[Milsurplus] A RAL clone

[Michael A. Bittner]

Bill, The way these things go, you will get halfway through your project, and a cheap RAL will show up at a swap meet.  Mike, W6MAB
  ----- Original Message ----- 
  From: Bill Cromwell 
  To: milsurplus at mailman.qth.net 
  Sent: Wednesday, March 20, 2013 9:32 AM
  Subject: [Milsurplus] A RAL clone


  Hi,

  I haven't had any success finding a RAL at any of the hamfests. I don't
  get to very many of those. My funds for a RAL are limited and the
  shipping cost for a distant RAL added to the three digit asking prices
  puts those out of reach and there are very few of those, too. While I am
  waiting to find a real RAL to pair with my RAK I am going to start
  construction on a RAL "clone". I'm not looking to "miniaturize" it nor
  make any "improvements". I am considering how I can use available
  materials to copy the function of the RAL. That will probably make my
  "clone somewhat smaller but not a mini by any means. I have noticed the
  manuals i got from BAMA contain detailed info about al the tuning
  inductors, etc. Mission critical info there.

  I will be using miniature tubes. Think 6BA6 or something like that. I
  have them by the dozens. To help with the decision about which tubes to
  use I'll compare their characteristics to the 6D6 and 41 tubes used in
  the RAL. There won't be any with grid caps. There will be shields even
  though they may not be needed with the grid lead not already exposed to
  the plate.

  I have been considering how I can mechanically implement a tuning
  mechanism that duplicates the presentation and operation of the one used
  in the RAK/RAL. I think I can acquire the needed gears to put one
  together. Not an exact duplicate but the same dual dial layout and same
  number of revolutions. There may be something easier to implement. My
  RAL clone will NOT be going into Naval combat any time soon! Some
  combination of cords, belts, chains, and drums may be reliable for home
  use.

  There is a lot of shielding and isolation in those radios. I intend to
  pay close attention to all of that and incorporate it into my "clone".
  The tuning mechanism, volume of shielding, and size of audio inductors
  will need some space but even so, the "clone" is likely to be a little
  smaller than the real deal. I'll be building on either two or three
  separate chassis inside the cabinet...not counting the power supply.

  Anybody have suggestions or known 'gotchas" to pass along? Resale value
  is NOT a factor. I'm only making one and it's for me to use until
  burial. The radio can be buried too.

  73,

  Bill  KU8H

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