G4FEV reports my QRSS3 LF signal at 56.7km

Path between G4FEV and G3XBM

This afternoon I was out and about with my E-field probe checking signal levels of my little 137.766kHz QRPp QRSS3 beacon at various locations around the Cambridge area. The furthermost point I tried was near Comberton, 21.5km WSW of the home QTH in Burwell. I have taken a lot of measurements, including the level of DCF39 at the same locations so that later I can work out my field strength and thence ERP.

G4FEV's screen shot of my QRPp QRSS3 137.766kHz beacon at 56.7km

When I arrived home I had an email from Dave G4FEV 56.7km due west of me to say he had copied my signal and had sent a good clear screenshot. Signals with Dave looked quite good, suggesting the signal due west may be stronger than signals in the Cambridge direction (SW - WSW). The earth-electrode antenna has directivity but, aside from a zero copy at one location orthogonal to the "loop" I have still to work out exactly which directions have the strongest signals. Based on the above I think it is close to W-E.

Disappointment on 137.766kHz

Despite running my QRP LF beacon for over 2 days continuously I have received no successful reports. A couple of people looked without success, but at least they tried. I am leaving it running QRSS3 today as I want to do some further reception tests this afternoon and measure my ERP by taking actual field strength measurements out to about 15km from home. Let's hope I get a few positive reports as the signal should be detectable out to at least 60km.

Checking my 137.766kHz ERP by measuring field strength

Well, today has been a bit of a disappointment: my QRP QRSS3 beacon has been running for over a day on 137.766kHz and, apart from my own highly successful reception tests out to around 8km (as far as I went in the best direction) not a single station has reported seeing it  ....yet.

Tomorrow, I am going to do one more experiment using the QRSS beacon: knowing the field strength of DCF39 on 138.830kHz, a commercial station in Germany, is around 1mV/m here in the south of the UK in daytime, I want to measure the S/N of this station about 5km from home using the mag-mounted E-field probe. Then, at the very same spot, I will measure the S/N of my beacon with the same bandwidth settings and RX kit.

Based on these two measurements, I should be able to work out the ERP of my beacon to an order of magnitude and probably to within +/-3dB. The field strength of my own signal can be worked out just by comparing the S/N with that of DCF39.  Knowing the field strength and the distance from the home QTH, I can work out the ERP needed to produce this.

Any guesses what ERP I am using? I'll tell you the answer tomorrow!

New 137kHz Transverter thoughts

IRF640 FET

This evening, I've ordered a reasonable sized heatsink to use with the new 137kHz transverter. I am aiming for a power from the transverter of at least 30W and want to be sure that with mismatch the PA is able to survive quite hard abuse. The IRF640 looks a good choice for the PA, maybe a pair, as it is rated at a high voltage (200V) and high current (18A) so I can run the PA from a 30V (or even 50V) supply to get more out. Even with 30W RF, the ERP will still be in very low milliwatts.

As I want to ensure the 10MHz LO signal is very stable so I can use it with WSPR-15 and QRSS30 modes, I may put this in a separate insulated enclosure and pipe the injection signal in via coax.

What I am most concerned about is the lack of activity on the 137kHz band: the last time I gave it a go with WSPR the biggest issue was the very few people actually monitoring WSPR on the band. At the moment, the new 472kHz band is very much the focus of attention with up to 50 WSPR users monitoring and/or TXing on any evening. On 137kHz however the number of WSPR users is often just 3 in the world with no-one on in Europe at all.

Still, I am convinced that with WSPR-15 I should be able to reach near Europe even with my 20m earth-electrode antenna if I can get the power up to around 30W from the transverter. It may even be possible, just, with WSPR-2.This is worth a go, before getting back onto other projects ...like finishing off the Tenbox transceiver!

Lightning across Europe

Lightning map of Europe http://www.blitzortung.org/Webpages/index.php?lang=en

Sometimes it is useful to know where there are lightning strikes taking place across Europe: for example, there are some theories linking sporadic-E propagation to a secondary effect of lightning, although I forgot where I read this. Also, it is useful to know how noisy the VLF and LF bands are likely to be as a result of sferics from such strikes.

Well, http://www.blitzortung.org/Webpages/index.php?lang=en gives a map showing this data.

Homebrew RF Circuit Design Ideas website

HA5KHC's useful website

Wandering around looking for 50W PA designs for 137kHz this afternoon,  I chanced on a website that I don't remember seeing before by HA5KHC. It consists of a HUGE list of very useful links to other websites arranged by design topic (transceivers, receivers,  etc).   It is a massive list of useful links that I could spend days trawling through for ideas and inspiration.  It was quite flattering to see a couple of my designs linked.

Unfortunately there is nowhere on the page with a contact address for the website owner, although I expect HA5KHC's details will be on QRZ.com.

UPDATE:  Adrian YO5PBG said:

"I believe it is a mirror of the original site... of Iiulian - YO3DAC/VA3IUL - http://www.qsl.net/va3iul/Homebrew_RF_Circuit_Design_Ideas/Homebrew_RF_Circuit_Design_Ideas.htm" 

New frequency for LF QRSS3 beacon : 137.766kHz

Using the strong German commercial station DCF39 on 138.830kHz (it is S9+ with me) as an accurate frequency reference, I have checked the frequency of my QRSS3 QRP beacon and it is running higher up the band than I thought due to the way the crystal is loaded. 

Frequency to look is 137.766kHz   +/- . It should be within 1Hz of this frequency. 

Reports and screenshots (looking now in the right place) would be very much appreciated. I shall leave the beacon running all today at QRSS3 speed.

137kHz E-field probe mag-mount

Tiny E-field probe on the car roof on mag-mount

This is the schematic of my simple mag-mount based E-field probe for 137kHz reception in the car. I use a low cost MPF102 FET and a low cost 2N3904 transistor. Performance seems to be totally adequate, detecting my very low ERP QRSS3 beacon as I drive around the local area up to around 10km (yet to test at greater range) from home. The whole unit is attached at the base of a 15cm whip on a mag-mount stuck on the centre of the car roof. The coax from the EFP connects into an FT817 with the IPO button ON - this makes the sensitivity better on 137kHz, a tip worth knowing.

QRSS3 tests with QRP on 137.685kHz.

This afternoon I started my tests on the 137kHz band again. With my 8W (RF out from the unit - ERP will be uW level) crystal controlled beacon sending QRSS3 feeding the 20m spaced earth electrodes, currently under 8cm of snow, I ventured forth in the car complete with an E-field probe built into the bottom of a mag-mount antenna on the car roof. The E-field probe whip is about 12-15cm long only. It looks like a small UHF quarter wave, rather than an antenna for 2200m! The TX frequency is currently around 137.685kHz and this QRSS3 beacon will remain on overnight. I am hoping that stations out to around 100km will take a look for it.

QRP earth-electrode antenna signal at 8.2km on 137kHz band

Well, results have been spectacular with some excellent signals around 8.2km away in the line of the earth-electrodes. Orthogonally, the signal was not copyable at all at a similar range. This is classic loop directionality again.

/M RX signal at 6km orthogonal to TX antenna.

The receiver consists of the 10-15cm long E-field probe feeding the FT817 with IPO button pressed (improves sensitivity when ON at 137kHz) feeding the PC running Spectran at 0.34Hz resolution.

I do find it unbelievable that such a TX "antenna" buried under the snow with NOTHING in the air at all and with earth rods just 20m apart can put out such a decent signal on the 2200m band.

New ERP calculations on 472kHz with earth-electrode antenna in 8cm snow

With several repeatable ground wave reports on 472kHz WSPR using the earth-electrode antenna, it is time for a recalculation of my ERP based on a formula (for 500kHz) supplied some years ago by M0BMU.  The assumption (from M0BMU, that I am not at all sure is right) is that the noise floor is around 3uV/m in a 2500Hz (WSPR) bandwidth. So, based on the WSPR S/N ratio the field strength when using the earth-electrodes can be calculated.

• G3ZJO at 79km gets me at around -19dB giving my field strength around 355nV/m. 
• G3XDV at 61km he gets me around -12dB S/N giving my field strength around 810nV/m.  
• M0BMU at 69km he gets me around -30dB S/N giving a field strength around 100nV/m

ERP Calculations

• ERP using G3ZJO's results = (E*d)^2 / 49; with E = 355nV, d = 79km   ERP = 16uW
• ERP using G3XDV's results = (E*d)^2 / 49; with E = 810nV, d = 61km  ERP  = 49uW
• ERP using M0BMU's results =  (E*d)^2 / 49; with E =100nV, d = 69km  ERP = 1uW

Now, to me these figures seem far too low, so perhaps the noise level is much higher than 3uV/m. Certainly that is the case here where I have an S4- S8 noise floor due to SMPSUs and other noise sources. I think these numbers can be doubled based on ground wave losses but, even so, the figures appear to be extremely low.  My Marconi antenna is some 8dB (average) better than the earth-electrode antenna and I am sure the ERP is well above 1mW using this antenna.

Conclusions

I am totally puzzled: measuring antenna current on the Marconi I get ERPs that are an order of magnitude higher yet measured results with the earth-electrode antenna average just 8dB down on the Marconi. This suggests ERPs for the earth-electrode antenna in the low mW region, which I find much more believable.

Any thoughts please?

Is this Chinese HF radio a wind up one?

As the person who started the FT818 hare running a year or so back (my thoughts and ideas for an FT817 replacement - thanks to a little Photoshop editing!) , I'm wondering if the attached is real or also a spoof?

It purports to be a new Chinese HF radio retailing for £299. It looks very much like an IC718 with some stickers on. It was brought to my attention by Steve G1KQH who found it at
http://s3.zetaboards.com/copythat/topic/7467118/1/ but the date on this is 2011. Surely if true the radio would be on sale now? Somehow I am of the opinion this is (also) a bit of wishful thinking, but I would be delighted to be proved wrong.

A real Chinese HF radio at this sort of price is not totally out of the question: labour costs are low and there are already some very nice Chinese VHF/UHF handhelds on the market that under-cut Yaesu and Icom by around 100%. It is surely just a matter of time before an FT817 or an IC718 look-alike radio is available from one of the Chinese makers.

UPDATE 1755z: maybe this IS real. See http://www.tradekey.com/product-view/1538868-518398/Hf-Transceiver-ft-808-.html

Back on the earth-electrode antenna on 472kHz

The red dots show where the wire to my far earth rod goes - under the snow!

This afternoon I've installed a coax cable from my operating shack down to the back of the garage where I do my radio building and where I can connect to the earth-electrode antenna running down the back garden. Now I have my 472kHz transverter in the garage too so it can connect directly into the earth-electrode antenna without any matching. Even with 8cm of snow on the ground and nothing of the antenna visible above the snow line (!) this antenna is still radiating a decent signal with reports already this afternoon from G3ZJO (-22dB S/N) and G3XDV (-12dB S/N) at good range. I find it truly amazing this system works at all.

I am signing G3XBM/1 on the WSPR database to distinguish my signal from that transmitted using a Marconi where I use G3XBM.  I hope no-one minds me using this suffix for a short period, but it is very much in the interests of good research. The signal level with G3XDV at 61km is about 8dB weaker on the earth-electrode antenna than on the vertical Marconi.

ILER-40 and ILER-20 QRP SSB transceiver kits

The ILER-40 and ILER-20 are low cost, simple 4-5W QRP SSB transceivers for 40m and 20m from Spain, designed by Javier EA3GCY.  They are designed around NE602 ICs working bi-directionally to save parts.

Built on a 12 x 10cm PCB, they look easy to build.  Details are available at http://www.qsl.net/ea3gcy/ . The price is a snip at just 67.50 euros plus 10 euros shipping. It looks a very well engineered kit.

ILER-40 (and ILER-20) QRP SSB kit from EA3GCY

See http://www.eham.net/reviews/detail/10700 for a number of (very good) reviews of this kit which looks like a neat introduction to QRP SSB operation. Kits now being supplied include a small AGC sub-board. The kit does not include a microphone or case.

IC7100 price

Whilst checking the trade-in value of my Elecraft K1 transceiver with Martin Lynch yesterday (in my case for another FT817), I asked when the IC7100 was likely to be available in the UK and its likely price.  Indications are that the IC7100 is going to be here in the spring with a price tag of around £1700. This does not include the D-star option. Clearly these dates and prices are not certain. It will be considerably more expensive than the IC7000 though. That much is certain.

An IC7100 at that price is rather more than I would want to pay, but if it was to last 12 years like my current FT817 already has, it might be worth it, especially with 4m,  2m and 70cm coverage. On the other hand, a second (additional) FT817 would do all I really need at under a third of the price!

E-field probe mag-mount now built

This morning I decided that it would be better to build the E-field probe for 137kHz RX at the base of the whip directly on the mag-mount base rather than inside the vehicle and having to tune out the cable capacitance. This way,  the cable capacitance is no longer an issue. I built the E-field probe into a small plastic box and arranged it so the whole unit attaches to the mag-mount using a PL259 plug in the bottom of the unit. Radio 4 on 198kHz is an S9+ signal with the mag-mount sitting on the bedroom window-sill with around 10 inches of whip. It appears to be working well.

The present design is a poor man's PA0RDT probe but using an MPF102 and a 2N3904 rather than the better devices used in Rodolph's high IP2/3 design. I may put a tuned circuit in the FET drain to increase the gain at 137kHz and reduce the gain outside the band. I will experiment with this before going out in the car.

Currently it is snowing continuously here, so road testing the EFP and checking coverage of my QRP 137kHz CW and QRSS3/30 beacon will now have to wait until later in the week.

UPDATE: I have modified the EFP so that the FET output comes from the drain with a drain tuned circuit tuned to 137kHz. I have the source resistor not decoupled initially but will consider adding this if I need a little more overall gain as the barefoot FT817 is very deaf on 137kHz.

A mag-mount as an E-field probe for 137kHz

Next week, assuming the snow has gone, I want to drive around the local area to plot the polar pattern of my earth-electrode antenna working on 137kHz.  My 7-8W beacon transmitter can send a range of QRSS and CW messages, so I want a way of driving to different places using my FT817 fed via a preamp and measuring the S/N using Spectran whilst remaining inside the car.

Portable RX loops are fine, but these are directional and need to be set up each time a measurement is taken outside of the car.  Ideally I need an omni-directional RX antenna like an E-field probe. So, I'm looking for a way to drive to a spot, take a quick measurement from inside the car, then move on; a loop works, but when it is -2 deg C outside and the ground is icy, it is not ideal.

Either I put the electronics for an E-field probe right at the base of the mag-mount (mechanically not ideal) or I have the electronics in the car and somehow tune out the coax cable capacitance.  At the moment I am still experimenting to find an arrangement that works with good sensitivity by checking the strong Greek commercial signal just outside the 137kHz band.

Based on 472kHz results, the earth-electrode antenna behaves like a loop with loop-like directionality. I 'd expect to see the same pattern on 137kHz.

K7AGE video of his KX3 build

Randy K7AGE has done a wonderfully amusing video of him building his Elecraft KX3. I won't spoil the fun, but recommend you watch it and see how it is done.

Square trade eBay Warranties - any good?

Just looked on eBay for various amateur radio items and noticed the Albrecht AE2990 10,11,12m handheld on sale from various UK suppliers from around £150. Now also shown was an optional 3 year warranty - see http://pages.ebay.co.uk/safetycentre/buyingwithconfidence/warranties/index.html which cover failures to the device outside the manufacturer's warranty period. So, for less than £200 you can have a multimode HF handheld complete with 3 yr warranty.

Peace of mind 3yr warranty for £27 - too good to be true?

My question is this. Has anyone here bought an eBay item with one of these warranties - they seem to be widely offered - and had to make a claim?  It sounds almost too good to be true. These warranties are also available on low cost VHF/UHF handhelds as well where the warranty cost is only around £8-9, which looks remarkable value if the product fails. This is as long as the warranty is a decent one that is honoured and the small print doesn't render it worthless. They also offer a 5 day repair or replacement service.

Mixed results with WSPR-X and WSPR-15

The new version of WSPR works well with plenty of reports given and received on 472kHz with it over the last 12 hours using the 2 minute version (as before but now with a waterfall and better interface), but mixed results on the slower 15 minute slot WSPR-15 which can detect much weaker signals.

My problem is TX drift over a long 15 minute transmission. My small 10W transverter is in a tiny plastic box. When using a 2 minute transmission the PA barely gets warm so there is little heat transferred to the crystal oscillator. With the much longer TX burst the PA warms more and the crystal warms up several degrees, moving the oscillator frequency by some 10s of Hz. So, although I was able to copy signals in WSPR-15, I was not able to be detected by others overnight. There are also far fewer stations monitoring yet on WSPR-15.

The solution is to rebuild the transverter into a bigger (metal) box with (a) better heatsinking so the heat rise with a mismatch is lower, (b) a slightly more efficient PA - problem here is with weather changes the antenna match goes off optimum sometimes and the heat rises as it the PA becomes less class E, and (c) put the conversion frequency oscillator physically further away from the PA, currently it is less than 10cm.

If I fix these issues and am sure that I transmit a more stable signal in the narrower (25Hz wide) WSPR-15 slot then I have a better chance of succeeding with the more sensitive version.  With another 7-9dB S/N detection improvement, my signal could reach some of the more distant stations like TF3HZ.

Iceland get the new MF band

Icelandic radio amateurs have been granted access to 472-479 kHz and temporary permits for 1850-1900kHz, 5.260-5.410 MHz 70.000-70.200 MHz have been extended.

WSPR-X and WSPR-15

A note from Joe Taylor K1JT informing us about a new version of WSPR.

WSPR-X and WSPR-15

Wed Jan 16, 2013 8:23 pm

Some of you may be interested in trying WSPR-X, a new version of WSPR that includes the slow mode WSPR-15. WSPR-15 uses 15-minute T/R sequences, rather than the standard 2-minute sequences; at MF and LF it is 9 dB more sensitive than WSPR-2, decoding signals as weak as -37 dB in the standard 2500 Hz reference bandwidth. WSPR-15 is not recommended for use at HF: the tone spacing is only 0.183 Hz, less than the Doppler spreading typical of many HF paths. The main intended application for WSPR-15 is for very difficult paths at 137 kHz and the new 472 kHz band. It may be interesting to try on 160 meters, as well. Note that the recommended WSPR-15 sub-band is a 25 Hz slice just above the 200-Hz WSPR-2 sub-band, i.e., 1600-1625 Hz above the standard "dial Frequency". This will be handled automatically if you set up WSPR-X in the normal way.

A brief online User's Guide for WSPR-X is posted at
http://www.physics.princeton.edu/pulsar/K1JT/WSPR-X_Users_Guide.pdf ,

and the Windows installation file is posted at
http://physics.princeton.edu/pulsar/K1JT/WSPRX_07r2948.exe .

At present, WSPR-X does not support I/Q audio (for use with direct conversion receivers and transceivers) and does not do “band hopping”. Otherwise most familiar WSPR features are present and working well.

For software enthusiasts: Unlike older versions of WSPR, the user interface of WSPR-X is written in C++ and the Qt programming framework. My expectation is that this shift will make for easier development and program maintenance in the future. At present a click-to-install package is available only for Windows. Source code for WSPR-X is available from the open-source SVN repository at berlios.de. Anonymous checkout of the full WSPR-X source code can be accomplished with the command svn co svn://svn.berlios.de/wsjt/branches/wsprx

User comments, suggestions, and bug reports will be very welcome!

-- 73, Joe, K1JT

Band Plans and AM - Feb 2013 RadCom

In the new February RadCom that just dropped on my mat at lunchtime there is a copy of the band plans for all bands from 136kHz to 134GHz.  What I fail to understand is why does the RSGB appear so anti-AM?

For many years now there has been a clear choice for an AM centre of activity on 144.55MHz. The RSGB has been made aware of this on many occasions and yet still we have a (begrudging) footnote, just about visible if you look hard, saying this is where to look. Even this comment ends with, "although this frequency is not officially recognised within the 2m band plan". Why not? We have a FAX calling frequency listed and goodness knows how many DV Internet Voice Gateway frequencies listed, yet we cannot be allowed an official AM centre of activity properly listed! AM is not a common mode these days, but those who enjoy the mode need to know where to meet on the band. The RSGB is giving no help at all here.

I also get frustrated with the 10m band plan where AM is again almost treated as a disease. Most AM activity has been in the 29.0-29.1MHz segment for years now: this is THE part of the band where AM users congregate, yet the all-mode section with up to 6kHz bandwidth does not start until 29.1MHz upwards! Does no-one who creates these band plans actually listen to see what actually goes on? In the last 30 years I have had many AM contacts on 10m and not one outside 29.0 - 29.1MHz.

So, next time you consider the band plans, please:

(a) Add an AM "centre of activity" frequency into the 2m band plan - it is 144.550MHz in case you don't know.
(b) Show 29-29.1MHz as the AM sub-band in the 10m band plan.

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.

eQSL cards

Brazilian QSL card received via www.eqsl.net

To be honest I'm not very good at QSLing.  In years past I would regularly write out QSL cards and send them out to the bureau and look forward to the next batch of cards. These days I do send out some paper cards, but not that many. Instead I tend to use eQSL cards instead, but I was way behind with reviewing incoming QSLs so this evening I spent an hour or so getting up to date. I rejected a few cards - one for a WSPR "QSO" where what had really happened was an exchange of reports via the WSPRnet database, and the other for a voice-over-internet QSL with a JA station.

Checking my totals I see that I have 55 countries confirmed by eQSL cards. All these will be with 2.5W or less on all modes, mostly SSB on 10m and 6m. Many of my DXCC countries pre-date the eQSL era and I have not been that active in DXing as such in recent years, apart from the occasional contest like CQWW SSB, which I enjoy with QRP.  As you know, I prefer to carry out crazy experiments somewhat on the edge of sanity on strange bands with odd antennas instead!

More IC7100 photos

http://www.universal-radio.com/catalog/hamhf/3071.jpg

Universal Radio staff in the USA had the new IC7100 multi-band multimode transceiver demonstrated to them in early December and they have posted a few informal photos on their website.  At this time there are no indications of price, but my guess is somewhere in the £1400-1800 bracket here in the UK.  A lot of money, but also a lot of radio, including for the first time full 70MHz transceive facilities and, if this floats your boat, D-star built in. It also has a touch screen interface. I'd like to see a QRP version of this although I doubt the price would be much less. The receiver also covers a wide band 30kHz-200MHz and 400-470MHz.

Another earth-electrode station on 472kHz

If you spot G4HJW/1 on the WSPR database on 472kHz this is Bernie who is about 9km from me on his 30m baseline earth-electrode antenna. G4HJW is him on his Marconi by the way. Looking at his unique spots, he is getting reports from all over the place: not as good as his Marconi but reports out to over 900km isn't bad (GM, F, PA, G etc).

Next week, after the snow has gone, we hope to have a 2-way CW QSO on 472kHz using earth-electrode antennas at each end. That should be fun!

An INDOOR loop on 472kHz TX?

Over the last few days I have been receiving quite strong WSPR signals on 472kHz from Richard G4KPX who is in Ely, some 14km north east of me.  Looking on the WSPR database I see he has been copied up to 573km on the band using WSPR. Now, in a email from Richard today he revealed his secret: he is using just 1W RF into an indoor 3m x 2m single turn loop made of 10mm pipe leaning against the wall of his spare bedroom!  The EIRP is at most 100uW and probably a lot less because of the losses with mounting it where he does and the capacitors used to resonate it. This is a pretty amazing set of results.

Richard has been spotted across the Atlantic on 160m using the same indoor antenna and has similar magnetic loop antennas for all HF bands I believe.

So, if you believe you have no space for an MF band TX antenna, and you don't even have a garden to put a couple of earth-electrodes in the ground, you could always follow Richard's example.

Some months ago I believe one of the German 136kHz stations (DF6NM?) tried something similar using a large coax as a big indoor loop on 136kHz and also got some quite decent results. Never say you cannot erect an antenna!  What you need is a bit of ingenuity.

.....and NOT a TS-990 - something better!

Just to put some perspective on things, this is a small CW transmitter that just about anyone could build for a few pounds only and use it to work stations all over the world with a modest dipole antenna or similar. The OXO transmitter was designed by GM3OXX and is a classic design.

http://www.qsl.net/g3pto/OXO.gif

Power from the OXO is around 800mW - 1.5W depending on the band and on the final transistor and its emitter resistor. I have used this design on HF and had hours of fun with it. Long after a rig like the TS-990 would be gathering dust, this little beauty will carry on giving pleasure with each and every contact.

Kenwood TS-990 - UK price

Well my fellow blog readers, I have some good news for you!

The new Kenwood TS-990 is now available to order for Martin Lynch, and I expect many others, for only £6600 with deliveries expected February. I am sure many will buy this fine radio, but as this is about ten times my budget (once every 10 years or so) for a new HF transceiver, I will not be one of them. 

http://www.jayceecoms.com/images/Kenwood-ts990s-1.jpg

472kHz update

With nearly 2 weeks of operation on the new band with very low EIRP levels (varying from typically 5-10mW with 100mW on just one occasion) perhaps it is time to summarise how things have been going. A check of the WSPR database shows almost 70 unique reports across Europe of my signals from just a few km away to 1736km. I have still not managed to be copied by TF3HZ in Iceland at just over 2000km and this is my next target. To achieve this will need me to re-erect and better optimise my Marconi vertical. With some optimisation it should just about be possible achieve 200mW EIRP.

Unique WSPR spots in the last 2 weeks on 472kHz

On CW I have received a report from over 160km away when I was calling CQ. A JT9-1 QSO with G3ZJO at 79km is still my best 2-way QSO, although I believe it should be possible to work much further with this mode (I worked OR7T in Belgium with it on 500kHz).

So, pretty satisfying results so far. This has been helped by the huge number of stations currently monitoring WSPR on the new band - frequently over 40 people at any one time. Right now there are 59 stations monitoring!

On 136kHz the challenge with small antennas and low power is considerably harder on WSPR as there are too few stations monitoring: even if the signal was getting several hundred km, one can only tell if someone is at the far end and reporting it.

Solar activity this month

A quick glance at the solar data over the last week or two will convince anyone that things are looking up. Many believe that a second peak, not that uncommon, is likely soon and that this peak will actually turn out to be the real peak of cycle 24. It is some time since we have seen sunspot numbers as high as this for so many days in a row. In the end, the peak is usually based on smoothed sunspot numbers so it will be very many months into the future before we will know if the recent upsurge has helped to make a new smoothed peak.

I see there is a possibility of M or X class flares in the next two days which could affect propagation, although I think it improbable these will be on a scale likely to knock out power stations and satellites. At some future point, most likely long after all of us are long dead and at a time when the cycles return to huge numbers of sunspots, it will happen though. Of course large solar flares can happen at any time, so you never know.

For more data on the recent solar activity see http://www.solen.info/solar/ .

Albrect AE2990 Albrect12/11/10m Multimode handheld

Albrect AE2990 multimode

On G4ILO's blog I noticed a reference to Julian's Albrecht 10m/12m handheld transceiver. A quick search on the net and I see these on sale via eBay for £159. See eBay item number 181059871622. This is also sold as a Magnum 1012.

Although I have used the FT817 handheld lots of times on 15 and 10m and had some excellent contacts with it using a small base loaded whip (a counterpoise definitely helps), I have no experience of the Albrecht unit, which looks like an oversized VHF handie.

Has anyone here used one seriously for handheld DXing? If so, how did it perform?  The interesting thing is this unit can be programmed for 12m, CB or 10m use by changing some solder pad links under the PTT rubber.

I can imagine that this handheld could provide hours of fun during a summer sporadic-E opening, although I would expect results to be disappointing without a counterpoise if using it handheld with ether the supplied whip or a longer whip.

True handheld DXing can be quite a challenge, but great fun.  Actually being able to move  the handheld around to get the best angle can sometimes really help, especially on signals coming in at odd angles. Some time ago I was going to see how many countries I could work on handheld SSB, although I've not seriously tried this lately. I much enjoy handheld DXing when on holiday in Devon from clifftop sites overlooking the sea as in these locations many dB can be gained by chosing a nice location with a slope towards the sea. One of my best contacts was a YV station on SSB (8000km) from my late mother's back garden.

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.

Earth electrode antenna conclusions (472kHz)

With some further tests today I am now able to arrive at some conclusions from my experiments with an earth electrode antenna at 472kHz. Many people including Jim M0BMU and Rik OR7T have been particularly helpful in analysing the data.

My current 472kHz earth electrode "antenna" - can you see it in the grass?

These are my conclusions:

1. The earth-electrode antenna at 472kHz (2 earth rods in the soil 15-20m apart fed from the TX output) behaves like an H-field loop transmitting antenna.
2. It has directivity, with strongest signals in the line of the loop and weakest signals at right angles to it.
3. It works as an effective RX antenna too.
4. In my environment the loop looks like about 50-60 ohms resistive, so a good match to my transverter directly without matching.
5. The structure works because much of the return current flows deep within the soil and rock beneath the earth-electrode antenna. In my case Rik OR7T calculated that the loop area in the ground is effectively 290m sq with a radiation resistance of 0.017 ohm and a loss resistance of 66 ohms.This is a BIG loop!
6. Performance compared with my 9m high top loaded Marconi antenna averages only around 8dB down, not a bad figure at all, even with the connecting wire on the ground and not elevated at all.
7. Where no other antenna option is available, the earth-electrode antenna is well worth trying both on 472kHz and on 136kHz both for RX and TX. Although it works well here, your geology may be different and results not the same.

These last few days have been most interesting and, with the help of many people - listeners giving me WSPR reports, advice from others on the Internet forums, suggestions by email - I have been able to do some quite useful science. Thank you one and all.

472kHz RX and TX with Marconi antenna last night

Overnight I was using a 9m high top loaded Marconi antenna on TX and RX WSPR on 472kHz. I have since taken this down so it doesn't interfere withe the latest earth electrode antenna tests.

The performance of this larger,"in the air" antenna was certainly better than the earth electrode antenna, although not by a huge amount (2-14dB). As you can see, I managed my first transatlantic amateur reception on the new band WE6XGR at 5640km amongst the 27 unique RX spots.

472kHz RX spots on Marconi antenna

On TX with the same antenna, results were equally satisfying with 34 unique station reports.

472kHz TX spots on Marconi antenna

472kHz earth electrode antenna: nothing in the air

Today, I took my experiments with an earth electrode TX antenna for 472kHz to new levels by placing the connecting wires on the grass i.e. not elevated at all.  The theory developing is that the earth electrode antenna works by forming a buried loop in the ground with the earth return path being in the soil and rock beneath the structure. If this is so, then even with the wire sitting on the grass there should still be a loop within the ground, so some radiation from it. Results this afternoon prove this is indeed the case. The following are the results with a 20m baseline between the far earth rod and the copper pipe ground at the home end and with the connecting wire just laying on the grass lawn.

472kHz WSPR reports with earth electrode antenna with wire on the lawn

TS990 Press Release

The new TS990 from Kenwood

Readers here will know I'm not a great fan of expensive transceivers: I cannot see the point of spending huge amounts of money on what is, after all, meant to be just a hobby. On top of the expensive transceiver some people go out and spend a fortune on towers, linears, big beams and other expensive accessories. Each to their own: although not my choice it is not for me to say how others spend their hard earned wages.

I see today that the modern cashbook amateur has a new toy to covet: the TS990 from Kenwood. With a price tag likely to be around £9000 it has to be SOME radio. Looking at the spec it does look very impressive. See http://www2.jvckenwood.com/en/news/2013/20130108.html .

Just one slot of WSPR - 15 reports on 472kHz!

Reports in just one 2 minute WSPR time slot with 100mW ERP on 472kHz

With the improved performance from a 9m long Marconi antenna on 472kHz, these were the reports I just got in one single time slot just now. 15 unique stations reported me! It is too easy, even with just 100mW ERP.

How far down is my 472kHz earth electrode antenna on a Marconi?

This evening I have been noting my WSPR S/N reports from stations across the country and nearer Europe using my 9m long Marconi antenna and comparing these with the reports last night when I was using just the 15m baseline earth-electrode "antenna". I crudely plotted the "improvement factor" in dB on a polar plot. Each dot represents a station reporting my signal with the dB improvement over the earth-electrode antenna plotted on a 0-20dB scale out from the centre.

Although in some directions the difference is very little, in other directions the reports are up to 14dB better on the (omni-directional) Marconi.

Stations with dB improvement using the Marconi antenna

M0BMU 10dB
G0KTN 6dB
G3ZJO 5dB
G3WCB 10dB
DL-SWL 2dB
G4HJW 6dB
M1GEO 14dB
G7NKS 6dB
M0LMH 11dB
G0MQW 10dB
G0MQW 10dB

My conclusion is that the earth electrode antenna is behaving somewhat like a loop with directionality along the line of the earth-electrode baseline and a null off the sides. With stations receiving me off the sides there is most improvement with the Marconi, and less difference with stations end-on who were getting a reasonable signal with the earth-electrode antenna.

CONCLUSION: the simple, stealth, earth-electrode antenna is a VERY useful antenna on 472kHz as long as one is prepared to accept a 2-14dB loss compared with a reasonable Marconi.

RFID chips and credit/debit cards

Many credit and debit cards now have embedded RFID chips to allow contactless transactions in cafes. bars etc. Did you realise that your card's RFID chip could be a way of cloning your card's number and expiry date? Neither did I.

Watch this video to see a demonstration of just how easy it can be to someone with the right technology at his disposal.Sounds like a security loop hole that needs fixing fast.

UPDATE: I am reliably informed that this is not an issue in the UK.

A Marconi antenna on 472kHz

So that I can better quantify the performance of my various earth electrode "antennas" I have today erected a 9m long top loaded Marconi vertical for 472kHz. Initial antenna current measurements suggest the ERP is up around 10dB to around 100mW. My plan is to run this overnight again and then tomorrow compare the signal reports against those with my smaller compromise Marconi and my two earth electrode antenna configurations.

Even more fascinating 472kHz experiment

Following on from yesterday's tests, today I started a further test using an earth electrode "antenna" on 472kHz WSPR.

This time I used 2 ground rods in the soil separated by 15m of wire (fed directly from the transverter output at 50 ohms) and powered entirely from a battery supply - PC, FT817, transverter, SignaLink interface - so that there was no connection whatsoever to the house mains earth or copper pipes in the house. The power out would have been slightly lower (lower supply voltage) and the baseline 25% shorter.

472kHz earth electrode "antenna" system in garden

So far, results are almost identical to those obtained yesterday when one side of the earth electrode system was connected to the copper pipes in the home on one end.

My best DX WSPR report this evening with 10W RF out from the transverter into the 15m separated electrodes is G0KTN at 210km. ERP is in the low mW region at best. On RX DJ8WX has been copied at 643km.

Although a large Marconi antenna will be far better, this set-up certainly works and gives highly credible results. Considering just how simple this is I hope others experiment with the earth electrode "non antenna" and see how they get on.

UPDATE: Best DX report of my few mW ERP signal with 15m spaced earth electrodes was from DL-SWL at 701km. I am copying lots of signals including SM6DHZ and DK7FC even after breakfast time. Amazing.

Analysis of 472kHz antenna tests today

With several hundred WSPR spots of my QRP signal received today on 472kHz, I have tried to do a crude analysis of the difference in performance between my short (1/100 wavelength long) Marconi and my earth electrode (ground) antenna. I did this using MS Excel. Now I have forgotten most of the things I knew about Excel, so this is basic stuff here!

I plotted the maximum and minimum signal reports for each type of antenna for a number of different reporting stations and plotted a graph showing the difference and the angle the station is from me to see if there was a clear directionality in the earth electrode system.

Analysis of signal levels with short Marconi and Earth Electrode antenna at 472kHz

Conclusion? I'm not sure, although the difference between the 2 antennas varies from as little as 0.5dB (PA3ABK) up to 16dB (M1GEO) with an average additional loss of around 7dB. Can you see any indication of directivity in the earth electrode antenna? I am assuming the Marconi is omni-directional, which of course may not be the case.

Not bad for an antenna that is invisible to the neighbours and still is capable of getting reports (so far) to 701km away with a few milliwatts ERP.

Codar AT5 transmitter

Image on G3XTZ's Radio Museum website

Way back when I was first licenced for VHF/UHF only in early 1967 as G8AWG, I used to operate under supervision at the HF station of Bill Honeywill G4PJ in Salcombe on 160 and 80m. Bill Had an old KW Viceroy TX and a Codar AT5, which was "state of the art" in its day.

The AT5 was a small valve TX producing around 10W on 160m and 80m. Using the AT5 we could work right up the English Channel in daylight on AM and CW over a mostly sea path.  I noticed a page about the AT5 on the W3EEE website and it took me back 45 years.

Image on G3XTZ's Radio Museum website

There was a companion RX called the T28 which I owned at one time - I got it as a university prize for writing one of the better final year theses - which was made using a couple of Mullard modules. The T28 was nothing special, but did make a useful tunable IF for my 2m converter used to copy signals from Oscar 6 and Oscar 7 amateur satellites.

Nowadays in a volume less than half that of these rigs one can have a complete multi-mode HF-VHF-UHF transceiver with performance far exceeding the AT5 and T28. We forget how much our hobby has changed.

Earth electrode TX/RX antenna at 472kHz

Signals received on 472kHz WSPR using the earth electrode "antenna"

This afternoon I've been experimenting with my 20m spaced earth electrode system (used at 8.97kHz VLF), but this time on 472kHz WSPR. One electrode is an earth rod at the bottom of the garden and the other is a connection to the copper pipes in the home. Although I need to analyse results more carefully after an overnight run, the system certainly works with spots of my TX already received across England and from Holland. G4HJW 9km away is as nearly strong on the earth electrode system as on my vertical Marconi.

UPDATE 1715gmt: just been spotted by DL-SWL at 701km!!!

I honestly do not understand why this system - with wire no higher than 1.5m in the air running along the fence between the earth rods - works as well as it does. This is a short video showing the system in operation.

The ERP with the earth electrode system cannot be more than around 5mW which makes the performance all the more remarkable.

Some of the TX reports this afternoon with the 472kHz earth electrode system

Half century reached on 472kHz with 10mW ERP

After less than a week on the 472kHz band, I see that my tiny QRP signal has now been copied by 50 unique reporters in 8 countries so far with the best DX over 1000km.

If anyone thinks they have no chance on this new MF band then please note my antenna has just 6m outside the house which is vertical - the other 6-8m is in the loft against copper pipes and wires. This wire is just the coax to my 10m halo taped to the aluminium pole and my ground just my central heating copper.  ERP is around 10mW from my transverter producing around 10W (i.e. about 30dB antenna efficiency loss because of the short size and compromised feed). The ATU is still just a ferrite rod coil on my desktop! I tune the antenna for maximum current and do not have an SWR meter for this band ( when matched the PA runs cool and the antenna current is highest).

My apologies for the small type size below, but I had to reduce the browser size to get all the reports on a page I could screen capture. Getting a signal out on MF is honestly not difficult at all.

50 unique reports on 472kHz WSPR so far with 10mW ERP

In the next few days I want to try my earth antenna (20m spaced earth electrodes connected by a wire only 1.5m above ground) used on VLF earth-mode TX to see how reports compare. Tests on 500kHz suggested reports were around 8dB down on my loop used at that time, but I have not yet compared results against my compromised 1/100 wavelength high vertical. It will be intriguing to see how I get on.

First JT9-1 QSO on 472kHz

This afternoon I had my first digital 2-way QSO on the new 472kHz band using JT9-1 mode created by K1JT. The contact was with G3ZJO in IO92. Solid -15dB S/N reports were exchanged. I am still getting to grips with the JT mode procedure.

QRP JT9-1 QSO with G3ZJO today on the 472kHz band

 I also tried to work G3KEV on CW but he was unable to hear my QRP signal. I will try for more JT9-1 QSOs over the weekend.

Chinese all-mode, all band handheld for under £300

The Yintong HVU1 is an all-mode, all band 1.8-1296MHz handheld designed as a real competitor to the FT817, KX3 and Ten-tec Argonaut VI and priced at around £299 in the UK and $299 in the USA. It comes with a 3 year warranty.

Small in size (about 80% the volume of the FT817) with Li-Ion battery, internal auto-ATU, OLED colour display, speech processor, DSP audio processing, with full support for digital modes like PSK31, JT65 and other WSJT modes. Power out is 5W pep on all bands apart from 1296MHz where the power is 2W pep. Control of the rig by PC is via USB. Free CD software is supplied with the rig to allow easy memory programming and to set up digital mode interfacing.

It is just about everything QRPers have been looking for at a price that people can afford, except that I woke up and realised I'd been dreaming.

Happy New Year everyone .............and dream on.
                                                                                                   

First CW QSO on 472kHz

Although my local noise level is a little lower on 472kHz than on 500kHz it is still not low, so working stations with the current TX antenna (using it on RX and TX) is not the best of set-ups. Nonetheless, this evening I had my first 2-way QSO (on any band) of 2013 and this was on 472.5kHz CW with G3XIZ in Biggleswade. We exchanged 579 reports, although I was rather generous with my report really because of the local SMPSU noise. Also heard was G3YXM who was rather weaker than Chris.

I am now continuing with WSPR beaconing and will run the beacon (TX and RX) through the night for the first time on the new MF band. So far my best DX report is from Germany, but I would dearly love to be copied, if just once, by TF3HZ in Iceland. Haldor is monitoring and it is just about at (or just beyond) the limit of range with my 10-20mW ERP.  With QRP I have learned that nothing seems to be impossible with a bit of perseverance and good luck.

Hello 472kHz!

Today I did my first proper transmissions on 472-479kHz, although I did operate for a few hours before Christmas when there was some confusion over the NoV start date. Results today have been excellent with just ~10mW ERP from the short vertical antenna.

14 unique stations reporting my QRPp WSPR today on 474.2kHz

 Best DX is 990km, a very promising start on the new band. In addition, I appear to be suffering less noise on the new band than on 500kHz so I have been able to copy 6 unique WSPR stations so far.

In summary, a good few hours on the new band.