Alan,
On 1/8/23 16:20, Alan G4ZFQ wrote:
On 01/08/2023 08:00, Roland Turner via groups.io wrote:
Is the "mic bias" issue written up somewhere?
Roland,
I'm sure it is written somewhere but you simply avoid any mic input that
has a polarising voltage on one contact.
I'm not sure about stereo on current laptops but older ones I've used
can have dual mic or line inputs on one socket, controlled by the
installed sound settings.
Always the problem is finding the settings, most manuals do not help.
Thanks. It appears that I misread Evan's message, in particular he was simply pointing out that while the dongles in question are missing the bias voltage required by some microphones, Softrocks don't require a bias voltage so its absence is *not* a problem. (I misread it as indicating that it is a problem.)
With respect to those sound cards which *do* provide mic bias, it would appear that it's a non-issue for Softrocks anyway; the blocking capacitor in the Softrock I/Q output path would appear to mean that it makes no difference at all whether a bias voltage is present or not. Quite apart from concerns about finding the setting, or whether there is one, or whether there is one but it doesn't work, is there any particular reason to avoid mic bias on a sound card used with a Softrock? Surely that's just one of dozens/hundreds of settings that can be safely ignored?
- Roland 9V1RT
