The old days

Discussion in 'Off-Topic' started by CDRIVE, Jul 3, 2009.

  1. CDRIVE

    Thread Starter Senior Member

    Jul 1, 2008
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    I think it was 1967, while working at a 3rd & > echelon maintenance facility repairing and refurbishing ARC34 and TRAC75 military aircraft radios, when a memo came down from the DOD stating that all specifications and recorded data related to frequency will now be given in Hertz. Apparently in honor of Heinrich Rudolf Hertz. I was a junior tech at the time and had no idea who he was. Back then he simply wasn't as well known as Marconi. Two world wars with Germany certainly couldn't have helped either! :D

    http://www.ideafinder.com/history/inventors/hertz.htm

    BTW. Probably not accurate; but when I think of Photocell vs LDR I think of a complete circuit vs the controlling element of it respectively.
     
    Last edited: Jul 3, 2009
  2. Oxbo Rene

    Active Member

    Feb 20, 2009
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    By golly !
    I used to work on ARC34's, even a couple of ARC3's (really old/simple).
    lemme see, I believe VHF101's, I can't remember nowadays, several kinds.
    Worked on C141's, F4's, F102's, occasional C130, was at Clark, Udorn, Bangkok, Tainan.
    Used to love sitting in the pilot's seat and calling the tower for radio checks, etc.
    If it didn't work = Red X, jerk the radio, take it to the shop, throw it on the bench, dig in....
    Oh yeah, Chris....
    I have a yard light out front of my house that runs by an LDR. It always stays on longer than seems proper (mornings), and always seems to come on way before it should (evenings). So, I see it as not quite accurate for sensible applications.
    However, I would propose proximity sensors. Out in the VAB near where I work they have proximity sensors that turn on the lights whenever you come to an elevator or bathroom, they work pretty darn good, etc...
     
    Last edited: Jul 3, 2009
  3. CDRIVE

    Thread Starter Senior Member

    Jul 1, 2008
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    Ah, memories... The ARC34 had very unique finals (nicknamed Lighthouse Tubes) that seated within a resonant cavity. The Plates of those tubes were the only element exposed. To the uninitiated the Plates looked like part of the chassis but were insulated from the chassis with a barely visible mylar sheet under a metal plate that secured the tubes. The whole metal plate would knock you on your ass by +400V supplied from a 28V DC input dynamotor. The Dynamotor was later superseded with a solid state inverter that plugged into the same octal socket. These were Germanium Transistors and were awfully leaky! Very difficult to tell a good one from a bad one. I was new to solid state back then and leaky transistors didn't help make the transition from vacuum tubes any easier! :eek:

    We made fuel stops on Guam (I think Andersen Airbase) and Clark 4 times between 1963 and 1966 on our way in and out of Bangkok and the Tansanut air base in Vietnam..... F4 heaven! Lots of C130 & AC130s were berthed at the Benhoa Airbase.
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    I split this set of posts off the original thread - http://forum.allaboutcircuits.com/showthread.php?t=25341 - as it was going way off topic.

    Oddly enough, from the goodies in the basement of the Physics Building, I managed to turn up a lighthouse tube. It's a GE 2C44, with 6 pins in an octal base.

    It's a wonder anybody got use out a a germanium transistor. Out power transistors were in huge cans, half the size of a doorknob, and ran 20 ma loops in KSR-15 TTY's while running too hot to touch.

    I did spend 7 lovely months cruising off the coast of Viet Nam controlling air strikes. You have to spend up to 45 days steaming in the same racetrack pattern to discover the true meaning of tedious. That's 45 days on, no days off. Food is a bit strange after that long out.
     
  5. Wendy

    Moderator

    Mar 24, 2008
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    Tanner's (a local parts outlet) still carries some germanium types, believe it or not. If anyone is interested I'll write the numbers down next visit.
     
  6. CDRIVE

    Thread Starter Senior Member

    Jul 1, 2008
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    BT, thanks for splitting this thread for reminiscing old dogs and sorry about hijacking the thread.

    Actually the Lighthouse tubes that the ARC34 implemented were totally unique and I don't think they were ever used in civilian, industrial or consumer electronics. Unfortunately I don't remember the model numbers. Funny though, as I still have some of them stored deep within my storage bay. I think I can draw one faster then finding them in that bay!!
    These tubes had only 2 pins at the base and were the filament. The glass envelope was only about 3/8ths of an inch in diameter and 3 inches tall. There were no physical pins for any of the control elements. The Cathode was a metal sleeve, just slightly larger in diameter than the envelope and about 1/4'' high. The Grid connections were made of progressively larger metal rings with the plate being the largest and looking like a round heat sink.
    I also have some 1930's vintage Acorn tubes... They really do look like a spiny Acorn!


    [/QUOTE]
    You can bet that your shipboard mess beat mine all to hell. Twelve months in the bush eating K rations ( I liked the 5 pack of Lucky's though) canned during WW2. Christmas & Thanksgiving was a treat. We had Turkey shaped Spam. :D

    If anywhere near it, it was SOP for my detachment to stop and chow down at the Benhoa Airbase. The Airmen there knew that the Army ate like lower life forms and they treated us very well, feeding us until we were engorged. If any of you reading this were Mess staff there, you served as a reminder that there was a civilized world still out there. .... God Bless You Guys!!
     
  7. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    All of the numbers are a little fuzzy now, remember Collins ARC5 transmitter, had a rolling contact on the inductor for tuning.
     
  8. beenthere

    Retired Moderator

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    I'll post up a photo when I get a chance. That basement storage room had everything in it. We had tube sets for SCR-540 radios. There was a partial APG-something-or-other airborn fire control radar with no electronics. A complete street vendor's pushcart. Even a painting that looked a lot like George Caleb Bingham. Fun place to rummage in.

    To Bernard - yes, we had one of those roller contact tuning inductors. Plus a Collins receiver to get WWV. It also picked up the Russian woodpecker - their over-the-horizon early warning radar.

    Someone turned up a harley-Davidson jeep (or at least 6 volt) battery charger. It was a single cylinder engine coupled to a little generator, about 10" high and perhaps 8" long. Cute as could be.

    We grabbed a new blowtorch that had a notch on the top of the nozzle that held our guttering iron. All we needed was a bold of sal ammoniac to wipe the hot iron on to get busy.
     
    Last edited: Jul 4, 2009
  9. CDRIVE

    Thread Starter Senior Member

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    Yeah, I think I remember the ARC5 as being a favorite among hams at the time because it was a low band radio. They were very basic as I remember them and hams wanted the LC tuning components out of them for finals and antenna matching.

    The ARC34 was a VHF AM transceiver and very complex. It sported, probably, the first known auto-tune circuit. The pilot selected the frequency by a series of rotary switches on a remote control head. The switch positions were translated into a value that was used by a circuit driving a beautifully made small (Hi Torque) DC motor. The motor would drive a ganged series of variable caps. Any cap section that was past the trippler were embedded in their own resonant cavity. When the sensing circuit detected that the caps had just past the desired freq it would reverse and slow the motor down until freq lock was achieved and stop the motor. This was the most maddening part of the 34 to understand and service.
    The jpg that I'm attaching is purely from 30 year memory. I have these tubes but I haven't seen them in that length of time. I can't even swear that they were Tetrodes, as they could have been Triodes. In which case, there would be only one ring. As you can see from the sketch, these tubes were not free standing and must be used in a resonant cavity.
     
  10. speeed_777

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    Oct 5, 2008
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  11. CDRIVE

    Thread Starter Senior Member

    Jul 1, 2008
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    So what are you confused about?
     
  12. beenthere

    Retired Moderator

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    This is the critter, which is a variation of some kind. But the layout is pretty much a giveaway. On the octal base, pins 2 & 7 are the filament, and 3, 5, & 8 are shorted together.

    The photo is right at the limit, so just a bit fuzzy. The tube measures about 2 3/8" high.
     
  13. CDRIVE

    Thread Starter Senior Member

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    Your first post regarding this tube did not ring any bells but after seeing it I now know that we've crossed paths. If I ever tunnel deep enough into my storage bay I'll dig out the Lighthouse and Acorn tubes to photograph and post. :)
     
  14. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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    I'm so old it Hertz. :D
     
  15. count_volta

    Active Member

    Feb 4, 2009
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    Jeepers!!! you people remember when the electric telegraph replaced the manual land telegraph? Ahh the good old days of candles.

    I heard this dude named Ford has come up with a horseless carriage in his basement!!! Burn him for he is a witch!!! That is nothing, I heard these 2 dudes in North Carolina have invented a horseless carriage that flies!!!! WTF flies ye say? Aye she flies. Burn them!!! Hang them!!! Stone them!!!

    Messing with ya. :D

    Anyway, nothing more than a typical day in Lancaster Pennsylvania, not where I live but have driven past a few times. They most likely wanted to burn me at the stake.
     
    Last edited: Jul 7, 2009
  16. CDRIVE

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    What in the world is, was, a manual land telegraph vs. electric telegraph? I know of no other than electric telegraph.

    .-- .- ..--- . .-. --.-
     
  17. beenthere

    Retired Moderator

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    Manual land telegraph = heliostat or wig-wag flags. Even drums.
     
  18. count_volta

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    Yep, I heard of land telegraph for the first time in the Count of Monte Cristo (novel) and I was curious what freaking telegraph are they talking about in 1815? So I searched it on wiki. Fascinating stuff. ;)
     
  19. CDRIVE

    Thread Starter Senior Member

    Jul 1, 2008
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    I considered that but I dismissed it, as I didn't think either method of communication constituted a telegraph. I sure would be pissed off if someone advertised a vintage telegraph for sale and then sent me a flag or drum. :rolleyes:
    Hey, how about smoke signals? :D
     
  20. beenthere

    Retired Moderator

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    What about them, Kemosabe?
     
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