[Milsurplus] BC-131 loop antenna?

[Marty R's GI-stuff haunt]

Hue there's a pic of a running one in 

  History of US Army WW2, Sig. Corps., Vol. I

Scaling from the ~14" for the 131 with RX panel vertical, I'd say the
thing was about 3' on a side.

The loop was the tank for the ux210-tube (vt25)

Loop worked fine on RX but, little known then, the I-vector on one side of 
loop mostly cancelled the I vector on the other side & it was one
p!$$-poor doo-dad on TX.

For some reason tx-loops came back to hams & mil-spooks mebbe 10 years
back.  & it took several years of bad results before math-head 
nay-saying given credence.

  Marty