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#1
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WWII Direction Finder Fix
Hello All:
I believe there was a posting here or maybe even in QST that talked about problems with Radio Direction Finders in aircraft and ships before WWII time frame. And the fix to repair them so that the Radio Direction Finders (RDF) did not point 180 degree's the wrong direction. I am researching information on the WWII Aviation Rescue Boats, (AVR's) 83 and 104 Ft long, Boats used by the US Army during WWII. I spent 5 years on a 104 AVR Boat, converted into a Commercial Fishing Boat for Albacore Tuna from 1966 to 1970 as a teen ager. Any information would be greatly appreciated. Thanks. Here's a link that shows some of the AVR Boats and spec's. http://www.warboats.org/crashboat.htm Jay |
#2
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WWII Direction Finder Fix
On Tue, 28 Oct 2008 08:18:33 -0700, Jay in the Mojave
wrote: I believe there was a posting here or maybe even in QST that talked about problems with Radio Direction Finders in aircraft and ships before WWII time frame. And the fix to repair them so that the Radio Direction Finders (RDF) did not point 180 degree's the wrong direction. Which one? http://www.angelfire.com/space/proto57/rdf.html Search Google for "sense antenna". This is a 2nd antenna that is used in conjunction with a loop or Adcock type antenna to skew the pattern on one direction, thus eliminating the 180 degree ambiguity. http://books.google.com/books?id=RfzF2-fHJ6MC&pg=PA237&lpg=PA237&dq=df+sense+antenna&sour ce=web&ots=OrVQdNKmQ-&sig=lF5RRtEjOoyQ22OPvMEFx3Ljrzg&hl=en&sa=X&oi=boo k_result&resnum=3&ct=result http://books.google.com/books?id=f3asJreno0YC&pg=PA446&lpg=PA446&dq=rdf+lo op+sense+antenna&source=bl&ots=068u54gGNR&sig=3R4X kY8aRiOWMv_cWhCRU94s0JQ&hl=en&sa=X&oi=book_result& resnum=1&ct=result#PPA447,M1 Incidentally, much of the pre-WWII DF work was done from fixed direction finding stations. A pilot would request location info via HF radio. Several ground stations would do their best to deliver a bearing using various types of antennas, with which the pilot would use to calculate an intersecting position. Gross and inefficient would be a nice term. Somewhat later, the "homer" was introduced. This was two wing mounted forward facing directional antennas. The receiver would rapidly switch between the two antennas. When the signal level from both antennas was identical, the transmitter direction was dead ahead. This worked fairly well, but did create problems for airline passengers as the pilot flew donuts trying to get a brearing. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#3
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WWII Direction Finder Fix
Jeff wrote:
"Somewhat later, the "homer" was introduced." The last topic in Terman`s 1955 opus is "Radio Direction Finding". On page 1048 Terman writes: "This behavior (simulated sense antenna) causes a signal to be delivered to the receiver even though the loop ts in the position for zero response;" I have a friend, N5CPA, who was a B-24 bomber pilot flying out of Italy to bomb Austria and Germany as WW-2 was ending. They had a direction finding station in North Africa to advise them of their positions when needed. Problem was, Germans often answered first with wrong location and direction in impeccable American English so Americans might exhaust their fuel. Walter Maxwell worked for the FCC at war`s end in Hawaii and equipped himself with an Adcock antenna so he could advise lost American aviators of their positions in the Pacific. I think Walter has published his story in a radio magazine. Best regards, Richard Harrison, KB5WZI |
#5
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WWII Direction Finder Fix
I hate to be a nit-picker, but my article was in the Jan 2007 issue of QST, not
2002. In addition, there were nine Adcocks in Hawaii, and at least 50 on the Mainland DURING WW2, not just me. The article is not on my web page, as indicated below, but for those who don't have the above issue of QST, let me know and I'll send you a copy. Walt, W2DU Walter Maxwell worked for the FCC at war`s end in Hawaii and equipped himself with an Adcock antenna so he could advise lost American aviators of their positions in the Pacific. I think Walter has published his story in a radio magazine. Yep. Walter Maxwell (W2DU) emailed me a copy of his article from the Jan 2002 issue of QST. Very interesting and well worth reading. I don't consider it good form to resend what looks like copyrighted material, so you'll have to either get your copy from the author or from the ARRL archives: http://www.w2du.com Best regards, Richard Harrison, KB5WZI -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#6
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WWII Direction Finder Fix
Hello All:
Thank you very kindly for all the great info and e-mails. It is greatly appreciated. Jay in the Mojave |
#7
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WWII Direction Finder Fix
Walt,
I had not heard of these Adcock antennas and am interested on the time of their deployment to Europe. By chance, do you know when that happened? My uncle was Robert LaMotte, radio operator of the ill-fated B-24 bomber "Lady Be Good" that was lost in a bombing run over Italy in 1943 and believed to have ditched in the Med. The ship and crew were found 16 years later in the Libyan desert, victims of a "read from the back of the loop" tragedy. They abandoned ship when running out of fuel, believing they were over water but had overflown their airstrip and in fact were over the desert. (Google "lady be good" for lots of links) The family has always followed any news about these types of mishaps, and I am curious to know how soon after my uncle's loss any technology might have appeared to prevent the accident. Thanks in advance for your response, -larry K8UT "Walter Maxwell" wrote in message ... I hate to be a nit-picker, but my article was in the Jan 2007 issue of QST, not 2002. In addition, there were nine Adcocks in Hawaii, and at least 50 on the Mainland DURING WW2, not just me. The article is not on my web page, as indicated below, but for those who don't have the above issue of QST, let me know and I'll send you a copy. Walt, W2DU Walter Maxwell worked for the FCC at war`s end in Hawaii and equipped himself with an Adcock antenna so he could advise lost American aviators of their positions in the Pacific. I think Walter has published his story in a radio magazine. Yep. Walter Maxwell (W2DU) emailed me a copy of his article from the Jan 2002 issue of QST. Very interesting and well worth reading. I don't consider it good form to resend what looks like copyrighted material, so you'll have to either get your copy from the author or from the ARRL archives: http://www.w2du.com Best regards, Richard Harrison, KB5WZI -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#8
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WWII Direction Finder Fix
-- ------------------------------------------------------ Antonio Vernucci, I0JX US call: K0JX Beacons: 50.004 MHz & 70.088 MHz Home page: http://www.qsl.net/i0jx e-mail: k0jx {at} amsat {dot} org ------------------------------------------------------ "Jay in the Mojave" ha scritto nel messaggio umnetworking... Hello All: I believe there was a posting here or maybe even in QST that talked about problems with Radio Direction Finders in aircraft and ships before WWII time frame. And the fix to repair them so that the Radio Direction Finders (RDF) did not point 180 degree's the wrong direction. I am researching information on the WWII Aviation Rescue Boats, (AVR's) 83 and 104 Ft long, Boats used by the US Army during WWII. I spent 5 years on a 104 AVR Boat, converted into a Commercial Fishing Boat for Albacore Tuna from 1966 to 1970 as a teen ager. Any information would be greatly appreciated. Thanks. Here's a link that shows some of the AVR Boats and spec's. http://www.warboats.org/crashboat.htm Jay |
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