JumboSpot with intermittent transmission
Posted: Wed May 08, 2019 5:03 pm
I have a v1.7 jumboSpot from a Chinese seller via eBay on top of a RPi zero W. I went through MMDVMcal to calibrate transmit levels using the F5UII method by pushing the Bessel level (j0) to minimum. I verified that transmit is on frequency (< 20 Hz frequency error). I verified that it's generating ~15mw power.
In spite of this, I'm getting intermittent transmit from the JumboSpot. I'm using a cs750 to receive. The cs750 will receive approximately 1 sec of audio from the jumboSpot, then stop decoding. Sometimes I only receive the first 1 sec of audio and nothing else from a 12 sec transmission. Other times receive will go in and out, at an uneven period. Approximately 1 sec of audio, 2 sec of silence, 1 sec of audio, 3 sec of silence, etc.
During the entire duration of a transmission, the jumboSpot is on frequency, and modulation and power are both consistent (~2.8 khz FM deviation, 15mw power).
I'm using a HP8920A to make freq, deviation, and power measurements.
Any ideas?
In spite of this, I'm getting intermittent transmit from the JumboSpot. I'm using a cs750 to receive. The cs750 will receive approximately 1 sec of audio from the jumboSpot, then stop decoding. Sometimes I only receive the first 1 sec of audio and nothing else from a 12 sec transmission. Other times receive will go in and out, at an uneven period. Approximately 1 sec of audio, 2 sec of silence, 1 sec of audio, 3 sec of silence, etc.
During the entire duration of a transmission, the jumboSpot is on frequency, and modulation and power are both consistent (~2.8 khz FM deviation, 15mw power).
I'm using a HP8920A to make freq, deviation, and power measurements.
Any ideas?