IFF vs. Transponders
Billy Beck
(headers)
Ladies & gentlemen of RAM, I am quite reluctant to do this, but I
see no serious way around it.
Please allow me to present Mr. Kurt Lochner, who has a question:
Kurt Lochner <kurt_1...@shotsnai1.messin.bee-cee.com> wrote:
>Silly Shlepp <wj...@mindspring.com> whined at:
>>Tell us what "IFF" is,[..]
>
>Tell me what you think an aviation transponder is, Silly..
>
>--I think you to be clueless on this matter..
In the wake of someone else's assertion of an "IFF transmission"
from American Airlines flight #11, on 9/11, the man is just a tad
confused over the differences between transponders and IFF, and I have
presumed that there are credentialled individuals here who might care
to explain this matter to him.
Thanx in advance, and my apologies if things are otherwise.
Billy
VRWC Fronteer
http://www.mindspring.com/~wjb3/free
Jerry Helms
the military uses SIF and IFF. SIF is the 4 digit octal code
the pilot sets at the request of ATC, and also includes
altitude transmissions (Mode 1, 2, 3A, and C). IFF is a
challenge/response system that is dependant on a crypto
key (Mode 4). No airline has an IFF capability, and many
military planes, while equipped, have no IFF capability
(witness the Helo shootdown in Iraq).
Both systems use the same frequency.
When a lay person says "IFF" merely replace that with "SIF"
and you will know what he/she is yapping about.
I deleted the alt.clinton bullshit from your posting.
Have a nice day
"Billy Beck" <wj...@mindspring.com> wrote
Ernest Brown
My, Billy, you're being especially and justifiably cruel to Lochner the
Ignorant and his bestest ever pal Gandy Ova...
--
Wisdom's Children: A Virtual Journal of Philosophy & Literature
http://ourworld.compuserve.com/homepages/billramey/wisdom.htm
Submissions welcomed.
Randy Haskin
> In the wake of someone else's assertion of an "IFF transmission"
> from American Airlines flight #11, on 9/11, the man is just a tad
> confused over the differences between transponders and IFF, and I have
> presumed that there are credentialled individuals here who might care
> to explain this matter to him.
Billy, since your tongue seemed to be pressed firmly into cheek on
this question, I'm not sure whether to take you seriously or not.
But, I'll have a go at it regardless and perhaps you might be able to
shut down another troll (good luck!).
Unless there's something that I really don't understand about the
electronics I use on a daily basis, there is really *little or no
difference at all* between "IFF" and "transponder". To me, using
"IFF" implies a military transponder that can squawk mode 1, mode 2,
mode 3, mode c, and mode 4 (and in the future, I'm sure, mode S, too).
The word "transponder" implies a civilian transponder that only
replies to mode 3 and (if properly configured) mode C.
Naturally the different modes used by the military are somewhat more
complicated, especially those that use crypto and are "secure"
squawks. Other than that....well, they work the same and provide the
same information.
I'm not sure what the sinister implication is that the comspiracy
theorists would infer by hearing that AA11 had an "IFF transmission"
-- to me, that just means they were squawking mode 3/c.
Randy Haskin
Strike Eagle Driver
Billy Beck
str...@hotmail.com (Randy Haskin) wrote:
>wj...@mindspring.com (Billy Beck) wrote...
Thank you, sir. (Memo to the cynics: this is what I mean by
"authority".) In the great scheme of the discussion at hand, this is
actually a fairly minor point, but I'm the one who picked it, so I get
to walk through it. I objected to a reference to "IFF transmission"
from an American Airlines flight, principally because it means that
the person who used the term really is not qualified to criticize Air
Force response to the threat on the morning of September 11, 2001.
The reason why I assert this, in this context, is because the person
who originally used the term in one of the two newsgroups to which
this is posted would not know IFF or Mode C from lawn-cuttings:
they're getting everything they say about the whole deal second-hand,
at least, from someone else who knows little or nothing about it, and
on & on ad infinitum into the foggy distance of the internet.
Now, to *me*, there is indeed an essential difference between IFF
and civilian transponder modes -- in their differences between the
implications for tactical operations in a combat zone and the rather
more prosaic task of civilian air traffic control -- which is the
whole reason for using terms precisely. It would not occur to me, for
one, to use "IFF" in reference to civilian ATC matters, for the very
obvious reason that nobody is seriously concerned with sorting
"freindly" vs. "enemy" civilian flights for the purpose of shooting at
any of them.
And when I see someone complaining about the fact that nothing
was done to head-off the 9/11 attacks, and they're starting to toss
terms like "NORAD" and "IFF", well, maybe you had to be there, but
it's kinda hard to know where to start on their arguments. We've seen
this roil through RAM before, and despite the fact a couple of those
people were marginally more adept with some of the concepts than the
people I'm dealing with elsewhere, I think you might agree that the
whole "Why didn't the fighters scramble and kill 'em all?!" angle is
bollocks.
Now, that's my story and I'm stickin' to it.
Thanx for ringing in, and you hang tough out there, hear?
Unknown
>IFF to the layman is the same as SIF. Civilians use SIF,
>the military uses SIF and IFF.
Further to that, IFF means "Identification Friend or Foe" and SIF
means "Selective Identification Feature". (afik)
--
Gord Beaman
PEI, Canada
"Old age is no place for sissies" -Bette Davis.
Jerry Helms
> "Jerry Helms" <jhel...@cox.net> wrote:
>
> >IFF to the layman is the same as SIF. Civilians use SIF,
> >the military uses SIF and IFF.
>
> Further to that, IFF means "Identification Friend or Foe" and SIF
> means "Selective Identification Feature". (afik)
Another term for the transponder beacon system:
ATCRABS = Air Traffic Control Radar Beacon System
Yes. And, they're both technically "transponders" with U.S./NATO
equipment in the same box. The ex-Soviet stuff is in separate boxes.
A "transponder" receives on one frequency, and transmits on
another. Satellites are all called transponders, but what is
transmitted, is identical to what is received. Aviation transponders
transmit a message based on what they receive, but the point
here is that they only transmit after receiving a signal. Well, in
the case of an "Ident" they violate that technical definition, and
the "ident" is considered a broadcast.
Here's a good/simple article:
http://www.airsport-corp.com/atcrabs.html
rea...@moron.com
wrote like a right wing scumbag:
> (headers)
>
> Ladies & gentlemen of RAM, I am quite reluctant to do this, but I
>see no serious way around it.
>
> Please allow me to present Mr. Kurt Lochner, who has a question:
Wow, BURGERKING
Are you going to give Lochner a few fine points in how to be the best
Burgerking Narc around?
==================================================
Isopropyl, the mental midget and right wing moralist write:
"whatca taLKIN' about, nigga? yer dick?"
"say WHAT, NIGGAH?? YOU GETTIN' YOU ASS CHAFED, AIN'T YOU, NIGGAH?"
rea...@moron.com
wrote like a right wing scumbag:
>My, Billy, you're being especially and justifiably cruel to Lochner the
>Ignorant and his bestest ever pal Gandy Ova...
Perhaps YOU can get BatShit Billy to explain what a BURGERKING NARC
does?
Then we can all laugh.
Cecil Turner
Well, there's little difference to you, because your transponder has an IFF feature
installed. But at the risk of being called a nit-picking purist, IFF has nothing to do
with modes 1,2,3 or C, nor any SIF feature--it only refers to mode 4. From JP 1-02:
identification, friend or foe
(DOD) A device that emits a signal positively identifying it as a friendly. Also called
IFF. See also air defense.
http://www.dtic.mil/doctrine/jel/doddict/data/i/02474.html
If someone is talking about IFF from an airliner in a general aviation discussion, it may
be just sloppy terminology for a transponder. If they're talking about air defense
issues, however, that sloppiness is inexcusable. Many US missile shooters interrogate IFF
prior to shooting--and the only launch-inhibiting reply is a properly coded mode 4
response from a compatible military transponder. Having it turned off, the wrong code, or
a civilian transponder all provide the same protection: none whatsoever.
rgds,
KTF
Ed Rasimus
>Randy Haskin wrote:
>>
>> Unless there's something that I really don't understand about the
>> electronics I use on a daily basis, there is really *little or no
>> difference at all* between "IFF" and "transponder". To me, using
>> "IFF" implies a military transponder that can squawk mode 1, mode 2,
>> mode 3, mode c, and mode 4 (and in the future, I'm sure, mode S, too).
>> The word "transponder" implies a civilian transponder that only
>> replies to mode 3 and (if properly configured) mode C.
>
>Well, there's little difference to you, because your transponder has an IFF feature
>installed. But at the risk of being called a nit-picking purist, IFF has nothing to do
>with modes 1,2,3 or C, nor any SIF feature--it only refers to mode 4. From JP 1-02:
>
>identification, friend or foe
>(DOD) A device that emits a signal positively identifying it as a friendly. Also called
>IFF. See also air defense.
>http://www.dtic.mil/doctrine/jel/doddict/data/i/02474.html
>
>If someone is talking about IFF from an airliner in a general aviation discussion, it may
>be just sloppy terminology for a transponder. If they're talking about air defense
>issues, however, that sloppiness is inexcusable. Many US missile shooters interrogate IFF
>prior to shooting--and the only launch-inhibiting reply is a properly coded mode 4
>response from a compatible military transponder. Having it turned off, the wrong code, or
>a civilian transponder all provide the same protection: none whatsoever.
>rgds,
>KTF
When I first read the question, I immediately said to myself, "Self,
IFF is a transponder, and as far as radar interrogation or secondary
radar for ATC purposed is concerned a transponder is an IFF." Then
there came the responses and my confusion level rose, until I finally
decided I've become so old that things that are clear and logical to
me are confused to folks who don't have my depth of experience. Back
when Wilbur and Orville were explainging to me about their new-fangled
machine....
Seriously, IFF which stands for Identification Friend or Foe was
created in WW II (AFAIK), and was a simple response to a radar
interrogation. When I went to pilot training in the mid-60s, it had
grown to three modes--1, 2, and 3 (logically enough) and the
explanation was that modes 1 and 2 were used by the military and 3 was
used by ATC. We controlled mode 1 and 3 in the cockpit with the
"squawk" for ATC handled by a 2-digit control dial. The I/P toggle
squawked flash for identification.
When the 4-digit mode 3 was introduced (I wanna say around '66?) the
IFF became the IFF/SIF with SIF meaning "Selective Identification
Feature"--the 4-digit that allowed individual aircraft discrete codes.
Still a secondary radar feature primarily for ATC.
In the early '70s we introduced encrypted Mode 4, keyed in by ground
crews before flight and changed daily. Also mode C to tattle on your
altitude and give ATC something to bitch about.
In the '80s we began to get NCTR and a follow-on to Combat Tree which
allowed tactical aircraft to interrogate others for a return to the
IFF role rather than simple Identification.
In the thread I noted someone refer to the Blackhawk friendly fire
incident and stating that some military aircraft don't have IFF--that
is patently false. It's simply a matter of turning it on to have it
work.
At least that's what I know about IFF/SIF transponders.
Ed Rasimus
Fighter Pilot (ret)
***ComputorEdge Magazine
***http://www.computoredge.com
Jim Yanik
<3d10c72a...@news.earthlink.net>:
The commercial and mil transponders are probably the same (or similar)
circuits. The 'transponder' receives an interrogation code and returns a
coded response. If military,it would look for a mil interogate code,and
return an IFF code,while a commercial TP would look for an ordinary
commercial interrogate code and return a compatible code.Maybe even the
same standardized frequencies,too.
That's my (swag)view of the systems.
--
Jim Yanik,NRA member
remove X to contact me
Darrell Earnshaw
Would it be correct to say that the transponders used on civilian aircraft transmit an unencyrpted data stream when interrogated by an ATC secondary radar? If so, presumably anyone with a decent scanner, computer and appropriate software could decode this data and display the aircraft's altitude, speed, and whatever other info is transmitted as part of the datastream. (Much the same way that ACARS data can be received and decoded.)
Or, am I missing the boat completely?
-- Darrell.
Cecil Turner
All perfectly correct, as long as you note that the selective identification feature (SIF)
refers to: "(DOD) A capability that, when added to the basic identification friend or foe
system, provides the means to transmit, receive, and display selected coded replies. "
(And essentially means everything except mode 4--which is the IFF part.)
rgds,
KTF
Ed Rasimus
>Ed Rasimus wrote:
>>
>> Seriously, IFF which stands for Identification Friend or Foe was
>> created in WW II (AFAIK), and was a simple response to a radar
>> interrogation. . . .
>>
>> In the early '70s we introduced encrypted Mode 4, keyed in by ground
>> crews before flight and changed daily. Also mode C to tattle on your
>> altitude and give ATC something to bitch about.
>>
>> In the '80s we began to get NCTR and a follow-on to Combat Tree which
>> allowed tactical aircraft to interrogate others for a return to the
>> IFF role rather than simple Identification.
>> Ed Rasimus
>> Fighter Pilot (ret)
>> ***ComputorEdge Magazine
>> ***http://www.computoredge.com
>
>All perfectly correct, as long as you note that the selective identification feature (SIF)
>refers to: "(DOD) A capability that, when added to the basic identification friend or foe
>system, provides the means to transmit, receive, and display selected coded replies. "
>(And essentially means everything except mode 4--which is the IFF part.)
>rgds,
>KTF
When my previous is snipped down to the essentials, you'll see the
source of my confusion. Maybe NOW you mean that mode 4 (the encrypted
tactical ID feature) "is the IFF part", but historically, the
transponder that a radar interrogates is "the IFF part." In general
the part that tells you whether or not to shoot is going to be a
combination of factors--including the Mode 2 (call-sign
Identification), the Mode 4 (coded reply de jur), and even some
non-cooperative thingies.
If you re-read the piece from the manuals that you posted, you'll note
it is a definition of the SIF (which was described in my post as the
extension from 2-digit to 4-digit identification) as "added to the
basic (I)dentification (F)riend or (F)oe system..." The "IFF part" is
the basic responder to a query from a ground radar. It "identifies".
The codes, the modes and the "if I tell ya, I gotta kill ya" stuff are
all icing on the basic transponder which Identifies--the basic IFF set
of WW II.
Damn, I gotta stop this. Next thing ya know I'll be sounding like
Tarver.
Cecil Turner
> When my previous is snipped down to the essentials, you'll see the
> source of my confusion. Maybe NOW you mean that mode 4 (the encrypted
> tactical ID feature) "is the IFF part", but historically, the
> transponder that a radar interrogates is "the IFF part." In general
> the part that tells you whether or not to shoot is going to be a
> combination of factors--including the Mode 2 (call-sign
> Identification), the Mode 4 (coded reply de jur), and even some
> non-cooperative thingies.
>
> If you re-read the piece from the manuals that you posted, you'll note
> it is a definition of the SIF (which was described in my post as the
> extension from 2-digit to 4-digit identification) as "added to the
> basic (I)dentification (F)riend or (F)oe system..." The "IFF part" is
> the basic responder to a query from a ground radar. It "identifies".
> The codes, the modes and the "if I tell ya, I gotta kill ya" stuff are
> all icing on the basic transponder which Identifies--the basic IFF set
> of WW II.
>
> Damn, I gotta stop this. Next thing ya know I'll be sounding like
> Tarver.
>
> Ed Rasimus
> Fighter Pilot (ret)
> ***ComputorEdge Magazine
> ***http://www.computoredge.com
Yep. Current usage is that the Mode 4 coded reply is the basic (IFF) feature or "signal
positively identifying it as a friendly" (though other considerations do go into the shoot
decision). Don't know about WWII definitions, but for the last couple of decades or so,
that's what the term means. So as long as we're talking about 9/11 or similar timeframe,
Billy is correct that talking about IFF and airliners in the same sentence is
nonsensical. (And you couldn't Tarver if you had to.)
rgds,
KTF
Attack Pilot (ret)
Jerry Helms
>
> In the thread I noted someone refer to the Blackhawk friendly fire
> incident and stating that some military aircraft don't have IFF--that
> is patently false. It's simply a matter of turning it on to have it
> work.
That was me. What I said was essentially the same as you mention here.
Jerry Helms
This is really complicated today, as most airlines have
TCAS, and they interrogate at much higher rates than
ATC does. The sorting of all these signals is non-trivial.
If you take a scanner and tune it to 1030 MHz in the AM
mode, you will hear the TCAS and ground interrogations.
If you tune to 1090 MHz, you will hear the replies to the
interrogations. It's pretty intense, and you will have to
process the data at very high speeds.
Accuracy won't be very high, because you are essentially
direction finding (DF) the emitter, and aircraft speed would
be derived from one DF to the next. You probably wouldn't
be able to associate an altitude reply with a mode code,
due to this poor resolution. Unless maybe at night, where
there may only be 3 or 4 aircraft in the system.
"Darrell Earnshaw" <Darrell....@sun.com> wrote
Randy Haskin
> people I'm dealing with elsewhere, I think you might agree that the
> whole "Why didn't the fighters scramble and kill 'em all?!" angle is
> bollocks.
Yes, I'd be interested in hearing any arguments from people who think
that fighters could have been scrambled, on station, and in a position
to intercept and/or shoot down any of the Sept 11th airliners. Anyone
who thinks that it could have been done has never sat alert nor
actually flown an air-to-air intercept.
It's easy to sit back after the fact and armchair quarterback what
"shoulda, coulda" been done.
Mike Marron
>>Billy Beck wrote:
>>people I'm dealing with elsewhere, I think you might agree that the
>>whole "Why didn't the fighters scramble and kill 'em all?!" angle is
>>bollocks.
>Yes, I'd be interested in hearing any arguments from people who think
>that fighters could have been scrambled, on station, and in a position
>to intercept and/or shoot down any of the Sept 11th airliners. Anyone
>who thinks that it could have been done has never sat alert nor
>actually flown an air-to-air intercept.
>It's easy to sit back after the fact and armchair quarterback what
>"shoulda, coulda" been done.
Most people don't realize that, in the post Cold War/pre-New War
(against terrorism) period (e.g: 1989-2001) the U.S. didn't have
fighter-interceptors and pilots sitting at the ready all over the
country pre-armed with missiles just waiting to scramble and shoot
down a domestic airliner that has been hijacked by suicidal Arab
terrorists. Prior to 9-11, the notion of such a gruesome scenario
actually happening on our own soil was simply unthinkable. Even
today, sometimes I wonder if America is *still* sleeping.
-Mike Marron
Billy Beck
mjma...@tampabay.rr.com (Mike Marron) wrote:
Some time back, someone at RAM quoted Gen. Daniel "Chappie"
James, from the mid-70's ('76, I'm pretty sure) as saying, "There is
no national air defense worthy of the name."
Does anyone know where that came from? I would be interested to
read more of what he had to say on the matter.
Mike Marron
>>Mike Marron) wrote:
>>Most people don't realize that, in the post Cold War/pre-New War
>>(against terrorism) period (e.g: 1989-2001) the U.S. didn't have
>>fighter-interceptors and pilots sitting at the ready all over the
>>country pre-armed with missiles just waiting to scramble and shoot
>>down a domestic airliner that has been hijacked by suicidal Arab
>>terrorists. Prior to 9-11, the notion of such a gruesome scenario
>>actually happening on our own soil was simply unthinkable. Even
>>today, sometimes I wonder if America is *still* sleeping.
>Some time back, someone at RAM quoted Gen. Daniel "Chappie"
>James, from the mid-70's ('76, I'm pretty sure) as saying, "There is
>no national air defense worthy of the name."
>Does anyone know where that came from? I would be interested to
>read more of what he had to say on the matter.
National Air Defense isn't the issue. The issue is whether or not
airline pilots should be armed. My view is that they obviously should
be armed. But my view doesn't matter one iota. The only views that
matter are those in the Bush administration who oppose arming
airline pilots. Apparently, the politicians and airline management are
worried about armed pilots missing their targets and putting puny
20-30mm sized holes in the pressurized aircraft hulls. As a former
A&P mechanic, I can tell you that normal cabin inflow and outflow
valves dump a lot more than just a piddlyass hole in the hull. In
their infinite wisdom, the powers-that-be think that silly stun-guns
is the solution to combating teams of trained and coordinated
terrorists. Brilliant, ay?
-Mike Marron
Darrell Earnshaw
From what you say, it sounds like the transponder does not report the altitude, nor the aircraft's position. (I've often wondered how the ATC receiver actually sorts out the data streams from the various aircraft, as I assume that when the secondary radar interrogates an aircraft, all aircraft within the radar's beamwidth would respond at the same time.) Clearly, it's a subject I know absolutely nothing about!
Thanks,
Darrell.
Jerry Helms
>
> Some time back, someone at RAM quoted Gen. Daniel "Chappie"
> James, from the mid-70's ('76, I'm pretty sure) as saying, "There is
> no national air defense worthy of the name."
>
> Does anyone know where that came from? I would be interested to
> read more of what he had to say on the matter.
Actually, I think it was in 77 or maybe 78. I seem to recall him
being forced to retire over the remark, but this may be completely
wrong, as I know he suffered a heart attack, and then retired. He
then suffered another heart attack that did him in, almost as soon
as he got relaxed.
I think if you did a Time magazine search at the library, you would
find the incident, but a google search seems to only turn up standard
fluff for his biography.
I was in the Air Defense Command at the time, and I think his remarks
were in response to TAC getting the AWACS. He was expecting to
get both AWACS and a new interceptor, and got neither. About 1978,
the whole of ADC was shut down and given to the FAA, which promptly
got rid of most of the radar sites in the US. Maybe someone at:
Could help?
I think he was only protecting his command, as he probably knew in his
heart that TAC was a better place for the most expensive aircraft
ever conceived (at the time). The USAF wasn't going to orbit these
things over the ocean like ADC, they were going to deploy them with
a squadron of F-15's, and RC/KC-135's to every hot spot there was
in the world (mostly Riyadh and West Germany).
Jerry Helms
bullshit. Arming pilots who can barely operate their vehicles
now, without flying into the ground, trying to land in thunderstorms,
and basically amateur grade performance, is just one more nail
in the transportation modes coffin.
I for one, would never ride on a plane where the pilot was
armed, nor a train, nor a bus.
It's all about the lack of an Air Defense system.
Just today even a Cessna at 100 knots couldn't be
intercepted by our boys in Blue. A very sad commentary.
A bullet hole in the hull won't do much for pressurization, but
like the C-130 that recently blew-up, a crack from that hole
can travel a long distance, and possibly destroy the aircraft.
These aluminum panels are very strong without cracks, and
very weak with cracks.
"Mike Marron" <mjma...@tampabay.rr.com> wrote in message
Jerry Helms
from a Mode A (discrete 4 digit octal squawk) and a Mode C
(altitude). Thus, a person with a scanner isn't interrogating
a particular Mode, so can't be sure which reply is which.
The sensor that is eliciting responses will do a Mode 3 and
get a Mode 3 reply, etc. It is actually a simple procedure to
filter out replies that aren't directed at your interrogator. They
won't synchronize in range (called FRUIT in the business).
A person trying to passively process all the data on the
transponder frequency has one hell of a signal processing
task ahead of them.
Today, monopulse receivers, and Mode-S are replacing the
old IFF/SIF systems. The way they determined azimuth, was
to take the arc of replies (as the antenna went through the
aircraft azimuth) and mark the center of replies the azimuth.
This is called centroiding. You get about 100 replies for every
aircraft who has a transponder. This arc of replies is
de-FRUITed and only the center reply is sent on to the computer.
The monopulse receiver can determine azimuth boresight with
even one reply. The result is several orders of magnitude in
azimuth accuracy, and thus better computer tracking.
"Darrell Earnshaw" <Darrell....@sun.com> wrote in message news:3D121BA2...@sun.com...
Randy Haskin
> National Air Defense isn't the issue. The issue is whether or not
> airline pilots should be armed.
Wow, that came out of nowhere! And here I thought we were talking
about being able to intercept a hijacked airliner.
Mike Marron
>>Mike Marron) wrote:
>> National Air Defense isn't the issue. The issue is whether or not
>> airline pilots should be armed.
>Wow, that came out of nowhere! And here I thought we were talking
>about being able to intercept a hijacked airliner.
It's hard to genuflect online and I admittedly strayed off-topic a bit
but if you scroll back a few posts in this thread you'll see where I
submitted my opinion (FWIW) regarding the possibility of intercepting
the hijacked airliners back in Sept. I'm convinced that arming the
airline pilots with firearms (not stinkin' stun-guns) could prevent a
hijacked airliner situation from escalating into a major
intercept/shoot-down catastrophe. What do you think?
-Mike Marron
Dave Holford
Jerry Helms wrote:
>
> "Billy Beck" <wj...@mindspring.com> wrote in message
> >
> > Some time back, someone at RAM quoted Gen. Daniel "Chappie"
> > James, from the mid-70's ('76, I'm pretty sure) as saying, "There is
> > no national air defense worthy of the name."
> >
> > Does anyone know where that came from? I would be interested to
> > read more of what he had to say on the matter.
>
Don't recall that particular item, but I do recall a rating of world Air
Defense Systems published around or during the Vietnam war which rated
the three top systems as those of: North Vietnam, Israel and The Soviet
Union.
Don't remeber who determined the ratings but I suspect either Aviation
Week or some U.S. Government agency - maybe someone here has a better
memory, or better archives than I do.
I do remember being more than somewhat surprised that NORAD didn't make
the top list but the details presented with the rating explained it
pretty well and seemed convincing at the time.
Dave Holford
Tarver Engineering
"Cecil Turner" <turn...@mindspring.com> wrote in message
news:3D110BAB...@mindspring.com...
Some mil pointers have the IFF encripted on the TACAN bit stream.
John
Jerry Helms
>
> Some mil pointers have the IFF encripted on the TACAN bit stream.
>
> John
That would be a bit bogus I'm afraid. I've worked on many U.S. and
Soviet designs, and nothing modern (70's till now) has merged
systems. Although, many cooperative ideas were undertaken, none
involved interference with navigation systems. There's a rule in
engineering (and health) that says "Do no Wrong." Basically messing
with navigation is a project failure from the first proposal letter to your
team lead :-)
We did do a design where we correlated TACAN air channel direction
finding inputs, to the computer track, but this was abandoned after
most U.S./NATO aircraft went to EMCON techniques in the 80's.
Side story: I flew a sortie with a large recon aircraft during the
Nicaraguan war. I was evaluating the performance of a receiver,
and I was taking a break and chatting with the flight deck, when I
noticed the TACAN was in active. I then looked at the channel,
and they were using the Managua VORTAC for navigation!
I didn't say anything, but EMCON wasn't the life and death thing
it is today. I was a little disturbed that they would use a hostile
emitter for navigation... But then again, maybe the person running
the site was on the Ollie North payroll :-)
Tarver Engineering
"Jerry Helms" <jhel...@cox.net> wrote in message
news:zV2R8.25744$781....@news1.central.cox.net...
> "Tarver Engineering" <jta...@sierratel.com> wrote
> >
> > Some mil pointers have the IFF encripted on the TACAN bit stream.
> That would be a bit bogus I'm afraid. I've worked on many U.S. and
> Soviet designs, and nothing modern (70's till now) has merged
> systems. Although, many cooperative ideas were undertaken, none
> involved interference with navigation systems. There's a rule in
> engineering (and health) that says "Do no Wrong." Basically messing
> with navigation is a project failure from the first proposal letter to
your
> team lead :-)
I was refering to airborne TACAN acually and you could ping wrong and eat a
big fireball.
> We did do a design where we correlated TACAN air channel direction
> finding inputs, to the computer track, but this was abandoned after
> most U.S./NATO aircraft went to EMCON techniques in the 80's.
The IFF based TACAN is more of a mobile station standard.
> Side story: I flew a sortie with a large recon aircraft during the
> Nicaraguan war. I was evaluating the performance of a receiver,
> and I was taking a break and chatting with the flight deck, when I
> noticed the TACAN was in active. I then looked at the channel,
> and they were using the Managua VORTAC for navigation!
That is pretty much a blank ping.
> I didn't say anything, but EMCON wasn't the life and death thing
> it is today. I was a little disturbed that they would use a hostile
> emitter for navigation... But then again, maybe the person running
> the site was on the Ollie North payroll :-)
The CIA could very well have had control of the station.
Even if it was off, what would you have done?
John
Jerry Helms
> "Jerry Helms" <jhel...@cox.net> wrote
> > "Tarver Engineering" <jta...@sierratel.com> wrote
> > >
> > > Some mil pointers have the IFF encripted on the TACAN bit stream.
>
> > That would be a bit bogus I'm afraid. I've worked on many U.S. and
> > Soviet designs, and nothing modern (70's till now) has merged
> > systems. Although, many cooperative ideas were undertaken, none
> > involved interference with navigation systems. There's a rule in
> > engineering (and health) that says "Do no Wrong." Basically messing
> > with navigation is a project failure from the first proposal letter to
> > your team lead :-)
>
> I was refering to airborne TACAN acually and you could ping wrong and eat a
> big fireball.
So was I. There is no air TACAN bit stream. It's a pair of pulses.
Bob McKellar
Jerry Helms wrote:
I haven't the slightest idea what you guys are talking about.
I have absolutely no technical expertise in this field.
I was only a lowly sailor.
But based on my NG experience, I bet Tarver's wrong.
Bob McKellar
( Who knows what he knows, and what he doesn't know)
M.J.Powell
<sac...@omen.net.au> writes
>On Wed, 19 Jun 2002 18:13:52 GMT, thund...@earthlink.net (Ed
>Rasimus) wrote:
>
>>Seriously, IFF which stands for Identification Friend or Foe was
>>created in WW II (AFAIK), and was a simple response to a radar
>>interrogation.
>
Have you got source for that, please?
Mike
--
M.J.Powell
Andrew Chaplin
Yes, I'd be interested too. My father worked with secondary radars
equipped with Mk 10 IFF during the War, as did I (in 1977!) with
Blowpipe. Their queries were invariable, as were the responses, IIRC,
so any encryption was pretty dubious as a protection from compromise.
(We eventually replaced the Mk IFF with a systems switch to rely on
Hostile Act Criteria and Aircraft Recognition -- more reliable, and no
false FRIEND signals.) I think the Mk XII was the first standard in
wide allied use with routinely changing encryption.
--
Andrew Chaplin
SIT MIHI GLADIUS SICUT SANCTO MARTINO
(If you're going to e-mail me, you'll have to get "yourfinger."
out, and change "home" to "rogers".)
Paul Saccani
<abch...@yourfinger.home.com> wrote:
>Yes, I'd be interested too. My father worked with secondary radars
>equipped with Mk 10 IFF during the War, as did I (in 1977!) with
>Blowpipe. Their queries were invariable, as were the responses, IIRC,
>so any encryption was pretty dubious as a protection from compromise.
Encoding is not synonymous with encryption. Early FFI did not
respond to every interrogation pulse, but skipped x number of pulses
after x interrogations etc... This was encoded by electo-mechanical
means, by a rotating cylinder. The cylinder could be changed on a
daily basis (but wasn't). Operators counted the pulses, using a CRO
which provided a calibrated visual display of the pattern of reply to
interrogation.
The need for FFI was recognised prior to the war, and manufacture
commenced in early 1939.
cheers,
Paul Saccani
Perth West Australia
John Hairell
Some of us military ATC people were still counting "pulse trains" as
late as 1981 (for me) and later for others. The AN/TPN-18 GCA I used
to operate didn't display squawk codes numerically - you looked at the
pulse train (which looked like a modern bar code) trailing the primary
radar target and decoded it in your head, slowly in my case. The
squawk consisted of wide and narrow bands, and the narrow bands were
so fine and so many of them were compressed together that it was very
difficult to read them. I no longer remember the decoding scheme,
although I do remember the 72-step radar operator calibration
procedure, which you had to do with a tweaker in a dark room.
John Hairell (guar...@erols.com)
M.J.Powell
<guar...@erols.com> writes
A 'tweaker' being a very small screwdriver. I first met that term in
1955.
Mike
--
M.J.Powell
Jerry Helms
> >
> >although I do remember the 72-step radar operator calibration
> >procedure, which you had to do with a tweaker in a dark room.
>
> A 'tweaker' being a very small screwdriver. I first met that term in
> 1955.
We called them 7-Levels in ADC.
Bob
<mi...@pickmere.demon.co.uk> wrote:
>A 'tweaker' being a very small screwdriver. I first met that term in
>1955.
Used to adjust within an rch...
M.J.Powell
<jhel...@cox.net> writes
Why?
Mike
--
M.J.Powell
Jerry Helms
> Jerry Helms <jhel...@cox.net> wrote
> >"M.J.Powell" <mi...@pickmere.demon.co.uk> wrote
> >> >
> >> >although I do remember the 72-step radar operator calibration
> >> >procedure, which you had to do with a tweaker in a dark room.
> >>
> >> A 'tweaker' being a very small screwdriver. I first met that term in
> >> 1955.
> >
> >We called them 7-Levels in ADC.
>
> Why?
A 5-level is a term for a journeyman technician (3-Levels are
trainees), and a 7-level was management-expert technician.
I'm not sure of the history, but it went something like the only
difference between a 5-level and a 7-level was the size of his
screwdriver. Then also, all the 7-levels ever did was wait for
the 5-levels to get done troubleshooting or rebuilding a piece
of equipment, and the 7-level would come over and adjust a
pot and get credit for the task. Then the 5-levels would have
to buff the floor and clean up the work area.
M.J.Powell
<jhel...@cox.net> writes
Hehe! Sounds familiar!
Mike
--
M.J.Powell
William Donzelli
> Encoding is not synonymous with encryption. Early FFI did not
> respond to every interrogation pulse, but skipped x number of pulses
> after x interrogations etc... This was encoded by electo-mechanical
> means, by a rotating cylinder. The cylinder could be changed on a
> daily basis (but wasn't). Operators counted the pulses, using a CRO
> which provided a calibrated visual display of the pattern of reply to
> interrogation.
Only one early (if we define early to pre-1945) IFF system used a
rotating electromechanical system for encoding. This was the very
seldom used Mk IV system devised by the NRL, and called ABA-1 by the
Navy and SCR-515-A by the AAF. "Every day" a little disk was changed
on the end of the dynamotor. The ground crews were initially offered a
choice of ten disks, however, I have heard that additional code disk
sets were issued later. The disks are only about one inch in diameter,
with various patterns of pulses.
The majority of early IFF sets (these being the Mk III sets) used a
coding system as well, but it was based on a bunch of relays sitting
on timing circuits. It was rather limited - only six choices were
possible, with no real hopes for upgrades as simple as a new set of
disks. The pilot had control of the code, with a simple selector
switch.
I do not think the very early IFFs - MK I, Mk II, and XAE - had any
sort of encoding at all. They were developed during a time when nobody
thought the other guys had radar technology.
Finally, I should say that I really have little knowledge about the
German IFF of the period. It was encoded in some fashion, and I
suppose it could have been with disks or cylinders.
William Donzelli
Tarver Engineering
The 7 level did no work requiring a larger screwdriver.
John
Joe Osman
I was in Marine Air Control Squadron-7, which, of
course, was located on top of a hill. One Friday the truck
bringing our rifles up to the hill from our armory located
next to our barracks down below the hill broke down, so for
rifle inspection we presented arms with our tweakers.
Luckily for us the head of the radar section, Gunner Sorley,
had a sense of humor.
I work in Rome, New York, which is home to Rome Catholic
High. I have had several women introduced to me as "former
RCH girls". They thought I was crazy because it cracked me
up everytime and they had no idea why.
Joe
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