First, happy new year for everyone, best for 2018.
I know its awaiting project for some people. APRS Tracker with DRA818V is under test.
Some issues with PCB and software has been discovered.
– GPS head don’t send correctly NMEA sentence, probably du to header connector problems. FIXED
– Some crystal issue, maybe due to PCB trace impedance. Trying to compile the code and running with the internal 8mhz oscillator. Also can be a good solution to avoid stability problems with temperature variations. I have also designed the PCB for a external SMD crystal @16mhz.
– Need some rework about ADXL335, to enable GPS only when movement are detected. Currently under testing.
– I have discovered that the PD pin (power saving control) of DRA module, need around 0.6/0.7v to wakup before sending PTT activation. It’s can be achieved by using PTT command also, but i have find a rising time, the module need to set PD high around 2000ms before sending data. It’s may be can be fix through a trick into the software. Right now best solution is to tie PD pin to Vcc, but with the cost of 70ma, instead 1uA with sleep mode. Sadly the datasheet of DRA module didn’t give lot of information’s.
– I will finally use RA08H1317M module for PA, because it can by powered directly from 12.5v and give 8W output power.
– FakeSmartBeaconing seem to work …