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Re: Can't now decode my own WSPR signals.....
"g4sfs"
Hi David/All
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That's interesting and I can now report that my WSPR is working once again! I found that I had to change FSK AdJ to 1,250 when previously it had worked without a hitch for weeks on 0,700!! I'm currently tx every 2 mins while I check that all is ok and I'm getting reports back with drift of 0 and -1. My own monitoring is providing decodes again!! I have to say that I'm really surprised that FSK ADJ has had to be increased so much with a minor shift in osc freq. Funny stuff this radio!!! I will revert to 10mins tx shortly and leave it running this evening to see what happens, before I put the covers on again! Hopefully neither actions will stop it from working!! 73 de Peter G4SFS --- In QRPLabs@..., "David Barber" <david.barber@...> wrote:
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Re: Can't now decode my own WSPR signals.....
Tony Volpe
Yes Peter, Mine moves down when the TX comes on too. I can't say exactly by how much. I had thought it was my not wonderful power supply, but it may be some kind of loading issue on the oscillator. To be frank, wspr asks a lot of an oscillator. If you were on cw, you'd hardy be likely to notice a few htz change. Here it counts, especially since the micro controller is varying the frequency by 1.4 htz to create the wspr tones and trying to hold the oscillator stable, though I don't think it does that when wspr is actually transmitting. Hans wrote me some interesting words the other day when I was discussing the way my fsk width changed. I hope he won't mind me quoting them here - it will save him the trouble of repeating them, and I know he has a lot of demands on his time. Here is his note to me on changing width of fsk when frequency alters:
HANS QUOTE STARTS: "Firstly it is important to realise that a graph of frequency (vertical axis) against varicap diode voltage (horizontal access) shows a curve, not a straight line. E.g. see this image??from my varicap diodes page??.?
The FSK applied by the microcontroller is a reverse voltage to the varicap (the 5mm reverse-connected Red LED In the kit). The microcontroller assumes that the frequency/voltage line is a straight line. It uses the FSK per Hz ("FSK Adj.") setting which you have entered in the configuration menu. However, this setting is only valid at one particular reverse voltage (i.e. one particular frequency). So if the frequency drifts far from the one you have set, then the actual FSK Adj value would differ from the value you set. This would case the FSK size to grow or shrink.
If your FSK Adj value is large, and your oscillator frequency is a long way from the actual target value you have set in the configuration menu, then the GPS will steer the frequency a long way, and this will cause the operating point to move along the line to a point where your FSK Adj value is now incorrect to generate the amount of shift that you need.
What FSK Adj. value do you use?
I think your problem could be resolved in one of two ways:
1) Put the kit in the TEST mode, with the GPS connected. In this mode, the display behaves as a frequency counter. The GPS doesn't lock the oscillator, it is just used to accurately measure the frequency so that you can tune it accurately. Then use the trimmer capacitor to tune the frequency as close as possible to the target frequency value you have set in the configuration menu. Now change the "FSK Adj" value experimentally to get the right amount of shift on Argo. Remember that in TEST mode it shows a square-wave, set the Speed to 003 for example and then you'll get 3 seconds low, 3 seconds high. With FSK Hz set to 4Hz, you should see a 4Hz shift if your FSK Adj value is set correctly. So the trick is to get a correct value of FSK Adj, to get the correct shift, and on the correct frequency (very close to the frequency you set). Then when you move to WSPR mode, the microcontroller will only have to make small adjustments to correct any drift occurring. The position on the curve I described will not move far from where you set the frequency up, and so the error in FSK will be small. In other words: the microcontroller + GPS is intended to be able to slightly correct the frequency due to drift. It is not intended to completely fix any situation in which the oscillator isn't well-tuned in the first place. Do you see what I mean?
2) If all that still doesn't work, then you could try increasing the value of C3 from 22pF to 47pF (or just put another 22pF in parallel with the existing one). This would let the microcontroller have a more aggressive control of the frequency drift. That gives it a greater tuning range, but with less precision. Anyway it would mean that the GPS would be able to correct a larger frequency error, without moving the operating point on the curve as far.?
Generally I think that if you set it up carefully as in 1) above, then that may well solve your problem. This is how I would tackle it, anyway. Please give it a try and let me know how it goes." END OF HANS'S remarks. That explains why it happens - and following the instructions put it right. BUT - the solution only lasts until the oscillator moves again, which in the case of mine, it certainly will do.?
In your case, putting the thing in a box may also change the frequency slightly from where it was set. We are talking very small changes here and the environment is important for that. I am compounding the challenge for my kit by running it at half a watt output (9.2volts on two BS170 fets). This generates extra heat even though I made a decent sized heat sink for them. I tried to get rid of the drift by clipping a crystal heater onto the 10.140 crystal. I have two old 16000mhz down convertors which use have two in each of them. These are old Murata BM500N crystal heaters in them. They are meant for twelve volts but I applied the 9.2volt pa voltage to them and they warm the crystal. However, they don't have a lot of effect on the frequency drift of -2 to -3 that I am getting on my 'hot' kit. I suspect that the frequency changing effects may be on changing capacitance by heating the board through he legs of the output fets. It is warm underneath them and it would only take tiny changes in capacitance to move the frequency by one or two parts in ten million which is all we are talking about. As I said, I have voluntarily compounded the issue by running it hotter and we really are talking tiny frequency changes. Nevertheless - I get loads of decodes from far and wide and get into VK about once every three days depending on the condx. It's a great little kit, even if it is a bit hands on at times. Keeps me out of mischief anyway and for next to no outlay too...
:)))
Regards and I hope Hans is OK with my quoting his explanation.?
73s
Tony G0BZB |
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Re: Can't now decode my own WSPR signals.....
"g4sfs"
Hi Tony - tnx for helpful comments. Yes noted re timing but that's ok, have the pc clock updating against an on line atomic clock and I then set the time on the tx using that so fairly sure that's not the problem.
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Interested in your other comments re fsk deviation and am about to look at signal on Argo. I think what may have happened is that when I was boxing the tx I may have knocked the trimmer C and shifted the freq, so that may have something to do with it. It's pretty close to where it was but the same settings are still not resulting in a decode! When you monitor your signals on WSPR v2.0, do you see a downwards shift in the display when the tx switches on? I'm sure I didn't see that prior to the problems. To clarify, when not in tx mode WSPR can hear the osc running and I see a continuous line on the display (actually more than 1 - usually two or three prominent lines) but they all move downwards on the display when the tx switches on, returning to their former position when it stops transmitting! When I monitor the osc on my rx, the centre freq is about 10.140.200 moving to 10.140.180 when transmitting - the latter coincides with the freq displayed by the counter which reads between 10.140.186 and 10.140.188. There's not enough "stray" signal from the osc when not in tx for the counter to register it! Puzzled by the drop in frequency but that may be a red herring?! Prior to the problems, I was getting plenty of reports with a drift of no more than -1 all this week! As you say, all part of the fun if not somewhat frustrating at times! 73 de Peter G4SFS --- In QRPLabs@..., Tony Volpe <tony.volpe.1951@...> wrote:
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Re: Can't now decode my own WSPR signals.....
"David Barber"
Just to add my penny's worth...
Switched the UQRSS + GPS on this morning (into dummy load), not been on since 15 August, I've been playing antennas having satisfied myself that I'd got the UQRSS ready to go. All appeared to start OK but my WSPR signal was no longer where I left it, frequency had dropped and when I did find it could not be decoded. So into "Test" mode to find the FSK lower than expected. Looking at the "FSK Adj." setting, I'd documented leaving this set at 00,900 however found it to be 00,700. Set back to 00,900 and FSK now correct. Tweaked frequency but can only reach 10.140103 maximum so had to go with that. WSPR now decoding again but showing DT errors of -1.4 to -2.1 seconds (with GPS locked and PC suitably synced to a time server). Other received signals are showing errors of less than 1.0 second. If anything I would have expected the other way round? Bad day in the shack! David G8OQW *** |
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Re: Can't now decode my own WSPR signals.....
"TONY_VOLPE"
Sorry about the typos above. I guess you can 'decode' my sloppy typing.
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Looking back over the posts, I see that you say the frequency has changed. This leads me to bet that this has affected the fsk width. I find them intimately connected. Move the frequency and the fsk width changes, especially if fitted with a gps I think - at least I never saw it in the days before my gps was fitted. Look on Argo and my bet is your fsk is a wiggly line. If so, just experiment with the values of fsk.adj to get the optimum as described in section 9 of the kit instructions. Mine is very sensitive to that value and changes in the base frequency. 73s --- In [email protected], "g4sfs" <g4sfs@...> wrote:
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Re: Can't now decode my own WSPR signals.....
Tony Volpe
Hi Peter,
The most common problems I have had with wspr not decoding related to timing errors. You most likely know that if the transmission you out out starts more than about four seconds from the optimum time (one second after the start of an even minute) there will be no decodes. After that, and relating to the kit, the width of the wspr transmission is pretty critical. Check with Argo that the fsk deviation has not changed. Mine certainly does if the frequency moves from the one I set it up on. The emission idealy should be 6htz wide. Narrower is more disruptive to decoding than wider in my experience. Mine varies during a twenty-four hour period from about 6htz wide to as much as 10htz wide. I monitor mine on a local transceiver all the time. After fsk width, drift can be disruptive. I suffer from that too, but find the distant stations quite tolerant of drift up to about 4htz, but that is way beyond acceptable really. Mine bumps along pretty effectively with drifts of between -1htz and -3.?
One thing for sure is that if You can't decode it, not many others will either. Best of luck - and the niggles are 755 of the fun of getting it going and keeping it working.
:)) 73s? Tony G0BZB |
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Re: Can't now decode my own WSPR signals.....
"g4sfs"
Hi Steve - I look forward to Hans' comment and like you I'd be a bit surprised if the chip has been destroyed but these things happen! I suppose I could test that by putting the v1.00 chip back in but as the kit is boxed and hard wired (I've totally enclosed the board to try and improve osc stability) it's not so easy to do so have resisted so far just in case someone comes up with a solution!
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73 de Peter G4SFS --- In QRPLabs@..., Stephen Farthing <squirrox@...> wrote:
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Re: Can't now decode my own WSPR signals.....
"g4sfs"
Hi Steve - tnx for swift reply.
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a. Yes I've powered down and up several times but it's made no difference. Also the tx has previously been running continuously for several days at a time without any glitches. b. I monitor my signals using WSPR v2.0 - using an FT817 with about 30cm of wire as an antenna! 73 de Peter G4SFS --- In QRPLabs@..., Stephen Farthing <squirrox@...> wrote:
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Can't now decode my own WSPR signals.....
"g4sfs"
Hi All
First can I just thank Steve and Hans for the kits and all the work they have done. Experimenting with QRSS and WSPR with their various kits has got me back into construction etc after a long break - it's almost addictive!! I have been running the ultimate QRSS kit on 30m WSPR with the v1.0 chip and all was fine except for the known problems. I upgraded to v1.04 last Sunday and everything worked really well until the early hours of yesterday (Saturday) morning when I realised that my own monitored signals were not being decoded and I was not getting any reports. This continued throughout yesterday and I have been unable to resolve the problem. I have checked all the settings and confirmed that the tx is transmitting and I have even adjusted some of the settings but still no decodes and no reports! If I ask the tx to send a cw ident it does that just fine but still no WSPR decodes. I have also reset the frequency as that had changed but still nothing! I'm now wondering if I have somehow managed to corrupt the microcontroller. Any thoughts or suggestions etc much appreciated as I've run out of ideas! By the way, I had to change C5 to 10pf to get the osc to tune the right part of the band. 73 de Peter G4SFS |
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Single mode QRSS transmitter 160m LO problems
"woodiescbj"
Hi, I think I have found the problem, I have not been able to get the Xtal oscillating it now looks to be a duff Xtal, I had ordered the single mode QRSS kit for 30m (which I have built and is working well) I also ordered a QRSS Xtal for 80m, as an experiment I put this across the 160m Xtal and got a lovely LO signal on 3.500Mhz.
73 de Colin DD5CF / G1ZOS |
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Some tinkering
"Philip"
Just started a new build of a UQRSS rig..
This one will be for experiment with trying different frequencies etc. Anyhoo, I've added a photo on here (G4JVF) of the PCB part way through showing that I'm using inline headers male/female to make changing components easier. In particular, capacitors C3/C4/C5 can be easily swapped by plugging in which saves damage to the PCB (C5 is shown plugged in on the photo). The crystal also has it's own socket. At the PA end, the filter will be external to the board so I can plug in a filter to suit the frequency in use. The two posts near the C10 position (bottom right) will carry the signal via coax to the filter sockets. The PA will be a pair of BS170 and their heatsink plate will sit in the space where the on board filter components would have been. All the other male posts will make soldering in/out leads easier than soldering direct to the PCB. That's the theory, more as it evolves Philip G4JVF |
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Re: Low frequency from U-QRSS-kit.
Tony Volpe
Hi Gerard,
I monitored you on a remote receiver since I like to keep my transmit beacon going too and don't like to overload my home receiver. I control the computer at the remote location with some software across the Internet. The receiver may not be set dead on 10.13870.
But you are not on the bottom of the band or anywhere near it. I just checked your spots and you are being copied by ?a number if stations including some American ones (at around the mid 130s on average, so you are certainly in the band.
I have experimented with c4 and c5 and you can even run without one of them, though if you do this you will raise the frequency a lot. Nevertheless, it can be brought back down with the trimmer. In your case, the way your kit is working, I would leave it alone.
By the way - if you are discouraged by a low number of spots today - I think it is about the conditions. today I have had very few and would say it is the worst for a few weeks.
Best regards Tony G0BZB |
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Re: Low frequency from U-QRSS-kit.
Stephen Farthing
Hi guys,
As the kit instructions say getting the output frequency in band can be a bit of a challenge. When I did the testing I used a frequency meter which can read down to one hertz which I calibrated against a 10 MHz Rubidium standard. When I get a round tuit I'll modify the counter so it is clocked by the standard so I can be really sure the frequency the meter reads is accurate at all frequencies. .?
I used the standard to check the calibration of my K2, FT817 and TS570 and was surprised to find the receivers were all reading 10.000,00 at zero beat. ?None of them have displays that will show the 0-9 Hz digit. So you really need to resort to using ARGO, or a similar piece of software, to get that information. You need to set it up correctly and make sure your RX is well calibrated.?
When the round tuit arrives I might try to more accurately determine the values of the capacitors Tony says needed to be changed to get into the WSPR band. But IIRR I could easily achieve this with the standard caps when I built the prototype. It's also worth pointing out that later kits in the first batch and all of the kits in the second batch will have a variable capacitor with a wider swing than the one we used to ship. This is because the people we buy from no longer stock it.?
73s Steve G0XAR |
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Re: Low frequency from U-QRSS-kit.
"f6gwb"
OK Tony, I managed to stay inside the WSPR band. However I think to be in the bottom of the lower part but yes it's enough to work. I am a little puzzeled with the freq you announce. I really think to be around 10140.130 and not 10140.190. I checked this morning yet my Rx calibration with the WWV carrier and other BCL stations (which are almost always on a 10kHz boundary) and I think my receiver (Yaesu FT897D) is accurate at +/- 3Hz. So I'm surprised you spotted me on 101403.190. Maybe I'm wrong; maybe your Rx freq is not accurately calibrated.
73's QRO. Gerard, f6gwb. |
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Re: Low frequency from U-QRSS-kit.
Tony Volpe
Yes Gerard, I spotted you five times last evening and my record shows that you were at about 10.140190. This is well into the WSPR band so do not worry about changing C5. You are already there and working well. My receiver setting may not be perfect, but nonetheless all is well for you and your kit.
Best regards Tony G0BZB |
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Re: Low frequency from U-QRSS-kit.
Tony Volpe
Gerard,
I had the same problem when I started with the kit. I replaced C4 & C5 with 18pf and the frequency went up to about the middle of the wspr band. Replace C5 as well as C4. Also, I have found that very small changes in circuit voltage will alter the frequency that the circuit oscillates at. In my kit, a change from 4.8v to 5 will move the frequency upward by about 20 or 30htz.? I run the logic side of the board with the power supplied by a small plug in power supply with an LM 7805 regulator controlling the voltage to the logic chips. The PA is powered directly by the plug in supply at about 6.2 volts. When the PA switches on, the voltage on the logic chips drops by about 0.1volts and the frequency falls a little. This can be seen on ARGO as the line moves down a little. If I run the input voltage on the PA at 9 volts, this does not happen at the logic chips side of the LM7805 and the frequency is more stable.
However - I am sure that if you chage c5 for a lower value, your frequency will rise. Bonne chance. de G0BZB - Op Tony |
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