Chirp search mode

[+arcs]

Does anybody know if the new 'chirp' search mode in the Garmins increase the power consumption in the gps? ie is there any benefit in turning that mode off?

[+g-o-cashers]

Yes, from some recent tests posted here by about 10-15ma or a 10% decrease in battery life.

 

http://forums.Groundspeak.com/GC/index.php...=262344&hl=

[+ecanderson]

I'm still curious as to the mechanism. If I were designing a Chirp for low power consumption, it would never transmit anything until pinged by a potential receiver. It would be in some low power receive mode waiting for an inquiry. That would place the transmit burden on the "client" (the GPS). That would explain the somewhat large additional current draw on the GPS side (if you consider 10~15mA large, but it is for a GPS).

 

Has anyone verified that the Chirp does/does not emit any sort of beacon signal (not sending the data, of course - just some sort of beacon)? I don't have a Chirp to play with, so can't sniff one for emissions.

[+dfx]

Has anyone verified that the Chirp does/does not emit any sort of beacon signal (not sending the data, of course - just some sort of beacon)? I don't have a Chirp to play with, so can't sniff one for emissions.

a simple but not 100% conclusive test would be with one chirp and two receivers. enable chirp searching on the receivers roughly at the same time, but not exactly at the same moment, let's say with a delay of half a second. then see if they still detect the chirp at the same moment, or if they also detect it with the same delay.

[+dfx]

a simple but not 100% conclusive test would be with one chirp and two receivers. enable chirp searching on the receivers roughly at the same time, but not exactly at the same moment, let's say with a delay of half a second. then see if they still detect the chirp at the same moment, or if they also detect it with the same delay.

tested this today with two oregons (one 450 and one 550) and one chirp.

 

the two oregons never detected the chirp at the same time, not once. i did a lot of repeats of this test, with chirp searching enabled at the same time and at different times, and with the chirp being in programmed state and in unprogrammed state.

 

there also seems to be quite a lot of frequency contention/competition going on when talking to the chirp. most of the time, the second oregon only detected the chirp after the first one finished download the data from it. occasionally one would detect it while the other one was still talking to it, at which point the "error downloading data from chirp" (or whatever the message says) was becoming a common occurance.

 

a few times one oregon would even fail to download the data after the other one finished doing that. once the data transfer error has appeared (under whatever circumstances) it became impossible to finish the data download (even with the chirp in unprogrammed state). only disabling chirp searching and enabling it again would fix things up then.

 

so while this isn't actual proof, it tells me that most likely the chirp is only a receiver unless prompted to transmit by some other device.

Edited November 29, 2010 by dfx

[+jackrock]

Does anybody know if the new 'chirp' search mode in the Garmins increase the power consumption in the gps? ie is there any benefit in turning that mode off?

 

When I left it on, my batteries died much sooner (by a few hours) than they normally do. So I only turn it on when I need it and leave it off the rest of the time.