I have the TST 510s, the kind in which I can NOT replace the battery, so I have to send them back to get replacements - which now cost $30/per. I have had to replace several and am honestly getting tired of paying for new ones.
So, when I had then on current trailer with a 2500 short bed truck, I had NO problems with signal loss....now with my new long bed dually (same trailer), I am having serious signal drop outs....I have not tried using the antenna that came with them, but will try placing them higher in the truck...maybe mounting in the overhead. If that doesn't work I will try the antenna.