M/M combine
The Open M/M combine by RemoteQTH.com is the black box designed for IG9Y contest group. This box allows you to share the MAIN antenna systems (MAIN OUT connector) for RX and TX to MAIN and SUB TRX. There is also PTT interlock build in. It could be use for both SO2R or MO2R operations.
Main features
RF RX:
- MAIN and SUB TRX can share MAIN antenna system(s) - connected to MAIN OUT port
- SUB TRX can use single RX antenna input - FA RX ANT
- MAIN TRX can also use RX ANT4 input ( if enabled by switch on the front panel)
- High power protection (low bands)
- RX antennas can by selected in all combinations by small box with switches
- SUB TRX can select RX antenna by rotary knob - SUB RX - on the front panel
RF TX:
- Build in PTT interlock system allows TX only one TRX at the same time
- MAIN and SUB TRXs do have the same out port - MAIN OUT
- Low insert loss
PTT:
- PTT interlock
- TRX MUST be PTTed from Open M/M combine
- PTT out for PA and DRV
- Independent RX and TX antennas configuration on Stack Match (Stack Match is option)
Technical parameters:
Isolation Main-Sub (RX): typ. 40dB (160m) / typ. 22dB (10m) Isolation Main-main, Sub-FA: typ. 90dB (160m) / typ. 60dB (10m) Isolation Main TX, SubRX FA: typ. 100dB (160m) / typ. 85dB (10m) Isolation Main ANT4, SubTX: typ. 85dB (160m) / typ. 62dB (10m) Insert loss TX: max. 0.08dB Insert loss RX: max. 3.4dB resp. 7dB (Main TRX , ANT4 enabled) DC power consumption: +12 - 14 V DC, 1A + stack match consumption
Stack match configuratin examples:
Please follow pictures at One to Three stack match for some typical situations.
 Isolation between RX ports Main-Sub |
 Main RX ATT for Main out (ANT4 enable) |
 Isolation tu Sub RX, Main is TXing |
 Main TXing, Sub RX from FA input |
 ATT for Sub RX, sharing MAIN out |
Download
| PCB | ||||
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| Main board | sch1  |
brd1  |
eagle194 | |
sch2  |
brd2  |
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| Control box | sch  |
kicad192 | Arduino code446 | |
| Manual | ||||
| .PDF833 | ||||
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We believe open source is a better way of doing things. View and download the Shield Schematic and PCB Kicad/Eagle CAD files, LibreCAD .DXF, or Inkscape .SVG files. The hardware designs are released under the Attribution-NonCommercial 2.0 Generic |
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Users implementation
 IT9YVO |
 IT9YVO |
