Title: A few remaning questions
Post by: sm0nor on 28. February 2018, 20:20:47
Hi All!
I'm very close to hitting the goal but I have a few details I'm wondering about:
1, There is a D4 marked on the board but nowhere else. What is the purpose of this diode?
2, There is no C110 in the BOM. Correct?
3, T3 was missing in the bags so I'm skipping this for the time being. Under what condition do I need the optional mic bias?
/Ulf |
Title: Re:A few remaning questions
Post by: peter_77 on 01. March 2018, 07:49:46
Regarding issue 1. take a look at the schematics.
https://www.amateurfunk-sulingen.de/data/uploads/ovi40-sdr/uhsdr_ovi40_ui_v17_sheet.pdf (https://www.amateurfunk-sulingen.de/data/uploads/ovi40-sdr/uhsdr_ovi40_ui_v17_sheet.pdf)
Right hand side where the mini USB connector is.
D4 is optional and it provides 5V to the mini USB plug.
Usually its not needed and can also cause problems cause the mini USB is a USB client where 5V is provided from the host (PC). This may conflict with the 5V from the connecting host.
Micbias in issue 3. you need in case you connect an electret condensor microphone. They will not work without a bias voltage of course.
Most of the cheap China Baofeng or Kenwood style microphones often used here are electret condensor mikes today.
See infos from DL1CR regarding this here https://www.amateurfunk-sulingen.de/forum/index.php?board=15;action=display;threadid=330;start=15 (https://www.amateurfunk-sulingen.de/forum/index.php?board=15;action=display;threadid=330;start=15) |
Diskussions- und Newsboard des DARC-Ortsverbandes I40 | Powered by YaBB SE
© 2001-2003, YaBB SE Dev Team. All Rights Reserved.
|