Beaglebone Black Rev.C backup of eMMC failed

Problem:
While fiddling with a Beaglebone Black Rev.C I run into a problem while trying to backup the eMMC content to external SD card. eLinux.org provides a description that I followed. However, when booting from SD card, I got only a short flashing USR0 LED and then a steady one. The resulting backup file BeagleBoneBlack-eMMC-image-XXXXX.img.gz was only 1kB in size with zero content.

Continue reading


Discone Antenna for GSM/3G/4G

Here is another DIY antenna, this time for GSM/3G/4G usage. The design was calculated for 800-2100MHz and works well in this range. The antenna has a very broad bandwidth with a low gain and can be used for any application within the frequency range. Since the results are very good even up to 3GHz the antenna is also useful for WiFi. As well as ADS-B (flight radar) because 1090MHz is covered too. In general an excellent antenna for rtl-sdr operations.

Based on this calculator.

IMG_20150718_105634 IMG_20150718_105610
Metal sheet cone and single side FR4 disc.

Continue reading