I bought one last week from Ebay for $62.00 and received it quick by the mail. The audio sounds better than the lab kit transmitter. Since it's October I am doing month long programming for Halloween and 2 month holiday programming November and December. The telescoping rod antenna is attached where the wire was which is like a 4 foot telescoping rod antenna. If the antenna did not work, the calibration would say "Err". It's running at 100 mW and covering a good area. The station does go off the air around 11 PM to 10 AM depending on my schedule. I just bought me a ground loop isolator to connect between the mixer and the transmitter it works very well, and it removed the annoying hum. Just like the transmitter was connected to a smart phone.
very cool! Im going to test the same thing you are doing when I get home.. I'd like to see if there is a noticble difference between the 4ft telescoping and a 9ft bit of wire..