+FM STEREO TRANSMITTER
MICONIC F35
https://pbs.twimg.com/media/DtajKIwUcAA-k5s?format=jpg&name=large
SVH-F35
Sound remote control that receives stereo audio

This sound remote control receives stereo audio from an FM stereo transmitter built into the VCR.

https://youtu.be/RLxllWS3oMM?si=dk7Ih63xeVB8UYMI

Sanyo VTC-MH5 - Japanese NTSC Beta Hi-fi Video Recorder

They don't mention what the FM frequency that the transmitter uses. Do you Know?..