3.7
Fitting an ultracap (a.k.a. supercap)
There is a place on the QLG2 board to fit an ultracap (a.k.a. supercap). This is a lot more
reliable means of providing backup power, than the little rechargeable battery on the QLG1.
Backup power permits the operation of the internal Real Time Clock (RTC) in the GNSS
module and also retains the downloaded satellite ephemeris data, which will enable a hot-
start (satellite fix computation) within a second or two of power-up.
Most amateur radio applications will not need this, but the pads are made available on the
board in case you do wish to use it.
Be careful to observe the correct polarity to avoid a possible bang and a nasty chemical
mess (don’t ask me how I know about this, either).
The photograph shows a 0.47 Farad, 5V capacitor installed on the QLG2 board. The pads
are separated by 0.2-inches (5.08mm) and the capacitor fits perfectly.
This capacitor
appears sufficient to backup the QLG2 GPS for at least 12 hours.
QLG2 manual for firmware 1.00a
12
