This morning I built a mic/PTT for the BITX 40. I used the little electret element that Farhan sent with the rig. The element sits atop the plastic tube from a pen. For the push-to-talk I used a little push switch that locks down (on) until you push it again (which opens it). This is very convenient — you don’t wear your thumb muscles out on long “old buzzard” transmissions! I used some PVC pipe and some wooden dowel to make the thing a bit ergonomic. It is held together with Gorilla tape.
It works great! I put the rig on the air this morning and very quickly worked KD3TB up in Pennsylvania — Irwin was testing his K3. Then I worked KM4LWP — James was only a mile or so from me, running 3 watts from a KX3. Then Mario, K2ZGW called in. Everyone said the rig sounds great.
In the picture above you see the rig, the mic and (on the right) the VFO.