Firmware update MMDVM_HS:021 v1.0 Problem

[G8SEZ]

40 years in professional RF design is what tells me the sort of changes that improve RF performance. This is one of them that is worth it because there is already another ground pin so it's trivial to make use of it.

In the case of the MMDVM HATs I have made measurements in the lab on them, what I found made an improvement was adding filtering on the 3V3 supply rail from the RPi coming through the GPIO connector. It's quite noisy and connects directly to the ADF7021 supply. This was added to the later versions of the HAT (mine are based on v1.2 I think), and on the later dual HAT there is a separate regulator from 5V down to 3V3 to avoid this problem entirely. The change improves the output spectrum and quite likely will improve weak signal reception. I don't suppose many hotspot owners worry about the latter.