The highest value capacitance, the better, I would use either a nonpolarized electrolytic or polyester caps for this audio application. Then a 1:1 dc- isolating audio or data transformer to get rid of ground loop issues. Another cap in series on the other end of the cable.
Il 04/mar/2019 18:20, "Joe Puma" <
kd2nfc@...> ha scritto:
What’s a good value for the blocking cap? If that’s the purpose of the one on the easydigi, it’s value is .1uf
Joe
KD2NFC?
Any 600ohm 1:1 audio transformer is a very good idea. 600ohms is a typical impedance presented by headphones these days, so it's a good value to shoot for. There is a voltage present on the MIC in of the uBitx, and this will confuse most modern soundcards and laptops, maybe totally distorting the audio, but If when You plug in a headphone or mic to your computer, the operating system detects this and says something in a dialog box, You need to use AT LEAST a blocking capacitor for the MIC IN on the uBitx/Line out on the computer, but most likely a 1:1 transformer also, otherwise the connection will be very unstable. You will find the computer will switch randomly between the input jack and any built-in mic especially on a laptop, unable to sense if the jack has a load on it correctly.
If You are unlucky enough to have a SINGLE jack for BOTH mic and headphones on Your laptop/tablet - for a headset, you should get one of these
Remember the Audio out using a splitter like this, or a (green) jack on a computer itself for headphones out is also STEREO, and using a mono plug either end of a lead for this will cause problems. So, You might ALSO need one of these which you can then adapt.
Once You get things worked out, You will be very happy with the uBitx for digital - audio using cables, and control via cat (ft817 emulation) with the CEC firmware.
