SPRAT # 137 (Winter 2008-2009) has a number of great articles on minimalist radio — very simple rigs with low parts counts. Roger G3XBM has a very nice re-make of the ET-1, first introduced by Glen Yingling W2UW in SPRAT 108. I remembered Glen’s article — I always wanted to try it. The ET-1 has just one active device: an MPF-102 FET. And it is a transceiver.
The schematic of the ET-1 appears above. I started building mine yesterday. Got the receiver done and — WOW! — heard some 80 meter signals this morning. More to follow…
Category: minimalist radio
AA1TJ’s Lightbulb Transmitter!!!!
This is a really excellent example of ham ingenuity. Michael, AA1TJ, has built an 80 meter CW transmitter from the components in one of the compact florescent light bulbs.
The Flea: Minimalist QRP from Catalonia
Here is a really interesting little rig from Joan, Ea3FXF, and Eduardo, EA3GHS. They have a very nice web site with more info, including SPICE simulation files and SPICE waveform results.
Check it out: http://ea3fxf.googlepages.com/flea
FB QRP Homebrew From India
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)