10
Operation
Enabling the tuner:
In the Jupiter setup menu, check the AUTOTUNER setting. If it is presently set to OFF, change it
to ON. You only have to do this once, the first time you use the tuner.
Normal operation:
Operation of your JT-11 tuner is controlled by the Jupiter's
Tune
button. To tune, simply set the
radio to the desired operating frequency and press the
Tune
button on the radio's control panel. A
tuning cycle will begin; stored tuning parameters will be used if available. The radio will transmit
a carrier of about 20 watts, and the tuner will cycle. You may hear the relays switching in and
out; they make a fairly loud buzzing noise. The tuning cycle will automatically end in a few
seconds. The radio will unkey, with power set back to the normal level. The letter "T" will appear
on the display, indicating that the tuner is active.
Bypass mode:
To transmit without using the tuner, simply press the
Tune
button again. This sets the tuner to
Bypass mode; RF goes directly to the antenna with no matching. The "T" indicator goes out,
indicating that the tuner is not active. Repeatedly pressing the
Tune
button toggles between
active and bypass tuner modes.
Forcing a full tune:
As you use your JT-11 it will automatically memorize tuning parameters for up to 200 of your
favorite frequencies and bands. When you transmit on or near that frequency again, your JT-11
will restore these parameters almost instantly, much faster than a full tuning cycle. Your JT-11
literally "learns" as you use it.
You can, if you wish, force the tuner to run a full tuning cycle even when there are tuner
parameters stored for that operating frequency. Press the
Tune
button to start a tune cycle, then
press it again to abort the cycle. Press
Tune
a third time to clear the "T" indicator, then once more
to start a full tune cycle. Yes, this procedure is a bit clunky, but then again, you won't need to do
it very often; your JT-11 is very good at finding a match.
Each time you power up your Jupiter, the JT-11 will automatically reset the last-used tuning
parameters, so you don't have to retune each time. Memory operation is fully automatic, and
requires no input from you.
SWR readings:
Due to the way that the Jupiter reads the SWR, you may get a lower SWR reading when tuning
than after the tuner stops. This is because the radio lowers the RF power during a tuning cycle.
For example, you may tune and see a 1.5 SWR, but then keying the radio at full power after the
tuning cycle will read a 1.9 SWR. This is due to non-linearities in the Jupiter’s SWR reading
circuits. Typically the lower the RF power, the lower the SWR will read. This may happen even
on a dummy load.
Disabling the tuner if desired:
If you wish to disable the tuner altogether, set the AUTOTUNER setting to OFF in the Jupiter
setup menu. Thereafter, pressing the TUNE button will have no effect. To enable the tuner again,
change the AUTOTUNER setting back to ON.