One of the biggest TH F6A problems is the modulation level. Compared with other transceivers, mine is 1/2 in 2m and 1/3 in 70cm, in terms of modulation.
One of the low modulation reasons is the microphone design: there is no case opening for mic. Instead, the sound must “travel” from the speaker’s holes, through a little channel, finally finding the mic. Sometimes, during assembly, the channel can be filled with speaker fix glue.
Another reason is the “Service Menu” setting.
That it, do not forget to close the transceiver ;-)
- Open the transceiver (as described in the MARS/CAP mod page) and check out if the mic channel is clear (using a small piece of wire). If this is not the case or the improvement is not enough (in most cases it will be not! ) go to step 2).
- Open the transceiver (as described in the MARS/CAP mod page), power on and close the “Service Menu” contacts instantly. The “Service Menu” contacts are located close to the 1 and 4 keys, as described in the following picture.
Warning! On the first service menu option, DO NOT press “OK”! You have been warned!
Once in the Service menu, press “Right” on the “Multi-scroll key” until you see a line like this: “MAX:?? f1:??”. The “??” will be a hex value between 00 and FE. Now press “BAND” to the desired adjusting band. Turn the “Tuning Control” for a bigger value. Press “OK” on the “Multi scroll key” to set the new value. Check out with your friends, not to get overmodulation. It will be better to make this test with the case closed.
Repeat the adjustment for all bands.
On my transceiver, the best values are “FE” for 2m band and “51” for 70cm band.
Enjoy your new toy :-)