Small but important update. I have received the female antenna plug connections and have more or less decided on one style of player. There are 2 questions remaining for the gentleman in China...are more of this style available? and how do you make the BT phone answering mode work? At this point I will admit the BT thing has been pretty much on/off and it may simply be that I don't understand it well enough. It receives BT transmissions, but then I haven't been completely able to make all samples answer the phone. Could be me. But the FM and MP3 (whether via USB stick or micro SD card) work just fine and I expect them to work well with a standard antenna, also.
The measurement for the opening is 20.5mm x 84.25mm
More as it is available.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end