Re: QCX40 GPS Connection Issue - No fixes. QCX clock undisciplined. Does receive 1pps


Hans Summers
 

Hi Tony

I recommend updating the firmware. 

QRP Labs kit firmware were tested with QRP Labs GPS. If other GPS modules are used, the sentences are not necessarily the same; if the QCX receives a sentence it is not equipped to parse, the checksum validation can fail. This was changed in firmware 1.06. 

You're using a non-QRP Labs GPS and a pre-1.06 firmware. So this could be your issue... upgrading the firmware is the first thing I'd try. 

73 Hans G0UPL 

On Sun, Feb 21, 2021, 10:58 <tony.volpe.1951@...> wrote:
I have two of the QCX family - both on forty meters. One is an early firmware v 1.0f and I want to devote that one to be a WSPR beacon at a remote qth for  period of time, so I need it to keep time and this requires proper GPS operation.

I spent a good while yesterday trying to get it to operate as my old U3 used to do, using the same known good GPS receiver, a Neo-6 type. The connections are good, the GPS has the 1pps pulsing led and the QCX is receiving that because it calibrates the oscillators correctly. What I was struggling with was getting the kit to read and action the GPS sentence from the GPS RX. It wouldn't do it and would not correct the time. It just ran from its default start time of something like, 00000. Randomly it got a 3d fix after a few hours and fixed the time, but I don't think it is reliably reading the data sentence from the GPS.

The baud rate is correct and the gps is configured through the U-blox utility to send NMEA sentences, but I get pretty random results on the QCX from Menu 8.13. 

At the moment I have ' - No f-- t10 s25'. Sometimes I see an A in there and 3d connection but never any number after the F for fixes.

Of course, the clock is running free and is not disciplined.

I am wondering if this is what Hans referred to once when he said:

"Regarding your "no fixes" problem this is simply a problem in the firmware with parsing the GPS serial data. The display f-- is incorrect. I found the solution only recently and implemented it in firmware version 1.06. Your QLG1 GPS is certainly using satellites in its position fix computation, at least 4... if it is not, it cannot display the A or produce a 1pps signal (green flashing LED). The problem is just a firmware bug which in some circumstances prevents the information being properly parsed and displayed. (Don't bother to take it to an open space, it won't change anything). "

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