RA7915
Built by RACAL Sydney as a single channel crystal controlled receiver. Fully solid state with crystal oven. Apparently a RACAL factory mod was to cut the tracks to the oven as it made the receiver more reliable. Used around Australia in coast stations. The example pictured is ex VID (Darwin radio).
COMMENTARY
The RA-7915 is a single conversion superheterodyne receiver. It has a single channel (optionally six) in the range 40kHz to 30Mhz. The receiver can operate off 12VDC or 110VAC or 240VAC . Various filters and RF boards are available depending on the requirements of the customer. There is provision for an optional remote control unit.
Design is fully solid state using transistors and integrated circuits.
Control of the radio is quite simple. Pushbutton switches select the mode. AM, USB, LSB and CW are possible. There are also two buttons to select AGC Fast or Slow. There is an aerial attenuation button for use when receiving extremely strong signals. The Mute switch mutes the receiver. RF and AG gain functions are available. The Clar/BFO control allows fine tuning of a signal being received. A squelch control allows the squelch level to be adjusted. There is a monitor loadspeaker and phones output jack.
There is no reason why the receiver can't be used for ham work. The major disadvantage is that it only covers one frequency. One possible solution is to have a rack full of them all on different frequencies. (You know who you are).
TECHNICAL SPECIFICATIONS
Frequency Range: Up to six channels in range 40kHz to 30Mhz depending on RF board fitted.
Channels: Up to six
Modes: AM, SSB, CW
Sensitivity: 1uV
Power Requirements: 12VDC or 240VAC
CONSTRUCTION
Below: RA-7915 top view.
The RA-7915 is a typical sort of commercial design. Fibreglass circuit boards mounted to a chassis. I understand that the RA-7915 did have some reliability issues. Nonetheless they were still in service until quite recently.
OVERALL RATINGS
Engineering rating (taking into time of design).
A typical sort of design for its time. Had reliability problems.7/10
Fitness for purpose rating
Was quite flexible with various options available. 9/10
Usefulness as ham equipment rating
Single channel reception only. 6/10