[Milsurplus] Fwd: Those P-39s Still in the Crates...

[Mike Morrow]

Hue wrote:

> That would make sense for later equipment, but i still miss how that would
> apply to, say, a BC-375, RU, BC-348, SCR-522 and so on.

To remove the transmitter unit to the maintenance shop and substitute
another of the same type would cause significant operational problems for sets like the BC-191/375, GP-*, and to a much lesser extent the ATB and ATD.  All of these had tuning units stored on the aircraft that were serial matched to the transmitter main unit.  For the BC-191/375 and GP-* sets, the volume and weight of the associated tuning units were more than twice that of the transmitter unit alone.  If the transmitter under repair was not to be returned to its aircraft, then all of its tuning units would require swapping out as well to keep everything a matched set.

It's unfortunate that ER'z Bruce Vaughn/NR5Q is no longer with us.  He was a radio mechanic in the ETO and could have clarified the usual practise.  (Bruce is the one who told me 20 years ago that the SCR-522-A was incontestably the most used and most important radio set that ever flew in the ETO.  But he said he really hated it when a flight's operating frequencies had to be altered.)

Mike / KK5F