Throat Microphone for bicycle mobile

I wanted to try using a throat microphone while operating the radio mobile on a bicycle. The big problem is wind noise on any conventional mic, but a throat mic is a contact microphone which picks up the vibrations directly through the neck.
Apparently they are often used by security guards and the like for discreet radio communications because they can be hidden under a collar.
I bought one of these.
https://www.amazon.co.uk/gp/product/B075D6PFPD

The two-pin jack plug connects to my TYT MD380 DMR radio, so it was quite easy to try out. The Ashford repeater GB7AS features an echo facility where you can talk for a few seconds, and then the repeater plays back a recording of your transmission. I found that the audio was quite muffled, but was best when I moved the microphone as high up the neck as possible.

But I also noticed another problem. On high power, there was a "puttering" noise on the transmission, which seems to be the radio frequency signal getting into the microphone and causing interference. The noise went away on low power, but was very noticeable on high power, where-ever I positioned the radio antenna.

Undaunted, I took the equipment for a 12 mile cycle ride up onto the North Downs. I was unable to raise anyone on the Charing repeater GB3CK (using analogue transmission), but I did manage to get a signal report from Peter GW6YMS on Anglesea in Wales on DMR, via GB7AS.
"Unintelligible"  was his verdict, and "there's terrible motor-boating on your transmission" - which didn't go away even when I switched to low power. I gave up and talked to him using the microphone in the radio.

The earpiece part of the device does work quite well, although it tends to fall out of my ear after a mile or two. It is quite clear to listen to, private and comfortable to use - and I can still hear traffic coming up behind quite well too.

Curiosity got the better of me and I opened up the microphone and the little "junction box" in the cable, to see what was inside.

 You can see that the "microphone" is just a very small "piezo bender". This seems to be connected directly to the microphone input of the radio. There is a soft pad of foam behind the bender, and a small piece of blank fibreglass PCB. The wiring looks pretty horrible, with joints insulated by little dobs of hot-melt glue.

The junction box is equally ugly inside with more blobby joints and hot-melt glue.

It was very inexpensive.

I might try to make a boom microphone like I use in the car, with an electret capsule in a wind shield of some kind. I could keep the earphone part of this and try and improve the RF shielding.

73 Hugh M0WYE