Thursday, August 25, 2016

A very interesting update from Jonathan posted on the facebook page 8/25/2016

After some investigating by some very clever people, it appears that a simplex (DMO mode) DMR system is possible without having to use radios with very fast TX/RX changeover times. Therefore I have started work on such a mode for the MMDVM. This would potentially allow for a tri-mode simplex gateway since D-Star and C4FM already allow for simplex use.
This will use exactly the same hardware as a duplex MMDVM, the same interface boards for example, but with only one FM transceiver instead of two, and of course no need for a duplexer.
I hope to get the first versions available next week. See the MMDVM Yahoo! group for more details.

Tuesday, August 16, 2016

Thursday, August 4, 2016

We’re back with a little update.

Sorry about keeping you in the dark. You know how it is: the family and a full-time jobs leaves us very little time for hobbies. Not to mention the irresistible nice weather (at least up here in Canada)…

That being said, we’re a little bit behind the schedule with the new boards but we’re moving in the right direction.

First of all, the unreleased revision 1.1 that we mentioned at the Dayton Hamvention this year got so many improvements that we decided to launch it as revision 1.2. The change in name won’t affect the end users, but it helps us keep track of the things we do.

Here’s what kept us busy all this time:

•             PCB change from 2 layers to 4 layers (New internal layers for 3.3V and GND)
•             New filters and amps (designed by EB4FBZ)
•             Improved routing of traces
•             Added protection diodes to all external pins
•             Adding one more op-amp in both transmit and receive paths for new filters
•             Added one more radio status and one more control line
•             Added two more status LEDs
•             Added circuitry for both TCXO and crystal for low ppm clock (the boards will ship with TCXO)
•             Corrected long standing connector spacing problem
•             Changed from 270 degree turn trimmers to multi-turn trimmers
•             Changed critical paths to higher quality resistors and capacitors
•             Added solderable jumpers to bypass large bypass capacitors
•             Added external RSSI input connector - goes to ADC pin on Due

Thank you for your patience and continuous support!