[GreenKeys] An older vacuum tube TU

[AI2Q]

I still have my homebrew 850-Hz W2JAV t.u., equipped with a WØHZR phase-shift 2-in oscilloscope.

Vy 73, AI2Q, Alex
Member: ARRL, FOC, RSGB, CWops, QRP-L, Antique Wireless Association, New England Radio Discussion Society, DXCC Honor Roll, 16ØM DXCC, 8ØM DXCC 
http://home.roadrunner.com/~alexmm

  ----- Original Message ----- 
  From: Ralph Irish 
  To: greenkeys at mailman.qth.net 
  Sent: Thursday, March 13, 2014 9:57 PM
  Subject: [GreenKeys] An older vacuum tube TU


  I recently got an e-mail from a friend, describing our first RTTY QSO, back in 1967.  He said that
  he was using an "FF-1" TU.  I seem to remember a modification to the old standby, W2JAV TU, which
  involved a "Flip/Flop" circuit between the "Triggers" and the 6AQ5 Keyer tube.


  Just wonder if anyone has info on the "FF-1" TU, especially a schematic.  Did it make it to the
  commercial marketplace?  Or was it just one of several quality circuits that made it from the
  printed page to many ham shacks?


  I had a friend who built the W2JAV TU several years before the TT/L was published.  He said that
  he spent literally hours just getting the filters tuned right to frequency, and with as close 
  matching "Q" as possible.  He said that the time spent was well worth the trouble.  He showed me
  printing with very marginal signals and producing near perfect copy.  He was an instrumentation
  engineer and had access to quality test equipment where he worked, like scopes, freq counters,
  etc.  This was before the great influx of freq. counters available for very reasonable prices.


  - - - -


  Back to the FF-1


  Would like to know anyone's experience with one, and most of all, would dearly love to see the
  schematic.  I have a hand drawn schematic of what I've described above, but the person who gave
  it to me, back in the mid 1960s, made no mention of anything other than the "W2JAV Flip/Flop"
  circuit.


  Putting that circuit next to the W2JAV circuit in the old RTTY Handbook indicates that the two
  are virtually identical if you ignore the Polar Relay output of the Handbook schematic and 
  look at the "Flip/Flop" circuit on the hand made drawing.  There might be a few part value
  differences, but for the most part, they are identical up to the "Triggers & Coupling"
  components.


  Both schematics available to anyone who wants one for reference purposes.


  For now,


  Ralph - W8ROI






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