| Page 1 of 2 | 1 | 2 |
|
|
HF Direction Finding
In WWII the allies were able to pinpoint the locations of German HF
transmissions very accurately. They were able to pinpoint the locations of U-boats, etc. when they transmitted. (or so I have been led to believe). What methods did they use to do this? Is it something duplicatable with Radio Amateurs in general or does it require some special type equipment? I hear lots of amateurs describing interference and other problems on HF, but no one seems to be triangulating the offending stations. I am guessing that the real secret was in their communications with the 'spotters' to triangulate the positions. Any suggestions? Thanks -- 73 for now Buck N4PGW |
"Buck" wrote in message
... In WWII the allies were able to pinpoint the locations of German HF transmissions very accurately. They were able to pinpoint the locations of U-boats, etc. when they transmitted. (or so I have been led to believe). What methods did they use to do this? Is it something duplicatable with Radio Amateurs in general or does it require some special type equipment? I hear lots of amateurs describing interference and other problems on HF, but no one seems to be triangulating the offending stations. I am guessing that the real secret was in their communications with the 'spotters' to triangulate the positions. Any suggestions? Thanks -- 73 for now Buck N4PGW Triangulating and so on, can and does work. You're talking a difference between "war" and the need to know - vs - finding an offending station - to shut it down, etc. The FCC isn't as involved as many would like to think. They can't keep up with it. For others to do so, would be nothing short of vigilante-ism. It's not worth being jailed or shot - trying to shut down an offending station. Not to mention, most signals heard over hundreds or thousands of miles away. Who really cares? Would you be willing to travel the 1000 miles to put a stop to it? Probably not. Most new people can't change a fuse - let alone triangulate. They're lucky they recall what a resistor or capacitor is or does or even looks like once they put the book down. |
On Thu, 17 Feb 2005 03:32:48 -0500, "cl" wrote:
Triangulating and so on, can and does work. You're talking a difference between "war" and the need to know - vs - finding an offending station - to shut it down, etc. The FCC isn't as involved as many would like to think. They can't keep up with it. For others to do so, would be nothing short of vigilante-ism. It's not worth being jailed or shot - trying to shut down an offending station. Not to mention, most signals heard over hundreds or thousands of miles away. Who really cares? Would you be willing to travel the 1000 miles to put a stop to it? Probably not. Most new people can't change a fuse - let alone triangulate. They're lucky they recall what a resistor or capacitor is or does or even looks like once they put the book down. I wasn't proposing that they 'shut them down' but to triangulate them. I don't know how accurate the locations were during the war, but I hear they were pretty accurate. I think you agreed with my assumption that, basically, it is a matter of amateurs not being coordinated, or more accurately from you, not in the right location. Sometimes the offending station is nothing more than a stuck keyer, but sometimes it is intentional interference. As for the competency, I hate to admit it, but sometimes what I see leads me to believe my IQ must be about 250. That isn't to offend those with high IQ's as those who have a real-life 200 IQ must be the equivalent of about 600 now. Oh well, off the soapbox. I wonder if there would be any interest in long-range fox hunts (not the QRP version.) :) -- 73 for now Buck N4PGW |
"Buck" wrote in message ... On Thu, 17 Feb 2005 03:32:48 -0500, "cl" wrote: As for the competency, I hate to admit it, but sometimes what I see leads me to believe my IQ must be about 250. That isn't to offend those with high IQ's as those who have a real-life 200 IQ must be the equivalent of about 600 now. Oh well, off the soapbox. I wonder if there would be any interest in long-range fox hunts (not the QRP version.) :) -- 73 for now Buck N4PGW Being one of the new nocode techs, I have no illusions re my overall radio technical competency. I have one slight advantage over my newbie brethren though. Having been a Jr. High shop teacher (woodwork, metalwork, drafting, and electricity) I at least have some idea where to look for info that will allow me to identify basic electronic components. Perhaps with license upgrades I'll widen my knowledge and competency base, but for now antenna building is my main DIY interest and such expertise is not yet required. Your comments on IQs is interesting. Many businesses, after laying off older workers for years, seem to be actively seeking elders again. Perhaps they've decided that it's desirable to have at least some employees that can both read and make change without a pocket calculator.(G) Harold KD5SAK |
Buck wrote:
"What methods did they use to do this?" Terman says on page 1046 of his 1955 "Electronic and Radio Engineering:: "The fact that radio waves propagate away from the transmitter alomg a great-circle route makes radio direction finding a useful navigational aid." Ships and aircraft have been equipped with shielded loop antennas for direction finding. At frequencies below 500 KHz,bearings can be read within 1%. Ionospheric reflection so scrambles polarizations at higher frequencies, that loop bearings have higher errors. An Adcock beam antenna can be made to ignore horizontally polarized waves from a certain direction and respond to only the vertically polarized waves. It suffers from very low signal pickup as compared with a loop, but gives accurate bearings at high frequencies over a distance of 100 miles where a loop would be useless. In WW-2, aircraft and ships were often equipped with radios such as the Bendix RA-1B multiband receiver and a loop antenna, or the navy `s AN//ARC-5 equipment for direction finding. Best regards, Richard harrison, KB5WZI |
Great Britain had many antenna farms located many miles apart for direction
finding. -- 73 Hank WD5JFR "Buck" wrote in message ... In WWII the allies were able to pinpoint the locations of German HF transmissions very accurately. They were able to pinpoint the locations of U-boats, etc. when they transmitted. (or so I have been led to believe). What methods did they use to do this? Is it something duplicatable with Radio Amateurs in general or does it require some special type equipment? I hear lots of amateurs describing interference and other problems on HF, but no one seems to be triangulating the offending stations. I am guessing that the real secret was in their communications with the 'spotters' to triangulate the positions. Any suggestions? Thanks -- 73 for now Buck N4PGW |
Some years ago, the local gov department (fcc to you) here in aus carried
out test on their hf df. They were able to pinpoint a station in soth australia within about 1 km or so. Impressive I thought at the time. JE "Buck" wrote in message ... In WWII the allies were able to pinpoint the locations of German HF transmissions very accurately. They were able to pinpoint the locations of U-boats, etc. when they transmitted. (or so I have been led to believe). What methods did they use to do this? Is it something duplicatable with Radio Amateurs in general or does it require some special type equipment? I hear lots of amateurs describing interference and other problems on HF, but no one seems to be triangulating the offending stations. I am guessing that the real secret was in their communications with the 'spotters' to triangulate the positions. Any suggestions? Thanks -- 73 for now Buck N4PGW |
Buck, N4PGW wrote:
"Is it something duplicable with Radio Amateurs in general or does it require some special type of equipment?" Much British success in WW-2 in eavesdropping on German transmissions had as much to do with information processing as it had to do with its interception. Germans used an "Enigma Machine" which was easily reset for a new code. They often changed the code and it was quite complicated. Germans used the machines to encode and decode their confidential messages. Early in the war, an Enigma Machine was captured. British code experts worked long, hard, and smartly to determine how the machine worked and broke its codes. Afterwards, the British were silent parties on the German`s war partyline. The British sometimes feigned ignorance so as not announce their access to Germany`s most secret information. It was a big factor in victory. Stationary direction finding can take the directional antenna arrays used for transmitting and use them for receiving insteaad. Reciprocity means that the reception pattern is identical to the transmitting pattern. I have no idea what the British did in their enemy reception stations in WW-2. For HF, they could have used Yagi-Uda`s on rotators and indicators. They also could have used crossed loops or Adcocks, feeding a goniometer and not rotated the antenna. Terman shows how this is done on page 1051 of his 1955 edition. During the "Cold War", when I worked in HF broadcasting, Radio Free Europe diligently monitored, recorded, and processed broadcasts from behinnd the "Iron Curtain". All the Communist news and commentary that was fit to broadcast from their point of view. To pick the desired transmissions from among the babble, some RFE receiving stations had the appearance of medium-wave multi-tower broadcast stations. Towers were tuned and phased to null interference and to grab the desired transmission. Other stations used sizeable loops. Some had air for a core and some had huge ferrite cores. Whatever proved best was used in any case.. Hams can surely use directional antenna systems. Best regards, Richard Harrison, KB5WZI |
In message , Richard
Harrison writes Buck, N4PGW wrote: "Is it something duplicable with Radio Amateurs in general or does it require some special type of equipment?" Much British success in WW-2 in eavesdropping on German transmissions had as much to do with information processing as it had to do with its interception. snip Stationary direction finding can take the directional antenna arrays used for transmitting and use them for receiving insteaad. Reciprocity means that the reception pattern is identical to the transmitting pattern. I have no idea what the British did in their enemy reception stations in WW-2. For HF, they could have used Yagi-Uda`s on rotators and indicators. Too broad a beam. Loop zeros are sharper. They also could have used crossed loops or Adcocks, feeding a goniometer and not rotated the antenna. Correct. U-boats used HF for reporting back to base in Lorrient, but MF for talk among themselves in the Wolfpack. It was this that was DFed by the shipborne CRT DF. Mike |
Brings back scenes from old WWII movies where the Germans were closing in on
an Allied spy, with a suitcase radio set, sending from an upstairs flat, in the dark of night. Vans crawling along with loop antennas on the roof, and guys inside with comm gear and headphones telling the driver where to go, etc. Wonder if loop antennas were what they really used, and how good they were? The spies generally used cw. How do you get a fix on the short dots and dashes? |
Buck:
Aegean Park Press has reprinted Navy OPNAV 20 - 26 under the title "Direction Finding". It is a summary of what was done and how as of 1947. Pretty complete summary of WW2 techniques. Aegean has a web site for descriptions and sales. Note the spelling. -- Crazy George the ATTGlobal.net is a SPAM trap. Use the att dot biz account. "Buck" wrote in message ... In WWII the allies were able to pinpoint the locations of German HF transmissions very accurately. They were able to pinpoint the locations of U-boats, etc. when they transmitted. (or so I have been led to believe). What methods did they use to do this? Is it something duplicatable with Radio Amateurs in general or does it require some special type equipment? I hear lots of amateurs describing interference and other problems on HF, but no one seems to be triangulating the offending stations. I am guessing that the real secret was in their communications with the 'spotters' to triangulate the positions. Any suggestions? Thanks -- 73 for now Buck N4PGW |
RB wrote:
Brings back scenes from old WWII movies.... Small loops are still used and seem to be very effective for DF. I think that the ARRL antenna book provides information in this direction. One system I saw used a short ferrite dipole array. In most cases, DF sets displayed their goniometer outputs on a CRT or as signal strength on a meter. In this case, the dots and dashes melded into a continous output because of the persistence of the CRT or the AGC delay of the receiver. The first DF equipment I used on the ships was WWII vintage and very effective on any type of signal. Irv VE6BP -- -------------------------------------- Diagnosed Type II Diabetes March 5 2001 Beating it with diet and exercise! 297/215/210 (to be revised lower) 58"/43"(!)/44" (already lower too!) -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/index.html Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada |
On Thu, 17 Feb 2005 23:32:36 +0000, "M. J. Powell"
wrote: U-boats used HF for reporting back to base in Lorrient, but MF for talk among themselves in the Wolfpack. It was this that was DFed by the shipborne CRT DF. By 'this', I assume you mean MF? Thanks -- 73 for now Buck N4PGW |
"RB" ) writes: Wonder if loop antennas were what they really used, and how good they were? The spies generally used cw. How do you get a fix on the short dots and dashes? With AGC turned off, just listen for the null in the signal as the loop is rotated. |
Intellgence agencies when they did HFDF used huge antenna arrays
called CDAAs (Circular Disposed Antenna Arrays). They were also known as Wollenwebbers (presumably after an inventor). These arrays were often very large, and sometimes were affectionally known as "elephant cages." The diameter of these arrays could be as small as 50-60 feet for a tactical unit to several hundred feet for large fixed sites in a secure area. Each circle had many vertical elements. They measured time difference of arrival by measuring the wavefront timing on each antenna in the array as the wave passed through the array. A computer then collated this information to calculate a bearing. The readouts varied depending upon the era. Some were digital, some were on an oscillicsope. I'm not quite sure how the really early ones worked (before my time). The results of several stations were then combined to get a "fix." Contrary to popular belief, their accuracy had significant error factors so despite many requests from military commanders who wanted to drop ordinance on a target, you really couldn't do that based solely on HFDF. HFDF was really originally intended for open ocean surveillance against things like German subs in both WW I and WW II. You could get a rough idea where a signal was coming from and then you would have to sent a destroyer or aircraft to actually locate the sub. There are other types of HFDF antennas as well, but none can give pin point accuracy unless you are mobile and close in as in transmitter hunts. As long at there was energy, you could get a bearing be it a sustained carrier or a single dit. You would have to rely on other externals (callsigns, radio finger printing etc) to figure out who was sending a given signal. W3JT On 18 Feb 2005 06:29:34 GMT, (Martin Potter) wrote: "RB" ) writes: Wonder if loop antennas were what they really used, and how good they were? The spies generally used cw. How do you get a fix on the short dots and dashes? With AGC turned off, just listen for the null in the signal as the loop is rotated. |
In message , RB
writes Brings back scenes from old WWII movies where the Germans were closing in on an Allied spy, with a suitcase radio set, sending from an upstairs flat, in the dark of night. Vans crawling along with loop antennas on the roof, and guys inside with comm gear and headphones telling the driver where to go, etc. Wonder if loop antennas were what they really used, and how good they were? They were simple and with a good null. Only with arrays will you get a better null. The spies generally used cw. How do you get a fix on the short dots and dashes? Just swing the loop for minimum signal. Mike |
In message , Irv Finkleman
writes RB wrote: Brings back scenes from old WWII movies.... Small loops are still used and seem to be very effective for DF. I think that the ARRL antenna book provides information in this direction. One system I saw used a short ferrite dipole array. In most cases, DF sets displayed their goniometer outputs on a CRT or as signal strength on a meter. In this case, the dots and dashes melded into a continous output because of the persistence of the CRT or the AGC delay of the receiver. I don't think there was a swinging goniometer with the CRT DF set. The output of the two loop aerials fed the X and Y plates respectively so that the trace appeared at the right angle and the bearing was read from the screen. Mike |
In message , Buck
writes On Thu, 17 Feb 2005 23:32:36 +0000, "M. J. Powell" wrote: U-boats used HF for reporting back to base in Lorrient, but MF for talk among themselves in the Wolfpack. It was this that was DFed by the shipborne CRT DF. By 'this', I assume you mean MF? Sorry for vagueness. Yes, they used the lower frequencies for short ranges, probably because the LF didn't travel far. (But far enough for the RN) Mike |
"M. J. Powell" wrote:
In message , Irv Finkleman writes RB wrote: Brings back scenes from old WWII movies.... Small loops are still used and seem to be very effective for DF. I think that the ARRL antenna book provides information in this direction. One system I saw used a short ferrite dipole array. In most cases, DF sets displayed their goniometer outputs on a CRT or as signal strength on a meter. In this case, the dots and dashes melded into a continous output because of the persistence of the CRT or the AGC delay of the receiver. I don't think there was a swinging goniometer with the CRT DF set. The output of the two loop aerials fed the X and Y plates respectively so that the trace appeared at the right angle and the bearing was read from the screen. Mike There were a number of different types of DF sets. Some, as you point out had x and y plates connected to the loops, another had a mechanically rotating gonio. We had one for radar detection which used horns with crystal detectors in it which went to x and y plates (through amps). The HFDF used loops feeding a mechanically rotating gonio with output to a crt. Irv -- -------------------------------------- Diagnosed Type II Diabetes March 5 2001 Beating it with diet and exercise! 297/215/210 (to be revised lower) 58"/43"(!)/44" (already lower too!) -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/index.html Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada |
All about DF, sense antennas, nulls, etc
http://www.avweb.com/news/avionics/183233-1.html Side note -- A WWII B-24 bomber (Lady Be Good) ran out of fuel because they were not sure of the DF readings --that is -- if they were going toward or away from the home station. Crashed in the Libyan desert -- all of the crew perished after walking as far as 85 miles in the desert. See URL: http://www.qmfound.com/lady_be_good_...r_recovery.htm ---------------------------------- On our Navy planes in the 50's we had two ARN-6 - ADF (Direction Finders), 100-1750 KHz In conjunction with Loran -- we usually knew where we were. (;-) But also the Navigator would take periodic sextant readings (weather permitting) thru a bubble on top of the aircraft No GPS in those days.(;-( On one of the squadrons flights -- a circuit breaker blew and refused to be reset -- avionics were off -- the crew flew dead reckoning most of the rest of the flight. -- Caveat Lector (Reader Beware) Help The New Hams Someone Helped You Or did You Forget That ? "Irv Finkleman" wrote in message ... "M. J. Powell" wrote: In message , Irv Finkleman writes RB wrote: Brings back scenes from old WWII movies.... Small loops are still used and seem to be very effective for DF. I think that the ARRL antenna book provides information in this direction. One system I saw used a short ferrite dipole array. In most cases, DF sets displayed their goniometer outputs on a CRT or as signal strength on a meter. In this case, the dots and dashes melded into a continous output because of the persistence of the CRT or the AGC delay of the receiver. I don't think there was a swinging goniometer with the CRT DF set. The output of the two loop aerials fed the X and Y plates respectively so that the trace appeared at the right angle and the bearing was read from the screen. Mike There were a number of different types of DF sets. Some, as you point out had x and y plates connected to the loops, another had a mechanically rotating gonio. We had one for radar detection which used horns with crystal detectors in it which went to x and y plates (through amps). The HFDF used loops feeding a mechanically rotating gonio with output to a crt. Irv -- -------------------------------------- Diagnosed Type II Diabetes March 5 2001 Beating it with diet and exercise! 297/215/210 (to be revised lower) 58"/43"(!)/44" (already lower too!) -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/index.html Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada |
In message , Irv Finkleman
writes "M. J. Powell" wrote: In message , Irv Finkleman writes RB wrote: Brings back scenes from old WWII movies.... Small loops are still used and seem to be very effective for DF. I think that the ARRL antenna book provides information in this direction. One system I saw used a short ferrite dipole array. In most cases, DF sets displayed their goniometer outputs on a CRT or as signal strength on a meter. In this case, the dots and dashes melded into a continous output because of the persistence of the CRT or the AGC delay of the receiver. I don't think there was a swinging goniometer with the CRT DF set. The output of the two loop aerials fed the X and Y plates respectively so that the trace appeared at the right angle and the bearing was read from the screen. Mike There were a number of different types of DF sets. Some, as you point out had x and y plates connected to the loops, another had a mechanically rotating gonio. We had one for radar detection which used horns with crystal detectors in it which went to x and y plates (through amps). That's interesting. I didn't know of microwave DFing. The HFDF used loops feeding a mechanically rotating gonio with output to a crt. Ah! Right. Now I've got it. Thanks. Mike |
Interestingly, aircraft used small loop type antennas for MF/HF DF in the
40s and 50s. Just turn loop for a null, and (maybe) use an omni sense antenna. Two spaced reception stations give a reasonable fix for a ground system. JE "John Edwards" wrote in message ... Some years ago, the local gov department (fcc to you) here in aus carried out test on their hf df. They were able to pinpoint a station in soth australia within about 1 km or so. Impressive I thought at the time. JE "Buck" wrote in message ... In WWII the allies were able to pinpoint the locations of German HF transmissions very accurately. They were able to pinpoint the locations of U-boats, etc. when they transmitted. (or so I have been led to believe). What methods did they use to do this? Is it something duplicatable with Radio Amateurs in general or does it require some special type equipment? I hear lots of amateurs describing interference and other problems on HF, but no one seems to be triangulating the offending stations. I am guessing that the real secret was in their communications with the 'spotters' to triangulate the positions. Any suggestions? Thanks -- 73 for now Buck N4PGW |
I hear lots of amateurs describing interference and other problems on HF, but no one seems to be triangulating the offending stations. I am guessing that the real secret was in their communications with the 'spotters' to triangulate the positions. Adcock arrays http://www.airwaysmuseum.com/HF%20CR%20DF%201.htm http://members.aol.com/BmgEngInc/Adcock.html worked quite well, but they require precision in construction, as well as the site. For VHF/UHF, there are all sorts of things available :) N0MKJ and I used to hunt with the "fox-copter", featured in the 3/94 73 magazine. Here's some references in 73 magazine: http://www.pejla.se/ardf_litteratur.htm And a bunch of links to play with: http://www.dxzone.com/catalog/Operat...ction_Finding/ |
Wullenweber: German for wool weaver. Germans had several in WW2, none existed elsewhere. Sites were stripped and
burned and the big iron goniometers buried during the closing days of the war. Took quite a bit of effort by ONR and OSS to retrieve enough material to reconstruct the concept. And a lot of work at U of Ill. and ITT/FTR to make one work. Beamformers, not TOA. That came a lot later. The initial question was set in the WW2 time period, I believe. Crazy George the ATTGlobal.net extension is a SPAM trap. Use att dot biz instead. |
One night in 1944, there were a thousand Lancaster killing machines and
other RAF bombers over Germany, complete with aircrews who well knew what they were about. It was a moonless and cloud-overcast night over the whole of Western Europe. Targets were civilian firestorm-raids on German towns and cities. Navigation was via GEE equipment, a British hyperbolic, pulse-radar, VHF, 1942 invention which later, as the LF and VLF versions, was given the American name of LORAN (who copied it in the same size boxes.) With GEE it was possible to accurately navigate several hundred miles from base and return safely even with fog over the airfield. Aircrews had become to depend on it and had neglected, forgotten how to use, other means of navigation such as dead-reckoning and the magnetic compass. From shot-down and crashed aircraft the Germans had discovered the frequencies used by GEE receivers and fathomed-out how the equipment worked. But instead of using jammers immediately as they came out of the factories they waited until there was an appreciable quantity of them, waited until navigation conditions were difficult, no moon or stars, dispersed the jammers around Europe, waited until there were a 1000 bombers in the air, and then switched them all on simultaneously. German radar-controlled anti-aircraft guns were always accurate. They were used in clear skies in daylight, sometimes in preference to optical instruments and range finders. Hundreds of bombers, lost, wandering about Europe were better than usual targets. More than 100 heavy bombers failed to return to base. Some crash-landed, running out of fuel in Sweden, Poland, central Europe, northern Italy, France, even in north Africa. Others came down in the north sea. It was the geatest disaster in one night ever incurred by the RAF. Although heavy losses and damage to aircraft was a normal event, the loss of more than 100 trained aircrews was a catastrophy. Incidentally, during the whole war 40,000 aircrew lives were lost due to enemy action and another 30,000 were lost due to flying accidents of one sort and another. But, as usual, Uncle Sam helped us out. GI's left behind 70,000 unmarried mothers in the UK. I just love statistics! ;o) ---- Reg. |
Caveat Lector wrote:
All about DF, sense antennas, nulls, etc http://www.avweb.com/news/avionics/183233-1.html Side note -- A WWII B-24 bomber (Lady Be Good) ran out of fuel because they were not sure of the DF readings --that is -- if they were going toward or away from the home station. Crashed in the Libyan desert -- all of the crew perished after walking as far as 85 miles in the desert. On DF antennas sense was always something to be taken with a grain of salt. It was quite easy to have a reading 180 degrees out. We always had to consider other factors about the targets such as where the coast was, or where the last reported position of the target was. I spent most of my time in the navy as an operator, then supervisor technician ('57 - '83) with shipborne electronic warfare. After commissioning I was Operations Officer at two Canadian stations who were part of the USN based Bullseye HFDF system (Wullenweber Antennae), and then as Operations Officer at CFS Alert, a small sigint/comint station at the northern tip of Ellesmere Island (300 miles north of Thule). Brrrr. I went from pre-WW2 DF equipment (Canadian Navy was always a little slow in updating), to the latest state of the art -- or at least it was in 1983 when I left. It was a most interesting career. It still is, for the guys who are still in it. You might find some good information and links on my Oldtimers Website listed below. Irv VE6BP -- -------------------------------------- Diagnosed Type II Diabetes March 5 2001 Beating it with diet and exercise! 297/215/210 (to be revised lower) 58"/43"(!)/44" (already lower too!) -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/index.html Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada |
And your problem is?
Being of German descent with relatives in Germany, I feel that the German people got what they deserved. Actions by the Luftwaffe were just as horrific in London, Warsaw, Stalingrad and Antwerp to name a few. The Luftwafe had similar devices to locate their targets in England with the same results when their systems were captured by British Military Intelligence (what an oxymoron). BTW the Lancaster was one of the finest aircraft of it's type ever. Dave WD9BDZ Reg Edwards wrote: One night in 1944, there were a thousand Lancaster killing machines and other RAF bombers over Germany, complete with aircrews who well knew what they were about. It was a moonless and cloud-overcast night over the whole of Western Europe. Targets were civilian firestorm-raids on German towns and cities. Navigation was via GEE equipment, a British hyperbolic, pulse-radar, VHF, 1942 invention which later, as the LF and VLF versions, was given the American name of LORAN (who copied it in the same size boxes.) With GEE it was possible to accurately navigate several hundred miles from base and return safely even with fog over the airfield. Aircrews had become to depend on it and had neglected, forgotten how to use, other means of navigation such as dead-reckoning and the magnetic compass. From shot-down and crashed aircraft the Germans had discovered the frequencies used by GEE receivers and fathomed-out how the equipment worked. But instead of using jammers immediately as they came out of the factories they waited until there was an appreciable quantity of them, waited until navigation conditions were difficult, no moon or stars, dispersed the jammers around Europe, waited until there were a 1000 bombers in the air, and then switched them all on simultaneously. German radar-controlled anti-aircraft guns were always accurate. They were used in clear skies in daylight, sometimes in preference to optical instruments and range finders. Hundreds of bombers, lost, wandering about Europe were better than usual targets. More than 100 heavy bombers failed to return to base. Some crash-landed, running out of fuel in Sweden, Poland, central Europe, northern Italy, France, even in north Africa. Others came down in the north sea. It was the geatest disaster in one night ever incurred by the RAF. Although heavy losses and damage to aircraft was a normal event, the loss of more than 100 trained aircrews was a catastrophy. Incidentally, during the whole war 40,000 aircrew lives were lost due to enemy action and another 30,000 were lost due to flying accidents of one sort and another. But, as usual, Uncle Sam helped us out. GI's left behind 70,000 unmarried mothers in the UK. I just love statistics! ;o) ---- Reg. |
On Fri, 18 Feb 2005 18:55:07 -0500, "Dave VanHorn"
wrote: I hear lots of amateurs describing interference and other problems on HF, but no one seems to be triangulating the offending stations. I am guessing that the real secret was in their communications with the 'spotters' to triangulate the positions. Adcock arrays http://www.airwaysmuseum.com/HF%20CR%20DF%201.htm http://members.aol.com/BmgEngInc/Adcock.html worked quite well, but they require precision in construction, as well as the site. For VHF/UHF, there are all sorts of things available :) N0MKJ and I used to hunt with the "fox-copter", featured in the 3/94 73 magazine. Here's some references in 73 magazine: http://www.pejla.se/ardf_litteratur.htm And a bunch of links to play with: http://www.dxzone.com/catalog/Operat...ction_Finding/ Thank you, I bookmarked the DF antenna and am reading the other articles. -- 73 for now Buck N4PGW |
In message , David G. Nagel
writes And your problem is? Being of German descent with relatives in Germany, I feel that the German people got what they deserved. Actions by the Luftwaffe were just as horrific in London, Warsaw, Stalingrad and Antwerp to name a few. The Luftwafe had similar devices to locate their targets in England with the same results when their systems were captured by British Military Intelligence (what an oxymoron). Do you consider Prof. R.V. Jones to be an oxymoron? Or any other kind of moron? Mike |
M. J. Powell wrote:
In message , David G. Nagel writes And your problem is? Being of German descent with relatives in Germany, I feel that the German people got what they deserved. Actions by the Luftwaffe were just as horrific in London, Warsaw, Stalingrad and Antwerp to name a few. The Luftwafe had similar devices to locate their targets in England with the same results when their systems were captured by British Military Intelligence (what an oxymoron). Do you consider Prof. R.V. Jones to be an oxymoron? Or any other kind of moron? Mike Individuals are always the exception... Dave |
Do you consider Prof. R.V. Jones to be an oxymoron? Or any other
kind of moron? Mike I wonder if he understands what "oxymoron" means. Ron |
Caveat Lector wrote:
"A WWII B-24 bomber (Lady Be Good) ran out of fuel because they were not sure of the DF readings." Too bad they ran out of gas and drash landed in the Libyan desert. The B-24 must have been covered with sand for most of the time because there was still most of it intact to be found. On April 4, 1943, the Lady Be Good radioed for a directional reading from the high frequency direction finding station at Bernina as the earth was covered with clouds and there were strong winds causing navigational errors. They needed a position fix. I had breakfast this morning with a WW-2 B-24 pilot who flew in the same area. He said that requests for position fixes were often answered by Germans pretending to be the direction finding facility, and they would intentionally lead the questioners astray. Best regards, Richard Harrison, KB5WZI |
"Richard Harrison" wrote in message ... Caveat Lector wrote: "A WWII B-24 bomber (Lady Be Good) ran out of fuel because they were not sure of the DF readings." Too bad they ran out of gas and drash landed in the Libyan desert. The B-24 must have been covered with sand for most of the time because there was still most of it intact to be found. On April 4, 1943, the Lady Be Good radioed for a directional reading from the high frequency direction finding station at Bernina as the earth was covered with clouds and there were strong winds causing navigational errors. They needed a position fix. I had breakfast this morning with a WW-2 B-24 pilot who flew in the same area. He said that requests for position fixes were often answered by Germans pretending to be the direction finding facility, and they would intentionally lead the questioners astray. Best regards, Richard Harrison, KB5WZI Interesting -- code operators could tell one operator from another just by their style or fist. Wonder if CW was used for the request and reply ??? -- Caveat Lector (Reader Beware) Help The New Hams Someone Helped You Or did You Forget That ? |
In message , David G. Nagel
writes M. J. Powell wrote: In message , David G. Nagel writes And your problem is? Being of German descent with relatives in Germany, I feel that the German people got what they deserved. Actions by the Luftwaffe were just as horrific in London, Warsaw, Stalingrad and Antwerp to name a few. The Luftwafe had similar devices to locate their targets in England with the same results when their systems were captured by British Military Intelligence (what an oxymoron). Do you consider Prof. R.V. Jones to be an oxymoron? Or any other kind of moron? Mike Individuals are always the exception... He had plenty of good companions. Blumlein for one. Who paid the price. Mike |
In message , J. Teske
writes Intellgence agencies when they did HFDF used huge antenna arrays called CDAAs (Circular Disposed Antenna Arrays). They were also known as Wollenwebbers (presumably after an inventor). Is 'Wollenwebber' really 'Wollenweber', which I reckon could be translated as 'wool weaver'? Possibly a graphic description of the antennas. Ian. -- |
In message , Crazy George
writes Wullenweber: German for wool weaver. Germans had several in WW2, none existed elsewhere. Sites were stripped and burned and the big iron goniometers buried during the closing days of the war. Took quite a bit of effort by ONR and OSS to retrieve enough material to reconstruct the concept. And a lot of work at U of Ill. and ITT/FTR to make one work. Beamformers, not TOA. That came a lot later. The initial question was set in the WW2 time period, I believe. Crazy George the ATTGlobal.net extension is a SPAM trap. Use att dot biz instead. -- |
In message , Crazy George
writes Wullenweber: German for wool weaver. Germans had several in WW2, none existed elsewhere. Sites were stripped and burned and the big iron goniometers buried during the closing days of the war. Took quite a bit of effort by ONR and OSS to retrieve enough material to reconstruct the concept. And a lot of work at U of Ill. and ITT/FTR to make one work. Beamformers, not TOA. That came a lot later. The initial question was set in the WW2 time period, I believe. Crazy George the ATTGlobal.net extension is a SPAM trap. Use att dot biz instead. Ah, Crazy, you got in first! Ian. -- |
On Fri, 18 Feb 2005 18:21:07 -0600, "Crazy George"
wrote: The initial question was set in the WW2 time period, I believe. I started the topic. It was set in WW2 because I see so much about RDF at that time. i realize it has to have improved by now but the heart of the question is 'since it was possible to be accurate then, why can't hams accurately do it today?' I am thoroughly enjoying this thread. Thank you to ALL that have replied. Buck N4PGW -- 73 for now Buck N4PGW |
On Sun, 20 Feb 2005 10:18:25 -0500, Buck wrote:
On Fri, 18 Feb 2005 18:21:07 -0600, "Crazy George" wrote: The initial question was set in the WW2 time period, I believe. I started the topic. It was set in WW2 because I see so much about RDF at that time. i realize it has to have improved by now but the heart of the question is 'since it was possible to be accurate then, why can't hams accurately do it today?' I am thoroughly enjoying this thread. There is really two types of DF. Long haul and close in. The close in type which generally uses some sort of null loop from a mobile platform (such as a car or on foot) is what is generally used in "fox hunting" types of transmitter hunts by hams and other hobbists. By extension, the military also use some of this close in technique from tactical aircraft although the technology is different. Long haul, such as was employed in WW II for sub hunting in the Atlantic was done from fixed shore facilities for the most part which exchanged their lines of bearings via a dedicated secure network. Close in DF is accurate only in the sense that the hunter can usually move in close to the target to the point that they can actually see the antenna. Long Haul DF cannot pinpoint a target. Long haul DF stations have known error tolerances and so-call "fixes" are stated with circular or elliptical errors of probabilities. So one might DF a transmitter operating in the Atlantic from shore stations around the perimeter of the Atlantic. The fix will be stated with some degree of tolerance such as there is a 90% chance the target is within an ellipse 100 miles long and 50 miles wide and a 10% chance it is within a 15 by 5 miles area within that larger circle. This is of course still many hundreds or even thousands of sqare miles to hunt for a target. I do not know what technology the Allies used during WW II for their HFDF or what sort of accuracy they achieved. In a WW II scenario, it would be an important intelligence fact if one could discern if a target was near Bermuda or if it was near the Azores. Then a destroyer or subchaser or small carrier with aircraft would have to be dispatched to try to find it if it were on the surface. Allied sub hunting was successful because German doctrine called for frequent situation reports from submarines to shore commands in France and Germany. US submarine operations in the Pacific were more successful in a defensive perspective since they usually operated with a doctrine of radio silence and only rarely sent messages to shore station or to each other. It must be remembered that WW II era subs generally operated on the surface and submerged mostly for attack or self protection. The German sub commanders were in essence victims of Doenitz' tendency to micromanage and they sustained casualty rates of 70% or greater. US sub forces by comparison had casualty rates of 15% which was still among the highest among US forces. Germany had roughly four or five times as many submarines as did the US. [Folks unfamiliar with WW II history must also note that the US had almost no sub forces in the Atlantic since Germany had only a very small surface Navy and almost no coastal or open ocean shipping. A sub of that era was a poor platform to wage war against another submarine. Japan, being an island, was dependant upon ocean shipping for supplies and so was more of a natural target for anti-shipping submarine operations. US subs of course also attacked combatants, but many of those combatants were escorts for shipping convoys. Virtually all US submarines operated in the Pacific Theater. The Brits did have some submarine operations in the Atlantic.] Jon W3JT Thank you to ALL that have replied. Buck N4PGW |
Jon, W3JT wrote:
"Folks unfamiliar with WW II history must also note that the US had almost no sub forces in the Atlantic since Germany had only a very small surface Navy amd no coastal or open shipping." The emphasis should be on the "almost"! Germamy began the war with 3 formidable "pocket battleships" as I recall. There were American submarines in the Atlantic. Headquarters are at New London, CT. My brother was a WW-2 U.S. Navy submarine officer. His boat was stationed in the Atlantic operating from the U.S. Virgin Islands. He managed a leave home by snagging rides on Catalina flying boats conducting anti-submarine patrols in the Atlantic. He observed real anti-submarine actions while a passenger aboard the Catalinas. My brother was assigned to a new ship from its keel laying. He took it through the Panama Canal to the Pacific where after several missions it became a craft on permanent patrol as the result of enemy action with no known surviors. His family misses him. Best regards, Richard Harrison, KB5WZI |
| All times are GMT +1. The time now is 06:15 PM. |
|
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
RadioBanter.com