I always liked the descriptions of the ingenious homebrew stations used by Indian radio amateurs. This morning I came across VU2LID's site and found this:
A typical Indian QRP station will use a modified AM broadcast (BC) receiver, for the receiving part. The transmitter will usually have a final RF power amplifier using BD139 (or some power MOSFET like IRF530), driven by a Variable Frequency Oscillator (VFO) and chain of buffer/driver amplifiers (2-3 stage). Most of the stations use Amplitude Modulation (AM). Commonly available medium power Hi-Fi audio amplifier modiles using integrated circuits (like the TBA810), driving a modulation transformer forms the AM modulator part.
The above drawing was done by OM Bhasi, VU2UCY (SK)
Re: restoring Millen GDO
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I would want to know the current capability of the 6.3 V winding before
raising the demand by your suggestion. The power xfmr is tiny and I don't
know how ...
2 hours ago
I love hand drawn circuit diagrams.
ReplyDeletereminds me of the computer equivalent Ralph.
Thanks so much for doing a blog, love the podcast of course too.
Good to see one of the most popular ckt in VU... one of my first transmitters...
ReplyDelete73,
Gopan
VU3HPF 2E0XUU.