the place too. Wit
Or even into MP3 players, iPods, laptops, or cell phones. Then they'd
wander all over the place too. With the latter two hosts, they could even
be controlled remotely and even be fairly powerful. Would you notice
having to recharge your battery a bit more often?
-John
===
> Magnus Danie
> Jamming Range : Average 40 meters radius
> Output Power : Total 6.5 Watt
> ratio : 40/6.5 = 6.15 meters/watt
Isn't received power 1/R-squared?
I think those calculations should be radius-squared/watts
I find it interesting that the products designed as jammers have ranges of
"only" a fe
Mike
Instead of relying on the dubious claims of those marketing an extremely
inefficient jammer it would be better to actually do some simple
calculations.
Typical commercial receivers stop tracking with a Jam to signal ratio of
not more than 60dB or so:
http://www.gpsworld.com/gps/jamming
cfhar...@erols.com said:
> What makes you think it needs to be CW, and cannot be pulsed and
> chirped?
> All it has to do is confuse the receiver enough so that you can't
> trust its readings.
Why is pulse or chirp likely to be more confusing per W of jamming power?
I thought the GPS signal w
Magnus Danielson wrote:
Chuck,
Chuck Harris wrote:
What makes you think it needs to be CW, and cannot be pulsed and
chirped?
May I roll in a noise jammer into the debate?
Absolutely! They can be extremely power efficient. Raise the noise
floor in the vicinity of the receiver, and it is al
Chuck,
Chuck Harris wrote:
What makes you think it needs to be CW, and cannot be pulsed and
chirped?
May I roll in a noise jammer into the debate?
All it has to do is confuse the receiver enough so that you can't
trust its readings.
Depends on the goal. For some strategies, blackout is the
What makes you think it needs to be CW, and cannot be pulsed and
chirped?
All it has to do is confuse the receiver enough so that you can't
trust its readings.
-Chuck
Mike Monett wrote:
Chuck Harris wrote:
> I guess the point you folks aren't getting is you can make a very
> effective
Chuck Harris wrote:
> I guess the point you folks aren't getting is you can make a very
> effective local GPS jammer that runs off of a 9V transistor radio
> battery, and will last for several weeks. It can be done for a
> total cost of a few bucks per jammer search the
Given that I learned the techniques from a bunch of wack-jobs, I don't
think I have upped the learning curve much.
-Chuck
Richard W. Solomon wrote:
After reading all the responses on this thread, all I can think
of is the numerous ideas you folks have given some whackjob out
there.
Keep up the
In message <20091115193126.gb5...@puck.nether.net>, "Majdi S. Abbas" writes:
>On Sun, Nov 15, 2009 at 11:37:11AM -0500, Mike Monett wrote:
> And if the jammer is attached to, saY a radiosonde balloon or
>other light aircraft and the footprint covers most of the US?
It doesn't.
Hint: http:
On Sun, Nov 15, 2009 at 11:37:11AM -0500, Mike Monett wrote:
> It should be easy to locate a jammer. Go to the area where the GPS
> signal is being jammed. Drive in some direction until the signal is
> regained. Repeat to find three locations where the signal is lost.
>
> Three points d
> Chuck Harris wrote:
>> I guess the point you folks aren't getting is you can make a very
>> effective local GPS jammer that runs off of a 9V transistor radio
>> battery,
>> and will last for several weeks. It can be done for a total cost of
>> a few bucks per jammer search the web, the desig
In message <4b004084.5060...@rubidium.dyndns.org>, Magnus Danielson writes:
>Chuck Harris wrote:
>The trouble is that civilian infrastructure [...]
That's actually not the biggest problem, the biggest problem is access.
If you put a jammer at the top of a tall building (by RC helicopter ?)
getti
In message <11603302.1258306016911.javamail.r...@elwamui-hound.atl.sa.earthlink
.net>, "Richard W. Solomon" writes:
>After reading all the responses on this thread, all I can think
>of is the numerous ideas you folks have given some whackjob out
>there.
I don't think you are up to date, all the w
Chuck Harris wrote:
I guess the point you folks aren't getting is you can make a very
effective local GPS jammer that runs off of a 9V transistor radio battery,
and will last for several weeks. It can be done for a total cost of
a few bucks per jammer search the web, the designs are out ther
In message , "Mike Monett" writes:
> It should be easy to locate a jammer. Go to the area where the GPS
> signal is being jammed. Drive in some direction until the signal is
> regained. Repeat to find three locations where the signal is lost.
Experience has shown that this is far from as ea
In message <1078.12.6.201.222.1258304694.squir...@popacctsnew.quik.com>, "J. Fo
rster" writes:
>The military have air deployable radio trucks. A LORAN station could be
>built into a few trailers, including generator, clocks, and transmitter.
>There are also fielded deployable masts.
In fact, that
of precise time and frequency measurement
Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator
accuracy)
After reading all the responses on this thread, all I can think
of is the numerous ideas you folks have given some whackjob out
there.
Keep up the good work.
73, Dic
, Dick, W1KSZ
>
> -Original Message-
>>From: Chuck Harris
>>Sent: Nov 15, 2009 9:51 AM
>>To: Discussion of precise time and frequency measurement
>>
>>Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference
>> oscillator accuracy)
>>
frequency measurement
>Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator
>accuracy)
>
>I guess the point you folks aren't getting is you can make a very
>effective local GPS jammer that runs off of a 9V transistor radio battery,
>and will last for se
Thanks Chuck,
My point EXACTLY.
1. It's well within the capability of dozens of countries or organizations
or even individuals.
2. They are trivial to distribute widely, and could be piggy-backed onto
other things.
3. Given enough of them with random on-off cycles, you'd force a giant
game of W
> John,
>
>> If a LORAN transmitter were destroyed by a terrorist team, a backup could
>> be in operation in hours. A damaged GPS system could easily take many
months or even years to fix.
>>
>> -John
>
> A LORAN site, with a several hundred meter high mast, a small house full
of transmitter, signa
> b...@lysator.liu.se wrote:
>> John,
>>
>>> If a LORAN transmitter were destroyed by a terrorist team, a backup
>>> could
>>> be in operation in hours. A damaged GPS system could easily take many
>>> months or even years to fix.
>>>
>>> -John
The military have air deployable radio trucks. A LORAN
I guess the point you folks aren't getting is you can make a very
effective local GPS jammer that runs off of a 9V transistor radio battery,
and will last for several weeks. It can be done for a total cost of
a few bucks per jammer search the web, the designs are out there.
Toss the GPS jamm
Francesco Ledda wrote:
The bottom line is simple: the military don't need it, the FAA see no value
in it; the avionics industry has discontinued the manufacturing of LORAN
receivers years ago, the General Aviation community has bigger fish to fry
(fight user fees); the Europen talked in the past
"J. Forster" wrote:
>> I've read and heard from this forum as well as a number of other
>> sources that GPS can be easily jammed. What makes GPS so
>> vulnerable? How can it be jammed?
> Signal strength.
> LORAN transmitters put out multi-hundred KW to MegaWatt class
to me, with GPS.
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
Behalf Of Magnus Danielson
Sent: Sunday, November 15, 2009 9:01 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] The Demise of LORAN (was Re: Refe
b...@lysator.liu.se wrote:
John,
If a LORAN transmitter were destroyed by a terrorist team, a backup could
be in operation in hours. A damaged GPS system could easily take many
months or even years to fix.
-John
A LORAN site, with a several hundred meter high mast, a small house full
of tran
rtial (ships
as well as aircraft, even some land vehicles) and are content to let LORAN go.
Robert G8RPI.
--- On Sun, 15/11/09, b...@lysator.liu.se wrote:
From: b...@lysator.liu.se
Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator
accuracy)
To: j...@quik.com, "Dis
John,
> If a LORAN transmitter were destroyed by a terrorist team, a backup could
> be in operation in hours. A damaged GPS system could easily take many
> months or even years to fix.
>
> -John
A LORAN site, with a several hundred meter high mast, a small house full
of transmitter, signal genera
take off to landing without ever tuning any
>>external NAVAID; not even INS can't do that. It is pretty amazing to me!
>>
>>
>>
>>
>>
>>
>>-Original Message-
>>From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.c
is pretty amazing to me!
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
Behalf Of Hal Murray
Sent: Saturday, November 14, 2009 7:13 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] The Demise of LORAN (was Re:
-nuts-boun...@febo.com] On
Behalf Of Francesco Ledda
Sent: Saturday, November 14, 2009 9:22 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator
accuracy)
LORAN is a good back up, but it has problems and limitations.
nt
Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference
oscillator accuracy)
> I've read and heard from this forum as well as a number of other
> sources that GPS can be easily jammed. What makes GPS so vulnerable?
> How can it be jammed?
The signal is very very very we
> I've read and heard from this forum as well as a number of other
> sources that GPS can be easily jammed. What makes GPS so vulnerable?
> How can it be jammed?
The signal is very very very weak. The question is not how can it be jammed,
but rather how can you find the signal at all.
There
of other sources
> that GPS can be easily jammed. What makes GPS so vulnerable? How can it
> be
> jammed?
>
> --
> David
> masondg44 at comcast dot net
>
>
> From: Francesco Ledda
> Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference
> oscil
On 11/14/09 3:28 PM, "J. Forster" wrote:
> Somehow, I think they will keep GPS running whatever the cost. There is a
> huge civilian constituency (everybody who cannot or is too lazy to read a
> map) and relies on GPS to guide their Lexus to the nearest Starbucks.
>
> Also, the military needs
I've read and heard from this forum as well as a number of other sources
that GPS can be easily jammed. What makes GPS so vulnerable? How can it be
jammed?
--
David
masondg44 at comcast dot net
From: Francesco Ledda
Subject: Re: [time-nuts] The Demise of LORAN (was Re: Refe
There is a difference between falling off a cliff and being pushed.
-John
==
> Indeed the uscg did agree to shut it down.
> They signed off on it.
>
> On Sat, Nov 14, 2009 at 3:40 PM, Christopher Hoover
> wrote:
>
>> David I. Emery wrote:
>>
>>> I have emailed my brother in law who is a
Indeed the uscg did agree to shut it down.
They signed off on it.
On Sat, Nov 14, 2009 at 3:40 PM, Christopher Hoover wrote:
> David I. Emery wrote:
>
>> I have emailed my brother in law who is a rear admiral (I think
>> now called a vice admiral) and currently CFO of the USCG (and as a note
>> r
ORAN and drop one spare bird.
>
>
> - Original Message -
> From: "J. Forster"
> To: "Don Latham"
> Cc: "Discussion of precise time and frequency measurement"
>
> Sent: Saturday, November 14, 2009 11:35 PM
> Subject: Re: [time-nuts] T
ot;
Cc: "Discussion of precise time and frequency measurement"
Sent: Saturday, November 14, 2009 11:35 PM
Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator
accuracy)
OK, so who is in a position to MAKE them care? How about those who
understand this is a Homel
John,
I have asked Alaska's representitives to reinstate LORAN funding due to the
large number of private pilots and small fishing boat operators that rely
on LORAN in Alaska. During periods of high aurora activity in the arctic
the interference with GPS makes it unusable and LORAN is the only viab
OK, so who is in a position to MAKE them care? How about those who
understand this is a Homeland Security (among other) issue? Perhaps FOX
news?
Likely LORAN costs about as much a year as a mile of fence along the
Mexican border, probably less.
FWIW,
-John
> You've hit it on th
You've hit it on the nose. NONE of them are interested in anything but
social issues. LORAN will not get any of them re-elected, and that's all
any of 'em care about.
Don
J. Forster
> Does anybody know who in Congress might take the lead in reversing the
> decision? None of the reps in this state
Does anybody know who in Congress might take the lead in reversing the
decision? None of the reps in this state are at all likely to give a damn.
Their interest is apparently only in social issues.
-John
=
> AOPA is pushing congress to repristinate funding for LORAN. General
AOPA is pushing congress to repristinate funding for LORAN. General
aviation is probably the heaviest user on this Nav system. The
aviation user community would love to see Nav systems with integrated
LORAN and GPS capabilty, but the industry has done little in this
area, due to lack of gov
David I. Emery wrote:
I have emailed my brother in law who is a rear admiral (I think
now called a vice admiral) and currently CFO of the USCG (and as a note
re your alma mater a MIT Sloan grad) and rather loudly said so myself.
He most likely was part of the group that made the decision... I i
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