ACOM Mod


The problem originates by improper TXOUT-to-RF timing (RF transmission exists still after a TX-EN prohibition), combined by too long decay of their CW pulses. 

The solution is simple: involving some hysteresis in the meant comparator make the power amplifier makes it immune to the threshold duration. The comparator will generate exactly one IRQ at each transmission end after the modification.

The modification is done on the Control PCB of the ACOM 1000, please onte that the components are of SMD type. If you are not familiar with SMD technology please ask a professionals to help with this modification.

Step 1. Remove C11 from the board

Step 2. Add resistor R11A, 220kOhm-size 1206, between pins 5 and 7 of the IC U3 - LM393D comparator

A hint: Please look over the soldering of pin 6 that will remain under the resistor that will be added. If there is excess of soldering please take away a portion of it in order to easy the R11A installation.

Good luck /SM7YEA



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