This is a FB-7 (really an FBXA) lineup as it might have existed in 1934.
The speaker is the pre HRO / three verical bar style with the
National emblem embossed directly above the speaker opening. The FB-7 did
not include an RF stage but National offered the PSK RF preselector
pictured here. This unit bolts on the side of the receiver with 1" spacers.
This allows the crystal filter contols to be operated. Band changing
required the removal/replacement of three coils.
The FB-7 required seven tubes plus one more in the PSK and another in the power supply. The knob on the rear left transformer is the BFO pitch. The "A" designation on this model comes from the use of improved IF transformers while the "X" signifies the crystal filter. The filter is installed on the rear right side. The crystal and phasing control are visible form the top while the switch on the side (between the receiver and the PSK) controls the filter function.
Back to W0VLZ's National tour.