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QMX+ with internal GPS
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I can’t get my QMX+ to connect to the gps. I have the setting for QMX-internal. The jumper is set option 2 for the battery. The clock is on. Real time clock set to QMX+ RTC I’ve removed and inspected all the gps connections all look good.? I’ve also tried a factory reset still no connection.? Is the gps antenna the same on the clock and U3S units, I have three other QRP Labs GPS on those. If they are the same I could test the antenna. ? Thank you ? ? |
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Hi Larry,
make sure your GPS jumper is not shorted to the GPS SMD connector. You can see it looking at the side of the board. Mine works fine, but I am jumpered to VDD. Your jumper needs to be very flat to not accidentally short to the SMD connector. As far as I know, those GPS antennas are all similar, so feel free to try another. Stick it on a cookie sheet if you want better performance. Good Luck, ‘Gregg W7GRM |
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Gregg I checked the jumper it was good, I had mine to VDD to start then moved it hoping it may make a different.? I’ll try the cookie sheet then an other antenna.?? On Sun, Jul 7, 2024 at 7:21 PM Gregg Myers via <gregg.w7grm=[email protected]> wrote: Hi Larry, |
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May not be your problem, but I ran into the same issue. Powered via the QMX+.
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Tried another antenna? - worked fine. Reconnected the one from the GPS option kit, and discovered I hadn't screwed it fully onto the SMA connector. DOH ... Greg
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Update.? I took the QMX+ back to the shack and removed the gps and reheated the solider joint on the module and the main board. No change. After reassembling everything and powering it back with the gps installed I noticed both my QRP Labs clocks with gos had lost much of their display. I unplugged the gps on the QMX+ and both clock displays returned to normal. It is acting like the gps in the QMX+ is acting as a transmitter not a receiver and is blocking to other two GPS receivers. I’m guessing the gps module is defective.? PS ? I did switch gps antenna it worked fine on the clock so that’s not the problem.? I’m open for ideas ????? ? On Sun, Jul 7, 2024 at 7:42 PM Greg McCain via <gamccain50=[email protected]> wrote: May not be your problem, but I ran into the same issue. Powered via the QMX+. |
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Larry,
That does sound like your GPS unit is defective. If you have an appropriate USB to serial cable , you could check it out stand-alone on just a PC. The pinouts are easy enough, but you need to make sure you power it with 3.3v and not 5v (I think I remember it as 3.3v). I have connected several GPS units to my PC in just this way and the data is just serial text streams you could see in a terminal window. But you would need that cable to test it. There isn’t much you could do to repair it if it were defective anyway, so I’m not sure it would be worth it if you didn’t already have the necessary cable. Sorry I don’t have any better ideas. 73, Gregg W7GRM |
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On 08/07/2024 03:09, Larry Christensen via groups.io wrote:
I unplugged the gps on the QMX+ and both clock displays returned to normal. It is acting like the gps in the QMX+ is acting as a transmitter not a receiver and is blocking to other two GPS receivers.Larry, I have had a similar effect a few days ago. I have used 4 co-located GPS antennas working with 4 different radio projects. All have worked properly for many months. I then moved one of the setups using a different GPS antenna, again mounted within 6" from the others. Next day I noted that all GPS units were not locked. Recorded frequency variations indicated this had happened intermittently overnight. After a while all locked again. During the day I noted that occasionally all 4 lost lock, I was suspecting QRM (Local BAE Radar test site) but nothing around 1.5GHZ. Moving the new antenna 6" further away restored lock on all. So far I have not discovered why this happened. I have not reproduced the fault by moving the antennas closer. I was wondering if the new antenna was oscillating or whether leakage from digital circuits was passing up an antenna cable. I think it unlikely the a GPS receiver would oscillate. Maybe a weird phasing effect involving the placement of antennas? Exact original cable runs and antenna placement not recorded and have moved. (None of the GPS are QRP Labs, the 4 not directly connected to any QRP Labs modules each discipline a frequency reference. Two Progrocks and a QDX are involved. I do also have a U3S with GPS but did not remember so did not check that.) 73 Alan G4ZFQ |
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Alan I thought of that I moved the QMX+ & GPS to a different floor across the house from the shack it still ?didn’t work.? The two clock GPS antennas in the shack are several feet apart.? The U3S antenna is three feet from one clock antenna.? Han has answered my support ticket we are working on options now.? On Mon, Jul 8, 2024 at 2:25 AM Alan G4ZFQ via <alan4alan=[email protected]> wrote: On 08/07/2024 03:09, Larry Christensen via wrote: |
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Update #2? Unbelievable customer service.? Thank You? |
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I've just finished building my QMX+ with internal GPS. I had similar problems - I could see the heartbeat flashing, but no GPS data. I was convinced that the link connecting the power was sufficiently flat to not short to the SMA socket. However, I pulled off the GPS board and stuck a tiny square of tape on the link and ran it again. Magic......even indoors my location came up within a minute or two, and my QRA locator.
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Tony
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Donald S Brant Jr