- Sun Apr 08, 2007 9:48 am
#28315
This is a post to add a little more to the knowledge base here on the Copernicus GPS compared with the SIRF III.
Like ohararp in this post: viewtopic.php?t=5427&postdays=0&postorder=asc&start=0 my copernicus also never got a fix. It's always pumping out:
My Trimble and V-torch antennas are hanging in a west facing window.
To create a control group, I tested the antennas with an ET-301/EM406 USB SIRF III GPS from SFE. It has no problems getting a fix with the V-torch, but can't get a fix with the Trimble antenna.
So, I stuck with the V-torch for my tests with the Copernicus since it was a known working antenna in a known working location.
I measured the output voltage from the Copernicus and got the requisite 3.29-3.3v so I know the antenna is active. Even with the V-torch I couldn't get a fix in that spot.
I moved my experiment so the V-torch was hanging in a south facing window. There, the Copernicus got a fix shortly. I didn't time it but I think it was probably 45-60 seconds. It also worked equally well in that location with both the V-torch and Trimble antennas.
Not surprisingly, the conclusion is that in marginal antenna locations and variations in antennas, the SIRF III ET301 20 channel can definitely make a difference vs the 12 channel Copernicus. The Copernicus sensitivity is rated -152dBm and the SIRF III -159dBm.
For the money and sensitivity, it seems like the 20 Channel EM-406A SIRF III is a better deal than the Copernicus. I would be interested to hear why people like the Copernicus vs the EM-406A.
Like ohararp in this post: viewtopic.php?t=5427&postdays=0&postorder=asc&start=0 my copernicus also never got a fix. It's always pumping out:
Code: Select all
After reading that thread, I tried numerous antennas - I have an active Trimble mag-mount, an active V-torch, and a short patch antennal like the one shown in the photo in that thread.$GPGGA,,,,,,0,00,,,,,,,*66
$GPVTG,,,,,,,,,N*30My Trimble and V-torch antennas are hanging in a west facing window.
To create a control group, I tested the antennas with an ET-301/EM406 USB SIRF III GPS from SFE. It has no problems getting a fix with the V-torch, but can't get a fix with the Trimble antenna.
So, I stuck with the V-torch for my tests with the Copernicus since it was a known working antenna in a known working location.
I measured the output voltage from the Copernicus and got the requisite 3.29-3.3v so I know the antenna is active. Even with the V-torch I couldn't get a fix in that spot.
I moved my experiment so the V-torch was hanging in a south facing window. There, the Copernicus got a fix shortly. I didn't time it but I think it was probably 45-60 seconds. It also worked equally well in that location with both the V-torch and Trimble antennas.
Not surprisingly, the conclusion is that in marginal antenna locations and variations in antennas, the SIRF III ET301 20 channel can definitely make a difference vs the 12 channel Copernicus. The Copernicus sensitivity is rated -152dBm and the SIRF III -159dBm.
For the money and sensitivity, it seems like the 20 Channel EM-406A SIRF III is a better deal than the Copernicus. I would be interested to hear why people like the Copernicus vs the EM-406A.