Hi, Greg,
I have not tried replacing the LED lamps with either incandescent or compact fluorescent, assuming the noise was generated by the dimmer as it abruptly chopped off the positive and negative swings of the AC waveform. The interference appears as single short positive and negative spikes of identical amplitude. The amplitude is constant regardless of the setting of the dimmer, which is not how a traditional manual dimmer and incandescent bulb combo behaves. Curiously, there is no RF hash generated on the ham bands or AM broadcast band.
I’m beginning to think the noise may be generated by the bulbs, so your suggestion seems reasonable. I’ll swap in some incandescents and check the effect.
Rep rate is always exactly 120 Hz. I can kill the noise pulses by increasing the thresholds/lowering the fixed gain and thus reducing the effective gain, but that degrades the station performance below what I’d like.
It seems odd the pulse amplitude is identical on both axes of the H field amps and all channels of the E field. That points to powerline ingress, but running the system off of battery power would seem to eliminate that. Odd.
Best,
Don F.