|In this photo, you can see the
pre-driver sub-board mounted alongside the TX mixer and
balanced modulator. With some care, each module can be
removed individually for servicing and adjustment.
A small hole drilled into the side of the aluminum chassis permits adjustment of the 1st pre-driver's output circuit using an insulated alignment tool.
In a later version of these two stages, untuned broadband transformer-coupled pre-drivers were substituted for greater stability and much higher RF drive across the band. This eliminated the need for stagger tuning.
|Here is the KISS transceiver's
driver and final amplifier stages. The driver was
originally a 2N338 NPN bipolar transistor. It's been
upgraded to a 2N3866 (with the original emitter bypass
capacitor removed). This stage is coupled, through a
lowpass filter, to the gate of a VN88 MOSFET.
The chassis in the background houses the separate driver and PA boards, as well as an output meter, changeover relay, and input/output connectors and power feedthru capacitors.
Click here to view the schematic for the driver and PA stages.
|Here's the driver board mounted along one chassis wall.|
|This photograph shows both driver and final power amplifier modules installed.|
of truth arrives. Feeling lucky, I hesitantly broke into
an SSB roundtable at about 3.85-MHz at 0012Z on January
4th (2004)---and immediately caught the attention of
KM1A, John in Connecticut.
He gave me a 5 x 4 report! Ain't too bad for what I measure on my scope at about 600-mW PEP (calculated output power as P = E(peak)^2/2R = 8^2/2(50) = 64/100 = 640 mW).
The exciting part of this milliwatt QSO was that other members of the roundtable chimed in! VE3VKH, Ray, in Ottawa copied me clearly, and I also got "clear copy" reports from other ops (didn't catch their callsigns, as I was so excited logging this) on Prince Edward Island and in New Jersey.
A few minutes later and a few kHz up the band, I made another SSB contact with WB1AIJ, Bob, in East Hartford, Connecticut.
|Click here to view the AI2Q logbook for the
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