Wednesday, August 20, 2014
Because applying DC to these piezoelectric devices causes electromigration, and therefore the filter destruction. Manufacturers warns about applying DC to the filters, but manufacturers have been ignoring this for decades.
A transceiver with this problem can be easily repaired by just replacing all the damaged filters, and to prevent this problem to appear again, a pair of DC blocking capacitors must be inserted at the filter input/output pins. In fact some manufacturers have modified their PCB in latest revisions to add these capacitors. But are these capacitors enough to keep DC out of the filters?
Tuesday, August 19, 2014
Friday, July 18, 2014
modification to the BG7TBL noise source, and put it in a shielded box, it was time to place it inside the spectrum analyzer, so I could use it as a poor's man tracking generator.
Wednesday, July 16, 2014
The tracking generator for my unit is difficult to find, and very expensive, so aimed by Iban, EB3FRN, I explored other solutions, for example a noise source.
Friday, July 11, 2014
One of the units is a Fortuna On Clip Bluetooth unit. This unit has been with me more than five years. The bluetooth side died, but the GPS side was still working, so I keep it to use in a future, maybe with a microcontroller. Also, this unit has connector for external antenna, so it is ideal for me. But, does it has the 1PPS signal?