G0UPL's Ultimates, GPS.

QRPLabs Program Chip With USBasp 

https://sites.google.com/site/g4zfqradio/qrplabs_program_chip_with_USBasp  November 2019 Details of programming all QRP Labs devices with a USB asp, Avrdude/Avrdudess.

This page is specific to the Hans Summer Ultimate 3 but will apply to most other projects. Group https://groups.io/g/QRPLabs

At the bottom of this page I am adding notes about other programming methods I see mentioned. 

Also:-

 June 2015 AD9830 DDS mod:- http://www.qrp-labs.com/ultimate3/u3mods/u3mod6m.html (Short R12).

 LC100A L/C Meter test

 The G8LCO power filter/voltage reducer applied to a Si5351 Synth board https://groups.io/g/QRPLabs/message/27199

 Polyphase unit for the U3 receiver oscillating:- https://groups.io/g/QRPLabs/topic/4412218?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,4412218

Connecting to the U3 for In-Circuit Programming.

March 2014:- The U3 now has a pre-installed socket.

This page http://benryves.com/bin/avr_tutorial/avr_tutorial.htm shows a simple in circuit programmer.

In the Files section of the io QRSSLabs group is a document http://groups.io  /QRPLabs/files/Firmware%20for%20U3%20kit"programming.pdf which describes an interface to the U2. Still there but the current place is https://groups.io/g/QRPLabs/files note there are several pages, not one big one like Yahoo.

Here are some pictures that show how I connected the U3

Above details of connections to the U3. Refer to "programming.pdf" for explanation. Pin numbers of Atmel168. Two are routed to currently unused pads. Pin 19 may be accessed on the marked via.

If you intend to use the bandswitching option then connections may be made directly to the IC socket pins. Or to the underside of the bandswitch header, I made connections to the top of this.

The programming connector.

A closeup of the Reset pin 1. The two tracks going to it are cut. I have put a 10K surface mount across one cut. A small wire component could be used instead. The wire link maintains continuity of the 5V track.

Various programmers are available but I cannot comment about those. I make my own if possible and the COM port one below is simple!

But see the bottom of this page, Cheap USB Programmer from Ebay (£2.67 inc.) cheap enough to tempt me! I now recommend this!

A Serial COM port Programmer

Please check!! I do make mistakes.

Two 5V1 zener diodes and a BC547 on top. In fact almost any small NPN will do.

Programming.

The Atmel program looks immense just for flashing a chip. 

You may decide to download and install this. http://www.atmel.com/tools/atmelstudio.aspx Refer to programming.pdf.

I decided to use PonyProg, about 1/1000 of the install size.

Ponyprog - not a 750MB download http://www.lancos.com/ppwin95.html use latest beta, earlier ones do not include the Atmel168. Later chips may not be supported in PonyProg, the Averdude/Averdudess combination will.

Let it calibrate. Set the COM port 

It looks as if it will only accept ports up to COM 4. I used a real port. A USB/serial adapter did not work for me. It will probably run on an old computer with a real port. I don't think flashing a chip will stress an old system.

Select the Atmel168

Connect the interface, power up the U3. Command - Read All.

You should get a "Read Sucessfull" and the window should be full of data with some recognisable text on the right.

Now select the updated hex file.

 If you do not see the hex file then use the drop-down.

And write the flash. 

March 2017 for some time there has not been an eep file, it is no longer needed.

[[Do the same for the eep. Select the file and "Write Data (EEPROM)]]

Rebooting the U3 I got "v 3.00d..."

Fuses:- 

If the Atmel168, or later 328, has been programmed before then they are already set so do not touch them.  But if you are upgrading a U1 to a U2 or U3 then note the fuses ARE different.

As  Hans' post June 2018 Slightly out of date, See 3 December. https://sites.google.com/site/g4zfqradio/qrplabs_program_chip_with_USBasp Hans says:- https://groups.io/g/QRPLabs/message/24845 All Atmel 328s:- L=F7, H=D1, E=FC (or 0x04, see message.)

3 December 2019 A slight change, Hans:- "from now one we will supply new chips with low fuse setting 0xD7 not 0xF7. F7 has a 65ms start-up delay which is NOT needed when you are using brownout detection." This is just Hans making the code as close to perfection as possible. It is not necessary to change this fuse. 

PonyProg fuse setting at bottom here.

Fuse Tutorial http://www.ladyada.net/learn/avr/fuses.html  with link to a fuse calculator http://www.engbedded.com/fusecalc/

Info on programming in the QRSSLabs group:- G3ZJO has some interesting information, Open Office reader available here http://www.odtviewer.com/ 

Other methods.

I'm sure there are many other sites giving a better way than mine. Or one that suits you better. Search!

Cheap USB Programmer from Ebay + Averdude    (Driver:- Use Zadig choose libusb-win32)

March 2014 All U3s will have a 10 pin header for a socket to suit these Usbasp avr programmers. In circuit programming made simple. Later models have the standard 6 pin connector.

Another from Graham, using Averdude for the Almel 328

 VE3KCL in the Photos section:- A completely different way, removing the chip and using a cheap ready-made programmer. Or I'd think it could be used in-circuit using the connections as I've described??  Yes! See below.

This shows  Averdude, a Windows command line application. (Or you may find Extreme Burner easier)

3] Cheap USB Programmer from Ebay + Extreme burner

Extreme Burner here http://extremeelectronics.co.in/avr-tutorials/gui-software-for-usbasp-based-usb-avr-programmers/ is an alternative with a graphic interface.. Versions for all platforms. But it may need caution, 

Look here for a file that adds the Atmel 328 to Extreme Burner.

 G0MJI Copied below:-

"I purchased: 1 cheap Ebay Usbasp avr programmer.  1 Olimex AVR-P28 development board. (Also on Ebay, not too expensive but I'd already prepared my U3 for in-circuit. And you risk damage every time the chip is removed.)

Download: EXtreme Burner 1.4 (well the latest version) set to correct chip type

The programmer and development board plugged together easily so long as pin 1 is taken note of. No outboard psu was required.

Then I lost six hours of my life.

I could clone existing working chips with 'read all' 'write all' buttons in EXtreme Burner. But using the load/write buttons with fresh code produced corrupted versions of Hans' code.

Eventually I discovered a possible bug in Extreme Burner and a work around. So long as I loaded the files using the 'file' menu, rather than the 'load' buttons It then updated the chips fine, even with 'write all'.

Using the above V2.05 was updated to latest version and V3.0 was updated to latest version.

Perhaps this may help someone else. If not I can look this up next time there is an upgrade.

Note to self: Do not use the BUTTONS in eXtreme.

73 Bri G0MJI"

I have now tried this, a cheap Ebay Usbasp avr programmer with the cable end cut off and connected to my U3 as described above. Using EXtreme Burner as Bri describes I programmed a Atmega168 in circuit. This does require the Ultimate* to be powered.

* Five connections to the Ultimate*. U3 as described at top of this page.

NC:- Some of these wires are connected to the programmer. Do not connect anything to these wires, these connections are not required.

I put a plug on the end of the ribbon cable to suit my in-circuit connector to the U3, as above, but no connection to the 5 volt contact. (Note this USB programmer goes straight to the U3)

CHECK THIS! Your cheap Ebay may be different or maybe I've made a mistake.

Saving the EEPROM data.

I had a problem, the EEPROM data got corrupted. This was because my brownout fuses were wrong. If the EEPROM data is saved from a working configuration it may be quickly restored by in-circuit programming. This might help to load different configurations when a lot of settings may need changing.

EXtreme Burner  will read the chip and save both the flash and EEPROM data and save as hex and eep files. I found there was no point in selecting just eep, it saved both even though I had not read the hex. Just the saved eep may be quickly loaded.

Links for More Information Yahoo group has gone, posts should be found in groupsio

 Graham VE3GTC has some notes about various programmers here  https://groups.io/g/QRPLabs/message/42104?p=,,,20,0,0,0::Created,,ve3gtc+programmers,20,2,0,69602173

https://groups.io/g/QRPLabs/photo/2153/6?p=Name,,g4pir,100,1,0,0 John G4PIR's off-board programming setup.

https://groups.io/g/QRPLabs/photo/2167/7?p=Name,,la3jj,100,1,0,0 Jon Ove LA3JJ's in-circuit interface. Looks familiar!

The module in the qlg1 GPS unit https://www.qrp-labs.com/images/qlg1/yic_module.pdf

5] Alternative GPS Units.

 And good advice from Paul, KE7HR, about setting up the Ultimates for use without GPS. This is for the U2 with DDS, the principle is the same for the 27MHz Si5351 crystal.

And https://groups.io/g/QRPLabs/message/29148 here, and in other posts Mikael describes how to use a 27MHz TCXO in a U3S to provide a stable frequency and timing reference. No GPS

Also note if you have a stable oscillator the PPS may not be required, just the NMEA from a GPS is needed to maintain accurate timing indefinitely.

I've been looking at various old GPS units. Possibly seen at rallies, maybe more likely in someone's junk box. Quite a few in mine! These are probably not quite as sensitive as modern ones and a reasonable view of the sky is required. (As all need for reliability).

The Oncore and Garmin 18LVC NMEA is one second slow, not perfect but adequate for WSPR. Note it is the NMEA that provides the time, the PPS the frequency correction.

The accuracy of frequency setting by the PPS will be shown at the higher frequencies, I use 10 and 12m. A few Hz variation here would not be noticeable on the lower bands.

Inverter

An alternative to a transistor is an inverter/buffer IC like the 7404. To remove the chance of damage I have used an IC as a buffer for all inputs/outputs of my GPS units. A single stage inverts, two will give the original polarity. It may be best to use a fast IC to preserve the accuracy of the PPS.

If an inverter is not needed then protection may be provided by a series resistor, 2K2, probably higher, will not usually affect the data.

Other old GPS units I've tested:- All require a separate, preferably active antenna and a PSU. The PPS is typically specified as +/- 1mS but I suspect that IS worst case. They all seem to set the U3 within 3-4Hz max at 28MHz.

A Rockwell Jupiter provides an adequate pps. And the U3 reads the 4800 baud NMEA with it's negative-going pulses.

It needs a 5V supply. It also has a 10KHz output locked to GPS time. Useful as a frequency reference to check counters and lock oscillators.

There was a "T" model with the PPS specified to 100nS but these were rare.

WSPR "DT" 0.0.

The Motorola Oncore SL is another with pps output. Specified +/-500nS. There are various 5V models, some with a more precise PPS. This has a negative-going NMEA and sets my U3. But it has the disadvantage of requiring initialising by a computer after it has not been used for a while. (Visual GPS 3.33, the "Legacy" version, will do this). I'm not sure how long has to pass before initialising is required again, more than one day.

WSPR "DT" 1.0 seconds.

A Leadtek 9543L provides suitable signals. It is a small 3V3 unit. Connections require a delicate touch! PPS +/-1uS.

WSPR "DT" 0.0 seconds. Negative-going pulses compatible with Ultimates.

A basic Blox LEA-5S module is a test of soldering skills. This is really a surface mount module but I managed with wires. They are available on working GPS modules like the others. 50nS is mentioned in the specs but I guess this refers to the LEA-5T timing version. It needs 3V3. The U3 reads the NMEA and the PPS holds it to within a few Hz on 12m.

This is a sensitive module. Indoor, unpowered antennas are possible. Negative-going pulses compatible with Ultimates.

This module is incorporated in an Arduino aircraft control module See here a message from Dave VE3KCL

I did not find sockets so I soldered directly to these boards.

On one I was trying I mixed the PPS and NMEA connections. Obviously the Ultimate did not read the NMEA but it saw the NMEA as a PPS! Care!

All these units have configuration utilities, possibly they may not be needed. As long as the required NMEA sentences are transmitted they should work with the Ultimates.

A page here on the u-Blox 6 & 7 with reference to their configurable output of up to 10MHz GPS-referenced signal. https://sites.google.com/site/g4zfqradio/u-blox_neo-6-7

 I have some notes about GPS units here http://homepages.wightcable.net/~g4zfq/chirp.htm (Now dead, but still available, email) including a download of the CSI-GPS utility. CSI-GPS will configure the Jupiter and Oncore and show NMEA navigational data.

Required for the Ultimates:-

$GPRMC: Latitude, Longitude, Validity flag

$GPGSA: Type of fix, None, 2D, 3D

$GPGGA: Number of satellites in fix, Altitude

$GPGSV: Number of satellites being tracked, signal strength

Monitoring Output on a Computer.

Not essential, Hans has incorporated the data on the U3's display but may be useful for any desired configuration changes.

A program like u-Centre Visual GPS or the older CSI-GPS will show the number of satellites from which a GPS is getting it's location and timing. The Azimuth and Elevation window is especially interesting for a GPS that is used with an internal antenna and a sensitive receiver. With a quadrifilar from a radiosonde hanging in the corner of my room I see 6, 7, 8 satellites being used often none of them visible directly from the window.

Test with your Ultimate switched off. Note if there is any degradation, maybe loss of signals, when the Ultimate is switched on. It just might happen that emissions from the Ultimates might affect 1.6GHz reception. Screening is important.  A remote powered antenna is always best. All the units I've tested have the facility to send power to a remote antenna.

The Survey window could be used as a record to compare antennas or antenna positions.

Use a CP2102 USB TTL UART  Bridge, cheap on Ebay. These interface directly, a 3V3  bridge will  connect to a 3V3 GPS unit and also supply power if required. Other 5V versions are available.. Details here https://sites.google.com/site/g4zfqradio/u-blox_neo-6-7

"Serial Ballpoint Mouse"

Very often the mouse cursor will move uncontrollably when first connecting a GPS to the COM port.

Windows (even Windows 10) sees GPS data on a COM port as a Serial Ball Point Mouse. The solution is to remove the GPS, leaving the UART plugged in, then disable this in Device Manager.

A registry fix may be more permanent. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SerMouse, and change the value "Start" from 3 to 4.  Reboot.

Computer port, usually 9 pin "D"

To connect to a real computer port the TXD signal from the GPS will normally have to be inverted and fed to RXD on a COM port (Serial or RS232 port). All COM port inputs are compatible with "TTL" data, even at 3V3 from a modern GPS. A USB/Serial (COM port or RS232 port) adaptor will work well with Visual GPS.

The inverter shown above will suit, converting the negative-going pulses that the Ultimates require to positive-going pulses the COM port needs. Either 5V from the Ultimate or 5/3V3 from the GPS power may be used.

Pulses from the older Garmin module I mention above do not need inverting, it needs the inverter to feed the Ultimate.

I recommend making your own cable to the computer COM port pin 2. If you use an "extension" lead be aware that many are "null modem" with pins 2 and 3 crossed.

The GPS TXD is an output, after inverting it connects to the RXD input of a computer. Male DE9 pin 2. Ground connection to pin 5.

DO NOT CONNECT THE COMPUTER TXD (Pin 3) TO THE GPS WITHOUT A RESISTOR/ZENER TO CONVERT TO TTL. THE GPS RXD INPUT IS NOT COMPATIBLE WITH COM PORT SIGNALS AND WILL BE DAMAGED. It is only necessary to connect the computer TXD in the unlikely event you wish to send commands to the GPS.

Note that any USB adaptor with a 9 pin connector is also likely to have +/- 12 volts on it's TXD output.

This is the same module that is fitted to the new QLG2. It is not obtained from QRP Labs so has different firmware and different settings than in the QRP Labs product.

June 2021:- The QLG2 has now been distributed https://www.qrp-labs.com/qlg2.html Note the manual at "Downloads". The Navitrack software may be used to check it, see NMEA, satellites, send commands and update. The $ of a command sentence is there already.  If a serial UART is used then you get direct connection to the module but I'm not sure  that makes any difference for any experiments you may wish to make.  The later QLG2-SE version will need a UART.

Note Hans' comments about the QLG2 Re: New QLG2 serial output (groups.io) 

To use the QLG2's USB connection as a computer serial input Windows 10 is required. To use W7 or 8 see the bottom of this page " Windows 7 COM Port Driver for the QDX/QLG2.."  or https://groups.io/g/QRPLabs/topic/83346729#66896

Note it IS still possible to use any version of Windows to update the firmware.

Using method 2 in the manual the QLG2 will start with the bootloader, the USB connection will show as a memory device.

The Datasheet for the QLG2 module https://qrp-labs.com/images/qlg2/e108.pdf

V_BAT pin This powers the RTC (Real Time Clock). About 200uA at 3.3 volts. Normally powered via D1,2 from 5 volts. A "supercap" may be fitted to provide a backup enabling a quick "Hot Start" for a period depending on the value of the supercap. (And the supercap's leakage current which can be high for large values.) See the manual.

The notes below refer to my tests of a module similar to the QRP Labs QLG2. They may be relevant to any experimenter using the QLG2.

In the picture above for my first tests I removed the uBlox module from the board and fitted the Ebyte. Fundamentally pins are equivalent. My embossing tool was not quite good enough, I found it possible to solder pins that had not reflowed with a Weller with a tip like that shown. The thin tip rests in the semicircle of the "pins". Apart from the default settings it programs the same as the QLG2 module.

https://www.cdebyte.com/products/E108-GN01/4#Downloads   NaviTrack software, module data

March 2023 Peter G3SPL    has found Ebyte site is updated and expanded.

Amongst the documents is   an updated English manual. https://groups.io/g/QRPLabs/message/98621

 https://www.cdebyte.com/Uploadfiles/Files/2022-7-6/2022761056555773.pdf 

NaviTrack Commands [PDF} www.ebyte.com/pdf-down.aspx?id=1657

Module starts with GPS/BeiDou. PPS starts when locked.

May be configured with the NaviTrack software

Only two constellations may be used. Will not let BeiDou and Glasnos  work together. 

Using two systems will enable lock under borderline satellite visibility. With good visibility lock is fast.

Default NMEA sentences:- GLL GGA GSA GSV RMC VTG will need reconfiguring for QRP Labs products. GLL, VTG not required. See configuration 19 below.

Study of the Commands PDF should reveal the correct command to send in NaviTrack. I have used Google Translate with the Section 2 of the Command PDF as a start to understand some configuration messages. Edit the Example, copy and paste into NaviTrack.

1 Command 001. Reply message, respond to the message processing result sent by the other party

2 System restart command

3 Erase auxiliary information in flash

5 Configure the interval for outputting NMEA messages (in ms)

6 Enter periodic low-power mode

7 Turn QZSS NMEA format output on or off

8 Turn QZSS function on or off

9 Command: 115 

 Arguments: 

Arg1: “1”，GPS on “0”，GPS off 

Arg2: “1”，Glonass on “0”，Glonass off 

Arg3: “1”，Beidou on “0”，Beidou off 

Arg4: “1”，Galieo on “0”，Galieo off 

Example:  $(NaviTrack incudes the $, do not add it.) Set GPS only PGKC115,1,0,0,0*2B   This is available in Navitrack. Use of Beidu and Glonass together does not seem possible.  ARg4 "Galieo" has no effect with my modules or QLG2.

10 Command: (146) Set the serial port input and output format and baud rate [NOTE the QLG2 is fixed at 9600 and my tests so far have resulted in the module returning to 9600 after a subsequent command.]

Command: 146 

Arguments: 

Arg1: “0”， “3”，NMEA 

Arg2: “0”， “3”，NMEA 

 Arg3: 9600，19200，38400，57600，115200……921600.

Example: 

 PGKC146,3,3,9600*0F

11 Set NMEA output baud rate. This changes output rate, it appears command 10 is required first? Mine reverts to 9600 after another command.

PGKC147,115200*06

Command: 147

 Arguments: Arg1: 9600，19200，38400，57600，115200……921600.

Example:   PGKC147,115200*06

12 Set NMEA serial port parameters. NMEA, Binary, speed.

Command: 149 

 Arguments: 

Arg1: “0”，NMEA “1”，Binary 

Arg2: 9600，19200，38400，57600，115200……921600.

Example:  PGKC149,0,38400*2C  This changes baud rate. No acknowledgment. Disconnect - Connect at new rate. Will revert to 9600 after another command..

13   (161) PPS settings Arg2 Pulse Width mS Arg3 Pulse period

14 (201) Query the interval of NMEA messages

15 Return interval of NMEA message (response to 201 command)

16 Turn SBAS function on or off. [SBAS combines core constellation satellites with Geo-stationary satellites and ground based reference stations to monitor satellite ranging errors.]

17 Query whether SBAS is enabled

18 Return whether SBAS is enabled (response to 240 command)

19 (242) Set the output frequency of NMEA sentences  Arguments: Arg1: GLL Arg2: RMC Arg3: VTG Arg4: GGA Arg5: GSA Arg6: GSV Arg7: GRS Arg8: GST 9-19 Keep

Example: PGKC242,1,1,1,1,1,5,0,0,0,0,0,0,0,0,0,0,0,0,0*33 <CR><LF>

$PGKC242,0,1,0,1,1,5,0,0,0,0,0,0,0,0,0,0,0,0,0*33  *********Applied removes GLL and VTG********* Arg 6 = 5 Means GSV is only output every 5 seconds, it is probably best set at 1.

20 (243) Query the output frequency of NMEA sentences  PKGC243*2A

21 Returns the output frequency of NMEA sentences (response to the 243 command) 

22 Set reference coordinate system

23 Query reference coordinate system

25 Set RTC time

27 Returns the output frequency of NMEA sentences (response to the 243 command) [Must be a typo! The command looks like a date/time entry.]

28 Set the speed threshold, when the speed is lower than the threshold, the output speed is 0

31 Query the version number of the current software

32 Return the version number of the current software (response to the 462 command)

33 Set approximate location information and time information to speed up positioning

34 Set positioning mode

Arg1: Lat Arg2: Long Arg3: Height  Arg4:Year Arg5:Month Arg6:Day Arg7:Hour Arg8:Min Arg9:Sec 

PGKC639,50.7,-1.3,60,2021,4,02,11,0,0*33

In Windows with a QLG2 connected via USB I used Navitrack to send

242,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*37 to my USB connected QLG2 and confirm, just RMC output. The QLG2 will pass all commands to the Ebyte module.

In the QLG2 settings appear to be saved if a backup battery is used (with series diode to prevent charging). Peter reckons a 2032 will last a year.

With my setup I used a 1.5 volt AAA simply connected to the VBKP pin 22. [2.8-4.2 is specified. A lithium cell is to be preferred.] This keeps the RTC going and retains your configuration. Startup "cold" about 5 seconds. 

Using a GPS other than the QLG1 or 2 with the U3. Disable unwanted NMEA messages.

Other GPS modules may not work properly, the “GPS Check” parameter has to be turned off giving rise to the possibility of transmitting a wrong locator. The U3 firmware is written for four NMEA sentences, the QLG series of QRP Labs GPS units transmit only those four sentences. The extra GLL sentence transmitted from default u-Blox modules is not compatible.

I investigated a u-Blox LEA-5S and found that by disabling the unwanted NMEA  GLL sentence then "GPS Check 1" works. see https://www.handheldgroup.com/support-rugged-computers/knowledgebase-KB/24331/

Summary:-

Open u-center. (Or the correct configuration utility for your make of GPS, the procedure will be different, maybe easier.)

Connect to GPS module.

Go to View > Configuration View.

Click MSG (Messages) on the left side list.

For DISABLING:

Choose a NMEA dataset at "Message".  eg"F0-05 NMEA GxGLL"

Uncheck all the boxes:

Click “Send” button in the lower left corner:

Switch to CFG (configuration) tab in left side list.

Select “Save current configuration”.

At "Devices:" select all 4 list entries.

Click "Send" button in the lower left corner:

 Click Receiver > Action > Save Config

 Done

Saving Configuration:- Most u-Blox modules will only save this configuration for as long as the supercap remains charged, you may consider using a battery. Some GPS use a rechargeable battery, more usually a "super cap" most have the facility to fit a battery. A 1.5V dry cell worked with my LEA-5 and Neo 7. Most people would use a smaller lithium cell.  Note the V.KEL VK2828U7G5LF with uBlox chip will save without a battery. Details here https://sites.google.com/site/g4zfqradio/u-blox_neo-6-7

GPS Computer Time Keeping

Note:- GPS time and UTC is different. UTC adds "leap seconds" GPS time does not. A GPS without battery backup may report GPS time for up to 12.5 minutes after locking. The satellites transmit the UTC correction figure every 12.5 minutes. When that figure is received the NMEA reported time will jump to UTC. At January 2019 GPS time was 18 seconds ahead of UTC, the actual difference seen depends on the age of the GPS module, new ones may be spot-on until the next leap second.

Timekeeping utilities:-  http://www.dxatlas.com/ToyNtp/ Uses PPS for high accuracy. WILL work on UART/USB Serial (Lower accuracy.) BUT must use 4800 Baud. QRP Labs/many newer GPS default 9600.

BKT Time Sync here https://www.maniaradio.it/en/bkttimesync.html  Can use NTP or GPS, connected to USB, serial port or Bluetooth.

http://4river.a.la9.jp/gps/  Will use NMEA to set the time, good enough for WSPR and the like. "A clock of a PC can be corrected cyclically by a GPS."

https://www.coaa.co.uk/gpstime.htm does the same, to the nearest second.

SatK Older Japanese, only COM1-4 supported. In Japanese - use translate, or the SatK.exe link is visible http://www2.synapse.ne.jp/haya/ghsosd/Satk.html

GPS2Time - a means of sync-ing your computer clock using a GPS Receiver (vk4adc.com) 

Buy NMEATime here visualgps.net I used this for evaluation, has the option of PPS input so should be very accurate with a real (not USB) COM port.

Computer Time Check:- This site https://time.is/ tells you how accurate your computer is.

Baud Rate:- uBlox - u-Centre - Configure Ports - Baudrate - Send.

Using the same antenna for your RX.

Antenna Switching.

September 2014:- This does not really suit the current U3 with relay boards.

I see no point in just operating in TX mode. As a radio ham I like to know how conditions are both ways. Even if you are in a rare DX location others want to know how their signals reach you.

I used a 5V reed relay but a 12V one could be used with a suitable supply.

My relay uses about 30mA so is switched by a small NPN transistor. The U3's Q1 switching signal is used, the resistor is not critical, 2-20K will work. The diode across the relay coil may be any small silicon type.

The output from the LPF is disconnected from the antenna on receive so the DDS signal leakage is greatly reduced, I have also grounded it thinking it might reduce the signal more. You may prefer a 50 ohm load resistor here.

I also ground the RX input on transmit, hopefully reducing any leakage from the U3 output.

A single pole relay could be used, just switching the antenna from the RX to the LPF, this would probably be adequate.

If you have made a connection for the in-circuit programmer described on this page then the required connections may be taken from there.

Note similar long term stability and a smooth curve without the jumps. (The slight irregularities are due to mechanical disturbance of my improvised test setup.)

Range 2.0Hz

Both are surface mount, mounted "Dead Bug". The Epson is really small about 2x3mm.

The question is "How do we find which type of control is used for any particular TCXO?" So far I have found no warning about the nature of the FOX devices.

ZL1RS:- "ECS-TXO-5032 27 MHz TCXO (from Mouser).  It jumps like the FOX does".

Another very small one Abracon ASTX-H11-27.000MHZ-T SM7ETW thinks it does not jump. 3V3 nominal.

The Connor Winfield D75F-027.0M is a more expensive choice. https://www.digikey.co.uk/product-detail/en/connor-winfield/D75F-027.0M/CW655CT-ND/1965863 but check the connections!

http://www.ebay.co.uk/itm/CRYSTAL-TCXO-26MHZ-SMD-MPN-X1G0042110002-EPSON-/391339155043?hash=item5b1da19e63:g:1MMAAOSw-nZTpJCO

NOTE:- these are EPSON - TG-5006CJ http://www.farnell.com/datasheets/1804154.pdf Nominal 1.8 volts, permissible maximum 3.3V. As the LM317 is set to 3V5 It may be wise to use a series resistor, maybe 270R. Better, change the LM317 voltage to 3V1 by making R5 820R (First version with no power smoothing.)  Then it is within the working range of the Epsom and the Si5351. (But note power output may be a little down because of slightly less drive from the Si5351.)

If used with the ProgRock's noise filter then the divider would need to be changed. I calculate if R5 of the ProgRock were changed to 27K then about 3V1 would reach the Synth board. This needs to be tested.

Another tiny device:- KA7OEI says there are no steps seen even at 432MHz   "A suitable device is a part made by Taitien and is readily available, being DigiKey part number 1664-1269-1-ND (Mfg. P/N TXETBLSANF-27.000000).  This device is tiny - only 3.2x2.5mm square"

This is the Epsom TCXO, minute, about 2x3mm! Mounted "Dead Bug". Surprising what can be done with care. Note modern components are tough and will usually survive a lot of abuse.

See here https://groups.io/g/QRPLabs/message/27233 for G8NXD'S nice method of mounting and connecting one of these tiny devices.

LM317:- Using the formula and typical values on the data sheet the output using R1=3K and R2=1K will be 5.15 volts +/- tolerances. [Iadj=50uA  = 0.000050 x 3000 = +0.15] Note in the QRP Labs Synth the LM317 is operated outside its specified drop-out voltage, a low-drop 3V3 regulator is probably to be preferred. A 3.3V AMS1117 maybe.

Possible Project? Slightly more precise GPS discipline for QRP Labs. Could be applicable to any crystal frequency in any project.

With the U3 would avoid any drift problems, VFO/Progrock/QCX equivalent to constant calibration but should hold to parts per billion. (The NMEA output of the NEO-7 can still be used to provide time/position data in the U3 etc. Just no PPS, I'm not sure if that is enough to keep time calibrated for WSPR.) Yes, NMEA sets the time, set Calibration to "00" to prevent any changes to the calibration figure.

Thought:- Use 27MHz VCXO, divide by 10 and use PLL with uBlox NEO-7 https://sites.google.com/site/g4zfqradio/u-blox_neo-6-7 set to 2.700MHz. (Or, similar divider/frequency relationship.) Note this is NOT  GPS disciplined, a NCO is used. The output is accurate, ideal for a frequency reference. But the basic signal is not clean enough for a receiver local oscillator. The PLL will need a sufficiently long time constant.

Jitter:- A component of phase noise, high values limit reception of weak signals next to strong ones, limit SNR etc. Figures I quote are from data sheets but I do not know if method/units are comparable. Low values are desirable for transmitters but for QRP not so critical.

More study required. Search "Jitter 1sigma" examples  http://www.mtronpti.com/sites/default/files/files/oscillator-jitter-basics.pdf   https://www5.epsondevice.com/en/information/technical_info/pdf/techl_notes_jitter0416.pdf

TCXO

Fox Jitter not spec.

Epson 26MHz Jitter not spec.

Si570 0.5ps

Si5351  100ps

VCXO

https://www.ebay.co.uk/itm/VCO-VCXO-27MHZ-7-X-5MM-CMOS-NWK-PN-6U-27-000MBE-T/272876780287?hash=item3f88b93aff:g:IeQAAOSwrP9Z16Rc

Phase Jitter ( 12 KHz ~ 20 MHz ) 1 ps

3V3 or 5V 45mA max

Control 0.1-0.9VDD 100ppm

SMD, 7mm x 5mm

Balloon telemetry

 information http://qrp-labs.com/flights/u4b17.html "U3" at altitude!  Look at the list on the left of the page for more recent launches.

Test of LC100A

Accuracy test of my LC100A 

Replacement of Si5351

A method I used to replace a failed device.

U3S QRPp

Originally investigated to avoid desensing a RX.

Turn the bias to zero, with a single BS170 I saw about 1mW output.

I used another BS170 to short the wiper of the bias pot to ground. Then I used it to short the gate of the BS170 PA to ground. 125uW measured. Not recommended, although I used my U3 for several weeks like this it does bring the Si5351 output to ground via C1. (Was this the one that failed a year later? Replacement link just above.)

12v on your U3?

 http://www.qrp-labs.com/faq.html#fry   (Not actually on the U3 pages)

Windows 7 COM Port Driver for the QDX/QLG2 STM Processor.

This needs a determined effort! It will work on W7 32/64 bit. Best get the driver from STM.

https://www.st.com/en/development-tools/stsw-stm32102.html STM XP-W8 drivers \en.stsw-stm32102_v1.5.0(1).zip

This requires you enter an email address, click the link in the email and download. This must all be done on the same computer.

Unzip and run. This places the drivers on the computer but Windows 7 is no longer updated so it does not recognise them, refuses to install.

Get this http://deviceinbox.com/drivers/859-stm-virtual-com-port-drivers.html

This downloads \STM_Virtual_COM_Port_1.3.1.zip. Unzip. In it are .inf files.

Updating the driver and directing the installer to the relevant .inf 32/64 bit.

Plug in the QDX, power it up.

Go to Device Manager, find the STM device, on my W7 it comes under "Other Devices" QDX Transceiver. It will have an exclamation mark signifying a problem.

Right click - update driver.

Browse my computer - Let me pick -

A long list of hardware is shown select Ports (COM and LPT).

Next select STMicroelectronics. One model is shown, select.

Next, you get a notice saying Windows cannot verify.. continue with Yes.

Now the QDX should appear as a STMicroelectronics Virtual COM port in Device Manager with the allocated number.

Try Putty as a test or see if it works with WSJT-X.

It should work but perhaps reboot both PC and QDX if it does not.

This will need to be repeated if you subsequently use a different USB port.

***********

I did this on my W7 laptop  It did not work...

Windows had assigned a COM port number that was reserved for a virtual port.

In Device Manager right click STMicroelectronics Virtual COM port - Properties - Port Settings - Advanced - Select a different port number.

My well-used W7 objected to choices I made so I just selected a high number that probably had not been used and selected "Yes" to continue.

After that I needed to reboot the laptop, then the QDX and finally Putty connected.

****

After this W7 did not see the QDX as a memory stick for updating.. It appears as a STMicroelectronics Virtual COM port with exclamation mark. Do not know how to get that working, possibly needs to be directed to a USB memory stick driver. That would probably ruin the COM port setting. I use a different computer if needed.

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