"Signal jamming a factor in future wars, general says"

In article ,
(Denyav) wrote:

Yes, wasnt it rather funny how trying to jam signals is just a big homing
beacon too?

They figured quite quickly how to make a weapon to home right on in
that jamming signal. Those "jammers" were eliminated rather quickly.

I doubt it,how could thousands of low cost jammers be eliminated quickly?

More to the point, how could thousands of such devices be *managed* by
anyone except a high-tech, high dollar military?

If they ran them off wall current, they'd lose them when the power went
out, and if they ran them off batteries, they'd spend a *lot* of money
just keeping them powered.

Even if they could be eliminated eventually cost benefit outcome of a
such operation would not be very favorable. Such jammers cost less
than one Grand and Iraqis had only 6 or 7 of them,thanks to
international embargo. So its not very hard to imagine what whould
happen if they had 6000-7000 instead of 6 or 7.

They'd spend several million dollars a month trying to keep them
working, and realize that they didn't have the infrastructure to keep
them going after about month three. You have to keep moving them
around, too, since they'd become nothing more than spotting points if
you don't, and give the incoming munitions something else to refer to.

Unless you spend a lot more money on them, they're also very vulnerable
to the newer EMP weapons.

The "piles of cheap low-power jammers" idea is nice, as long as you
don't have to keep using them.

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

Chad Irby wrote:

snip


Unless you spend a lot more money on them, they're also very vulnerable
to the newer EMP weapons.

In WWII the real secret weapon (proximity fuses) could only be used over
water until mid 44,in the UK with the V1 and not over enemy territory intil
the start of 45. The reason was fear of of copying a dud shell as the
allies had more to lose.

What is the better target for EMP weapons a GPS jammer or the NY stock
exchange?

The "piles of cheap low-power jammers" idea is nice, as long as you
don't have to keep using them.

At a rough guess the cost for a 1W jammer using cellphone components would
be ~$5, just keep sending them up with balloons (add $1).

--

regards

jc

LEGAL - I don't believe what I wrote and neither should you. Sobriety and/or
sanity of the author is not guaranteed

EMAIL - and are not valid email
addresses. news2x at perentie is valid for a while.

jc wrote in message ...
Chad Irby wrote:

snip


Unless you spend a lot more money on them, they're also very vulnerable
to the newer EMP weapons.

In WWII the real secret weapon (proximity fuses) could only be used over
water until mid 44,in the UK with the V1 and not over enemy territory intil
the start of 45. The reason was fear of of copying a dud shell as the
allies had more to lose.

Actually, proximity fuses did not have the "self-destruct" mechanism,
therefore they would explode when hit the ground. Hence the limitation.


What is the better target for EMP weapons a GPS jammer or the NY stock
exchange?

The "piles of cheap low-power jammers" idea is nice, as long as you
don't have to keep using them.

At a rough guess the cost for a 1W jammer using cellphone components would
be ~$5, just keep sending them up with balloons (add $1).

Well, it is a bit under-estimated. I don't know much about how GPS works
(electronically), but I know it has commercial and military channels/
frequencies and commercial and military encoding. For civilian use, optimum
accuracy is receiving three GPS signals from three satellites (somebody
correct me if I am wrong, but I read it somewhere for more expensive GPS
devices for use, let's say in aviation) for elevation and position. As you
travel, the sattelites "switch" (just like GSM) control. Is it a same
frequency/coding? I don't know, but it is sure as hell that if you manage to
jam one channel, there are other two sats. Jam the other two signals, there
is one. In the meantime, your GPS receiver "struggles" to get signals from
the other two. And we are talking about civilian device.

What method are you going to use-noise or deceptive jamming? Read the
history of updates of "AN-ALQ" devices-or just one! Noise? In that case, you
are a flashbulb, and you will be attacked with alternate weapon on jamming
station. The band is narrow AFAIK, so if your opponent knows what to
"listen", you're toast.

Deceptive jamming. Well, it is not analogue signal anymore but digital and
probably encoded signal-actually, it IS encoded even for the civ use in the
matter of digital design-and probably scrambled in mil use. Thus, you have
to "doctor" the signal. Actually, signals -three satellites, remeber? You
can go to make this simmilar to tripled digital FBW system on, let's say,
F-16. Well, if you have failure on one channel then other two will feed the
aircraft with flying info, or in this instance, the weapon itself. Two of
them gone, you have one channel and two duds and you think that the flying
computer thinks that all three are duds? Wrong. Even your modem has
sufficient let-me-check-if-this-is-wright capabilities (CRC, CS) so it is
possible to imagine that FBW computer might have something simmilar. And
your jamming signal has to feed the encoded and encripted digital channel
switchig-multiple sattelite signals with false data, and it is desirable to
feed them with something meaningful to drive the weapon away, not to
owerflow it with garbage. And it's been a long time since F-16 digital FBW
was designed (I actually don't know is it possible to fly it on one channel,
but I would require it that it would! ))).

Oh, the output power. In the Battle of Britain, there was a German bombing
device called X-Gerat. Basically, you had three signals for guidance, based
on the Lorentz blind-landing system (Morse dots-too left of course,
dashes-too right of course, single tone-on course), and the offset signal to
mark the bomb dropping. Once discovered, it was jammed by the Brits by
sending "dashes". Well, it sometimes worked (and it seems it worked well!)
but there were cases that the crew was able to depict the jamming-slight but
ear-noticeable change of modulation or change of volume and to offset it.

Or back to Your cell phone-it can "sense" the distance from the GSM
station-actually, my Motorola CD920/930 has a hidden option that, when
activated can measure and display the DISTANCE from the GSM broadcast
(albait in very weird units )). Sattelites have very low output power and
if you send a "heroic" signal which is by magnitude stronger then satellite
signal, the system might think "this is too powerful", or "this is too
close" and simpy switch to something else. Remember, expirienced LW pilots
were able to depict the false signals. And code-breaking is not a trivial
thing; put a password to a MS-Word-file that is, let's say 5 characters long
and try to crack it with some program designed to do it, let's say Advanced
Office Password Recovery. Yeah, it will eventually break it, but count how
long it will take!

Also, You have A GPS and GLONASS (a Soviet GPS); while GLONASS is reportedly
in a bad shape, as far as I can remember India (I am really not sure!) uses
BOTH systems which might suggest that it is not in such bad shape after all.
While I am not aware of Russian GPS bombing/missile systems in use, some of
their (export?) weapon systems use both.

I agree that we are talking about the weapon (figter, bomber, cruise missile
or JDAM) that might not have all the "offset" capabilities that I have
mentioned here; I might not even be correct in numerous things. Actually,
you will need a (really, really) good sample either of the good portion of
the knowledge how -military- part of the system works or the system itself.
And once you develop a system, it will certainly not be of the cell-phone
size but rather of an underwing or wingtip pod size, weight and cost.

Nele

NULLA ROSA SINE SPINA

On Mon, 19 Jul 2004 15:20:40 +0200, Nele VII wrote:

At a rough guess the cost for a 1W jammer using cellphone components would
be ~$5, just keep sending them up with balloons (add $1).

Well, it is a bit under-estimated. I don't know much about how GPS works
(electronically), but I know it has commercial and military channels/
frequencies and commercial and military encoding. For civilian use, optimum
accuracy is receiving three GPS signals from three satellites (somebody
correct me if I am wrong, but I read it somewhere for more expensive GPS
devices for use, let's say in aviation) for elevation and position.

You need to receive signals from four satellites to obtain a 3-D
position. Most GPS receivers can make do with three satellites, but
when they do they give only a 2-D position, and assume your elevation
is constant.

Modern consumer GPS receivers can receive and use signals from up
to twelve GPS satellites simultaneously. With the current GPS
constellation, it's not unusual to have ten satellites above the
horizon and useable. Most receivers will use the additional
satellite signals (above the four needed for 3-D position) to
determine your position more accurately.

As you travel, the sattelites "switch" (just like GSM) control.

Actually, the satellites are most likely traveling faster
than you are. Their orbital period is just under 12 hours, so
you'd have to be moving more than 2000 mph to stay directly
underneath one. The GPS receiver computes which satellites are
above the horizon, and listens for their signals. As satellites
rise and set, the receiver updates the group of satellites it's
listening for.

[...]

What method are you going to use-noise or deceptive jamming? Read the
history of updates of "AN-ALQ" devices-or just one! Noise? In that case, you
are a flashbulb, and you will be attacked with alternate weapon on jamming
station. The band is narrow AFAIK, so if your opponent knows what to
"listen", you're toast.

[...]

Deception jamming might be possible if you have a civilian receiver,
but you'd need to crack the encrypted signal to spoof a military
receiver.

There are a number of introductory descriptions of how the GPS system
works on the web -- for example, check out

http://www.aero.org/publications/GPSPRIMER/


ljd

Laurence Doering wrote:

On Mon, 19 Jul 2004 15:20:40 +0200, Nele VII
wrote:
snip

What method are you going to use-noise or deceptive jamming? Read the
history of updates of "AN-ALQ" devices-or just one! Noise? In that case,
you are a flashbulb, and you will be attacked with alternate weapon on
jamming station. The band is narrow AFAIK, so if your opponent knows what
to "listen", you're toast.

[...]

Deception jamming might be possible if you have a civilian receiver,
but you'd need to crack the encrypted signal to spoof a military
receiver.

Probably the best (cheap) method would be noise with digital transmissions
(as per psuedo random code no need to crack the encryption) on the correct
frequencies. 1W dosn't sound much but with the low recieved power of the
GPS signal it dosn't take much to overwhelm or confuse it.

The cellphone industry has ensured VERY low cost components eg power output
transistors/amplifiers for a few cents. No need for elaborate environmental
enclosures just attach balloon and battery stick a ziplok bag over the
electronics and release. To avoid ECCM attacks change location immeadiately
to another school, hospital etc although a vehicle outside the Chinese
embassy for a release point is a possible.

The cost of hitting the balloons once they are released makes them a rather
assymetric weapon.

--

regards

jc

LEGAL - I don't believe what I wrote and neither should you. Sobriety and/or
sanity of the author is not guaranteed

EMAIL - and are not valid email
addresses. news2x at perentie is valid for a while.

In article ,
jc wrote:

Probably the best (cheap) method would be noise with digital
transmissions (as per psuedo random code no need to crack the
encryption) on the correct frequencies. 1W dosn't sound much but with
the low recieved power of the GPS signal it dosn't take much to
overwhelm or confuse it.

The cellphone industry has ensured VERY low cost components eg power
output transistors/amplifiers for a few cents. No need for elaborate
environmental enclosures just attach balloon and battery stick a
ziplok bag over the electronics and release. To avoid ECCM attacks
change location immeadiately to another school, hospital etc although
a vehicle outside the Chinese embassy for a release point is a
possible.

The cost of hitting the balloons once they are released makes them a
rather assymetric weapon.

You're forgetting something.

Power.

For a 1 watt output, you're going to need a battery or other power
supply that can supply at least twice that for a significant period of
time. If you're going for a balloon launch, to get to significant
altitude, you're going to need a couple of hours of capacity, at
*least*. Increased weight equal increased balloon size, by the way.
With increased tankage for your lifting gas, and massively increased
transportation costs.

Not to mention, of course, that you're transmitting that 1 watt
omnidirectionally, which means that you're only going to cover a couple
of square miles with one jammer, at *best*. If you're going for a pure
white noise "drown them out" system, plan on a *hundred* watts or more
(to beat the directional antennas used on most modern weapons systems).
If you're going for digital spoofing, use lower power levels, but spend
a lot of money on electronically-steerable transmitters and high-end
hardware to make the signal work past the dozen or so GPS sats in view
at any one time.

Suddenly, the "$5 balloon-borne jammer" is a "$500 balloon-borne jammer
that only lasts a few hours."

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

Chad Irby wrote:

snip
You're forgetting something.

Power.

So what is the power of the satellites at what distance. Square dist law.

Not to mention, of course, that you're transmitting that 1 watt
omnidirectionally,

Last (only) time I have tried for an isotropic ( within ~ 3 dB, which is
what you need for GPS jamming from balloons, not omnidirectional) antenna
with 125 mW input we got ~ 120 dBm at 30 clicks which in flat terrain,
enough to get a reliable signal with an 11 dB omnidirctional recieve
antenna. Now what is the level from the satellites?

Suddenly, the "$5 balloon-borne jammer" is a "$500 balloon-borne jammer
that only lasts a few hours."

How long does an RPG blast go for and how much does it cost


--

regards

jc

LEGAL - I don't believe what I wrote and neither should you. Sobriety and/or
sanity of the author is not guaranteed

EMAIL - and are not valid email
addresses. news2x at perentie is valid for a while.