I decided to put some of the comments into their own post because they were top-notch comments and should not be buried.
Anon contributed "Foil/metal reflectors around the pipe could also boost pretemp passively, and if designed proper be adjusted for movement of the sun for optimal capture."
ERJ responds: Yes, you are absolutely right. But I know my limitations. I can get sucked into pursuing "optimum" and risk never getting started. I banged together a system with materials on-hand. Incidentally, materials that are commonly available in most places, hence of interest to others.
Jonathan H. asked "What are your procedures for making sure your product is dried enough and packed properly to make sure it lasts?"
ERJ responds: I am still feeling my way along. I don't have a good answer. Maybe one of the other readers can give guidance or point to some websites or articles or videos they found useful.
Anon (2) wrote "If possible, consider raising your inlet 6 - 8 ft off the ground in an
open sunny area to reduce inlet humidity. When I've visited humid
places, the moisture content seems much higher down low, and in shady
PS - Arizona is horrible - everyone should stay away."
Regarding Arizona, I liked the town of St Johns. It resonated with me. Otherwise I have to defer to your expertise.
Scrivener asked "Bug / dust filter on the open end of the pipe?"
ERJ responds: Not yet. Maybe never. Most bugs follow scents that flow with the wind so they are more likely to enter via the outlets on the dehydrator. It is not very dusty where I live. We had the foresight to purchase a property that was on the up-wind side of the gravel road.
Fido also voted for raising the pipe off of the grass "That culvert should at least be insulated from the lawn. Maybe just a few 2x4s."
ERJ responds: You bet. I have lots of empty dog-food bags so that is what I used.
Old NFO wrote "Interesting fix, and makes sense!"
ERJ responds: If I have one skill it is being able to see ways to repurpose common items to fill a need. Thanks for the comment.
Thanks for all of the great comments. I apologize for not always being good at recognizing them.