Hi all,?

i am about to connect my Raspberry Pi via a usb souncdard to the uBitx.

in relation to the mic out from the rig to the sound card - does the dc voltage present on the tip of the plug (for the electret mike) pose a problem? I am confused as to whether or not I should add a capacitor in line to block the dc? Should I, and would that even work?

thanks.

Daimon. G4USI.

Hi Daimon
I must admit I'd never thought of the potential problem you mention. However FWIW I use a Signalink USB between Raspberry Pi and ubitx and it all works fine in every mode I've tried.
Cheers
Jeremy

The signaling has a serious capacitor built into it

On Dec 1, 2018, at 12:28, Judd Telemetry <juddtelemetry@...> wrote:

Hi Daimon
I must admit I'd never thought of the potential problem you mention. However FWIW I use a Signalink USB between Raspberry Pi and ubitx and it all works fine in every mode I've tried.
Cheers
Jeremy

Daimon,

I have not connected anything other than a mic and amp to the uBitx, however I have a lot of experience with both Arduino's and Raspberry Pi's. Both are susceptible to high voltage on their inputs (5 volt limit for most, 3.3v for some), and can be damaged if more is applied.? The dc available on the uBitx mic connection is over 8 vdc (limited by the cureent resistor).? I would strongly recommend you use a cap on both inputs and outputs to the uBitx (note there is already a cap on the audio out).

Just my 2 cents

Evan

AC9TU?

I ?use series capacitors often, especially to avoid the transformer output shorting out the DC! 1 microfarad works usually

On Dec 1, 2018, at 05:35, Daimon Tilley <daimontilley@...> wrote:

Hi all,?

i am about to connect my Raspberry Pi via a usb souncdard to the uBitx.

in relation to the mic out from the rig to the sound card - does the dc voltage present on the tip of the plug (for the electret mike) pose a problem? I am confused as to whether or not I should add a capacitor in line to block the dc? Should I, and would that even work?

thanks.

Daimon. G4USI.

That surprises me. I always use a sort of psk interface, i. e. isolating transformer (to avoid ground loops), fixed attenuator (the signal from the sound card might be too strong for an mic input), volume potentiometer (to tailor the max output of the rig up to half of full output, to save finals and have a cleaner output) and blocking caps.

Il 01/dic/2018 20:30, "Daimon Tilley" <daimontilley@...> ha scritto:

Thanks Evan.

On 1 Dec 2018, at 17:28, Evan Hand <elhandjr@...> wrote:

Daimon,

I have not connected anything other than a mic and amp to the uBitx, however I have a lot of experience with both Arduino's and Raspberry Pi's. Both are susceptible to high voltage on their inputs (5 volt limit for most, 3.3v for some), and can be damaged if more is applied.? The dc available on the uBitx mic connection is over 8 vdc (limited by the cureent resistor).? I would strongly recommend you use a cap on both inputs and outputs to the uBitx (note there is already a cap on the audio out).

Just my 2 cents

Evan

AC9TU?