Look Who's Talking: The VK3YE DSB/CW TFR
The ARS Sojourner
It is a VXO-controlled double sideband/CW direct conversion transceiver for 40 metres. It covers 7.005 - 7.095 MHz using a three-crystal, one transistor VXO circuit. Unlike most VXO circuits, the tuning is very linear - indeed the 0-100 dial on the 6:1 vernier drive was so accurate over most of the range (within 2-3 kHz) that I didn't bother to recalibrate it. RF power output is 5 watts. NE602s are used in both the receiver and transmitter sections.
The whole station (except for key and antenna) fits in a Rubbermaid plastic tool box measuring 12.6 x 6.9 x 5.3 inches. It is a bit big for the long-distance hikers, but OK for most others. Double sideband is a big plus - most SSB operators don't know it's not single sideband.
The transceiver is in an aluminum case that fits snugly inside the Rubbermaid box. It is about half the size of the plastic box, leaving room for the microphone, field strength meter, L-match ATU, 3 feet of coax, and battery pack comprising 8 C-sized nicads. These provide operation for about 2-3 hours.
The radio is on the left, the accessories on the right.
The rig's ergonomics are pretty good. There are no plugs/sockets/knobs on the bottom or left hand side of the box. All controls (tuning, microphone gain, AF gain, on/off, CW/DSB) are on the top of the box.
Apart from the large (2-inch) vernier dial, which occupies the top left of the top panel, the larger sockets are in a single line across the lower section of the top panel. The order of these are: microphone socket (1/4-inch), microphone gain control, a large gap (2-inch) AF gain control and then the 1/4-inch key socket.
The speaker takes up the top right of the top panel, thus facing the operator. Because contacts are generally made with strong QRO stations, no headphone socket was thought necessary. If one was desirable, it should be near the right-hand side of the set, near the AF gain control, but a fair distance from the key socket. The rarely-used on/off and CW/DSB switches are toggle switches between the microphone socket / microphone gain control and the tuning dial.
A 2.1mm socket was used for the power connection and a SO239 for the antenna socket. These are on the right-hand side of the rig - quite accessible when the accessories are removed from the right part of the Rubbermaid box.
As for improvements, the main one is the lack of CW transmit shift thus a need to always do this manually - not the best arrangement, especially when it's cold. Also, the rather large size of the package plus the absence of a headphone socket. The external L-match ATU could have been made into an internal unit, with a fixed inductor and a variable capacitor on the front panel. This would be satisfactory if you were using only a 1/2 wavelength wire for the antenna, and had no need to match other impedances. This would save the external ATU and a connecting cable.
Results from this rig have been very good. It's pretty normal to make 400 - 600 mile DSB and CW contacts during the day with a half wave wire.
The best DX was to ZL in the late afternoon - a distance of about 2,000 miles. For me it's pretty close to the ultimate TFR radio, especially on DSB.
* * * * * * * * * *