M8 screw and nut, note how the nut had to be grinded a bit so it fit perfectly
in the spectrum antenna.
We filled up the antenna black plastic foot with hot melt glue, nice and easy
The 7 Pin DIN connector DONT use pin 6 normally ! so it is free to use for PPM
The PPM out signal is 3V positive pulses ! so it matches perfectly the demand on
a spectrum module.
add a wire like on this picture, pin 4 is PPM input as normal. so you can use a
student tx unit at the same time.
R2 on spectrum removed as usual, the idea about R2 is good if you use spectrum
with any JR or Graupner TX
those have floating PPM signal.
The 4 mounting screws are M2.5
Spectrum uses a long and super thinn RF coax with tons of loss, tiny connector
and 2mm coax soldered carefully directly to spectrum rf module pads.