[Milsurplus] RA38, SCR-268, GL434

[Unserviceable but Repairable]

WARNING, lengthy.  If you're gunning for a $5 spy radio, delete now.

I know something about subject but can't quote TMs.  All I had was a 
hand-copied engr. book on the unit fm Chicago '38.  Gave to HEMUS @ Balto.

Army's 1st radar.  Used 12 100TS tubes in 205 mhz ring oscillator.  These
later called VT127s.  10,000s in surplus.  Allegedly a 250th fil
surrounded by 100th glue & a "uhf envelope."

Later '268s had 16 VT127s.  

Pulse modulators were unknown in '36 so it used EIGHT paralleled 304TLs
in a series transformerless AM modulator.  Ring osc. wud only go on top 20%
of each sine wave.  Here's where all the 304s went!

That WA5CAB 1-ton RA38 had the huge HV bridge-xfrmr included... hence 4 371s
in same RA38

My PP-1182 giz is 3-phase w. 6 371s.  No HV xfrmr tho, hence I can lift.

GL434.  First '268s had two acorn front-ends.  Because 2 rx collinear
(bedspring) antennas for lobe switching.(1)  Hearsay has it that the
last '268 rxs used these 1st 'lighthouse' GL434s as sub.s for acorns.(2)

SCR 516 vs 268.  Was GCI conversion of '268 & huge antenna drives were done
by motors rather than busy handwheels.  Was a flop per Chesson.  I had one 
516 RX that's now @ HEMUS & ID plate sez it was done by Wm Terpenning Co.
in NYC

Who's Wm Terpenning?

I adsorbed all this stuff for a radar presentation @ AWA 4 yrs. back.  I
was driven to doit since I had some parts for the Ft. Screven (Savannah)
'516.  Ft. S was coastal art'y.  My RX still had a NYC-Savannah
railway express sticker attached.  Parts came out thru MARS in '49.

Enuf

  Marty

(1) lobe-switching on Navy SBD 500 mhz ASB radar.  There's one here that
    works.  Jump back channel 44.

(2) Scr 270 back-fit 832A & E1148 radial-beam RFA with cascode 6J4s

footnote:

  Dennis I MUST have a GL434 I can send ya

  Bet Ft. MacArthur had a '268 or a 516 too.  Coastal art'y, right?

  Hey on that.  Met CO fm fort guarding entrance to Delaware River @
  Lewes.  Had a '268 there for searchlight aim.  they had ten 12" 
  guns in Dela, 2 in Ocean City, MD.  Fort was decomissioned 1 noonday 
  in 10/45.  At 11:59A, they pulled the lanyard on all 12 guns & broke 
  dozens of nearby windows & even a pane or two 12 mi's away in Wilmington.
  Naturally all pillboxes still there & those of us that have recently
  discovered some of these 12" fouling pieces on ebay might donate 'em.

  Closest I can come is neighbor's potato cannon fueled by spray pledge.