Transmission works with wires but not always with wireless

[dhouston]

I'm curious as to why you use the 20ms pause between packets? I know you said that the pause would reset the AGC & threshold, and that certainly makes sense. But I would figure if you're continuously sending bi-phase encoded data (manchester encoded) practically non-stop, wouldn't everything stay where it would need to be?

AGC reduces the gain as the signal gets stronger. Repeating the signal at close intervals can cause the gain to taper off, resulting in poorer reception. A gap between transmissions lets it reset to its baseline. You can play with the duration of the gap - in this case 5-10mS is probably adequate but its hard to say without hands-on experience to determine typical signal strength and performance. Also, I'm eliminating the manchester encoding - the NEC protocol assures a relatively balanced ratio of pulses/spaces for the dataslicer threshold.

Another reason for inserting a gap is to allow the receiver time to analyze what it has received and decide what action to take.

It is possible to get a measure of signal strength by taking ADC readings of the receiver's Linear output pin. I measure the difference between a pulse and space which, while it is not an absolute measure (due to AGC), gives a good relative indication of signal strength. IOW, if one signal registers 700 and another 500 I know which signal is stronger (and can use it for tuning) but I cannot definitively compare measurements from separate receivers since I'm not measuring an absolute magnitude.