If the tuner is not sending back a packet, it means that the value is "wobbling" too much (ie, too much noise) - it doesn't settle.

There are 2 parameters which define when the tuner will send a stalk command to the host: "fuzz" and "loops". The value has to be stable, +/- "fuzz" for "loops" trips round the main loop before it gets sent.

Defaults (not changed by the player s/w) are: fuzz=2 loops=100

You can set these with a command to the tuner: 0x01 0x08 <fuzz> <loops> - you should get a reply 0x01 0x08 0x00 0x08. Try, for example, fuzz=5 loops=100. Reducing loops is probably a bad idea as this gives some form of debouncing.

Obviously, you need to be sure that the values are spaced well enough that it'll work given the fuzz you're using.

The values can be sent over serial from the shell using /bin/echo (not the built-in as ISTR it doesn't support -e) with something like:

stty raw 38400 </dev/ttyS1 (I think it's S1, can't check atm)
/bin/echo -e -n \\001\\010\\005\\144 >/dev/ttyS1

...but remember when the display goes off the tuner loses power and so will loose these settings.

Hugo