The addition of PI4 to the U3 TX by Hans Summers suite of modes has lead to my testing it on 28MHz.
PI4 is not really a suitable mode for QRP but some users asked for it and Hans is always up for a challenge. Where those that asked for it are I don’t know, but myself and EA2KV are using it on 28.303MHz time shared on the same frequency.
I have now been running the mode for over a month and there has been one solicited report from Greece. I always disregard solicited reports on established modes from any results but this is different the frequency has to be publicised.
I have also been running other tests concurrently awaiting unsolicited reports. These are possible because the signals are in a window where hundreds of highly skilled expensively equipped Hams are monitoring worldwide. WSPR remains the mode for propagation tests. It knocked QRSS off its perch when it was introduced. I have been running a comparison test on 28MHz for over 5 years and the report numbers are in excess of 100,000 WSPR to 1 QRSS.
For the test to be fair I TX each mode from the same transmitter and for the same period of time. WSPR carries Callsign, Locator and Power in 2 minutes, DFCW5 takes slightly over 2 minutes to send my Callsign only.
I have recently added FSKCW7 to the list, in just under 2 minutes it manages just a ‘G’. That’s fine, many years ago I grabbed a ‘G’ as my international identifier on QRSS, to keep it legal I also ident with the full Callsign. That has been running for over a month with the PI4 with no reports despite the fact I often see it on Grabbers.
Now I have just gone and publicised it so reports no longer count 😀
Above. My little signal holding its own among signals into VE, some running 10 times more power. It took nearly 2 minutes to convey a not very readable ‘G’, in the same 10 minute time frame full WSPR decodes were made in the USA.
2014-12-07 14:48 G3ZJO 28.126190 -26 0 IO92ng +20 0.100 KB9AMG EN52tx
In order for QRSS to perform a useful service in the digital age it needs to be several times slower and the Grabbers need to have matching FFT times. The message time then gets to be so long that as a communication mode it is boring. However with an MEPT and Grabber set up it is ideal, after the first frame you can view and admire your own signal when ever you like.
I didn’t intend to start a debate when I mentioned the blatant difference in the number of reports from my low power QRSS and WSPR tests actually ZERO unsolicited QRSS reports against copious every day for WSPR.
I have been running low power tests on HF and MF for several years, and the results are the same. Reports of QRSS reception require humans, decent equipment and skill, WSPR is relatively more simple.
With QRSS the receiving station once he has bothered to look, bothered to adjust the DSP software, bothered to understand displayed Morse, then he has got to be bothered to post a report to a site or send a report by e-mail.
In fact I have known ever since I was first licensed that psychology is involved in signal reporting.
The other human imperfection reporting system I have known since I was a young licensee is the OPA, Old Pals Act system. I have only ever mentioned this in closed circles. Well you have to get on with folk down at the Radio Club despite their foibles, otherwise how would you get to be Chairman / President.
However when you get older you don’t care about speaking your mind, lots of those involved are dead and why should those still alive be allowed to get away with their blatant rudeness.
The prime case of the OPA system is the ‘our best pal moved to VK syndrome’, I have observed it for years with more than one local who went down under. When the VK station has his sked with his pals he puts up with all levels of signals QSB noise etc. missing bits are filled in and ignored, the little net continues. Reports are 5-9 for all the group no matter how modest their set up. Just let another local call in on the sked, funny thing the VK gets the Call Sign, Name, QTH then “can’t hear you mate sorry” he is ignored and soon goes away.
Another local group on 40m found some other locals calling in to their net a nuisance and had a code, QRM can’t copy a thing try channel 2 if the interlopers found them after the QSY it was time to end the net, it just dissolved.
My own experience of OPA rudeness was another local who moved to VK and was calling the sked one Saturday morning and getting no results. I called him, exchanged the haven’t spoken for a while stuff then he said, “have you heard Tom, Dick and Harry this morning”. Nope. “Oh dear maybe we have got the time confused, can you ring them”. Well I don’t have phone, (it was when home phones were rare). “Can you go to a phone box and call them”. Well its a fair way away, you know I live in a village. “Oh go on please get the car out and go give them a ring mate”. So I did and when I got back the group were on with him, I called in, ‘so the phone call worked then’. “Sorry can’t hear you mate”.
OK, one more personal experience, the CK report Californian Kilowatt. I was an early user of Slow Scan TV, we had to build our gear, give the authorities a description of it and only then they gave you a special permit to use it. I answered a CQ with a test card, QRP of course, back on phone came a US station he had read my call and location. “Your a noisy picture turn up the power”.
Your my first US station on SSTV can you give me a report please,(on phone), followed by a picture with lettering, QRP SSTV 10 Watts.
“I see you are running QRP, only 10 Watts come back when you’ve gotten a linear”.
He was reading every word of my SSTV picture cards but still refused to give me a report.
So when you put the radio on in the shack be sure to put a white coat on too so you can analise the inner meaning of any reports you might get.
Here are the photos of the U3 on test showing the really nice blue screen display and with my hand to reference the true size.
It really is a little beauty. Currently I am setting up the 20MHz clock oscillator and checking free running with no GPS, frequency stability. It is very good, I have no Xtal heat sink fitted and see no problems. The dirty finger nail is ‘an in joke’ here since I did a picture of poking a dirty finger on a switch and the photo didn’t do it justice.
Rear view showing the 600m LPF, those scruffy ‘almost impossible to wind’ inductors don’t look too bad.
I thought my LPF’s were small but the U2 / U3 ones (green) are tiny, the one on the right is the even more impossible to wind 2200m LPF, a little fatty, but it fits the board with a little overlap.
The U2 circuit board layout gave problems of interference to the GPS, my test lead for the U501 is shorter than the one I used on the U2 and I forgot to put ferrite beads on the wires at either end, so far I have seen no problems.
The Ultimate v2.02 chip was released and I had the chance to Beta test it.
Current release is v2.02a if you have a U2 with v2.01 please, please shell out the mere £3 and update ASAP. Other band users will love you for it.
Good news:-
Gone are the transients due the software zero setting the DDS before every small wanted frequency shift. This made the signal socially unacceptable, the Gentlemen operators of the past would have turned in their graves to have heard the clicks which sounded on air like someone banging a spade with a hammer.
Sorted is the linearity of the frequency shift which went awry as the band frequency got higher and caused WSPR to produce non decodeable signals. The linearity correction has also made Slow Hell Mode clean and readable.
Gone is the broad band interference which wiped out Radio 4FM on 93.3MHz when the U2 was TX’ing on 7MHz.
Gone are the bands of interference which wiped out 6m (50MHz) when the U2 was TX’ing on 28MHz.
These were the major bugs which kept me off the air with the U2.
WSPR-15 Mode has been added, also some ergonomic improvements in menu settings and cosmetic updates.
Results have been good on air, Power Output using just the one supplied Output FET at 474KHz is 250mW, I tried WSPR15 on that band and it works fine one report from 127Km was -40dB.
The Power drops as the frequency rises to give 109mW on 18MHz, at 28MHz efficiency seem to go back up a bit and 190mW is measured. I consider 28MHz to be the upper limit of operation.
All modes were found to work fine across the bands.
Bad News:-
The GPS facility which worked perfectly I though on v2.01 with my Trimble GPS Module totally fails on v2.02. Actually on re checking with v2.01 the time is always one second faster than UTC.
Using v2.02 the system time gallops on in 2 second leaps and soon is faster than real time. The 1PPS Frequecy control does not work.
Some GPS users had problems with some GPS Modules on V2.01 and some parameters were changed in an attempt to accommodate those. As far as I can tell only 2 Modules now work, which worked previously as well, and the Trimble lost out.
The GPS facility was the clinching factor on buying the kit for me and its a real let down to have it fail.
The utilisation in code of GPS Data is something I have never done, however I do note that the $GNRMC Position Data used in the U2 contains the UTC Time of the Position Fix. It is known that this time can be 1 or 2 seconds late. If one sets the system time from this Data then clocks that with 1PPS the next Data read may well be different, giving rise to erratic time keeping symptoms experienced by me and others.
It would appear that different GPS Modules have various accuracy levels and I would guess from my limited study that the better accuracy ones have a shorter PPS pulse time. No doubt that given a particular set of parameters a compromise can be achieved. I do hope a setting for diverse modules can be attained.
From my study I have concluded that the correct way to deal with GPS time is to read the $ZDA Data which is the correct UTC Time then clock that with the 1 PPS, when that Data is read again the two will agree and time galloping in 2 second leaps would be impossible.
The U2 generates noise on RX because when it is not TX’ing, the DDS is not disabled, it actually is working away on 6.25MHz doing calibration tasks, this signal is output to the PA and the PA power is still applied, Key Down being by gating the FET Source to Ground. Signal leaks out via the Drain Load to the Antenna socket.
This situation is disturbing to me, I have never had such a noisy sprog ridden shack, several times during testing I was caught off guard and confused by the spurious signals both on RX and TX.
There are some odd effects also reported by another Beta tester of pick up from the U2 via its own leads, I couldn’t improve this using decoupling, earthing changes or anything. This can manifest itself with 50Hz and 100Hz sidebands on WSPR when monitoring your own signal.
To be fair the crud, S2 on 28MHz, is not devastating but as a QRP RX station as well as TX I take great care to get as low a noise floor as possible. I complain bitterly about my neighbors Plasma TV’s the U2 competes from within.
Finally:-
The U2 has earned a place in the shack and Ultimately, pun intended, as a portable MEPT with GPS. Hence it also earned a box and it is off the bench.
It is interesting to see the Enclosures used by various assemblers of the kit. They have been of all types, ranging from large and roomy with a bit of spare room for a few sandwiches and a flask as a picnic portable to solid Die Cast Boxes which would fend off a WW2 Tank attack and some small, compact jobs too.
I went for small, compact, light weight, Hand Held with the 5Volt Regulator inside, I wanted to avoid having the LCD display fixed through the front panel and worked on avoiding having its fixing screws, which are in an odd 3 screw configuration showing. The Data Entry buttons can be quite awkward if not ergonomically arranged I mounted them for modern two thumbs use and it works out well.
The DDS has an LED indicator I didn’t add another panel LED with extra current consumption, I have a spy hole in the front panel which shows the DDS one, a light pipe will be a nice addition for that.
Band changing requires a swap of the plug in LPF. On the bench I found this quite awkward to get at, in the box the PCB is mounted so as to present the LPF at the top right hand corner, open the front and it and the PA transistors are looking at you, it is easy to hook a couple of grubby finger nails underneath to remove and change.
Input and Output, Power, GPS, and Antenna Sockets are on the rear.
Here is the U2 Boxed on Video sending WSPR on 28MHz.
When it comes to QRP, QRSS and WSPR TX’s I usually experiment, program and build units and run them for ages as modules which can be added to and new ideas tried, many never get boxed up, they go in the archives and new projects take their place.
I do however enjoy building kits, and some projects are much easier to build from a kit. The recent introduction from QRPLabs the Ultimate2 caught my eye as a tiny feature loaded, build it box it use it project. With a GPS Module added the thing knows the Precise Time, Where It Is, so it enters its own Locator for WSPR and sets its Frequency Calibration with GPS timing accuracy too. Ideal for my touring trips I bought one. It goes anywhere frequency wise too by courtesy of a Chinese 9850 DDS. The kit is produced and dispatched Worldwide on a low cost basis and comes at a great price.
Unfortunately some bugs have slipped through in the software, somehow my particular unit seems to be among the worst effected, I would not like to use it on air, further reports on it will have to wait until a new updated AVR chip is installed.
Here is a Photo of my assembled unit, it really is tiny, the individual LPF’s plug in alongside the DDS, here I have it rigged up for external my LPF’s, I thought I made mine small the U2 ones are half the size.
RIGHT CLICK ans select View Image for larger size Photo’s
Another kit dropped through the door today, the very best sort, a free one. Back in 2009 I developed an idea and published it here In my Blog.
At least one person in this big old world liked the idea and said so, it has taken some time but he, W5OLF of Comcast asked if I would mind him producing a kit based on it, I said no problem, hence my gift.
Jay has added an Xtal timing circuit to my design I do the timing in the PIC but my system is not market reproduce able. He uses a PICAXE PIC so the unit becomes the WSPR-AXE Organ The kit uses a quality well spaced out PCB and a good 3 bag system for components and parts which should make construction foolproof even for a beginner.
It comes in a plastic box which can serve as the housing for the completed unit, or if you wish it will fit in an Altoids tin.
Setting up was easy the timing looks pretty good from my first calibration, after a good soak to age the Xtal I will do the fine adjustment. Xtal aging shouldn’t apply to the audio calibration due to the use of matched Xtals from the same batch, they should drift both for age and temperature in the same direction and the spacing just stay constant.
The Box, PCB and three bags of components.
The completed unit on test.
The results. The advantage of the XORgan system, clean spike less WSPR with no sidebands, produced from a frequency and time stable low power circuit and no Computer, OK, OK no PC, if I have got to tiptoe round the pedantic.
I am often running a Grabber on some Band and Mode or other. My interests are too varied to dedicate my efforts to Meteors, 8.27KHz, 474KHz, ZEVS, Sferics, LF, MF, HF the list goes on.
What I could do when monitoring VLF is use the same Computer to provide a QRSS Grabber on any HF band, something I haven’t done up to yet.
I have also given a Toshiba Satellite Pro 4600 Laptop its last escape from the grave. The thing has hardly been used, looks brand new but is so ancient it is as slow as a snail. I tried to palm it off on the XYL, installed the first ever release of Ubuntu and Puppy Linux but the thing just can’t cope.
So I have installed a minimised version of XP with Argo, WSPR2 and the necessary peripherals this can run as a Grabber or WSPR RX 24/7 on request, its much quieter than a desktop with the fans raging and less current consuming. Last night it survived an overnight run.
It’s not perfect, it likes to generate its own little descending pulse on the trace every so often but its adequate.
One last thing that enables reliable Grabber operation is my new, never drop out, Wifi Router, it was hardly worth leaving a Grabber on overnight when most likely the Web would disconnect 3 seconds after I went to bed.
Here is the G3ZJO HF QRSS Grabber location. QRSS GRABBER
It won’t be one of those wonderful full time Grabbers for the reasons stated but a I will fire it up in response to a Message to Knights QRSS or QRPlabs Groups, there are many new QRP / QRSS stations coming via the latter efforts.
Roger G3XBM recently produced a simple design for an 80m to 500KHz Transverter. The output is way above my power level interests but 500KHz antenna’s, particularly mine are so inefficient that the radiated power will still be in the uW levels.
I decided to test the reproduce ability of the circuit, I think I was the first to try, there were a couple of head scratching moments before I discovered a couple of notation errors on the circuit diagram due to values left over from previous versions creeping through.
It was fun to be the Alpha tester of the design, particularly the last test, with my FT897 connected, my Netbook running WSPR and my power measurement 50 Ohm load on the output socket. Previous tests were with a short carrier to measure / set up levels. The 2 minutes of WSPR was a bit OTT for the load and some of the smoke inside was released, there is still some left in there though.:DD
I used the new pad cutter from GQRP Club and double sided PCB. I have used both copper planes as extra heat sink for the PA, coupling ‘studs’ for heat transfer being situated around the PA heat sink. Roger mentioned drift due to PA heat so I also used a metal box, that too coupled thermally to the PA.
Results using QRPp power levels previously were spectacular but many stations were not able to see my or Rogers’ signals. When Roger ran his test using the 472/500KHz Transverter many previously difficult or impossible stations appeared as if from the mist.
My first on air test in daylight brought reports from PA3FNY at 409Km a very good start. OPERA and QRSS tests will follow.
I have waited for the TX experience of ROS OPERA digital radio data mode until I had my QRPp home built PIC controlled TX running. Yesterday evening I ran OP4 on 500kHz, the TX produces less than 200uW ERP from my antenna which is now a simple inverted L 5m up 5m out.
The TX was built for QRSS FSK so I had to modify it to run A1A on off keying although I have proved that OPERA does not mind being sent as FSK. The TX had been running on QRS3 and QRS10 on 500kHz with zero reports. I therefore was not expecting much in the way of results.
But results we got, very impressive.
My PIC Code sends selectable OPERA Speeds/Modes followed by 12WPM Morse ident, it is simplistic and like my WSPR PIC Code, written only for my call sign so please don’t ask for a copy. G4JNT has produced a sophisticated multi user code for both OPERA and WSPR which are available for download.
The ROS/Opera software is still in its Beta versions, the CPU load is very high which tends to put me off. No problem for me if I don’t want to receive too, everyone else uses oodles of computer power to receive me.
A nice visual report arrived by e-mail yesterday from Ray W2XC, he was pleased to be seeing my 200mW 28MHz MEPT on WSPR regularly and I was pleased to see his screen shot.
Now this is not exceptional, what I do find odd is the lack of reports from QRSS stations and Grabbers of the same 200mW TX when it sends QRSS. The contrast is daily reports from America, Europe, Africa, Asia and Australasia on WSPR, zero reports for years on end from anywhere for QRSS.
OK so most activity is on 10MHz, but stations and Grabbers do go on to 28MHz regularly, QRSS needs to be strong enough to be visible but just look at the waterfall display of my signal on the screen shot, (2nd signal up in the second column from the right), on the scrotty little non optimised display which is no more than an indicator for WSPR stations.
The Boxing day test transmission from SAQ on VLF had a problem today. I listened to a tune up and test yesterday and it ended abruptly at 09:29. Maybe then was the moment that the Speed Regulator went wrong, unfortunately the team couldn’t sort it in time.
They do a sterling job of keeping the World Heritage old girl running lets hope it isn’t too serious.
Luckily I did capture the Xmas Eve Eve transmission a good signal 30dB above the noise.
At least my efforts worked out OK today, last night I decided to build an HF Grabber site to make the most of the improvements in the 10m Band and the fellow QRPp’ers who are showing an interest in 28MHz.
Last night I tested using my existing VLF Grabber grabs, today the HF rig provided signals on 28MHz and some Spectrum Lab user files were produced, now its on test for real.
Radio - LF/MF to Microwaves 