Thanks Peter,
I will play with a set of RCA terminated leads in a similar way and
measure voltages. It could be that the tolerance in the position of the
1st and 2nd ring on the mike plug are slightly different (was a cheap
headset), magnified there is about a 0.2mm difference between the one on
the headset and the audio plug or that on a typical stereo plug grabbed
from the junk box.
I have a feeling it might be better to build a unit that uses a 4
connector plug and plug that into the KX3 and the the headset into that,
and then any hand held or foot PTT?
What is odd as with a mono mike (both headsets are the same just one has
a mono mike plug) I had to do nothing in the KX3 menus and and both VOX
and PTT on the KX3 operated without having to alter either.
I think the drawings are 99.99% complete but missing a few minor things
especially the details for the inter connections as you have discovered
as well.
72
Dom
M1KTA
On 13/05/13 15:13, Peter Eijlander (PA0PJE) wrote:
Hi Dom,
When I plug in the mic of my PC-headset I can operate the vox without
any problem. MIC BTN=off and MIC BIAS=off...
When I measure the mic connection with a standard 3.5 mm. stereo cable
with two RCA plugs at the other end, I end up having no voltage on the
tip of the 3.5 mm plug and 2.4 volts on the middle ring. That is the
situation I'd expect it to be: These mics are usually wired for mic
inputs of soundcards and they carry the bias supply voltage on the
middle ring and the AF output comes from the tip.
Switching on the MIC BIAS ads an audible noise on my monitor as does
setting the MIC BTN either to PTT or to PTT UP.DN.
Of course in the MIC BTN=off you have no PTT function on the plug
available, so use of VOX is the only option to transmit.
In fact the PTT function is off but the logic level stays high and
that supplies the microphone with the necessary bias form the VPTTUPDN
line that comes straight from the PIC U10 via a 1k resistor if I
understand the schematic part 'KX3 Control Panel: Connectors' right.
I don't know whether J8 in the drawing signifies the MIC connector but
I doubt that for it does not have that extra ring on on the MH3
microphone plug for nothing. I looked through all drawings but could
not find that connector.
Maybe someone else can fill in the gaps...?
72/73,
Peter - PA0PJE
[email protected] schreef:
HI,
KX3, I have played about with the two mike settings BIAS (on/off) and
pgupdwn/ptt/off with a computer headset where the 3.5mm mike has a
stereo plug and no joy. Noted it initially as got the PTT error message
and TX stays open when plugged in. No amount of combinations of with VOX
on/off and setting the mike options seems to make it work where pressing
the PTT on the KX3 keys the mike (or VOX does).
A stereo to mono adapter doesn't seem to help.
Anyone had a similar problem and got a cure?
The headset is identical to another I have as I wanted to get a second
set (for second KX3) but the earlier one has a mono mike.
I looked at chopping the cable and rewiring (The mike has a tiny + screw
in it so I undid it just to see how it was wired) but I noted the wires
are not the easy to solder type.
72
Dom
M1KTA
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