Radio, I finished building it about two months ago, and I fire blanks (1/2 lb. Fg) about once a week. I've been getting choosy about under what conditions I fire it: about 30 minutes after sundown, and I wait for one of those dead calm evenings. The smoke hangs and you hear the echo of the retort bounce around the hills 3 or 4 times.
Rick, the downside of those critters is you have to watch where they were before they come to your fields. They can bring in lots of weed seeds with that 'fertilizer'!