Announcing the SS-40 Digital Transceiver: The site includes all the information you need to build your own, with schematics, parts lists, Gerber files for the PCB and all the microcode to run it. All the parts needed are easily available to the builders.
The SS-40 Digital Transceiver project is a high-performance transceiver built for 40 meters. This is a “quarantine” project designed by Jim Kortge K8IQY with Mike Maiorana KU4QO. The basis of the receiver is Jim’s excellent SS-40 receiver. The transceiver is built with separate functional modules.
- Digital VFO and Control
- Transmitter and PIN switching
- Input Attenuator
The receiver is based on the ADE-1 mixer with an NE602 product detector. There is a 7-element IF filter at 11MHz. There is a very effective AGC that controls both the input RF amp and the IF signal level. The receiver is exceptionally quiet and sensitive.
The transmitter is a class-E design similar to that in the QRP Labs QCX. It provides 4 to 5 watts out with a 12v supply that is easily within FCC purity requirements. It also uses a PIN diode T/R switch that is sequenced by the CPU, which greatly reduces big-signal intermodulation artifacts of simple diode-switched transceivers.
The Arduino NANO based Digital Control board provides agile VFO and transmit signals, as well as an iambic keyer, sideband switching, RIT and T/R control.
The modules can be built as needed to create different configurations.
The receiver can be built alone and driven with an external VFO.
The attenuator can be used on other transceivers.
The digital VFO/control can be used stand-alone as well.
The transmitter/PIN board can be used to add a CW transmitter to an existing receiver.
This project is being released to encourage experimentation. It is released under the license listed on this github page.
The firmware, as well as the schematics and gerber files for the boards are contained in this GitHub repository.