With PTT pressed and key not closed, this is like an SSB transmitter with no audio. ?There will be some residual carrier, since that balanced modulator is not perfectly balanced. ?I doubt this residual carrier will be strong enough to cause trouble. ? When you push the key down, the modulator gets a DC current through the new resistor, and the modulator becomes very unbalanced resulting in a strong carrier.?
If we want to avoid the residual carrier, the Nano could tell the Si5351 to shut down between dots and dashes. ?The I2C interface into the Si5351 is plenty fast to do this in well under a millisecond, I have no idea how fast the Nano or Etherkit library will be when sending these commands to the Si5351.
Jerry, KE7ER
On Sun, May 14, 2017 at 04:32 pm, Dragan 4O4A wrote:
I'm still not sure what to say about CW-carrier. It must be something with my still-on-board setup. When I manually press PTT, I can hear tone on other, control RX, giving me signal with strength of 4 S-units. When I keep PTT pressed and when I press key, I can hear signal which is about 30 dB stronger (S9 on control RX).
?
