Found this site for a cheap external mic w/ 17-foot extension (battery powered mic)
https://id79.securedata.net/matco/pricing.htm
Looks like an external mic that can be connected to a portable audio recorder (comes with RCA jack and DC-In for the mic, but if you are good with a soldering iron, you can modify it for stereo jack, etc.
Only 10-15 bucks for the mic... not too bad.
CCTV ACCESSORIES
A-230AU-4
A-230AU-17
Miniature Microphone with
Built-in Amplifier + 4' or 17' Cable
A-230AU
Miniature Microphone with
Built-in Amplifier
* Built-in amplifier
* Ultra sensitive
* Listen to the sound through walls or block away
* Powered by 9 VDC
* Comes with 4' or 17' cable
* Built-in amplifier
* Ultra sensitive
* Listen to the sound through walls or block away
* Powered by 9 VDC
- Mark