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WWII HF communications reliability question

Discussion in 'Ham Radio Discussions' started by K9KQX, Oct 15, 2020.

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  1. N3HGB

    N3HGB Ham Member QRZ Page

    Here is something I have no idea of:
    Was there some informal separation of Allied and Axis traffic? Did they spend a lot of time trying to QRM each other? I have read a lot of pilot's memoirs of the era and neither German nor Allied pilots seem to recount much in the way of being jammed by the other guys.
     
    PU2OZT likes this.
  2. G8ADD

    G8ADD Ham Member QRZ Page

    During the North African campaign, I've been told by a veteran, the German and British tank radios used the same frequencies, causing a lot of QRM and attempted spoofing. The British troops got around this by using phonetics that apparently didn't make sense, such as A for 'orses, D for Kate, F for vescence and so on.

    During the night bombing campaign special aircraft were sent out to interfere with and confuse the German night fighter control system, the "Kammhuber Line" of radar "boxes" within which a night fighter was directed onto a target from ground control.
     
    WA1GXC likes this.
  3. WA1GXC

    WA1GXC Ham Member QRZ Page



    Lots of electronic counter-measures history, much of it no longer secret but not well-researched or generally available on widely-disseminated
    public spaces like "Wackypedia".

    Just checked the WorldWide Intertube--No mention whatsoever in generalist entries for WW II electronic warfare from station below:

    USAAF 8th Air Force had very secret "lodger" unit at RAF Oulton, Norfolk, a bit north of Norwich.
    Beat-up B-17s packed with radar jamming equipment, blanketing known frequency spreads for German 'Freia' and 'Wurzburg'
    long-range warning radar.

    Noise-generating tube and amplifier to put out jamming noise at VHF then low-UHF as technology became more advanced.
    Starting with AN/APT-1 Dina, APT-2 Carpet, APT-3 Mandrel, APT-5 Carpet IV. I have a APT-1, -2, -5 sitting on shelves at home.
    By today's standards, put out pathetically low power, I suspect they weren't very effective.



    One of the reasons all adversaries demanded rigid adherence to radio-circuit discipline and clean manual CW is that intercept
    operators and traffic analysis efforts were often tipped-off to station location, unit identification, and code-breaking cracks by identifying
    individual operators' 'fists' and procedural quirks. The German Kriegsmarine U-Boat "Enigma" code-breaking was facilitated by a sloppy and lazy German
    code-clerk enciphering "TOMMIX TOMMIX", his favorite American Western cinema serial-star, as the message cipher-discriminant
    setting day after day, instead of changing it daily as procedure required.



    By the way, long-range BC-375 "Liason" transmitter, standard installation
    on B-17, B-24, and early B-29 airplanes was a mess. Look thru any CQ Magazine or
    E & E "Surplus Conversion Handbook" from the 1950's and it will tell you essentially,
    "This thing is a pile. Don't even bother getting it on the air. Strip it for excellent-quality
    parts." Chirp, Yoop, FM'ing--Three modes simultaneously. The "Command Sets" could
    put out a substantial fraction of the power in far less cubic, electrical draw, and weight
    and fuss.
     
    Last edited: Oct 16, 2020
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  4. WZ7U

    WZ7U Ham Member QRZ Page

    Came for the potential history lesson, stayed for the Burtish exercise in pedantry. :( :rolleyes:
     
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  5. NN3W

    NN3W Ham Member QRZ Page

    One of the fascinating bits of radio spectrum usage was the early years of WWII when the Luftwaffe was trying to perfect night precision bombing. One chapter included the requisitioning of (IIRC) Hallicrafters S27 HF and VHF receivers by the RAF to get a fix on the Knickerbein system which the Luftwaffe used in the early years. Knickerbein involved finding one radio beacon and riding along its path and dropping bombs once a second beacon effectively zero beat with the first beam. X marked the spot of the bomb drop (aurally).

    My grandfather taught radio theory and Morse Code at NavSta Treasure Island for much of the war. He did mention that the low bands were a mess owing to the traffic volume.
     
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  6. PU2OZT

    PU2OZT Ham Member QRZ Page

    Isn't that Germany, still, had a tremendous advance, that it was primarily Allies own inherent mess? No radio expert myself, but it seems that such beauty https://cdvandt.org/t_200_fk_39.htm ought to be reliable.

    Oliver
     
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  7. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Just found this WWII German Luftwaffe internal film on radar detection, jamming and intel. Some English subtitles.
     
    KD2ACO, US7IGN, PU2OZT and 1 other person like this.
  8. WA1GXC

    WA1GXC Ham Member QRZ Page






    German Knickbein (literally means 'knee") had a Brit counterpart called GEE. Don't know if the Brits reverse-engineered it or came up
    with the concept themselves. Several "searchlight" beams from UK locations could be electronically phased to point to intersecting fix
    over target. I think there was some kind of built-in resolution decrement or electronic fuzz built in to prevent enemy use or spoofing, just like built-in
    delay to LORAN-A pulse trains. Navigator looked at CRT on the airplane's GEE-Box. I will have to look in some reference books for more info. Do not trust what I would find on Web.

    The Brits did, in fact, totally adapt a German-designed instrument landing system called Lorenz Beam with few changes from the German
    configuration. But it was originally a pre-war civilian system, so not much secret. Very similar to today's landing system Localizer,
    two sub-audible tones superimposed at less-than-saturated modulation on sharply-directional fan beams aligned with the runway centerline.

    Not all command pilots in bombers were completely instrument-flight qualified--The squadron lead airplane had one, and the other six flew formation with the lead.
    Many mid-air collisions forming-up airborne groupings over the UK--a very dangerous part of the mission in bad weather. Better tactics for amassing large elements
    came along, but very unwieldy and still dangerous.


    Add: Too many years out of school. Properly spelled "Knickebein" and means
    crooked leg. In German, the "K" is pronounced, not silent.
     
    Last edited: Oct 17, 2020
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  9. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    The Secret War is a BBC series from the early 80's. Covers, Radar development, Magnetron, Jamming and Spoofing of Navigation signals, War at sea. Has interviews with many of the original inventors and key men, including RV Jones, etc.

    It's 6 shows, but lumped together. Fabulous for history buffs.

     
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  10. W6RZ

    W6RZ Premium Subscriber QRZ Page

    Another good video (first half).

     

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