[Hallicrafters] Head Scratcher

[GBrown]

OK, maybe someone has asked this before but here it goes again.
#1. When Hallicrafters assigned a number to a piece of equipment, why did
the receiver get designated "S". I assume the "T" ment transmitter.
#2. This is a hard one. How were the numbers assigned to the different
equipment. From SX-62 to SX-71 we are missing the ones in between. Were the
missing numbers experimental and never made production? Were the numbers
just a random pick? Were the numbers pulled from a hat?
    As you can see, I have to much time on my hands, hehehehehe
Regards,
Gary...WZ1M