I went back thru this thread to look for the answer, and did not see it
so am asking. The one of these I have has a threaded female connector
on it. One of the ones in Tom's page has a smooth sided connector, FWIW.
I wonder if this would work with one of the 5m SMA male active antenna
units will work with it?
http://www.ebay.com/itm/321295751672
This one happens to be 5 meters long and is active. I am guessing
because the unit has antenna power this is the sort of item to use?
I want a long run because where I plan to use it is some distance from
clear line of site.
thanks
Jim
On 6/20/2014 8:31 AM, Tom Van Baak wrote:
Hi Ernie, Jason, (also Hal, Chris),
I'm able to get NMEA and 1PPS out of the Fastrax/iTrax130 board now.
Before I sink any more time into this project, have any of you made 1PPS
measurements?
Compared to ublox, using the same antenna, these units take tens of minutes or
even hours to lock. And they have a bad habit of being close to UTC for a few
hours but then gradually wandering off by tens or hundreds of microseconds.
A power cycle puts them back on track (aligned with UTC), so it would seem to
be a firmware issue rather than antenna or reception. A similar thing happens
on three different boards I have evaluated over the past two weeks.
Now, when they are working right, the 1PPS has an RMS deviation of around 20
ns, which I've come to expect as typical for cheap GPS/1PPS receivers these
days. But the long lock times and unexplained 1PPS drift make them unreliable
for GPSDO or serious timing work, even at $12 each.
It might be me, so I'm asking if you've seen anything similar. The binary
command set looks tempting, but I usually don't play with that until the unit
can be trusted to give reliable NMEA and 1PPS output.
Unfinished page: http://leapsecond.com/pages/itrax/
/tvb
----- Original Message -----
From: "Ernie Peres" <erniepe...@aol.com>
To: <time-nuts@febo.com>
Sent: Wednesday, June 11, 2014 4:11 AM
Subject: Re: [time-nuts] FASTRAX GPS
Hi Jason,
I figured out a different pin assignments....
hold the PCB so that the SMA antenna connector is looking to right and under
the PCB.
open- 1 2- Ant power presently connected to pin nbr 4
TX- 3 4- Main power +3 volt
RX- 5 6- 1PPS
open- 7 8- Grnd power -3 Volt
the unit takes about 60mA @ 3,0 volt and comes-up in NMEA mode.. 9600 Baud.
I use the FASTRAX_WORKBENCH_522 software.
I wonder if anybody has other pin arrangement/connection. The 2 open pins is
UNK and also not sure if pin nbr 4 is the main power or perhaps the pin nbr
2......??
Rgds Ernie.
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