I'm referencing 2 threads here, an earlier one and a later one respectively.
Multiple radios, 1 speaker/master volume
Multiple Radios/One speaker
So, against Halfpint's judgment in the first thread. I tried a Behringer MX-400, and as he said, it doesn't like "speaker" level inputs, it distorts and won't take the full volume to my speaker. My issue now is the the definition of "line level input." Halfpint used the words "line" and "speaker" level inputs where line is low (mV) and speaker is high (V).
I know this unit will work, but it costs too much.
Fleet Radio Combiner
A unit called the Radio Design Labs ST-MX3 is purported to do what I want in the first thread, but there isn't much reinforcement that it does what I'm looking for. It uses the words mic level for low I'm assuming and line level for high, but I don't really know what our radios put out on this whole spectrum. Anyone have any experience with it? I bought one because one guy is selling them for 14 bucks shipped on eBay right now, so if I don't get any responses, I'll know next week.
eBay link for Radio Labs ST-MX3