Hard To Find National FB - 7 Receiver 1932. Exc Operating, 20 And 160
Item History & Price
| Reference Number: Avaluer:4376596 | Brand: National |
Here is a National FB-7 superhet receiver that's in very nice condition. This came out just after National's ground breaking AGS receiver but several years earlier than the HRO. This was National's first affordable ham superhet and was very popular but still pretty expensive for the average ham.
This is a surprisingly good receiver, especially on the lower bands. It actually works well for SSB reception and is a big step up from the classic National SW-3 regenerative re...ceiver.
From National's ads:
Single Control Tuning (No trimmers).
Full Vision Dial with SLF 270º Condenser.
Front-of-panel coil change.
CW Beat Oscillator Switch on panel.
Front of Panel Switch for "cutting" B voltages during transmission.
Phone Jack, connecting ahead of final audio stage.
Calibrated Volume control located under tuning knob, for one hand operation.
This includes band-spread coils for 20 and 160 meters. Other coils including band-spread and general coverage coils show up on the net.
Several resistors and capacitors have been replaced but it's surprising that most of the original parts are ok.
One note Early National's had the phone jack in the detector plate circuit and the jack was hot with B+. I added a plastic piece to cover the outside of the jack to reduce the chance of getting a shock. Don't use a metal phone plug!
This is the original FB-7 version that uses 2.5 volt tubes. It works excellent with lots of audio to a speaker with 175 volts B+. I use a 10K to 4 ohm transformer to match the speaker, the impedance ratio isn't too critical. I wouldn't run much higher that 200V B+.
It is possible to change the 2.5V heater tubes to equivalent 6.3 volt types. The type 59 has no 6.3 volt equivalent, but you can make an adapter to go from the 7-pin socket to say an octal socket for a 6K6 or a 6V6. I've used a 1625 tube base to make an adapter.
The manual is available from several sites including BAMA.
Shipping is by UPS for 22 lbs I pack very carefully (see my fb).
California buyers must add 7.75% sales tax.
Thanks es 73
This is a surprisingly good receiver, especially on the lower bands. It actually works well for SSB reception and is a big step up from the classic National SW-3 regenerative re...ceiver.
From National's ads:
Single Control Tuning (No trimmers).
Full Vision Dial with SLF 270º Condenser.
Front-of-panel coil change.
CW Beat Oscillator Switch on panel.
Front of Panel Switch for "cutting" B voltages during transmission.
Phone Jack, connecting ahead of final audio stage.
Calibrated Volume control located under tuning knob, for one hand operation.
This includes band-spread coils for 20 and 160 meters. Other coils including band-spread and general coverage coils show up on the net.
Several resistors and capacitors have been replaced but it's surprising that most of the original parts are ok.
One note Early National's had the phone jack in the detector plate circuit and the jack was hot with B+. I added a plastic piece to cover the outside of the jack to reduce the chance of getting a shock. Don't use a metal phone plug!
This is the original FB-7 version that uses 2.5 volt tubes. It works excellent with lots of audio to a speaker with 175 volts B+. I use a 10K to 4 ohm transformer to match the speaker, the impedance ratio isn't too critical. I wouldn't run much higher that 200V B+.
It is possible to change the 2.5V heater tubes to equivalent 6.3 volt types. The type 59 has no 6.3 volt equivalent, but you can make an adapter to go from the 7-pin socket to say an octal socket for a 6K6 or a 6V6. I've used a 1625 tube base to make an adapter.
The manual is available from several sites including BAMA.
Shipping is by UPS for 22 lbs I pack very carefully (see my fb).
California buyers must add 7.75% sales tax.
Thanks es 73
