Elektret Condenser Mike Connections by DD9ZO

Problem: You cannot connect this microphone to the radio due to
low-impedance (600 - 1200) input-terminal.

Solution: Here is a small adittion-device to connect nearly all typ of
elektret-condenser-microphones to the rig. You do not need to open the
FT1000MP. All you need is a resistor of 1200 Ohms, a electrolyt-condenser of
33 mykrofarad with about 10V Voltage and a 8-pin-microphon-plug. If you use
small components you can put it inside the microphon-plug.

It is easy to built because the FT1000MP has a positive-voltage-pin (+ 5V)
already inside his microphone-socket.

Lets start it:

To pin 2 of the plug (+ 5V) solder a 1K2 resistor. The other end of this
resistor solder to the positive terminal of a 33 Mycrofarad
Electrolyte-capacitor. The negativ side of this capacitor solder to pin 8
(Mike-In) of the plug. The connection between the resistor an the capacitor
is now your new hot MIKE-IN-Point feeding the positive Voltage to the
microphone-unit.
Connect the electret-mike via a shielded-cable with this point and solder
the shield to pin 7 of the plug an to the negative side of the
microphone-unit. Also connect the PTT-switch to pin 6 and 5 of the plug.

To prevent of ground-loops never connect pin 5 an 7 together!

That is the whole work. You can use all typs of electret-microphones, even a
amplifed electred-mike like a SM2 from ICOM can be used. Cheap headsets from
the computer-industrie works also with this connection.
Here on my side I am using a SM2 Deskmike and alternately a small
elektret-mike from a wireless-telefon built in a HEIL-Headset. The original
HC4 Microphone from HEIL works on a FT1000MP like Mickey-Mouse in a can due
to wrong microphone-impedance (abou 3K) of the HC4.

The FT1000MP Menue-point 4.4 (TX-AUDIO-EDSP) is switched to off. I often get
a ...excellent-audio... report from other stations. Even with the
...german-legal-power... from a pa-stage and the dipol-antenna only 10 meter
away from the shack, I never had RF-feedback in the mike-line.

With the monitor-funktion on the rig, a headphone on your ears, and a
dummyload on the output you can easyly test all kinds of mikrophones also
usind the menue-settings 4.4, 5.9, 7.7, and 8.9 to create a good audiosignal
for your transmissiion.



I am not resposible for malfunktion of your equipment after doing this
modifikation. No warrenty of funktion for this addition-device. Guenter
DD9ZO www.dd9zo.de