Military Wireless in the Midlands Museum
Virtual Museum site
This is a RBJ version, i.f. is 456khz, 6D6 type valves, no xtal or S meter,
transformer like box just right of aerial terminals is headphone tranny. Can anyone help me with a
circuit of this model please.
and the set after restoration. I dont think the lamp was origonal, but someone had drilled a large hole there so
it was the best option to fit. There are 4 screw holes to the left of the lamp where the
name plate went.
Below are 4 HRO models, please see if you can ident each model.
HRO No1: This one is a table version (T ?), s/n M455, square IF can, 6D valves with Xtal on top of can. It has a toggle switch for meter and headphone jack.
No 2: This one is a table set, no meter, two jacks in that location, only the one control on right hand side. no s/n evident, square cans, 6D valve type, no xtal, and has the US Navy Anchor stamped on top of gearbox.
No 3: Another table set, meter switch, crackle black front (5T maybe?), s/n J110, square cans, 6K7/6J7 valve types, no external xtal.
No 4: Rack mounted set, meter switch is push/pull type, plain black front. S/n AP972, square cans, 6D valve type, fitted xtal on top of can.
No 5: I Have a further HRO, MX type, s/n C754, square can, 6D valve type, no external xtal, modded with 6H6 on read wall, toggle switch in place of headphone jact below meter.
If you can put an age, date of manufactor or any further info to each model number please let me know at