I used mine at a club fly last weekend, it went for 9.5 hours straight on one set of batteries and was still going strong when I shut it down. It would miss a radio now and then, but if I would hold it up in the air or walk toward the flight line it would pick up the missinf radio on the next pass. I would guess that the extenal antenna would cure that. It did find a person flying without the pin, so it does come in handy.
Call me dumb, but what would I need to make my own antenna? 39" of wire and a plug. Would the wire be soldered to the center pin of the plug? I would like to try it this weekend with a external antenna to see if that works as good as I hope it to

Thanks
Terry