Hi Matthew, Do you really mean 500 ms (milliseconds) start bit? I think that the bitslicer would probably re-set its zero point in less time than 500ms. Looking at your scope shot, the bit in the middle doesn't look stray to me - it looks like some aspect of the bitslicer changes in the middle of the byte and from then onward it is considering only the very lowest level of your signal as a digital 1 (it looks like the slicer is inverting). Notice how, after the apparent "stray" bit in the middle, the subsequent bits seem to start off very narrow and get wider? Also notice how the analog output develops little jogs downward at the base of the waveform? I don't know what is causing those but it is almost certainly caused by some aspect of your circuit or modulation scheme violating the timing requirements of the bit slicer or AGC. Sean On Thu, Jan 19, 2017 at 7:43 PM, Matthew Miller wrote: > Thanks everyone, > > Good to know this behavior I've been experiencing isn't unusual. The > SparkFun module (#2 above) is https://www.sparkfun.com/products/10532 > (I've > tried enough modules that I was looking at the wrong datasheet!) > > The encoding scheme I'm using is one that Roman Black wrote about and it > seems very attractive: http://www.romanblack.com/RF/cheapRFmodules.htm > I was writing this as Bob replied. > > For a preamble, a 500ms start bit is being used. I've attached a capture > from one of my tests. The top trace is the digital output and the bottom > the signal strength output of the module (which matches the data being > sent). > > I'll take the suggestion to extend the preamble out to several bit period= s > and see if that helps. This WRL-10532 item from SparkFun is the best modu= le > I've tried so far, no random pulses on the digital output, and the data i= t > decodes is good except for the dropout in the middle. > > I appreciate everyone's replies; this part of the project has been a real > stumbling block. > > Take care. > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .