>From the looks of the circuit any small signal n-channel mosfet will work.
It's just acting as a solid state relay to switch in the impedance your
radio expects for mic element. This circuit won't work for anything but a
sound modem as it requires a "stereo" signal, the right channel audio signal
is sacrificed to become a switch signal. If you wanted to modify the
circuit to be a VOX for phone use you'd have to put a buffer (op-amp would
work well) to prevent your primary audio signal from be modified.
Mike
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Jamie Morken
Sent: Wednesday, July 19, 2000 10:24 PM
To: [EMAIL PROTECTED]
Subject: vox circuit
Hi all,
This is a bit off topic, but does anyone know of a widely available
replacement for the n-channel BS170 mosfet?
here is the circuit:
http://www.ife.ee.ethz.ch/~sailer/pcf/ptt_circ/ptt.html#vox
I am soldering on a IRFZ20 n-channel mosfet since I couldn't find any BS
series parts. Might work..
Would there perhaps be a vox circuit compatible with the AX.25
soundmodem using the MPF102 J-FET?
cheers,
Jamie Morken
http://142.104.54.173
