KK1L 2x6 Antenna Switch
Relay Unit & Control / Band Decoder Unit
2 Radios to 6 Antennas
"I gotta build me one of them!"
Material on this page © Ronald D. Rossi, KK1L

Relay Unit Information
New High Isolation Relay Board Schematic (PDF) 22-DEC-2008 Click image above to view 12V activated relays with 50Ohm termination for unused antennas to reduce reradiation and unwanted internal coupling. NEW: I measured port to port isolation to be -61.2dB worst case! This is a whopping 24dB improvement over the previous version while keeping the same features and size with a lower parts count!	New High Isolation Relay PC Board Layout (PDF) 22-DEC-2008 Click image above to view High quality FR4 double sided 2oz copper, masked, and silk screened both sides. Available for purchase. Email for availability. Basic construction information Chassis Drill Template - mirrored Chassis Drill Template - standard

Control / Band Decoder Unit Information
Controller / Dual Band Decoder Schematic (PDF) Latest version (4.8)! Click image above to view Includes two fully independent band decoders and the logic to control the 2x6 switch relays. The configuration is highly flexible. Use the decoders to drive the relays or something else if you wish. Provides antenna lockout to prevent putting both radios on the same antenna (a bad thing!). Includes hot switch protection and optoisolated band data & PTT inputs. Band data can be wired on 25 LPT connectors (defacto standard) or BCD inputs on header pins. Version 4.8 includes the feature to make it easy to combine both the auto band decoding and manual antenna switching!	Control / Dual Band Decoder PC Board Layout (PDF) Latest version (4.8)! Click image above to view High quality FR4 double sided 1oz copper, masked, and silk screened both sides. Designed in sections so all sections do not need to be populated. If you have no need for the band decoders then you can just populate the relay driver and antenna lockout section. An AC to DC regulator section is included in case you don't have a 12V DC source. If you have a decent junk box and are creative, then you can build this pretty cheaply. Available for purchase. Email for availability. Construction Notes (and other info!) Auto Band Decode Modification Instructions for previous versions 4.7 and 4.3

Other Information
	Detailed Bill of Materials in XLS format with Mouser partnumbers Click image above to view
Switch Writeup and Measurments (PDF) Click image above to view All the details you need...I hope.	Mouser Project Files: Controller/Band Decoder Parts Relay Board Parts Other Parts Sources: Source for relays (AZ755-1C-12DE) Alternate source for relays (AZ755-1C-12DE) Source for Relay Board CHASSIS (7112C) Source for Control Board CHASSIS (TG-28)

Orginal Control Board / Dual Band Decoder Errata & Addendum (PDF) Click image above to view Highlights changes to original controller board. NEW BOARDS HAVE BEEN FABRICATED!	Gallery! Click image above to view A few dozen folks have built this project. I only have pictures of a few. Here is their FINE work!

Original Relay Board Schematic (PDF)	Original Relay Board Layout (PDF)

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