[Milsurplus] Question about SCR and AN nomenclature

[J. Forster]

I'm still trying to understand the structure of military nomenclature. It seems
that SCR and AN/XXX are almost top level packing lists. Consider these examples:

SCR-506

 BC-653 Radio Transmitter
 BC-652 Radio Receiver
 DM-42A 12 VDC Transmitter Dynamotor
 DM-43A 24 VDC Transmitter Dynamotor
 DM-40A 12 VDC Receiver Dynamotor
 DM-41A 24 VDC Receiver Dynamotor
 AN-24 22.5 Foot Wire Antenna

For the AN/APN-1:

       RT-7/APN-1 Transmitter-receiver,
       2 ea AT-4/APN-1 antennas
       ID-14/APN-1 Altitude indicator,
       SA-1/ARN-1 Altitude limit switch

But for the AN/APN-2, it appears a mix of stuff is allowed:

AN/APN-2

       RT-1A/APN-2 Transmitter-receiver
       1 ea AT-1/APN-2 antenna
       2 ea AT-2/APN-2 antenna
       C-3/APN-2 Control Box
       BC-929-A Indicator.

My questions are:

Is my assessment about the SCR and AN/XXX being basically a top level packing
list correct?

It appears that the AN/XXX replaced the SCR sometime in the middle of WW II.
Approximately when, and was it about the same time as JAN component numbering
came out?

Is the continued use of BC designations in AN equipment basically grandfathering
in the old nomenclature (because renumbering everything would have been a big
PITA)

Has anyone taken something like the Hereford listing:

http://hereford.ampr.org/millist/m1.html     and put it into a database like
Access?

Furthermore, has anyone taken the Hereford listing and added the applicable
manual and TO numbers to it?

And finally, has anyone amplified some areas of the list where details are
sparse, especially the Navy equipment.

Thanks,
-John




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