WA4GEG's scratch built home-brew ham station equipment

After receiving many requests from those interested in home constructed equipment, I've put together the following info. Enjoy!

73, Byron - WA4GEG

 


The main station Solid State SSB/CW HF transceiver:

Construction on this rig began in the early '80s and finished (almost) by 1990. The front panel is 17" x 7", attached to a 3"x 17" x 12" chassis for lots of elbow room. The transceiver covers all HF amateur radio bands from 160 through 10 meters and operates modes QSK-CW and VOX-SSB at 100 Watts power output + AM receive. Circuit info: Single conversion (+23 dBm diode ring front end mixer) into a 9 MHz I.F., > 100 dB receiver agc range with a pair of MC1350 IF amp. ICs', direct digital frequency display, high stability VFO controlled tracking-loop (PLL) LO system, diode T-R antenna switching.

The S-meter is illuminated with red LEDs' to match the frequency display red LEDs':

transceiver, front view



A look inside; top view. Center bottom; F-Display Unit sitting atop the PLL shielded enclosure. Right bottom section; TX Bal. Mod. w/ speech amp. and USB/LSB BFO crystal oscillators. Above (larger section) contains RX IF Amps. w/ main and tail-ending xtal filters, IF derived AGC, SSB/CW Product Detector and AM detector. Large box w/ heat sink: detail below. Note: those wires dangling out of view go to the Noise Blanker board; removed for better view of the RX IF Section.

transceiver, inside, top view



A look inside; bottom view. Square box at center bottom is the VFO. Above it is the TX Mixer Unit containing a double-balanced mixer IC: MC1496, pre and post amps. (2N3866) and band-pass filters (diode switched.)

Right chassis and extending from front to back (or top to bottom in this view) is the band switch section; bottom section and working up are the VCO Unit, RCVR Front End diode mixer section containing twin roofing filters and post amplifier. The section above this contains the two-pole RCVR front end Preselector. Following it is the switch section that band switches via DC control voltage the transmitter LP Filters, transmitter mixer band-pass filters, PLL down-mix HET OSC and VCOs'.

Left chassis main board contains RCVE Audio, VOX, ALC, SWR Protection, AVR and T-R Control circuitry:

transceiver, inside, bottom view


Power Amplifier Unit hinged out of it's shield box; Power transistor line-up: 2SC1306 predriver, push-pull MRF476 driver and push-pull MRF455 final stage. The larger bottom pc board contains the SWR Bridge, dip-reed relay switched Low Pass Filters and Diode T-R Antenna Switch. The smaller bottom pc board contains bias control circuitry for the power amplifier final and driver stages:

transceiver, inside, power amplifier



* Page updated 01/07/2017 

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