Today I set up my KX3 outside with a 40 meter portable whip antenna and matched the LBS through my HB antenna tuner which is attached to a vertical antenna on the tower. Set my phone on record and went to the shack and began transmitting. The results are not really a surprise, lots of noise, but at least when the LBS was tuned to the KX3 freq. my voice could be heard clearly through the noise. So at least I can surmise that my circuit for the electret mic is working properly and not the cause of the noise.
Here's a link to listen: https://www.dropbox.com/l/s/OkepNNEJw5NWnnp6DZMwLr
Comments welcomed.
At this point all intelligent troubleshooting has been done. At least as far as I'm concerned intelligent and now I've resorted to trying anything that can be moved on the boards, well move it. So I've probably buggered up the BPF a little but that's not to difficult to get back. I did notice that if I hold onto one of the toroids on the bpf that the noise goes away and the output signal seems to remain. Adjusting the bpf caps can reduce the noise but that's only because the signal is been attenuated. The only other thing I have not tried is to operate the LBS on a battery. I don't think the power supply is the issue, but you never know. In fact maybe I should hope it is as the cure is then simple. hihi.
73, Peter
