Wilderness / NorCal 40A
The Wilderness / NorCal 40A is the commercial version of the NorCal 40, the first kit offering of NorCal (Northern California QRP Club). It was designed by Wayne Burdick, N6KR and has undergone extensive field testing during its development. The kit is available from Bob Dyer, K6KK at Wilderness Radio, who also offers two additional QRP transceivers that will appeal to the outdoor operator.
The 40A is a single band 40 meter CW transceiver that is primarily designed with the back packer in mind. It will operate very easily from a 12 volt pack of AA batteries. Receive current draw is only around 15 mA and the transmitter generates about 2 watts of power with a current draw of about 225 mA.
It features an excellent superhet receiver with a 4 pole crystal filter at the 4.915 MHz IF frequency. The VFO operates at a low frequency near 2 MHz and is extremely stable. NE602 mixers are used in the front end and product detector. Receive Incremental Tuning (RIT) is standard equipment. The kit includes a single turn potentiometer to control the varactor VFO tuning and the 40A will cover about 40 KHz of the band. The user can internally adjust the VFO to any part of the 40 meter band with a board mounted band set capacitor. Audio derived AGC is used to control receiver gain in the presence of strong signals.
The transmitter has very clean keying characteristics and has a T/R delay of about 200 milliseconds. Power output is internally adjustable. A BNC connector is used for the antenna connection. Transmit sidetone is the actual transmitted signal as heard by the reciever.
The kit includes the painted and drilled case. There are two latches on each side of the case that permit the top cover to be removed in the field without tools. The circuit board is unique in that it does not use any wiring harnesses. All connectors are mounted on the board which makes the unit very rugged and easy to service.
An optional frequency counter and keyer module, the KC1, is available from Wilderness and has been installed in the unit shown in the photograph. The KC1 reports the operating frequency audibly in Morse code and includes a memory keyer. Also available is a replacement front panel that has been drilled and painted for the KC1 option. Wilderness also has an optional noise blanker, the BuzzNot, that will fit into the unit.
The WØCH 40A in the photograph has been modified to use a ten turn potentiometer for the main tuning control. Tuning is silky smooth and there is no perceptible frequency drift. With the KC1 keyer and counter added, the 40A makes an outstanding QRP transceiver. I have taken this unit on many trips, including two trips to Europe and it has worked flawlessly.
The interior view of the NorCal 40A shows the excellent engineering of this transceiver kit. The case top is secured with two snap fasteners for easy field access to the rig's innards. The case bottom is held in place by two nuts and can be removed easily for modifications or repairs. The optional KC1 keyer/frequency counter is mounted on the inside of the front panel. Although this is a compact transceiver, the circuit layout is not crowded and uses standard through hole components.
The standard tuning control has been replaced with a ten turn potentiometer on this transceiver. The VFO toroid inductor and the band set capacitor is visible beside the tuning control. The power amplifier transistor and it's finned heat sink is seen in the lower right corner of the board. There are seven toroid coils to wind in this kit.
There are two key jacks on the rear panel, one for a standard straight key and one for electronic keyer paddles.
Support for the 40A is available both from Wilderness and the many hundreds of users on the QRP-L Internet E-Mail reflector. It would make an excellent choice for a "first kit" for novice builders.
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Page updated May 30, 2007