[Elecraft] Kenwood T91-0352-XX Mike

[Ron D' Eau Claire]

> I have a doubt. I have setup a K2 with KSB2 board wired to use a Kenwood
> T91-0352-XX (it came with a TS-870) microphone. I have adjusted
> it (or so)
> and I find that there is no much power output using this mike. At a quick
> glance I get on spectrum analizer less power than I get when tunning it.
> Any ideas? I don't know if this mike has a preamp.
>
> 	Eduardo/EA2BAJ

Check your ALC action, Eduardo. (Press and hold the Display/RF/ALC button
and you will see ALC in the display). You should see at least one bar on
audio peaks on any band. Remember, the bargraph reads backwards - right to
left -  when you are viewing the ALC to remind you that it is in ALC instead
of RF output mode.

If you can't get one bar to flicker on peaks with the power set to 10 watts,
you probably, 1) don't have enough output from the mic for some reason, or
2) aren't able to get the r-f power output from the transmitter that you are
requesting with the POWER control.

The number of ALC bars will vary from band to band, since the K2 is
adjusting the audio level to produce the desired r-f output and the K2 has
differing amounts of "gain" in the transmitter circuits for the various
bands. You should be able to see one bar flicker on any band though. On some
bands you will see two or three bars light on peaks.

First, be sure that you can actually get the power you are requesting when
in "Tune". That is, if you set the POWER for a full 10 watts, do you get the
10 watts when in "Tune". If not, you must address that first.

If the POWER output is okay in Tune, be sure that you have the SSBA menu
setting at either 2 or 3. SSBA 1 inserts an attenuator in the mic input that
cuts down the audio level. It is only needed with some amplified mics and
other higher-level sources.

Next make sure that you have the mic wired correctly. If it is an electret,
you may need to provide +5 volts to the element.

Finally, some mics have low output for the K2. My dynamic mic could not
fully modulate the rig in 10 meters where the greatest audio gain is needed
to produce 10 watts peak-to-peak. I was able to raise the audio to an
adequate level by changing the 1k ohm resistor, R14, on the SSB board to 5.6
k.

Ron AC7AC
K2 # 1289