From: skunk-works-digest-owner@harbor.ecn.purdue.edu To: skunk-works-digest@harbor.ecn.purdue.edu Subject: Skunk Works Digest V4 #83 Reply-To: skunk-works-digest@harbor.ecn.purdue.edu Errors-To: skunk-works-digest-owner@harbor.ecn.purdue.edu Precedence: bulk Skunk Works Digest Tuesday, 7 December 1993 Volume 04 : Number 083 In this issue: miscellany, OTH, airships Re: miscellany, OTH, airships Re: miscellany, OTH, airships Re:OTH radar, missles & ECM _SCRUBBED_ Re: re: Airships, balloons... See the end of the digest for information on subscribing to the skunk-works or skunk-works-digest mailing lists and on how to retrieve back issues. ---------------------------------------------------------------------- From: I am the NRA Date: Mon, 6 Dec 93 06:32:20 PST Subject: miscellany, OTH, airships >>good enough to do 10s of meter resolution "imaging" >This would be very good if it is real, somewhere In the back of my head >there is the number 2000m for the australian one. Or one of them. The folks at Jindalee said they could see the tip vortices from the B2, whatever the wing span on that is. Maybe 100m. (I have my doubts: notably, the B2 was always flying with unstealthy chase planes, so whether the could see them or the B2...) When we toured the Control Point in Maine, they showed us a stored screen of three a/c, in formation, over London. England. They couldn't do that all day, every day, but they could do it. >> rich to burn, the fabric exposed for too brief an instant. >Is there any "Hindenburg" out there? I dont think helium burn. Right. The US (by happenstance has He. On the other hand, if the thing is unmanned, expendable, H had advantages, as it can be produced on site. >>>Transmitter in Moscow (really)??? >>>That was very interesting, does that mean that they use civil broadcasters? >>>Should be possible. > heh. Moscow is a small town in Northern Maine. And i may have > the Tx and Rx reversed. But one end IS in Moscow. >The main idea is to "record" the broadcast and use this as a pattern in an >spread spectrum type of radar. The real broadcast can be picked up near the >actual tx and relayed to the rx by satelite for example. I do not understand how this would be practical. Maybe using a resaonably high powered code transmitter, but they tend to be too fast, which clutters the returns. >The rx part must also sample and store the broadcast for later processing. >An ideal rx seems to be Radio Moscov. Reason? It is one of the worlds most >powerfull short-wave tx. Radio Moscow is several of the worlds most powerful transmitters. In a variety of locations. Unfortunately, they don't send Pulses, which is wnat is needed for this sort of work. (If doing CW radar, the the program modulation gets in the way...) >When it comes to bi-static/multi-static/OTH-B/OTH-M/OTH-SW/../radars I found >this in IDR 7/93, Russia develops OTH and anti stealth radars: Exactly. Bi Static is not necessarily MW or OTH. (I think the capability of bistatic to "defeat" stealth is somewhat over stated tho. Indeed, reflective stealth leaves the "glint" somewhere_else, but from any one somewhere else, the glint from any given target will be momentary. It would need massive numbers of receivers and massive integration fo their outputs to "beat" stealth. =========== Compressors of lift gas in air-ship, I don't KNOW, (that is, i'm not a compressor system design engineer) but thats what i was speculating on, about 4 para's further down: modern tanks could be light (composites?) and compressors, lighter than anything Zeppellin dreamt of, and faster. ============ And for those who missed it: Yes this (at least some of it) is SPECULATION. There's a difference between that and "lies". I tried to label the speculation. If the skunkworks list was limited to what people Know(tm) i mised it in the charter.... >in front of a reflector. Something like this: > ------------------------ <- Reflector > o o o o <-driven element > > o o o o <-director-parasitic To borrow someone else's ascii art, this is effectively, a top view of the a section of the USAF/GE arrays in Maine. Tx and Rx arrays are roughly identical in this case. There are several subarrays, each sized for a sub section of the 5-30MHz spectrum... regards dwp ------------------------------ From: rakoczynskij@agcs.com (Jurek Rakoczynski) Date: Mon, 6 Dec 1993 09:35:37 -0700 (MST) Subject: Re: miscellany, OTH, airships dwp writes: > The folks at Jindalee said they could see the tip vortices from > the B2, whatever the wing span on that is. Maybe 100m. > (I have my doubts: notably, the B2 was always flying with unstealthy > chase planes, so whether the could see them or the B2...) I have never been able to confirm the following, but when a news broadcast several years ago reported on the Jindalee "seeing" the B2, they stated that a software rewrite was looking for the doppler shift and matching amplitude variation expected from counter-rotating vortices. - -- Jurek Rakoczynski, AG Communication Systems, POB 52179, Phoenix, AZ. 85072-2179 Inet: rakoczynskij@agcs.com Voice: +1 602 581 4867 Inet: JUREK.RAKOCZYNSKI@gte.sprint.com Fax: +1 602 581 4022 ------------------------------ From: John Erling Blad Date: Mon, 6 Dec 1993 18:18:07 +0100 Subject: Re: miscellany, OTH, airships Some more OTH.. if anyone is interested. > The folks at Jindalee said they could see the tip vortices from > the B2, whatever the wing span on that is. Maybe 100m. What they see is probably the vortices when they reach a size comparable to the radars frequency. Because of this they do not necessarily have an resolution of the same size as a B2. This come in just now: >> The folks at Jindalee said they could see the tip vortices from >> the B2, whatever the wing span on that is. Maybe 100m. >> (I have my doubts: notably, the B2 was always flying with unstealthy >> chase planes, so whether the could see them or the B2...) >I have never been able to confirm the following, but when a news >broadcast several years ago reported on the Jindalee "seeing" the B2, >they stated that a software rewrite was looking for the doppler shift >and matching amplitude variation expected from counter-rotating >vortices. >Jurek Rakoczynski, AG Communication Systems, POB 52179, Phoenix, AZ. >85072-2179 I have seen it also, I gess this is possible and it dont imply 100m resolution. In addition you dont need to separate the vortices, you look fore a spot with two of them *within* the resolution. > > Right. The US (by happenstance has He. On the other hand, if the > thing is unmanned, expendable, H had advantages, as it can be produced > on site. Good idea but I dont think any country will accept the risk. If you build something like this (I DONT Th....) the extra cost of He versus H is insignificant. This is in peace-time.. > I do not understand how this would be practical. Maybe using a > resaonably high powered code transmitter, but they tend to be too fast, > which clutters the returns. I do not talk about whats practical, I talk about whats possible. The idea is simple, you use the program in the broadcast as a "code" but as you dont know the correct code at the rx site you must record it and forward it. The pros ar you got an powerfull tx close to interesting sites where you cant go, the cons are the HUGE amout of processing involved. What the rx must do is to sample the incoming brodcast and store it for later correlation with the true output from the rx. It will be like a spread spectrum radar but with unknown code. Any with some knowledge should ask how this can give a good resolution, as the "chiprate" will be very low. The answare is simple, there is no chiprate in this system. A standard SS-codegenerator are a clocked system, in this system you can say the codegenerator are caotic. That is the code is random in value *and* time. But youre right, it is probably not practical. Parhaps if you had a satelite over.... > Exactly. Bi Static is not necessarily MW or OTH. (I think the > capability of bistatic to "defeat" stealth is somewhat over stated tho. > Indeed, reflective stealth leaves the "glint" somewhere_else, but from > any one somewhere else, the glint from any given target will be > momentary. It would need massive numbers of receivers and massive > integration fo their outputs to "beat" stealth. If you talk about something like radars in the SHF band and F117 I say youre right, but if you have a multi/bi-static radar in the VHF/UHF I say youre wrong. >Compressors of lift gas in air-ship, I don't KNOW, (that is, i'm not a >compressor system design engineer) but thats what i was speculating on, >about 4 para's further down: modern tanks could be light (composites?) >and compressors, lighter than anything Zeppellin dreamt of, and faster. One state of the art 20l 250bar bottle have a weight of 12kg. That is 12kg weight for 5 m3, or approx 6.5kp (or something). With a bigger bottle you get less weight and more gas. Perhaps I shall call about the 200l bottle and ask who is buying it... If I use a square relation for the weight and add a little bit that would give something like 40-50kg, with a possible lift around 65kp. This should fly. There is no problem to recompress the gas, the problem is how long time you have available. >>And for those who missed it: > Yes this (at least some of it) is SPECULATION. >There's a difference between that and "lies". I tried to label the >speculation.If the skunkworks list was limited to what people Know(tm) i >mised it in the charter.... Sorry, but I got some mail from people that think I stept over the line stating that I dont think this "thing" exist. I will like to state that someone obviously have seen something, but I dont know what and all I have written is pure speculation. >>in front of a reflector. Something like this: >> ------------------------ <- Reflector >> o o o o <-driven element >> >> o o o o <-director-parasitic >To borrow someone else's ascii art, this is effectively, a top view of the >a section of the USAF/GE arrays in Maine. Tx and Rx arrays are roughly >identical in this case. I foregot toshow the Rx array for Irda HF OTH, it consist of several loop antennas. In the figur it looks like this from above (16 loop antennas): - - - - - - - And in front: O O O O O O O The orientation of the loops is stranga as they seems rater small. If so they will have a zero-direction in front of the array. Any comment? The Tx seems to be ordinary shortened (?) dipoles, and all elements are equal so I think all are driven. Each element have three large "drums", probably aircooled coils: -------------------- <-boom ! ! ! ! <- mast - ! ! ! <-coil? To be continued - ! ! - ! ! - ! ! - ! ! - ! ! - ------------- ////////////// <- ground >There are several subarrays, each sized for a sub section of the 5-30MHz >spectrum... In the article about the russian OTH-B-HF-SW (ehh forgot something?) radars there is nothing about alternative arrays. Are there anyone with any info about the british concepts (several)? And isnt it one from Thompson? And one in Germany? There was an article if I can remember where.. >dwp Regards John (With lots of errors and much speculation) ------------------------------ From: John Erling Blad Date: Mon, 6 Dec 1993 18:48:55 +0100 Subject: Re:OTH I forgot one thing about the use of a broadcast as a Tx for a radar and the relations to spread spectrum and caos. If this shall work properly there must be an unsampled source of sound, if not the resolution will drop. There is also the narrow bandwidth of the brodcast, but this gives a longer time before you have position (or speed) fix with some accuracy compared to a system with higher bandwidth. There is the problem of recording and forwarding of the broadcast, but this can be solved with random sampling. For those unfamiliar to this, in cloced system you samples one time each clock cycle. In a random sampled system you sample, wait a random time, sample, wait a random time... One point in this is to draw from an continous distribution, otherwise youre back in good old Shannon. One problem exist which may be serious, if the atmospheric properties is not sufficient stable during the necessary time for a fix of specified accuracy you will never achieve the assumed accuracy. Even if the algorithm gives nice correlation peaks, the atmospheric turbulence have introduced a lower bound on the error. John ------------------------------ From: I am the NRA Date: Mon, 6 Dec 93 13:34:08 PST Subject: radar, missles & ECM _SCRUBBED_ Just got & verified word: the 8 Dec IEEE presentation in Bedford, NH has been POSTPONED. MAY take place in February. Or may not. If I hear, you will hear... regards dwp ------------------------------ From: Jeffrey_Lo@ccm11.sc.intel.com Date: Mon, 06 Dec 93 15:19:24 PST Subject: Re: re: Airships, balloons... > An airship, rigid, (zeppelin, akron, macon) is just a bunch of balloons > tucked in an aerodynamic cover. At lift off, the individual bags are > usually modestly underfull. As the ship rises (statically, due to > bouyant lift, or dynamically, due to aerodynamic lift, if motors > running and ship "pitched up"), the bags "fill" as the gas expands. > Typically, the bags fill around 6,000 feet. [1] This is called > "pressure height" where the gas pressure inside balances tha outside. > Rise above this and the bags burst, except.... The bags are always > fitted with pressure safety valves to keep them from bursting. BIG > VALVES. > >Would/is it possible to put a compressor on the valve and stuff the >excess gas into a can for later re-use at lower altitude? I may be wrong, but if you compressed the gas into a can as you got higher into the atmosphere where the air is thinner, you are still carrying the weight in essentially the same volume as you were, so the overall density (weight/volume) of the airship would be the same while the density of the air is going down, so I imagine you wouldn't be bouyant anymore. Jeff Lo jlo@gomez.intel.com ------------------------------ End of Skunk Works Digest V4 #83 ******************************** To subscribe to skunk-works-digest, send the command: subscribe skunk-works-digest in the body of a message to "listserv@harbor.ecn.purdue.edu". 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