ON THE METERS
The other popular meter was manufactured or at least sold under the Sun Ray brand. I have both the Digisearch and the Sun Ray III which is unique in that it uses a 9 volt battery to back-light the LCD at night, otherwise it is powered off of the Sovereign's circuit like the Digiseach. There is no significant operational difference, in my opinion, between the two meters. The Sun Ray stands a bit taller and is a bit easier to see and the III has the back light. IF you hunt at night you will probably wear a headlight which takes away the back light advantage of the Sun Ray.
Once I heard that the Digiseach meter was going the way of the Sun Ray (both are no longer made), I bought one of each to reverse engineer, which I did, in fact I made one for a hunting buddy, it is not powered off of the control box but uses its on 9 volt battery. The simplest and cheapest way at the time.
I was going to etch my own circuit board using the design of the Digisearch, I choose Digisearch because the Sun Ray was unnecessarily complicated in its design. Shortly there after a few folks started making the meters, including a forum moderator and even a guy in the UK, both of which are most likely very good meters. In fact the UK meter looks very similar to the Digisearch. The UK meter is no longer offered, as far as I can determine.
The one thing I did different, I chose a multi-turn wire wound potentiometer to use for the calibration of the meter. It worked wonders, once calibrated the meter would hold the calibration between on and off cycles and was much easier to dial in to 180 during calibration. With the wire-wound pot, it was set it and forget. The multi-turn pot draw back, way more expensive that the simple wiper carbon resistor pots.
The Digisearch is a compact design and because the multi-turn wire wound pot is necessarily much more bulky in comparison to the cheaper pots, it could not be directly fitted into the Digisearch housing. So a new housing would be required, which would have required me to make a mold for vacuum molding if going for the Digisearch look. Sun Ray housing is what I used for the proto type mentioned above.
My occupation picked up and its requires a lot of travel, so I walked away from the project about a year or so ago and now I am selling the Sovereign.