QRSS (very slow beaconing)

This is something I have never tried and I have no idea how it compares with WSPR or FT8.  The advantage is the signal (often real QRPP) may be viewed as a trace on a screen. and no real special software is needed, although I expect QRSS enthusiasts have their favourites.

I guess even non-licenced people can try this on ISM bands if permitted.

See https://swharden.com/qrss/plus/ 

QRSS software?

QRSS receive is not something I have tried. I am wondering what the best software I should use? Any recommendations would be appreciated.

QRSS or WSPR?

Although WSPR comes in several guises and speeds, I have no idea how QRSS (slow CW) compares with WSPR. Maybe Googling will tell me the answer.

For very low power (QRPP), one of these modes is probably better. WSPR has the advantage of being widely reported via WSPRnet.  Certainly very slow WSPR is probably better than QRSS at reasonable speeds.

The answer is probably the same as, "how long is a piece of string?", but any pointers would be appreciated.

136kHz experiments

Before moving to the current QTH about 7.5 years ago, I did some tests on 136kHz QRSS. I used the E-field probe for 136kHz on a mag-mount on the car and drove around to see where the beacon could be copied. The beacon produced 8W into 50 ohms, but the beacon ERP was only low milliwatts or even less. The antenna was the earth-electrode "antenna" in the ground. After successfully receiving the beacon on the far side of Cambridge (20+ km?), I just stopped as it was obviously working well both on TX and RX. The E-field probe is shown in the photo.

Other than a brief test with the earth-electrode "antenna" on RX, I have never yet tried 136kHz at this QTH.

My old site (links may not work as this old site is not maintained) has a description of the E-field probe RX antenna and other tests at 136/7kHz.

See https://sites.google.com/site/g3xbmqrp/Home/136k .

See also http://g3xbm-qrp.blogspot.com/2013/01/137khz-e-field-probe-mag-mount.html for more on the LF EFP.

137kHz E-field probe on the car mag-mount

Many years ago, I tried looking for my tiny 137kHz beacon with a small E-field probe mag-mounted on the car. After seeing the signal quite well on the far side of Cambridge at about 24km, I stopped the test. As you can see, the EFP used readily available parts and was very simple.

At some point I should rebuild this and try from the QTH we moved to almost 5 years ago, maybe using the earth-electrode "antenna" on TX. I have felt too unwell since my stroke.

See https://sites.google.com/site/g3xbmqrp3/antennas/137efp

QRSS and WSPR frequencies

Being a keen WSPR user, I have not used QRSS on HF, although I have done on MF, LF and VLF.  A useful page about QRSS is here.  QRSS requires manual intervention to interpret the signals whereas WSPR using WSPRnet is automatic. This is one of the reasons why WSPR gets used here a lot.

Ultimate 2 QRSS beacon TX

The Ultimate2 QRSS kit

The latest edition of SPRAT, mine arrived yesterday, reminded me that G0XAR and G0UPL have produced a very nice QRP beacon transmitter for weak signal modes including QRSS and WSPR. This unit can run stand-alone without tying up a PC to generate the WSPR message, although a GPS module is needed to get the WSPR time sync. The beacon will work on all HF bands with a suitable low pass filter and do other modes like QRSS too. There is even a version that can do WSPR and QRSS in alternative time slots.

See http://www.hanssummers.com/ultimate2.html . At just £17.50 this is a great value kit for those interested in weak signal beaconing.

Back on 137kHz TX

QRSS and CW beacon TX for 137.685 kHz

Today I went into the shack with the intention of making a new transverter for 137kHz based on my recent design for 472kHz.

Instead, I ended up building a new CW, QRSS3 and QRSS30 8W beacon transmitter using an IRF640 PA device. This evening and overnight the beacon will run QRSS3 on approximately 137.685kHz and I have requested reports and screenshots.

The antenna being used is my 20m spaced earth-electrode pair set-up used very successfully on 472kHz last weekend. On 137kHz signals are much weaker than on 472kHz, so I await reports with interest.

The whole unit runs quite cool when housed in a plastic box. Switches on the front of the boxed unit allow up to 7 pre-programmed messages to be beaconed at varying speeds. As normal, I use the K1EL beacon chip for the beacon message generation. The signal source is a 3.579MHz crystal in a divide by 26 circuit implemented in a PIC like device and kindly supplied to me by a French amateur Francis F6HSI a few years ago.

Thoughts turning to 136kHz again

After a few weeks on the new 472-479kHz band, my thoughts are again turning to 136kHz, a band that I experimented with a year or more ago now. This band is MUCH harder work than 472 or 500kHz with around 20-30dB more of everything (!) needed.  By this I mean that for the same power, the "effort" to get a contact or report seems to be about 20-30dB more. This is partly because the short antennas I use have a very low radiation resistance at 136kHz so losses become more significant. Also, noise can be even more of an issue.  Despite all of this, I plan to make a 136kHz version of the transverter I did for 472kHz, but maybe with a bit more RF output (in the 20-30W region). Most of the design is ready done (in my head) so it should only take a few days to do. The plan is to TX using my earth-electrode antenna.

On 136/137kHz there are fewer stations using WSPR, so I will probably use QRSS more. In the past I have made QRSS crystal controlled beacons for this band, but with a transverter and my FT817 I will be able to generate a QRSS signal wherever I want in the band and also be able to have QRSS QSOs.

Does anyone have recommendations for SIMPLE PC program that will allow me to generate QRSS (various speeds) as an audio tone? 

This way I can use my SignaLink USB interface and VOX to send QRSS (or DFCW) using audio tones. Please don't suggest Spectrum Lab unless you can give me a "Noddy guide" on how to use it for QRSS! This is a very good program, but to a simple soul like me it seems like you need a PhD to drive it. In the past I've used it for VLF reception, but it took me weeks to work out how to drive it and every time I go back to it I need to learn it all again. I just want a simple QRSS tone generator.

Ultimate QRSS/WSPR kit from Hans Summers

Hans Summers G0UPL has just announced a wonderful new kit. Amongst other modes it also supports stand-alone WSPR beaconing when used with a GPS timing reference, without a PC. This was his announcement on the GQRP Yahoo group earlier today:

All,

This is to announce a new standalone QRSS/WSPR kit by Steve G0XAR and Hans G0UPL. The kit supports WSPR, QRSS, DFCW, FSK/CW, CW, Hell (full speed and half-speed), Slow Hell, and customisable FSK patterns. The WSPR encoding is on-chip. It supports the connection of a GPS module for frequency locking, accurate time, and location (for WSPR). Power output is measured at 185mW on the 30m version. We are selling versions for 30/40/80m and perhaps later 20m and 160m. It does not require a PC, it has an LCD and two buttons to control it.

The price is GBP 15.39 (EUR 19 or US $24 approximately) plus shipping.

You can see all the details here: http://www.hanssummers.com/qrsskitmm and order online at http://www.hanssummers.com/shop . We expect to be shipping by 27-29 June.

The kit supports the following modes:

+ QRSS mode (plain on/off keyed slow CW)
+ FSK/CW mode (frequency shift keyed slow CW)
+ DFCW mode (dual frequency CW, dit's and dah's on different frequencies)
+ WSPR mode (Weak Signal Propagation Reporter)
+ Slow-Hellschreiber (frequency shifted slow Hellschreiber)
+ Hellshreiber (full-speed standard Hellschreiber, and half-speed Hellshreiber)
+ CW (plain CW)
+ Customisable FSK patterns

Other features:

+ 24-character LCD + two-button user interface
+ User-programmable (callsign, message, speed, FSK, mode, etc.), settings stored in EEPROM
+ GPS interface, for locking the frequency in slow-speed modes
+ On-chip generation of WSPR encoded message (no PC required)
+ WSPR maidenhead locator can be generated from GPS-derived latitude/longitude
+ Selectable “frame” size, for stacked QRSS reception
+ Plain CW callsign identifier at selectable interval
+ Produces 150mW RF output, or AF output for driving an SSB transceiver
+ Higher output power by additional PA transistor and/or higher PA supply voltage

73 Hans G0UPL and Steve G0XAR

Weak signal modes compared

There has been quite a bit of debate recently about just how good certain weak signal modes are when compared against similar modes. So, ON7YD has done some research and straw polling to compare them and published the results on his wonderfully informative website. He asked people to try to decode some weak QRSS signals by eye - these were at defined S/N ratios and compared the results against OPERA at various speeds and WSPR.

Amongst his conclusions is that "Opera8, QRSS10 (or DFCW10) and WSPR should have a more or less equal performance."  This is very much as I have found from practical experience on 136kHz where QRSS3 does not perform as well as QRSS30 which is somewhat better than WSPR. So, WSPR being much the same as QRSS10 seems spot on. The advantage of WSPR is of course the internet database reporting which allows you to see where you have been received. QRSS reports depend on someone decoding the signals by eye and then manually sending you a report, which rarely happens. So, WSPR remains my favourite weak signal beaconing mode.

ON7YD's graph showing the effectiveness of various weak signal modes

Mains hum powered beacon

Recent tests with earth electrodes at VLF have got me wondering about a simple QRSS HF/VHF beacon TX powered entirely from the rectified mains hum and other crud coming from a couple of earth rods in the ground.  Not sure of the available power, but I suspect it would be in the 0.1 to 2uW region, maybe more. This may be enough to drive a low voltage QRSS beacon for example. You can buy power harvester ICs these days for this purpose, but with a step-up mains transformer there may be a volt or two available at a few tens of uA and that alone may be enough to drive a keyed oscillator. The ultimate in free power beaconing!

G3XDV on 136kHz QRSS

Getting a very strong signal this evening from G3XDV on 136.177kHz QRSS60 receiving Mike on the earth electrodes fed straight into the deaf (at 136kHz) FT817. He is sending "XDV" preceded by G3XDV in normal speed CW.

14.9km on 136kHz QRP (earth electrode antenna)

This morning I did some more tests using my little 136.93kHz 2W QRSS3 beacon feeding into the 20m spaced earth electrodes. The TX end was unchanged, but this time on receive I used my 30t 80cm loop resonated with about 700pF and fed straight into the high impedance input of my E-field probe. Results were as follows:

• At 2.4km good copy by ear (12wpm CW would have been very solid)
• At 8.6km good copy using Spectran
• At 14.9km clear copy of my callsign and locator in QRSS3 with Spectran on the Gog Megog Hills near Cambridge (see screenshot)

All these locations are more or less in the line of the earth electrodes that run NE-SW from the home QTH (JO02dg).  Another RX test some 11km to the south of the QTH  resulted in no visible trace, suggesting the TX earth electrodes are behaving as a loop antenna with some directionality. This was not the case when the same earth electrodes were used at 0.838kHz some weeks ago and when the mode was mainly conduction through buried utilities. Remember, this is ultra simple stuff:

• 2W out crystal controlled QRP 136kHz beacon TX on a 5 x 5cm board (see picture)
• Invisible ground "antenna" that can't be seen, even when a few metres away from it.
• No attempt to match the TX to the earth electrodes.
  
• Simple loop + FET impedance matching circuit and deaf FT817 at the receiver end.

It would be interesting to work out what the ERP must be and interesting to speculate what would happen with such a system at 73kHz. Pity there is no allocation there today.

4.6kms with earth electrode "antenna" and 250mW on 136kHz

Today I tried some more experiments with my 20m spaced earth electrode "antenna" and small QRP beacon TX on 136kHz. I switched over to QRSS3 and  used the FT817, E-field probe and PC with Spectran to see where copy stopped. 1.5km from home and solid copy on QRSS3 when holding the E-field probe box as high as possible above the car roof. Then I drove on to a spot 4.6km from home and copy was again achieved, albeit not as strongly.  I'm certainly getting a signal radiated beyond the near field.  I'd like to check "antenna" directionality by looking for signal levels with the QRSS3 beacon at all compass points some 4-5kms away from the QTH.

In the meantime, if anyone near Burwell, Cambs wants to look for the QRSS3 signal near 136.93kHz I'll leave it running until about 8pm tonight when I have to switch off as my grandson is sleeping in the shack bedroom. Any reports would be amazing.

Further 8.97kHz earth-mode tests

All being well, I'll be carrying out some more earth-mode (through ground conduction current) WSPR and QRSS tests on around 1kHz and 8.97kHz in about 10 days time. My aim is to achieve a new personal DX record for the mode using about 4W. My previous best distance is 0.3kms, but I'm pretty certain that with QRSS or WSPR this can be bettered. Remembering an earlier post, 18dB more system gain is needed to double distance using this mode of propagation.  This can be achieved by raising TX power or effectively improving the RX sensitivity, in this case mostly by better filtering and signal processing.

G3ZJO in QRSS3 on 500kHz

G3ZJO has a QRSS3 beacon sending in FSK built in Altoids tins and running QRPp power. This is is a screenshot (from Spectran) of his signal this afternoon. I have superimposed his callsign, which is clearly visible on the upper line. The first dash of the G in his call is missing in my capture.

Simple beacon keyer IC: the K-ID2

Looking around for a simple beacon keyer to use with a QRSS beacon, I discovered the ICs sold for $6 (available via Paypal) from K1EL. This 8 pin IC looks ideal as it allows a variety of pre-programmed messages to be selected and sent at predetermined keying speeds.

See http://k1el.tripod.com/KID.html . At $6 each you can hardly go wrong with this. I shall be ordering a few shortly.