Battery consumption observations

[mitaux8030]

Just out of interest, I measured the battery consumption under various receiving & transmitting conditions and found that:

Consumption increases approximately 6% when receiving a digital signal, versus an analogue one of similar transmitted volume;
However reception of an analogue signal when a digital conventional channel is selected has 110% more battery consumption than if the analogue signal were received on an analogue conventional channel;
Scanning increases consumption by approximately 5%, as does dropping into CC scan or WA scan
Consumption increases approximately 6% when static on an EDACS control channel, but scanning groups does not increase consumption at all.

However one thing I did find intriguing was that occasionally when either static or scanning groups in EDACS, the consumption sometimes *dropped* by 10% compared to sitting static on a conventional channel. I couldn't reliably reproduce this effect, and it leads me to believe that either there is some form of digital TDM 'sleep' mode under EDACS, or that certain parts of the circuitry are shut down by a bug in the firmware of the test unit... and this observation may go partly toward explaining why occasional (empirical estimate of 1-3% depending on site configuration) entire transmissions are missed - not just late entry, but an entire transmission.

For transmitting, I note that the power control loop is very fast acting; even changes in the return loss of the antenna due to changing proximity of the user's hand / head etc are instantaneously compensated for.

 

[EnidPuceflange]

I'm assuming you're looking at a P7100, LPE or 700P radio yes?

The core of the radio has hardware to decode EDACS control channel data, so in EDACS mode the radio shuts down the DSP - this is what gives you the power savings. Group scan in EDACS doesn't move the receive frequency at all (unlike conventional scanning which moves from freq to freq) so you'd hope that group scan didn't "cost" any battery life. Once the radio has to move the receiver, then the battery drain starts to tick up.

As an aside, you'll probably find that ProScan ticks the current draw about 5% up when it is running....