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Thursday, July 14, 2011

Sputnik Madness! But was it CW? or AM?

Our worldwide team of Sputnik enthusiasts continues to seek out the elusive schematic diagram of the spacecraft's 20 MHz transmitter. American, Cuban, Russian and German radio amateurs are involved. Recently Bruce, KK0S, visited the Kansas Cosmosphere in an effort to get a look at the innards of Sputnik's "flight spare." The picture above is his -- it shows the Sputnik antenna connection. (More pictures from Kansas here: http://s747.photobucket.com/albums/xx120/trader_vic/Kansas%20Cosmosphere/)
There was bad news and good news from the visit: The bad news was that the spacecraft on display was a hollow sphere. The good news is that the internal parts --including the transmitter -- might be in storage someplace, just waiting for our reverse engineering. Stay tuned (to 20 MHz!).

Speaking of which, I have a question: OK so the crafty Soviets picked 20.oo5 MHz for some good reasons: Being so close to the WWV freq, it would be easy for hams and SWLs to find it with precision. In the November/December 2007 issue of "Break In" (from NZ -- thanks Jonathan-san!) ZL3DW notes that this frequency selection would allow a receiver set to exactly 20 MHz to "produce an audio tone plus or minus the Doppler shift without ever going through zero beat." But zero beat with what? Most of the receivers out there would not have had BFOs, right? So the Soviets wouldn't have been using ordinary CW, right? Were they using AM, with the beeps produced by an audio oscillator modulating the carrier?

Here is a update from our Chief Designer, Comrade Mike, AA1TJ:

I currently have a prototype for a simple "Sputniker" transmitter on the bench using a 1sh29b in the oscillator and a 1p24b working as the PA. As in the original, the input
DC PA power is 1watt. The crystal-controlled oscillator uses an inexpensive ESS 21.060kHz xtal. So far, all systems are GO.

BTW, here's an example of how inexpensively these lovely little tubes may be purchased. Oleg, RV3GM, and his pals might be able to do even better.

Although there are only so many ways one can build a two-tube, crystal-controlled MOPA transmitter, we'd still very much like to nail down the original transmitter circuitry. Bruce, KK0S and Peter, DL2FI are following up leads to that end.

Once we're a bit further along I'm hoping that someone will step-up to produce a kit. Actually, last evening someone raised their hand to ask if a kit were already available.

Dasvidania,
Mike, AA1TJ

7 comments:

  1. I wonder if the one hanging from the ceiling at ITU-T in Geneva is more complete, or if that is also an empty shell?

    ReplyDelete
  2. It's likely an empty shell and not a complete PS-1.

    I base this on the fact that there many shells manufactured by the Russians in order to produce a few that were acceptable for flight whereas only 3 transmitter pairs were assembled; 1 in the satellite that was launched, 1 that was used in range tests dangled from a Soviet bomber and 1 spare. Each pair consisted of one 20 and one 40 MHz unit.

    I'm beginning to doubt that what's on display at the Cosmosphere in KS is the PS-1 flight spare. My bet is that the actual flight spare is the one shown hanging in the Energia Museum located at RSC Energia in Moscow in 2007.

    http://www.npointercos.jp/Energiamuseum.html

    73.......Steve Smith WB6TNL
    "Snort Rosin"

    ReplyDelete
  3. And the transmitter was CW. You can hear the backwave from the continously keyed oscillator in the recording here:

    http://www.amsat.org/amsat/features/sounds/sputnk1b.wav

    73.......Steve Smith WB6TNL

    ReplyDelete
  4. I posted this comment to the first blog entry on this subject with no follow-up so thought I would post again. Read to the end about a possible source (June 1957 issue of Radio magazine) for info on details about the transmitter.

    Don't know if this is new info to you but there is a fantastic space race history titled "Sputnik, The Shock of the Century" by Paul Dickson.

    The author makes several references to hams and how they were able to hear the "beep-beep" of Sputnik as it passed overhead.

    A paragraph on page 129 might help with the quest for the schematic. It reads:

    "It was a popular belief at the time that the Soviets chose the lower frequencies to allow ham operators around the world to receive the signals and track the satellite. This scheme, it was thought, not only popularized the project but also provided cheap worldwide tracking reports from hams around the globe. In 1990 Konstantin Gringauz, the man who designed the transmitter, confirmed the suspicion in an interview when he told Brian Harvey of Spaceflight magazine, "Korolev was adamant that signals should be received by as many people as possible throughout the world, including amateur radio hams." In addition, the Soviets had gone out of their way to make the frequencies known. As Gringauz reminded Harvey: "In the summer of 1957, announcements were made of the impending launch of Sputnik I. The June 1957 issue of Radio magazine...published a complete description of...its transmitters, and how to pick it up, but no one took it seriously."

    Someone, somewhere might have old issues of Radio magazine and it might have a schematic or at least a good description that will provide clues about the construction of the transmitter.

    ReplyDelete
  5. Here's a link to a bunch of "Radio" magazine scans:

    http://publ.lib.ru/ARCHIVES/R/''Radio''/

    I didn't recognize anything in June, '57 that was a Sputnik transmitter schizmo and I don't read Russian so I couldn't glean anything from the text.

    73.......Steve Smith WB6TNL
    "Snort Rosin"

    ReplyDelete
  6. Is that the right 'Radio'?

    I seem to remember that there is also a Russian professional journal called 'Radio'

    ReplyDelete
  7. Good question! Will have to pursue that lead. Thanks!

    73.......Steve Smith WB6TNL

    ReplyDelete

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