K8IQY Magic Box
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Announced at OzarkCon 2010
Kitted and Offered For Sale By The Four State QRP Group
Code named MagicBox during development, this all solid state fully functioning
microprocessor based T/R switch is truly a "Magic Box". It was designed by
Jim Kortge, K8IQY, to provide seamless tranceiving using separate transmitters and receivers
It is extremely user friendly, in fact it's fully automatic,
and absolutely silent. It completely protects your valuable receiver, and it is
fully compatible with any transmitter final design up to 10 watts.
AND it tracks beautifully up to at least 50 WPM!
All that is neccessary is to plug in your antenna, receiver, transmitter,
keyer or straight key, and begin sending.
It is then exactly like using a tranceiver. The switch provides full QSK
(semi if desired), sequenced T/R switching between the receiver and transmitter,
plenty of protective isolation between the receiver and transmitter,
a smooth sidetone, and receiver audio muting,
To our knowledge, a TR switch with these features has never been offered
before by anyone, either large company or club, and is not available
anywhere - except here!
The kit includes all the parts required to the build - PC Board,
ALL connectors, programmed controller, transistors, caps, diodes - everything
but the enclosure and power plug. A Ten-Tec TP41 enclosure or similar is recommended.
NO SMD's, all parts are thru hole parts.
First time builders please note: This kit is not difficult to build.
The pc board is large with plenty of space between components for easy
installation. There are NO SMD's, all parts are thru hole parts, and all
connectors are board mounted to eliminate point to point wiring.
Specifications and Design Features
Creates transceiver operation using a separate receiver and transmitter.
Completely automatic operation.
Greater than 80dB isolation between the transmitter and receiver during transmit.
All solid state MOSFET switching.
Negligible receive or transmit signal loss through the
Sequenced switching ... the receiver is off first and on last compared to the transmitter.
The receiver audio is also switched to provide complete audio muting during transmit.
Smooooth 700Hz Sine Wave Sidetone
Fully automatic Full QSK up to 50 wpm. Semi QSK can be jumper selected.
Tested at 10W and probably will safely go higher.
Covers all HF ham bands, 160-10 meters.
ALL documentation required to build the kit is listed here, just click the links below.
Assembly Manual in Spanish - Translation by Jon Iza EA2SN, thank you Jon.
R46 Note: 100 ohms is now being shipped rather than the original 10 Meg.
Schematic Page 1
Schematic Page 2
Auxillary keying circuit for transmitters requiring keyed power supply voltage, i.e Glowbug,TT2, etc.
Easy Hookup (plug and play)
Drill/Punching Template for Ten Tec TP-41 Enclosure Doubles as front Panel Label.
K8IQY's OzarkCon 2010 Presentation (.pdf)
in the K9YA Telegraph (posted here with permission) Thank you Philip.
The cost of this kit is $50 US and $60 DX, Choose a Paypal button below. Shipping will be via USPS Priority Mail with a tracking number.
If paying by check or money order
(US dollars only) please make it out to "Four State QRP Group"
and it send to:
Pay With PAYPAL
Four State QRP Group
Tom Brown WØMFQ
PO Box 627
St. Charles, MO 63302
The MagicBox is carefully kitted and shipped by Paul Smith, N0NBD.
Please direct shipment related questions to Paul
All proceeds are applied toward funding OzarkCon.   Thank you for supporting The Four State QRP Group.