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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. W4KJG

    W4KJG Subscriber QRZ Page

    I was directly involved in a number of very serious US Navy situations during the Viet Nam era, but usually not at all involved with things happening in Viet Nam. HF comms were not always reliable, sometimes not even under the best of conditions, and like in foreign ports when SSB was becoming the primary HF short range voice communications mode.

    These were in the days before satellite communications. Satellites certainly have brought about reliable military and civilian communications, but IMO they are also very vulnerable to disruption, but for very different reasons.

    We had many very serious situations where ships could not communicate with higher authorities, or even with other ships within several hundred miles. HF communications was not always reliable. Many ship communications crews did not fully understand MF/HF propagation. It was in the time after WW2 and before the Navy Electronics Laboratory Center (NELC) defined Mininum Usable Frequency and Maxiumum Usable Frequency (MIN/MUF). Solar storms had their effects. We didn't have GPS and were reliant on clear skies to know precisely where we were -- if we could also get very accurate time signals from world wide time and frequency standards like WWV/CHU, etc. Otherwise our positions were determined by "dead reckoning" which wasn't a whole lot different than the ancient Vikings using ropes with knots for depth and direction, sometimes by pulling buckets on ropes to know speed.

    To add to it, we were using encrypted teletype for most of our communications. The stations we were attempting to communicate with had to have the same punch cards as we did. If we lost communication and synchronization, the code card had to be replaced with the next in the series. The previous card was sliced by razors in the machine, making it unusable as soon as the replacement door was opened for replacement. If the stations/ships got out of synchronization it became very difficult to figure out which card within the series that others were trying to use.

    Many times we were also under very short duration transmit periods, and often were under transmit power restrictions. This was to reduce the chance of being located by direction finders. Sometimes we ran without any radio transmissions and without any externally visible lighting. We didn't have anything like WSPR or some of the other one-way or two-way communications modes. Even Morse (CW) was only minimally effective in many circumstances.

    In times of somewhat less danger we ran with transmitters constantly sending random data so that we didn't lose synchronization with other communication platforms and sites.

    Overall, it was often difficult to reliably communicate with other important sites several hundreds, or sometimes a few thousand miles away.
     
    Last edited: Oct 18, 2020
    M0IND, KD2ACO, K0UO and 3 others like this.
  2. KA4DPO

    KA4DPO Platinum Subscriber Platinum Subscriber QRZ Page

    If you think about the comms systems from WWII up through Vietnam, they really didn't change all that much. The technology got better but the basic systems were pretty much the same. Things didn't really change a lot until the mid1980's, when the military started relying more on portable satellite systems in the field.
     
    W4KJG and K0UO like this.
  3. N3HGB

    N3HGB Ham Member QRZ Page

    I remember a time when ALE software and hardware was an export restricted thing.
     
    KA4DPO, K8XG and K0UO like this.
  4. WA1GXC

    WA1GXC Ham Member QRZ Page



    When the USS Pueblo was attacked and captured by North Korea in 1968, the ship was unable to maintain communications with its command
    via the preferential and customary synchronous radioteletype crypto circuits, as explained-well above. The RATT lost synch, unable to re-establish in poor radio
    propagation. The message finally informing of the attack and follow-on traffic was passed via manual CW by CT(R)-3 Ralph McClintock who although
    not a Radioman rating, was holding a billet on the ship in that capacity.
    His mom, Mrs. McClintock, worked in the lunch line at my public school cafeteria.

    The USS Pueblo (AGER-2) is still listed on the roll of commissioned U S Navy ships, held in the
    illegal custody of the People's Democratic Republic of Korea to this day.
     
    KA4DPO, KD2ACO and K0UO like this.
  5. PU2OZT

    PU2OZT Ham Member QRZ Page

    Hence the «knots» And no Decca, no Loran, no inertial navigation, no Radar?
    Except you forget, a common misconception, maybe, that while Allies were to destroy everything, III Reich was building the whole Europa. And quite from scrap, everything has to be very well built. Should have been the most modern Continent in the World. Wehrmacht were stabbed in the back, by french-commies, among others. Highest goal the US ultimately shared with Germany was halting stalinism pest, which half failed.
     
  6. KP4SX

    KP4SX Premium Subscriber QRZ Page

    Even the incinerators were efficient :(
     
    2E0CIT and W4NNF like this.
  7. N3HGB

    N3HGB Ham Member QRZ Page

    I am not sure I am getting this.
    French communists were supposed to be HELPING the Nazis? If the Allies had gone home and left Hitler to his own devices he would have made Europe a modern high tech paradise?
     
    2E0CIT likes this.
  8. PU2OZT

    PU2OZT Ham Member QRZ Page

    Europa within Pax Germanica is still a fiction no one dares depicting as a paradise. Albeit, from a tech-only point of view... There was that German-Soviet pact, up to Operation Barbarossa. Curious also, where the line was drawn between Soviet/German radio-tech, and its post-war, Ost-Berlin blending.
     
  9. W4NNF

    W4NNF XML Subscriber QRZ Page

    The Reich was nothing but a gang of murderers--and blunderers. Their stupidity wasn't just their idiotic invasion of Russia. It manifested itself in foolishness like their wonder-weapon tank, the Maus, a huge and useless lump of steel. Its speed was 3 km per hour, and it had no small arms protection. While the buffoons wasted time and resources on junk like this, the T-34 ate them alive. And that was a very good thing.

    The only wonder is that some still believe they were strategic and tactical geniuses. And that the fools held on as long and caused as much misery as they did. :mad:
     
    W6MDA likes this.
  10. SM0AOM

    SM0AOM Ham Member QRZ Page

    This is quite easy to answer.

    After WW2, a lot of the German radio industry ended up in the SBZ ("Sowjetische Besatzungs-Zone"), among the captured parts were the Telefunken, Körting and Lorenz Berlin operations.

    The Soviets and East Germans built on the WW2 designs for quite a while, and the same but not as marked happened in the Allied zones. where the Telefunken southern operations in Stuttgart and Ulm together with the Rohde&Schwarz plants in Munich and Memmingen fell into the hands of the Western Allies.

    A lot of WW2 designs were produced afterwards, slightly modernised such as the FuMB 4 "Samos" which was produced well into the 50s as the R&S ESD VHF/UHF measuring receiver.

    upload_2020-10-18_22-42-29.png
    Also, the R&S ESM series was very much influenced by WW2 SIGINT receivers:

    [​IMG]

    Equipment made in the DDR was sometimes very similar to mid-40s equipment, such as the Telefunken E52 "Köln" HF receiver. This early 60s EKV 10 and the late 50s FGS 401 from VEB Funkwerk Köpenick still shared some internal features of the WW2 receiver.

    upload_2020-10-18_22-52-43.png

    upload_2020-10-18_22-58-11.png

    73/
    Karl-Arne
    SM0AOM
     
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