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Returning to amateur radio after a break of about 30 years, I'm having a blast with WSPR, initially with an Ensemble RXTX and, in the last week, with my newly built U2 QRSS. It's been running fine on 40m with a GPS unit attached but I may have spiked it with a dodgy power unit for the PA vdd when switching from 9v to 12v. Ever since then I've only had a couple of spots so I'm thinking something got damaged and I probably should at least replace the two BC107s.

I'm sure I'll get it working normally again soon but my question here is about the LCD display in idle mode, and in particular the three characters that follow the mode indicator "WSPR". When I first built it and it was running just fine, the code was always 100. Ever since the dodgy PSU incident it has been showing 000.

Forgive me if this newbie is the only one who doesn't know what that three digit number means, but I've had a bit of a look round here and haven't been able to find any reference to it. Could someone please enlighten me? I'm hoping it might help me get back on the air again soon!

Many thanks
Chris
G8AJM

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Just been playing here with a design for the 60m band which may be
of use to U2'ers, or Hans if he's requiring a 60m LPF design.

Take one of the 80m LPF's.

L1 = 23 TURNS (WAS 25)
L2 = 24 TURNS (WAS 27)
L3 = 23 TURNS (WAS 25)

Change C1 and C4 change to 680pf

C2 and C3 remain at 1200pf.

So all you really need in terms of new components are 2 x 680pf caps!

1st harmonic is -58db down
2nd harmonic is -79db down

73 de Andy G0FTD

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Sorry to disagree with the designer Hans, but I would say that the upgrade is essential for all U2's.

U2's on QRSS can be identified on air by the LF and HF spikes which are still clearly visible at 1000Km on 7MHz (capture available) and hopefully will be eliminated by your sterling work.? Who for the sake of ?3 + post or possibly pay post both ways for an exchange would not want their signal to be perfected.

Again apologies but it is there, and I cannot ignore it.

73 Eddie G3ZJO

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On 02/06/2013 16:20, Hans Summers wrote:

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Hi John

The upgrade is mainly useful for people wanting to use GPS, because v2.01 is evidently much too fussy about GPS modules it supports. It is also useful for people wanting accurate frequency shifts on the higher bands, which is mainly of use for people wanting to use WSPR.

You wouldn't need v2.02 for QRSS/CW, without GPS.

73 Hans G0UPL

On Sun, Jun 2, 2013 at 3:52 PM, john <johnmb@...> wrote:

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Would the upgrade be useful to anyone planning on deploying their kits as
either a QRSS beacon sans GPS or CW beacon?

73
John

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Now I appreciate that there's a new version of the firmware on the way that fixes the issue described below but something else has just happened.

Earlier today I switched from QRSS to WSPR. ?I've just gone back to FSKCW and there is no stabilisation taking place whatsoever. ?I can tell by cycling through the menus that the calibration figure isn't changing and I'm transmitting around 55Hz away from where I'd expect to be.

I've tried everything I can think of to get it to kick back in again, disabling the GPS, renabling it, inverting the signal, changing modes etc but nothing is working. ?It's not correcting it whatsoever.

If I put my original calibration figure back in (the one I worked out before I had a GPS), it's on roughly the right frequency.

It's very odd that it was working OK previously when first starting in FSKCW mode but now it's not even doing that.

73 Keith.

On 30 May 2013, at 23:09, Keith Maton <nentecular@...> wrote:

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All (specifically Hans),

I've found what I think is a problem with the frequency stabilisation routine in the U2.

The manual says:

"When using the connected GPS module for frequency stabilisation, you must choose a non-zero Frame parameter. This is because the frequency stabilisation must take place when there is no transmission from the kit, i.e. during a pause between transmissions. The frequency stabilisation takes 12 seconds and occurs just before the start of a transmission. Therefore you need to ensure that the Frame parameter is sufficiently large that there is a minimum gap of 12 seconds between the completion of your message transmission and the start of the next one."

This is all great in WSPR because there is a period of non transmission between each frame but it's not possible to do this when running FSKCW (and probably other QRSS modes, I've not checked them all).

I have my kit all working well and when I first start it, the frequency is absolutely spot on because it's calibrated. However, when starting from cold, there's always an initial drift as it all warms up.

My callsign takes 9 minutes and 40 seconds to send, leaving a period of 20 seconds or so before the next frame starts but the kit continues to transmit the lower tone for those 20 seconds and so it doesn't calibrate.

With the kit built into a box which works well as an oven, I've just watched it start transmitting on the correct frequency and then drift 20Hz upwards. When the next frame started, it carried on drifting so I simply cycled through all the menus and after the next frame had completed, I pushed the right button and when it started transmitting a few seconds later, it had run the stabilisation and was back on the correct frequency. It still hadn't reached the stable temperature in the box so it continued to drift upwards.

So as it stands, when running FSKCW (and possibly other modes), there's no stabilisation apart from the initial routine, no matter how long the callsign is because there isn't a pause between transmissions.

I don't think the transmitter should be switched off between frames because that will cause a temperature change of the overall unit, especially if it's built into a sealed enclosure and it will drift again once the transmitter comes back on.

I think a fix would be to force the transmitter off automatically for fifteen seconds prior to the end of the frame to allow stabilisation to take place.

Has anyone else noticed this?

I've uploaded a screenshot of what happens when I cycle through the menus at the end of the frame here - You can see that it's dropped back down to the correct frequency but I'll need to do it again at the end of this cycle as it's still not quite warmed up fully yet.

The automatic stabilisation routine is fantastic but it needs to work every frame to be worthwhile.

Or have I got something wrong in the menus that's stopping this from working? I have my frame length set to 10 and the start set to 1.

73, Keith.

Great News Hans !!

We all enjoy the fruits of your labor and more especially the passion which you perform the tasks with .

You bring many of us , the world over , untold hours of great joy , building , using , learning from , and enjoying your always great projects .

Thank you.

Best 73 ,

Charlie , W5COV

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All

Just to let you know, I worked on the v2.02 firmware over the last week and have completed it, I am now testing. On Monday I am planning to have a few sent to some people who can also do some testing. I have managed to incorporate ALL requests, and fix ALL reported issues. I made careful notes since the launch of the U2 kit and I don't think I have missed any requests that I agreed to include, or bug fixes for any issues.

However code space is extremely tight and I had to do some space-saving modifications, including removal of a few unnecessary features! To be precise, the code currently occupies 99.9% of the available space, there are just 14 bytes of 16,384 spare!

List of changes:

1) GPS: I put the GPS back to as close as I could, to how it was done in the U1, since that seemed to work well. The existing U2 method in v2.01 worked with some GPS modules but apparently was much more fussy than the U1 kit. Note that there is no longer an "Inv. GPS" menu item, since the U1 will trigger off the correct edge by itself.?

2) DDS resolution on high frequencies: I have corrected the precision issue in the arithmetic, so now you get full accuracy shift steps at any operating frequency.?

3) Removed the upper frequency limit of approx 42.5MHz, so you can now use the full range available from the DDS

4) New mode WSPR-15 is now supported, for experimental use on LF bands (8 times slower WSPR tones, 8 times closer together). Note that I will also be providing Low Pass Filter kits for 135kHz and 475kHz (600m) bands.

5) New mode "FSK" which is a fast FSK mode for 10m beaconing, where the speed setting is interpreted in words per minute. The "FSK (Hz)" setting is now 3 digits (default "004" i.e. 4Hz) so that shift can be up to 999Hz. Note that I removed the "Inv. FSK" parameter, because I had never heard of anyone using it, and I needed desperately to create some code space.?

6) Added an indication on the display when the kit is GPS locked. Of all the enhancements and bug fixes, this one took the longest to do!

7) Added 1 digit to the baud rate setting, so that it can now handle 115kbps (this was a request for support of a particular GPS module). At the same time I removed the number of bits in the data word setting, which is the right-most digit of the "GPS Baud" parameter. I haven't heard of a GPS which uses other than 8 bit data words, so it seemed superfluous. Getting rid of it saved me some code space which I could use for other requested features. The default "GPS Baud" setting is now "009600,01,1".

8) Removed the DDS "reset" every time the frequency was updated, which caused the frequency to briefly go to zero before being updated to the new frequency. This should improve the spectral purity of the output.?

9) Put a "stop" on the cycling through characters when you are editing the Message (and other text) parameters, by holding down the right button. The character cycling now stops at Z, 9 and the Enter symbol. In order to continue cycling through, you have to release the right button and start pressing it again. This will make it easier to program the text parameters e.g. Message.

10) Moved the "Time" parameter menu to the start of the menu, when the kit is in WSPR mode. This is because the Time parameter is what you would most commonly want to adjust, when operating in WSPR mode, if you did not have a GPS to regulate it. In other modes, "Time" still comes right at the end of the menu.

11) CW, FSKCW, DFCW, QRSS and FSK modes can now contain the '/' character in the message

12) Bug fix (cosmetic only): When setting the time, the 10 minutes digit incorrectly allowed numbers >= 6. So it was possible to set a time such as 15:89.?

13) Bug fix (cosmetic only): If you went back in to the time parameter to edit it a second time immediately after finishing the first edit, the display was overwritten incorrectly, with the system clock frequency display.

14) Bug fix (cosmetic only): If using FSKCW mode an 10 second dit speed (for example), in the interval between frames the LCD display did not have space to show the seconds digit of the clock. I have now changed the "Waiting" screen so that it does not show the mode etc., it now only shows the time and the minutes to wait until. E.g. "15:43:21 >50" means 3:43pm and 21 seconds, and the kit is waiting for minute 50 to start the next frame. The "Waiting" screen also shows the GPS heartbeat if a GPS is connected and GPS lock is successful.

15) Bug fix: In FSKCW mode, the GPS frequency stabilisation operating in the waiting period between messages, only worked the first time after cycling through the menu. Subsequent waiting periods did not perform the calibration because the kit was always in key-down (transmitting the low tone between messages).?

16) I changed the default speed setting to 006 for no other reason than that I think 6 second dits are more common and useful than 3 second dits, so make a better default.

17) I have removed the mode message "CW Ident" when transmitting the CW callsign identifier, and replaced it with just the text "CW". This was purely a space-saving measure - sacrificing something unnecessary for the sake of gaining more space to include important features and fixes.?

73 Hans G0UPL