Stryker/C-130 Pics

"Thomas Schoene" wrote in message k.net...
"Kevin Brooks" wrote in message
om
Think of it as another system using the same
concept as current spaced armor and ceramic composites, which also
hinge upon diffusing the jet over a larger area, a;beit one with
extremely fine tolerances for successful initiation.

As I understand it, the system actually self-initiates -- the plasma jet
actually bridged the gap and shorts out the capacitor on impact. No timing
mechanism required.

OK, I can see where that would complete the circuit, though now you
are left with a plate capacitor with a hole in one plate, if I am
understanding this properly--how well is it going to work a second
time? How much power is required? How are other systems to be
protected from your own protective capacitance discharge? Sorry, but
this does not sound like the most promising of developments against
the HEAT round, and I can't see how it would be that effective against
a kinetic round, so is this another wonderful research project that
sees little opportunity of realistic fielding?


Again, you seem to have the defeat mechanism wrong, from the way I
read it. And pray tell what this wonderful system does to a shaped
charge using a non-conducting liner (glass (which is a liquid in its
customary "solid" state, as we know it...) is a not uncommon alternate
liner in place of the usual copper)?

In the very heated, very compressed sonditions of a shaped charge plasma
jet, I suspect you'll find that even glass is conductive.

Mea culpa. You are right, Tom; I was a bit surprised to find that this
is true for glass, which apparently has some level of sodium in its
structure.

Brooks

On 22 Sep 2003 18:23:29 -0700, Kevin Brooks wrote:
And just as usual, the accuracy of computer simulations of tactical
ground fights is strongly suspect.

Garbage in, garbage out.

No, not so much GIGO as it is a matter of the goals of the simulation,
which is usually to stress the side being exercised. That retired USMC
GO who ran the JFC exercise last year was whining about how he could
not conduct true "free play", and that certain actions of his were
rescinded by the exercise controllers, but that ignored the fact that
the game had for one of its primary goals, for example, the validation
of the IBCT/SBCT as a tool for the JTF commander--sliming the APOD
that was to serve that unit might be a "real world" thing to consider,

Care to "de-jargonize" that? I get the general gist, just not the
details.


--
"It's easier to find people online who openly support the KKK than
people who openly support the RIAA" -- comment on Wikipedia

(I'm not an electronic engineer, so I've cross-posted this to some
newsgroups which might be able to give informed comment on a number
of points.)

On 23 Sep 2003 05:51:41 -0700, Kevin Brooks wrote:
(phil hunt) wrote in message ...
[regarding battlefield internet]
The signal must be such that the extended receiver can hear it. So
others can too, in principle. (Though detecting the signal and
knowing where it's from aren't the same thing). I'm not a radio
engineer but I can imagine a few ways how direction-finding might
work; for example place two (or 3) detectors a few meters apart
and calculate the time delay between each one receiving the signal.

No. Paul is correct, DF'ing a "frequency agile" (or "hopping")
transmitter is no easy task. For example, the standard US SINCGARS
radio changes frequencies about one hundred times per *second*,

Bear in mind that I'm talking about automated electronic gear here,
not manual intervention. Electronics works in time spans a lot
quicker than 10 ms.

over a
pretty wide band of freq's (this is why synchronization of the radios
on a time basis is critical to succesful operation of the net).

So the frequency changes are pre-determined on a time basis?

If there is a radio receiver, is it better able to detect/deceive a
signal whgen it knows the frequency in advance? Or can it "sniff"
for lots of frequencies at a time and pick out what looks
interesting?

If two receivers, placed say 10 m aparet, both pick up a signal, how
accurately can the time difference between the repetion of both
signals be calculated? Light moves 30 cm in 1 ns, so if time
differences can be calculated to an accuracy of 0.1 ns, then
direction could be resolved to an accuracy of 3 cm/10 m ~= 3 mrad.

Alternately, would something like a pinhole camera work? What I mean
here is: imagine a cubic metal box, 1 m on its side, with a vertical
slit, about 1 cm wide down one of its vertical faces. On the
opposite face, there are detectors for detecting radio waves. If the
elevctromatnetic ratiation coming into the box can only go in
through the slit, and goes in a straight line, then knowing which
detectors are lit up would allow someone to tell where the
radiation was coming from. It may be that, depending on the
wavelength, the incoming radiation would be diffracted by the slit
and would get spread all over the detectors. If this is the case,
perehaps multiple slits could be used, and the diffraction pattern
would differ dependent on the angle with which the radiation strikes
the slitted face? (because the radation at each slit would be
out-of-phase with the radiation at other slits). Has anything like
this been tried?

It is
hard enough for the average "rest of the world" intel unit to DF an
old fashioned non-hopping transmitter if the radio operator uses good
RTO procedures--trying to pluck enough of these random
fractional-second bursts out of the ether to determine a direction is
more difficult by a few orders of magnitude.

What methods are used to do DF?

--
"It's easier to find people online who openly support the KKK than
people who openly support the RIAA" -- comment on Wikipedia

"Kevin Brooks" wrote in message
om...
"Thomas Schoene" wrote in message
k.net...
"Kevin Brooks" wrote in message
om
Think of it as another system using the same
concept as current spaced armor and ceramic composites, which
also
hinge upon diffusing the jet over a larger area, a;beit one with
extremely fine tolerances for successful initiation.

As I understand it, the system actually self-initiates -- the
plasma jet
actually bridged the gap and shorts out the capacitor on impact.
No timing
mechanism required.

OK, I can see where that would complete the circuit, though now you
are left with a plate capacitor with a hole in one plate, if I am
understanding this properly--how well is it going to work a second
time? How much power is required? How are other systems to be
protected from your own protective capacitance discharge? Sorry, but
this does not sound like the most promising of developments against
the HEAT round, and I can't see how it would be that effective
against
a kinetic round, so is this another wonderful research project that
sees little opportunity of realistic fielding?

It seems far-fetched to me as well although for long rod rounds. I
went back and re-read the article and the jet "is virtually
instantaneously dispersed by the high temperatures and powerful fields
generated by a pulsed power system carried by the vehicle". A Warrior
was used as the testbed and it was subjected to multiple attacks with
no major damage.

As far as holes in the capacitor are concerned, an enemy may have
difficulty hitting the same spot twice. I would have said "unlikely"
except last week's AwWeek mentioned that two JASSMs hit the same spot
in rapid succession without benefit of a LASER spot. If the optical
tracker used for precision targeting for JASSM can do that, a similar
seeker can do that for ATGMs. Which also means "let reactive armor
designers beware".

Power apparently isn't a problem. The IDR article says that the
electrical load is "no more arduous than starting the engine on a cold
morning"

If you're interested, the (brief) description is found in the current
IDR (September) on page 55.

(phil hunt) wrote in message ...
On 22 Sep 2003 18:23:29 -0700, Kevin Brooks wrote:
And just as usual, the accuracy of computer simulations of tactical
ground fights is strongly suspect.

Garbage in, garbage out.

No, not so much GIGO as it is a matter of the goals of the simulation,
which is usually to stress the side being exercised. That retired USMC
GO who ran the JFC exercise last year was whining about how he could
not conduct true "free play", and that certain actions of his were
rescinded by the exercise controllers, but that ignored the fact that
the game had for one of its primary goals, for example, the validation
of the IBCT/SBCT as a tool for the JTF commander--sliming the APOD
that was to serve that unit might be a "real world" thing to consider,

Care to "de-jargonize" that? I get the general gist, just not the
details.

JFC- Joint Forces Command
Free Play- No restrictions on player actions as long as they are IAW
his units' abilities
IBCT - Interim Brigade Combat Team (a brigade combat team being a
combined arms force built around a maneuver combat brigade, including
"slice" elements such artillery, engineers, field arty, service
support, etc.)
SBCT- Stryker Brigade Combat Team (what the IBCT became after the LAV
was selected and named "Stryker")
JTF- Joint Task Force; typical designation of the joint/unified
elements contributed by the seperate services for a contingency
operation, ensuring unity of command
APOD- Aerial Port of Debarkation, or the airfield where the forces are
arriving (APOE being the *E*mbarkation site)
Slime- slang for hitting a target with chems; against critical targets
such as the APOD, likely to be persistent chems.

Brooks

(phil hunt) wrote in message ...
(I'm not an electronic engineer, so I've cross-posted this to some
newsgroups which might be able to give informed comment on a number
of points.)

On 23 Sep 2003 05:51:41 -0700, Kevin Brooks wrote:
(phil hunt) wrote in message ...
[regarding battlefield internet]
The signal must be such that the extended receiver can hear it. So
others can too, in principle. (Though detecting the signal and
knowing where it's from aren't the same thing). I'm not a radio
engineer but I can imagine a few ways how direction-finding might
work; for example place two (or 3) detectors a few meters apart
and calculate the time delay between each one receiving the signal.

No. Paul is correct, DF'ing a "frequency agile" (or "hopping")
transmitter is no easy task. For example, the standard US SINCGARS
radio changes frequencies about one hundred times per *second*,

Bear in mind that I'm talking about automated electronic gear here,
not manual intervention. Electronics works in time spans a lot
quicker than 10 ms.

So what? Unless you know the frequency hopping plan ahead of time
(something that is rather closely guarded), you can't capture enough
of the transmission to do you any good--they use a rather broad
spectrum.


over a
pretty wide band of freq's (this is why synchronization of the radios
on a time basis is critical to succesful operation of the net).

So the frequency changes are pre-determined on a time basis?

Yes.


If there is a radio receiver, is it better able to detect/deceive a
signal whgen it knows the frequency in advance? Or can it "sniff"
for lots of frequencies at a time and pick out what looks
interesting?

Both radios have to be loaded with the same frequency hopping (FH)
plan, and then they have to be synchronized by time. When SINGCARS
first came out the time synch had to be done by having the net control
station (NCS) perform periodic radio checks (each time your radio
"talked" to the NCS, it resynchronized to the NCS time hack); failure
to do this could result in the net "splitting", with some of your
radios on one hack, and the rest on another, meaning the two could not
talk to each other. I believe that the newer versions (known as
SINCGARS EPLRS, for enhanced precision location system) may use GPS
time data, ensuring that everyone is always on the same time scale.

Yes, you can set up to scan various nets (we did so for command post
operations where we wanted to monitor multiple nets), but they all
have to be on that same time hack, and you have to have each net's FH
plan loaded; you can't just decide to operate it like a police scanner
and listen in on whoever you choose to.


If two receivers, placed say 10 m aparet, both pick up a signal, how
accurately can the time difference between the repetion of both
signals be calculated? Light moves 30 cm in 1 ns, so if time
differences can be calculated to an accuracy of 0.1 ns, then
direction could be resolved to an accuracy of 3 cm/10 m ~= 3 mrad.

The fact is that the direction finding (DF'ing) of frequency agile
commo equipment is extremely difficult for the best of the world's
intel folks, and darned near impossible for the rest (which is most of
the rest of the world); that is why US radio procedures are a bit more
relaxed than they used to be before the advent of FH, back when we
tried to keep our transmissions to no more than five seconds at a time
with lots of "breaks" in long messages to make DF'ing more difficult.


Alternately, would something like a pinhole camera work? What I mean
here is: imagine a cubic metal box, 1 m on its side, with a vertical
slit, about 1 cm wide down one of its vertical faces. On the
opposite face, there are detectors for detecting radio waves. If the
elevctromatnetic ratiation coming into the box can only go in
through the slit, and goes in a straight line, then knowing which
detectors are lit up would allow someone to tell where the
radiation was coming from. It may be that, depending on the
wavelength, the incoming radiation would be diffracted by the slit
and would get spread all over the detectors. If this is the case,
perehaps multiple slits could be used, and the diffraction pattern
would differ dependent on the angle with which the radiation strikes
the slitted face? (because the radation at each slit would be
out-of-phase with the radiation at other slits). Has anything like
this been tried?

Hey, I just *used* the critters and was fortunate enough to attend new
equipment training from the manufacturer when we got it; suffice it to
say that use of FH makes DF'ing a remote concern, pretty much
eliminates any concern over jamming (even broad band jamming can only
take down a small percentage of the available spectrum, making voice
transmissions still very clear), and the use of FH combined with
crypto key makes it darned near impossible for the bad guy to decypher
it in any realistic timely manner.


It is
hard enough for the average "rest of the world" intel unit to DF an
old fashioned non-hopping transmitter if the radio operator uses good
RTO procedures--trying to pluck enough of these random
fractional-second bursts out of the ether to determine a direction is
more difficult by a few orders of magnitude.

What methods are used to do DF?

You'd have to find a signals intel puke to answer that one (but you
can rest assured that any really good methods/systems remain
classified).

Brooks

"phil hunt" wrote in message
. ..
So the frequency changes are pre-determined on a time basis?

Oh yea.

If there is a radio receiver, is it better able to detect/deceive a
signal whgen it knows the frequency in advance? Or can it "sniff"
for lots of frequencies at a time and pick out what looks
interesting?

Both.
To "sniff" takes the time needed for a bunch of transmitted
cycles to come through so the receiver can determine it's
not random noise.
The receiver for a hopper *assumes* there is a signal in the
expected slot and integrates it into a bigger signal for the
rest of the system.

If two receivers, placed say 10 m aparet, both pick up a signal, how
accurately can the time difference between the repetion of both
signals be calculated? Light moves 30 cm in 1 ns, so if time
differences can be calculated to an accuracy of 0.1 ns, then
direction could be resolved to an accuracy of 3 cm/10 m ~= 3 mrad.

Measuring the time difference between reception by two antennas
yields a curve (all points such that the distance between the two
antennas and the point is a constant). Add another antenna and the
possible transmitter locations are the points where the curves cross;
by doing the A-B, B-C and A-C comparison you should have a single
point left.
If your antennas are too close together the curves stay in proximity
to each other so long you don't have the angular resolution to get a
good fix.

You can measure the angles quite accurately by using multiple
directional antennas and measuring the phase & amplitude differences.

Alternately, would something like a pinhole camera work? What I mean
here is: imagine a cubic metal box, 1 m on its side, with a vertical
slit, about 1 cm wide down one of its vertical faces. On the
opposite face, there are detectors for detecting radio waves. If the
elevctromatnetic ratiation coming into the box can only go in
through the slit, and goes in a straight line, then knowing which
detectors are lit up would allow someone to tell where the
radiation was coming from. It may be that, depending on the
wavelength, the incoming radiation would be diffracted by the slit
and would get spread all over the detectors. If this is the case,

It all most certainly will defract.

perehaps multiple slits could be used, and the diffraction pattern
would differ dependent on the angle with which the radiation strikes
the slitted face? (because the radation at each slit would be
out-of-phase with the radiation at other slits). Has anything like
this been tried?

Sounds good, unfortunately your detectors hung on the wall still have
that problem with determining a short burst signal is really there and
not random noise. There's also the problem with which slice of the
spectrum they are listing too at any one time.
There are ways to do the listing with a really wide band but they require
boat loads of processing that's not done real time and none I'm aware
of preserve the phase information for DFing.

In message , phil hunt
writes
On 23 Sep 2003 11:22:50 -0700, Kevin Brooks wrote:
this does not sound like the most promising of developments against
the HEAT round, and I can't see how it would be that effective against
a kinetic round, so is this another wonderful research project that
sees little opportunity of realistic fielding?

Sounds a bit like a waste of money to me. Perhaps the MoD should be
more concerned with making sure British soldiers have rifles and
radios that work.

*Still* waiting on Bowman, but PRR works really well at unit level.

As for L85/L86, after such a shrill whine the silence is suddenly
deafening. Where _are_ all those stories about British soldiers doomed
to death by their flawed faulty useless rifles?

Did the rifles actually *work*? How embarrassing! What will people
complain about now?

--
When you have to kill a man, it costs nothing to be polite.
W S Churchill

Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk

On 23 Sep 2003 20:00:32 -0700, Kevin Brooks wrote:

No. Paul is correct, DF'ing a "frequency agile" (or "hopping")
transmitter is no easy task. For example, the standard US SINCGARS
radio changes frequencies about one hundred times per *second*,

Bear in mind that I'm talking about automated electronic gear here,
not manual intervention. Electronics works in time spans a lot
quicker than 10 ms.

So what? Unless you know the frequency hopping plan ahead of time
(something that is rather closely guarded), you can't capture enough
of the transmission to do you any good--they use a rather broad
spectrum.

OK, I now understand that DF generally relies on knowing the
frequency in advance.

BTW, when you say a rather broad spectrum, how broad? And divided
into how many bands, roughly?

Both radios have to be loaded with the same frequency hopping (FH)
plan, and then they have to be synchronized by time. When SINGCARS
first came out the time synch had to be done by having the net control
station (NCS) perform periodic radio checks (each time your radio
"talked" to the NCS, it resynchronized to the NCS time hack); failure
to do this could result in the net "splitting", with some of your
radios on one hack, and the rest on another, meaning the two could not
talk to each other. I believe that the newer versions (known as
SINCGARS EPLRS, for enhanced precision location system) may use GPS
time data, ensuring that everyone is always on the same time scale.

That would make sense.

If two receivers, placed say 10 m aparet, both pick up a signal, how
accurately can the time difference between the repetion of both
signals be calculated? Light moves 30 cm in 1 ns, so if time
differences can be calculated to an accuracy of 0.1 ns, then
direction could be resolved to an accuracy of 3 cm/10 m ~= 3 mrad.

The fact is that the direction finding (DF'ing) of frequency agile
commo equipment is extremely difficult for the best of the world's
intel folks, and darned near impossible for the rest (which is most of
the rest of the world); that is why US radio procedures are a bit more
relaxed than they used to be before the advent of FH, back when we
tried to keep our transmissions to no more than five seconds at a time
with lots of "breaks" in long messages to make DF'ing more difficult.

So transmissions of 5 seconds tend to be hard to DF? Of course, with
the battlefield internet, a text transmission will typically be a
lot less than 5 s (assuming the same bandwidth as for a voice
transmission, i.e. somewhere in the region of 20-60 kbit/s).

transmissions still very clear), and the use of FH combined with
crypto key makes it darned near impossible for the bad guy to decypher
it in any realistic timely manner.

Modern crypto is good enough to withstand all cryptanalytic
attacks.

--
"It's easier to find people online who openly support the KKK than
people who openly support the RIAA" -- comment on Wikipedia

On Wed, 24 Sep 2003 21:32:39 +0100, Paul J. Adam wrote:
In message , phil hunt
writes
On 23 Sep 2003 11:22:50 -0700, Kevin Brooks wrote:
this does not sound like the most promising of developments against
the HEAT round, and I can't see how it would be that effective against
a kinetic round, so is this another wonderful research project that
sees little opportunity of realistic fielding?

Sounds a bit like a waste of money to me. Perhaps the MoD should be
more concerned with making sure British soldiers have rifles and
radios that work.

*Still* waiting on Bowman, but PRR works really well at unit level.

I heared the army had radio problems in Kosovo -- don't know which
model of radio.

As for L85/L86, after such a shrill whine the silence is suddenly
deafening. Where _are_ all those stories about British soldiers doomed
to death by their flawed faulty useless rifles?

Did the rifles actually *work*?

Oh, the rifles, have always worked... it's just they were prone to
not working if they got dirty. If I'd been the MoD, I'd have
specified burying them in sand overnight then firing them as part
of the acceptance tests.

--
"It's easier to find people online who openly support the KKK than
people who openly support the RIAA" -- comment on Wikipedia