The 433mHz AM beacon was updated. The Atmel 328p now has its own PCB instead of the “legs-up-beetle” style of previous versions. The further reduce the size of the unit, the 328p board was placed in a sandwich orientation with the transmitter module.
Despite the small size, the board now has a programming port to enable reprogramming of the module.
Below the 433mHz beacon module in front of an Arduino Uno for size comparison.
The DRA818U radio module is known to produce harmonics at higher frequencies. To avoid problems with other radio equipment a low pass filter was installed in the latest version of the Talky GPS transponder.
To check the efficiency of the filter, a spectrum analysis was performed. Tx power at the ground frequency was unaffected (1 Watt) while the harmonic was reduced from 2.2 milliWatt to 13 microWatt.
Turning the O-ring groove in a 120mm diameter graphite nozzle.
Turn slow (30-45rpm) to avoid dust getting airborne.