MagicBox V1R2B, Assembly Manual

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Assembly Manual
V1R2B-Rev1.0D
for 4 State QRP
MagicBox
- Solid State Transmit/Receive System
Designed by: Jim Kortge, K8IQY
Copyright 2009-2012 - All rights reserved
This system is the result of some brainstorming with Terry Fletcher, WA0ITP and Joe Porter, W0MQY
at the Dayton Hamvention in 2009. We were talking about kits that might be suitable as revenue
generators to fund the Ozarkcon activities in 2010 and beyond. The "MagicBox" project is the result.
It is an all solid state, Transmit/Receive switching system that allows one to connect single band CW
transmitters (up to a maximum of 10 watts) and receivers together to turn the pair into a transceiving
station, "like magic". The system can be used on any band from 160 through 10 meters. It can handle
both solid state and cathode keyed, tube transmitters. It supports full QSK CW up to about 50 WPM.
And, a non-QSK mode is also provided, for those who don't like QSK CW.
There are five pieces of functionality within the system. First, is a keying circuit to turn on the
transmitter. Second, is a PIN diode switch used to connect the transmitter to the antenna so that it can
transmit and also to isolate the output impedance of the transmitter from loading the receiver. Third, is
a four element, series-shunt switch that disconnects the receiver from the antenna and shorts the
receiver input to ground while the transmitter is transmitting. Forth, is another series-shunt switch
(three elements) used to disconnect the receive audio from the speaker (headphones) during transmit.
Fifth, is an sine wave audio oscillator and series switch that supplies side tone audio to the speaker
(headphones) during transmit so that transmit keying can be monitored. All of the control timing for
the system is supplied from an AVR ATtiny2313 microprocessor.
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