WaveShare 7" LCD Screen

Yesterday, I received my new, small screen for the Raspberry Pi.

I bought this so that my power consumption for a solar/battery shack is cut by 60% (to about 5W) from that of using a full sized screen (around 12W).  More importantly for radio, it also gets rid of the very RFI-noisy large monitor, restoring peace to the HF bands.  The extra space freed-up by the diminutive screen is also very welcome.

The screen is a 1024 x 600 WaveShare 7" (17.8cm) LCD, which I bought for £60 from ModMyPi.  It has a HDMI input, and touchscreen capability. 

Success, but it took me a while to get there!  The very high display quality is not really evident in this photo.

The screen comes complete, but you have to assemble the plastic enclosure, which is machined to a very high standard.  Fitting the whole thing together is quite fiddly, but simple.  You can save a fair bit of money if you buy the screen without a frame.  For radio purposes, the lack of plastic frame often makes mounting the screen easier.

There are no instructions with the screen, which is strange, because it doesn't need a lot of instructions; just a few lines are enough.

Instead, you have to visit a Wiki page for the device.  This is fine, but a little 'Chinglish' in its delivery. 

What is not clear, until you spend hours playing around with the Raspberry Pi's config.txt file, is that the configuration changes simply need to be added at the end of the config.txt file.  You don't edit those values already in the file, which is how I thought it worked.  I think the maker and/or the seller should stick a simple few lines of advice on this in the box.  But margins are so low they don't bother.

For posterity, and to help those struggling as I did, what you have to do is:

(1) Connect your Pi to a normal-sized HDMI screen such as a TV, PC monitor, or recycled laptop screen (the latter idea, with a suitable screen driver from ebay, is a good, though more cumbersome (and non-touchcreen) alternative to the Waveshare, and a little cheaper, that also does not need any of these config file modifications)

(2) Boot up your Pi.  With normal-sized screens, it detects the correct display setttings without user input.  The Raspberry Pi 4B may settle down into correct screen display without these settings, but it might prove unstable; you are much better to change the settings as given.

(3) Click on the command dialog box

(4) Type in sudo nano /boot/config.txt  (note, there must be a space between 'nano' and /boot). 

(5) Immediately below the last command that is already in the config.txt file, (i.e. do not insert spaces or blank lines, but immediately below), enter the lines below accurately:

max_usb_current=1
hdmi_group=2
hdmi_mode=87
hdmi_cvt 1024 600 60 6 0 0 0
hdmi_drive=1

There must be no spaces before or after the '=' sign, and the numbers in the hdmi_cvt line have a space between the 'cvt' and 1024, and then spaces between each number (i.e. hdmi_cvt<space>1024<space>600<space>60<space>6<space>0<space>0<space>0)

If you use the LCD with Raspberry Pi 4 B, you need to remove the line 
dtoverlay=vc4-fkms-V3D from config.txt file

(6) Press CTRL X and press 'Y' for yes to save.

(7) type sudo reboot and press <return>  It may be better to disconnect the Pi from the large display and reconnect it to the Waveshare before pressing <return> 'blind' (without a screen to see proceedings).

(2019 December 23 - REMINDER TO ME: Audio input and output in the WSJT-X software settings should be sysdefault:codec; also on new Pi installs, make sure audio input/output is USB Codec).

One reason for making the instructions clearer is that if you get it wrong, you will have to go and edit the config file on another computer (if you can access the config file, which isn't always the case). If you can't see it on a PC, for example, the fastest turnaround is to quick-format the SD card again on a PC and reinstall the NOOBS files, then insert into the Pi for it to reinstall its OS, then go to the top of the instructions above at number (1).

Once I understood and wrote these lines into the config file, the screen immediately went from being a mess of flashing lines to a full-colour, vibrant display.  Power from a USB 'powerbank' is enough to keep both the Pi and the screen running for several hours, making backpacking a reality.

Other people have commented that this screen has a high quality display, and indeed it does!  Instead of a low resolution display like you get with so many other models, this is just like using a full-sized monitor in miniature.  It isn't a struggle to read the screen at all.

The screen has attachments for the Pi itself on the back, which then effectively gives you a Pi-based tablet, or a small laptop, with the considerable advantage of being modifiable for many practical projects.

One piece of advice for Raspberry Pi 4B applications: the screen comes with a micro-HDMI male to female adapter, which is very bulky and doesn't make for a very robust connection.  I strongly advise you to buy a micro-HDMI male to full size HDMI male cable, which is far more secure and much less heavy on the Pi's HDMI board socket. 

A great product, provided it stands the test of time! UPDATE: I've been using this screen for 4 years now, and it's seen some tough action: left in my /A site for months, which is cold and damp, and also a lot of roughing it in my car with /P seaside operations.  This is a good product!

Like 2011...

Yesterday saw sporadic E activity at least up to 144MHz.  Atmospheric radar showed PMSE above Wales, and powerful thunderstorm activity has been extremely widespread across Europe the past few days.  The solar flux index is also much increased over past months, to around 78.

Strong middle atmosphere radar returns, often related to Es conditions.

This all seems to have conspired to produce one of the busiest days on the upper HF bands I've seen for a long time.

A particularly unusual feature in the mid-evening was very short skip at 24MHz (SSB) between North Wales and the South East of England - clustering at distances of only around 350km.  Unusually for very short skip, the signals were extremely stable and strong, just about everyone being 59 or over.

On WSPR, which I left running overnight, 24MHz reception here remained open until 00:56UT, with my spots continuing to be heard sparsely until 02:18UT.

I didn't work flat out, as it was a lovely warm, sunny day and nicer to be outside.  But I did manage around 70 QSOs across the day, which really did feel more like the last ramp up from solar minimum.
The solar cycle is predicted to increase in activity as early as this summer, so maybe that forecast is now becoming true? 

RSGB: Gender equality a long way off.

Yes, I know.  There has been quite a lot about the RSGB again recently.

I make no excuses for keeping a constant eye on what the RSGB does and looks like, not least because it is the sole representative body for amateur radio in the UK.

Gender equality within my household is good.  We are four people, two males, two females, and the gender proportion of those involved in radio is exactly half.

This seems to be way better than how the hobby appears in public, as presented by the RSGB.  What does that look like?  Well, the society itself can provide exact numbers on membership, and sometimes does.  But people like me have to go on what is presented in public, and use that as a guide to how the hobby appears to the outside world.

Here is an analysis, very simple, admittedly, of the proportion of men and women appearing in images on the RSGB's Facebook page (accessed 25/5/2018), and in the pages of RadCom, the RSGB's monthly magazine.  You can click on the image to make the text clearer:

It's pretty obvious that there's a serious and consistent lack of female representation and/or participation in amateur radio.  We have to be slightly cautious about these figures, because images are not neutral (someone decides when to take them, what they include, etc.) and the selection of images for publication is similarly prone to potential bias (an editor or article writer may like images of men, but not women).

In general terms, we can take these numbers to conclude that there is something that strongly inhibits female participation in amateur radio.  I am not exactly sure what that is.  But it is a clear message to the RSGB, in these times of vocal campaigns for gender equality, that it is failing to make the hobby attractive to females.

If you are female and would like to jet-off on a sponsored DXpedition to some far-flung Pacific atoll, you can pretty much forget it.  The strongest gender bias was in the 'HF' section of RadCom, where none of the photos included anything other than white, middle aged men (18 men, 0 women).

The gender inequality (RSGB website, accessed 25/5/2018) is also very strong at the society's Board level - 10 men, one woman, significantly lower (at 9% female) than the proportion of females appearing in images.

Worse than this, within the same analysis of both image sets, the proportion of people that appeared to be of an ethnic background other than white Caucasian was precisely zero.

According to the Office for National Statistics, the 2011 census showed 14% of the UK population identified as something other than white.

At board level, there is no non-white presence at all.

Overall, it is a regrettable and worrying fact for UK amateur radio, at least as far as its representatives and portrayal in public is concerned, that women have little place in the hobby, and those of non-white identity with no place at all.

Does such a gender bias matter?  Of course it does.

It is simply unacceptable to be somehow, no matter how inadvertently, inhibiting females from taking part in an enjoyable, self-improving, educational hobby.  You can only justify this sort of thing if you want to cling on to believing that females are incapable of participating in and benefitting from a technical hobby like this. 

Sadly, there are some people who really do think this way and I would suggest it is they, not females, who should have no place in radio.  They are the kind of people who tend also to argue that the hobby 'is not meant for children'.  My daughter passed her exam aged just 11 years.  She is a good operator - much better than the 'older' people who tune up, shout abuse and cause QRM on the bands.  Age is not the determinant of participation, but interest and a willingness to learn.

We need to look at those numbers, accept them, and start making an effort to present a much more balanced image of radio in public. We need to actively silence as irrelevant those who argue for prejudice and bias to continue.

Some will complain this is positive selection, and indeed it is.  But we are already, wrongly,  positively selecting - for males - by very many, complex means that relate to upbringing, society and expectations.  That needs to change, urgently.

RadCom book reviews - always good news!

I recently came across a blog site that hasn't been upated for many years.  Despite this, it had an interesting criticism of book reviews published monthly in RadCom, the RSGB's magazine (that isn't actually for sale on newsstands, and probably wouldn't sell many if it were).

The site makes the general point that RadCom's reviews of books are rarely, if ever critical of anything much, as one expects with normal, independent reviews.  The post suggests the reviews are unduly positive, always concluding that the books are worth buying.

I should say at this point that I've written book reviews, certainly with plenty of criticism where warranted, for technical magazines over some 25 years.  Many have been used as official reviews by major science publishers.  Only once did a review not get published, and that was because I highlighted the complete refusal to mention, in a book about the Hawaiian astronomical observatories, of the vigorous and empassioned protests by native Hawaiian islanders about desecrating their ritual sites.  It seemed ethnic battles were just too hot an issue for a modern publisher ever-more desperate for advertising income to get involved in.

Of course, unlike many magazines the RSGB sells most of the books reviewed.  Its accounts typically show a large proportion of its income arising from book sales.  There have been several high-profile attempts to boost book sales by the RSGB over the past few years, and books have been seen as a way of keeping the bottom line from slipping in the face of falling and ageing membership.

The blogpost made me realise something that was staring me in the face, but had never really dawned on me. I have sometimes bought books from the RSGB, but often find them repeating material found in other books.  Many illustrations are endlessly republished, apparently being drawn from a central, shared repository of such images and diagrams operated between the RSGB and ARRL.

A lot of the books are written by the elderly, trying to record their WW2 radio and other exploits before they die, for example.  These can be interesting, and indeed should be interesting.  But often, they are very dry and extremely old fashioned and almost unreadable in their style.

It seems odd, therefore, that I have yet to read any such criticism of repetition and lack of novelty in the reviews within Radcom.

I had a look at the two latest editions, and can indeed confirm that the same self-congratulatory, uncritical mindlessness continues unabated, several years after G3XLW's blog post.

Indeed, I had to rub my eyes a couple of times when I read the following in respect of 'Get on the Air with HF Digital' (Steve Ford, WB8IMY/ARRL) on page 56 of the June 2018 edition:

'Although primarily for the US reader, as the book is specifically aimed at HF digimodes, most of what it covers...' 

Huh?  It seems the reviewer believes only US operators use HF digimodes!  Where the hell did that come from?  One can only assume the review author has spent the last 20 years in his shack, steadfastly refusing to use a computer because the only mode worth using is CW.

I think RadCom should use the same process as most other magazines for reviews.  Receive books from publishers, send one to the reader, who then issues an independent review in return for keeping the book for free, no matter what he/she thinks of it.

RSGB and Facebook - bun fight.

Facebook isn't something I use very much, other than to keep up with a very few, generally educational sites.

I do tend to quietly follow the posts that appear on the RSGB's Facebook page, and was interested to see a photo there of a few people in RSGB 'uniform', attending the Dayton 'Hamvention'.

This prompted a small number of comments as to whether this attendance was a financially sensible decision.  The RSGB has, in essence, membership and books to sell.

The RSGB responded, clearly rather irritated by the scrutiny, that the sales at Dayton covered the cost of the trip there.  It later claimed the sales "more than" cover the costs.  We might be forgiven for wondering which of those two is correct, and by how much more than the costs do the sales exceed?  Asking isn't very welcome, it seems.

Such concern about how the RSGB goes about spending its money is entirely justified, because it suffered very serious problems of both financial control and accountability, which were not resolved until as recently as May 2013.  It involved the repaying of an amount, called a 'debt' and a 'financial irregulairty' by the RSGB, believed to have been around £41,000, to the society by its then General Manager, Peter Kirby.

There was also a lot of unpalatable activity concerning the purchase, prior to gaining planning consent, of a large and fabulously expensive Luso tower, which some influential people at the RSGB thought would be a great addition to their new National Radio Centre site at Bletchley Park.

Bletchley, though, is very obviously an incredibly important and sensitive site of global significance, with many listed (protected) buildings.  So it was clear to anyone that there was the very highest hurdle - higher even than the Luso's 12m minimum height setting - to jump before any planning authority would approve a steel lattice tower on this site, no matter how related it was to radio, computing and communication.

Of course, the RSGB eventually found itself in the utterly ludicrous position of having already bought the £31,000 tower, but planning permission for it refused.  The RSGB later advertised the tower (copy text retained here) for "just £13,500", or less than half what they paid for it not very much earlier. 

This kind of activity may well be seen as something the society would like to forget.  It does, of course, need to move on, and has.  Quite drastic changes of upper staff and procedures have taken place since.

But the membership should not easily forget what has gone before, not least because the society dealt with much of this under the cloak of 'minimal comment due to legal reasons', which also conveniently allowed avoidance of further scrutiny, not least how an entire Board of Directors lost control of the ship.

That 'say nothing much' approach may have been legally necessary.  But that is not to say that the RSGB didn't owe its fee-paying members a better, more transparent explanation for how things came to be the way they were around 2011.

How did the RSGB's structure allow £31,000 to be spent before planning consent was secured?  Why was such a gargantuan tower necessary anyway?  Were they the same kinds of structures and attitudes that also led to the financial troubles?  The detail is, for the most part, still unknown - at least to its members.  So they can't meaningfully be learned from.

So, RSGB, before you take offence at people scrutinising your activities, take a good slice of humble pie, and remember how badly things got just a few short years ago.  Better still, make a promise to us all that you welcome constructive scrutiny and criticism - and act on it.

£3499.95

This blog started out, as its header says, to highlight the fact that ham radio does not need to involve huge amounts of money in order to enjoy the hobby and enjoy it effectively.

It also started out to challenge the way things are done, who represents us (if anyone), and promote a more dynamic response to the problems facing modern radio.

I often criticise RadCom, the RSGB monthly magazine, for promoting an elitist vision of the hobby through its reviewing of high-end equipment.

I've written for magazines for about 25 years.  It's clear that 'reviews' are useful and interesting to the reader.  But they are also highly-prized, free advertising for the manufacturer, if not the shops selling them.  There is usually associated advertising set close to the pages containing the 'review' in most magazines.  After all, magazines cannot exist without advertising.  Indeed, they are better perceived as advertising publications, with some articles thrown in between. Facebook's free services in exchange for serving up advertising is not as modern a model as people imagine!

Despite this understanding of advertising, I'm genuinely disheartened, yet again, to find this month's RadCom reviewing a transceiver costing just short of £3500. 

There is a lot of soul-searching that is endlessly repeated about the lack of newcomers and youngsters in the hobby.  With the promotion of products like this through 'reviews', it is hardly surprising that the hobby appears out of reach to so many.

'Entry level' antenna.  Just £4 million (see advert opposite page).

The problems facing the working age population today in the UK are many.  Lack of remotely affordable housing (typical homes for sale now going for between 7 and 10 times average incomes - even the deposits are unaffordable.)  Half the working population in expensive, insecure rented accommodation.  Jobs are insecure, short term, zero hours and/or not very well paid.

With all these problems, £3500 for a hobby radio is, well, obscene.  I can only imagine that, for the immediate future, radio manufacturers are trying to cash-in on those post-war generations that are in or about to reach retirement age.  A bit like expensive 'luxury' ocean cruising holidays came out of nowhere as the population turned white-haired en-masse and looked for ways to enjoy the pensions they 'paid for all their lives' (except, they didn't; pensions of today are paid for from the current working population.  Nobody expected people to have a 50:50 chance of reaching 100 years old and being in retirement for 40 years or more). 

It would be wrong to say that RadCom never reviews the cheap end of the market.  But it does seem, no doubt driven by the money to be made out of expensive equipment, compared to little or nothing from cheap Chinese or other products, not to cover them as much as it could.

There are things like the micro-BITX transceiver costing only $109 as a part-built kit.  I haven't noticed a 3-page review of this yet.  Then again, the small Indian cooperative that makes this unit doesn't advertise in RadCom.  Could there be a link?

In fact, in my view, it would be much better to increase membership fees slightly to cover the cost of a magazine that is not so heavily reliant upon advertising.  Sure, let's have some adverts, but let's also see a much greater focus on just how many effective transceivers and antennas can be made out of everyday materials at very low cost.

LED Montor RFI: the biggest ham radio mystery?

A while ago, I wrote about my troubles with a 21" LG computer monitor (no TV reception circuitry), which produced copious amounts of interference to all bands up to at least 50MHz.

The best solution I came up with was to wind a 10m VGA cable on a wide PVC former to make a choke.  This worked to a degree, but the bands were still simply nowhere near as quiet as they were without the monitor.

I quickly decided to discontinue the use of the £100 monitor as unsuitable for radio station purposes.

During and since those days, I've read the various discussions and blogs about screen RFI.  In fact, given LED screens' popularity in 'NASA-style' ham stations, and that there are so many hams out there, it is a genuine mystery as to why there is not much more discussion about the problem.  I think a lot of it may be to do with the fact that so many people live in RFI-infested areas already.

A search for videos, perhaps to see someone showing RFI on their monitor, yielded no results.

I found a strong element of capacitive coupling with my screen's RFI.  If I brought my hand closer to the screen, or just simply stood in front of it, rather than behind, it would produce much stronger RFI.  I don't know of a potential solution to that problem.  Grounding the screen also provides a handy path for the monitor-generated RFI, which similarly increases in strength.

Most people who claimed to have resolved RFI from screens clearly hadn't.  They had simply added chokes or other measures that only moved the RFI in frequency and maybe reduced its level somewhat, thinking this 'fixed the problem'.  There's a big difference between reducing RFI and eliminating it, especially if you are interested in weak signal work.

When RFI moves in frequency, it doesn't do so to such a degree that it falls magically outside the ham bands.  It just appears in other parts of the band.  So you might find the FT8 section of 20m free of RFI, but parts of the SSB portion displaying very strong birdies.  You can often simulate the 'fixing' of RFI from screens just by changing the resolution.  You may find your WSPR portion nice and free of noise at lower resolution, only to find the RFI is now down at CW parts.

Things that do NOT reduce RFI are:

(1) The PSU. Powering the LED screen from 12V batteries yields the same RFI.
(2) Screening cables.
(3) Grounding the screen and/or cables
(4) Using HDMI instead of VGA cables

Things I found that do reduce the RFI, but not by remotely enough to return to no-screen, RFI-free conditions:

(1) Connecting a random wire to a grounding point on the screen (e.g. connector chassis), causing the chassis to detune slightly. With a laptop screen (HP), I find this detuning is effectively enough to call it a complete fix.
(2) Different positions and distances of screen from transceiver.

(3) Not having your body close to the screen.
(4) Taking cables away from the screen at right angles as far as possible.
(5) An air-wound choke of around 20cm diameter (VGA only; HDMI cables are generally too short for this).

It seems that LED screens, more especially more modern ones, produce high RFI levels across the board.  It doesn't much matter which one you buy.  I've tried our home TV, a four year-old Samsung LED unit, and it also produces the same noise, although at a significantly lower level than the LG, despite being physically larger.

I also found the same capacitive coupling RFI effect with a Nexus 7 tablet connected to a charger.  Whilst it produces no detectable RFI when simply sitting there on a desk, it produces a low but detectable (by ear) change in noise levels when I place my hand near the screen. 

If you have any ideas or example of fixes that actually work and eliminate RFI altogether, then I and many other people would like to hear from you!






 

"Your Delta sure is low"

If there's one thing I enjoy, it's proving prejudiced people wrong.  Not in an angry sort of way, but with evidence, plain and simple.

During QSOs with folk, almost invariably from America, it is a frequent irritation to hear the dismissive assertion that my delta loop, which has its base (its inbuilt 'radials') at 'only' 1.8m above local ground, is "way too low" for it to be effective.  Apparently, I should be raising the base to '30 feet' (the US has yet to drag itself out of Imperial measurements).

Well, there is plenty written on this blog to show that is simply a failure to take all factors, including the highly unusual ground, into account in reaching a conclusion. Most of them think that only 'big' antennas and amplifiers are what makes ham radio work.  That, of course, from the country that generates nearly three times more carbon dioxide per capita than the UK.

So the latest poke in the eye to my more machoistic American bretheren is this: the past 24 hours of reception reports for party balloon WSPR station, ZL1RS.  It's sending just 10mW.

My "way too low" delta is one of only two stations in Europe (I am not a Brexit supporter!) that is receiving ZL1RS, at a fairly good -24dB SNR.  Even more satisfying is that there are no reception reports from America at all.  And there are some very good stations there, some with directional antennas.  

Beaming America...

So for those of you who are just stuck in a trench about antennas and how high they should be, please remember: it depends on ground characteristics, both near and far field, and having a low noise floor.  After all, how many stations have an old copper mine underneath their antennas?

On an associated note, the now fairly constant balloon transmitter launches provides interesting WSPR tracking. But use of amateur radio from any airborne vehicle is not permitted in the UK. 

This is quite odd, because it seems to be perfectly legal in many countries.  The safety risk for those balloons that fly above most aviation traffic seems to be negligible, and I'm not aware of any incidents reported about small balloons conflicting with aircraft.  It seems to be a legal conflict between licensing ham radio and licensing aviation radio that causes the problem for balloon-borne WSPR in the UK.  Rather perversely, we can, with prior notification to the CAA, launch balloons, but not balloons with transmitters!  Even as a holder of a CAA pilot's radio licence, I still can't launch a WSPR beacon into the air.  How silly!

Crossing to Alaska.

KL7L is a station that I always think is in a very interesting place in terms of HF propagation. 

Overnight, I ran WSPR at 14MHz, using 1W from the vertical delta loop. 

This is the plot of all the spots from 19:38UT 14/05/2018 to 07:50UT 15/05/2018:

The appearance and very sharp peak of signal at around 06:30UT is quite interesting. It is exquisitely linked to sunset at KL7L.  Here's the picture as my signal peaks at 06:36UT in Alaska:

And as the strong peak falls away at 06:44UT, less than a quarter of an hour later:

I've been thinking a fair bit about the likely propagation path for this event.  My transmitter has been in daylight for some hours at 06:30UT, although it's clear from the overall signals received here that the D layer is not yet strongly formed.  In fact, we are just before the point where DX signals vanish and local signals come to dominate.

At the same time, it's the sunset period in Alaska, and the D layer will be weakening rapidly.  At the moment, during the depths of solar minimum, the Lyman alpha radiation is fairly low, too. 

Is there a component of long path propagation?  I'm not sure.  The duration of the peak signal is similar in length to that seen in UK-VK long path propagation, roughly 20 - 30 minutes.  If it was just D layer weakening, then perhaps the peak signal might last considerably longer, given that KL7L evenings are now constant and quite strong twilight.

Any thoughts?  Please post a comment!

HF Propagation predictions - is there any point?

Most of us have too little time to waste.  As a result, fine people, many with impeccable qualifications, attempt to make the most of our precious time by issuing propagation predictions.

But are these predictions relevant to a world where digimodes provide effective operation way beyond the noise level?

On the ITU-based prediction sites out there on the internet, you can choosea 'SNR' (signal-to-noise ratio) output.  But this effectively has a cut-off of 0dB SNR.  I regularly operate JT65A down into the lower minus 20s dB, WSPR down to around -30dB, sometimes deeper, and FT8 down to around -25dB.  Even CW 'by ear' gets us down to around -18dB.

To underline the argument, -30dB SNR is a signal one thousand times weaker than the noise level (as specified for the rather odd, ham radio way of doing things, a 2500Hz bandwidth - see here for a useful explanation).

So what is the point of continuing to use 0dB as a lower marker, with its implication that there is no point in operating when the prediction yields that result?  I have started to think, perhaps wrongly, that predictors aren't keeping up with digimode developments, and are continuing to issue predictions for the SSB operator. 

Steve Nichols' blogsite currently has a similar sort of prediction.  It, like Gwyn Williams' predictions for May 2018 (see RadCom), strongly suggests that there is nothing much to be found at 12m, even at very moderate distances.

This isn't the reality.  My logbook has perhaps a couple of hundred 12m FT8 QSOs so far for May, with especially good days on the weekend of 12-13th May out to Bolivia (at +01 dB) and ZP9 (+9dB).  OK, I'm not using a dipole with a (unrealistic) 0dBi gain, but perhaps that itself is too restrictive a model.  You can alter antenna and noise settings with online models.  But printed monthly summary forecasts are pretty much fixed.

Even if dipoles for 24MHz had been in operation at both ends, and we take the ZP9 signal as an example, there was still around 30dB 'spare' for a potential QSO, at around the limiting SNR of -25dB, with FT8.  JT65 or JT9 could have offered even deeper plunges into the noise.

Now, to be fair to both men, their predictions make specific assumptions on mode of propagation and gain of antennas at both ends.  So it would be unjust to say that their predictions are wrong simply because a good day of multi-Es hops in fact allowed working distant regions for hours on end using a 3-element Yagi.

And there's the rub.  Is there any point in presenting predictions based solely on F-layer propagation when the summer months are well known to bring Es conditions, for example? 

There is also the fact that ham operators are quite sheep-like in their conduct.  The majority follow the DX cluster or predictions like those under discussion.  Even if the intention is not to say 'don't bother operating when the prediction is simply a blank line', the effect will tend to be that operators will receive and act on the prediction in precisely that way.  You only have to see what happens on 12m to prove that.  Take an empty band.  Call CQ and get a random response.  Announce it on the cluster.  Within seconds, the band will be full of signals.  Hams are simply waiting for others to do the work for them, when it comes to probing empty bands.

Another criticism I have is that propagation can, and often is, very different from various regions of the UK, further limiting the usefulness of predictions.  A station in southern England will often have very different conditions to those in the north of Scotland, or, indeed, in the north of Wales.

Overall, even where the predictions might be generally correct for their given set of assumptions, they are very rarely, in my experience, particularly reliable indicators of which regions of the planet can and will be working each other in practice.

That is why I never even bother looking at predictions.  If I did, I would miss out on a lot of QSOs for thinking it would be a waste of time in trying.

Spanish Burst!

Nothing particularly new, but a very nice example of 50MHz propagation brought about by a substantial cold front passage this tea time.

6m propagation very tightly linked to the passing cold front.

All stations received here in North Wales were from EA land, with the odd CT thrown in for good measure.  Signals came, peaked and passed in step with the front's passing.  Peak signals on FT8 were topping around +15dB S/N.

EA-festival!

More Pi?

I was waiting for the postman to arrive with excitement this morning.  He was bringing me a new Raspberry Pi - my latest ham radio fascination!

A wonderful aspect of the Pi - apart from its tiny physical size and low cost - is the fact that it boots up from an SD card, where all the software and data is held.

The Pi 3B+.  Much faster but still fits in Model 2 cases (if you use one).

This meant that, having only just downloaded the latest NOOBS package a couple of days ago, getting the Pi 3B+ going was simply a matter of removing the SD card from the Model 2 and sticking it in the card slot of the new unit.

I was glad, at this point, to see that the Model 2 SD socket, which had a relatively high failure rate in its spring-loaded card capture mechanism, has been abandoned in favour of a friction-only unit.  Very much better!  The Model 3B+ also comes with in-built WiFi connectivity, so there is no need for a USB dongle any more, at least if you have strong signal coverage around the house.  That's one USB port freed up, too!

Booting is, of course, pretty quick, and the WSJT-X software already downloaded earlier this week was sitting there on the SD card, needing only a click to start it up.  If only a Windows OS and files could be transferred across so easily!

Since posting about WSPR reception with the Model 2, I have progressed to using my ZLP data interface on the Pi, allowing transmission.  The Model 2 handled all this with no need for driver installation or complexities like that.  It was just slightly slow, in that the Pi took a second or so to activate the rig.  But not so slow as to cause problems.

Where the Model 2 couldn't work very well was with the very fast turnaround mode, FT8.  It took several seconds to decode everything, which made having a QSO impossible.

With the Model 3B+, and the 'Decode' menu item selected on 'Fast', FT8 works very well indeed.  If it's set to 'Deep' decoding, it's then too slow for QSOs.  There is a similar delay on deep decoding even when using my recent HP laptop.

Usefully, the Model 3B+ is fast enough to both handle digimodes and internet browsing at the same time, something the Model 2 couldn't really do at all.  It also looks like it is fairly good at keeping accurate time; most signals were within a small fraction of a second.  I think that, with an internet connection, the Pi keeps itself regularly time-updated, though I need to look into this a bit more.

Overall, I feel the latest Pi is equal in performance to my 1-year old HP laptop - at a tenth of the price!  It can also be easily deployed in my field shack, where there is only a 12V DC supply - much better than stepping up to 19V for a laptop.  All I need now is a 7" LCD screen for it, although even my spare LG monitor will work off 12V DC, sparing some cash for this month!

To give you a flavour, here's a 1.5 minute video of how it looks in practice (at 28MHz!).  CPU use with FT8 running is only about 13%, and the CPU runs at only a warm, not hot temperature:

Raspberry Pi - at last!

After years of not really getting to grips with my various Raspberry Pi computers, I decided to spend as long as it took this morning to get WSPR running on a Model 2 B.

I didn't expect an easy ride with this, because whilst I love the idea of using Linux rather than Windows, it is not always for the short of patience.  I am very short of patience!

I updated the whole NOOBS package and installed the latest Raspian OS.  This went fairly easily, though I had to download a special SD card formatter, as Windows' own formatter wouldn't handle it.

This went easily enough, though quite slowly.

I got the new OS going with no problems.  Then I had to download WSJT-X, which should have WSPR included, alongside many other modes.

Of course, when I opened the WSJT-X from the repository of packages, WSPR wasn't there.  It looks like the latest version, but isn't.

I eventually found that I had to manually download and install the latest WSJT-X directly from the Princeton University site, using GDebi installer package.

The best instructions for the whole thing comes in the form of a very user-friendly and brief couple of pages at www.qsl.net/aa5kv/wsjtx.html

Be careful if you look up some help online, because most of it is very outdated and relates to past versions of Raspian, which has changed a lot over a short period.

Lots of connections, but it works.  Just about...

The package installer and download of WSJT-X went fine.

Then a problem on trying to install WSJT-X at the last minute: administrator password needed!

WTF?

After a lot of cursing, I found the simplest way was to just type in "sudo passwd root" in the command line box.  No doubt people will tell me this leaves me open to Russian hackers, but it will have to do for now.

Apparently, a bug fix for this is to type:

"gconftool2-2 --type bool --set/apps/gksu/sudo-mode true"

It all seemed to work now, installing WSJT-X to completion.

Now all I had to do was get sound into the Pi!

I have a Chinese £1.50 USB audio stick that works well on my laptop for receive (only).  To my amazement, the Pi saw and shook hands with the stick with no need for some obscure commands.  I just had to select it as a sound source, like a Windows machine!

WSJT-X on WSPR, Raspberry Pi style!

Of course, my Pi was two rooms away from the rig.  So a very long USB extension cable made the distance between equipment.

Remarkably, it works!  Slowly, but it works!  The Pi takes a leisurely 37 seconds to decode signals, which is pretty good for a matchbox computer.  I've overclocked the Pi 2 B to 900MHz, but it doesn't make much difference to the decode speed.  Decodes seem to be as sensitive as running off a proprietary interface.  I've ordered the latest, Pi 3 B+, which should improve significantly on this and allow me to venture onto some real QSO modes, like JT65 and the dreaded FT8, later.

If you're wondering why anyone would bother with a matchbox computer, the answer for me is that it is a low power device that runs off 5V (easily stepped-down from 12V), and costs just £32.  This makes it ideal for field use, following the addition of a small screen.

Better than spending £250 minimum for a laptop just for ham radio.  I even learned a little.  But it is definitely not good for the blood pressure!

1mW

There may well have been soome geomagnetic storms lately, but things this afternoon are certainly picking up on 14MHz.

Astonishing to find a tiny 1mW making its way (all 7182km)  at -20dB S/N - still plenty of room for yet lower power to be tried - from AD5SJ.  Only one other station - SM0BRF - also heard it outside the US, at the same S/N - and he's using a triband Yagi.

1mW !

G3 Storm!

Overnight, a significant, G3 geomagnetic disturbance, peaking at Kp = 6 hit Earth.

The field disturbance caused the 14MHz WSPR signal from HZ1SK to vanish as the Z component underwent a strong deviation to the south:

Lots of variation, then - gone!  Signal from HZ1SK at MW1CFN 05 - 06 May 2018, 14MHz.

At the onset of the southerly deviation in the Z component, at 00:38UT, G8WQB's signal crept - but only just - out of the noise, maintaining a steady -29 to -27 dB S/N all the way to the dawn period, when the field had returned to near-quiet conditions:

G8WQB just about popping up out of the noise during the G3 storm.

I'm starting a campaign...

Yes, I know.  I like moaning about interference with WSPR.  Well, not really.  It's not that I like it, it's that I have to, because it is simply unacceptable.  I am going to redouble my efforts, somehow, to get things changed.

Yet another weekend where RTTY happily obliterates ongoing WSPR transmissions (5/5/18)

What is the problem?

(1) WSPR has been launched onto the amateur radio world stage with little or no proper consultation.  It has been slotted in where it seemed it might work a long time ago.

(2) The slot it was given happens to share lots of other modes - any mode in fact.  By convention, digital modes are the most likely to come into conflict with WSPR.

(3) WSPR is the only widely-available, free of charge, human bias-free means of testing propagation and antenna performance.

(4) WSPR is in everything but strict legal definition, a beacon mode.

(5) Traditional and what we can now justifiably call 'old fashioned' beacons operate in clearly-defined areas, usually low in the bands, that should mean they experience little or no interference from other modes, including digital modes.  In the UK, beacon band segments are clearly labelled in glaring red to highlight their importance.

(6) WSPR suffers regular interference from, especially, RTTY.  Weekends are particularly bad.  For the most part, this is actually illegal, because it is the interference of ongoing transmissions.

(7) There are a lot of people, especially in the US, who don't understand WSPR, never use it, and are actually so ignorant and stuck in their ways that they positively and energetically argue a beacon mode like WSPR - needing just 200Hz (and, potentially, less) bandwidth, should not be protected.  They argue that if every other mode had such protection, the bands would soon be clogged-up with protected areas.

(8) Given that thousands of people can fit into the tiny WSPR window, and that the results from WSPR use is of fundamental importance to everyone in some way or another, the argument not to protect WSPR is very weak indeed.

(9) I have queried, on more than one occasion, Joe Taylor, as the author of WSPR, what he thinks.  He hasn't replied - ever.

(10) I have asked the RSGB.  They didn't know much about WSPR at the time (ca. 2015), and told me to 'QSY'.  This is pathetic and ignorant - from a radio society meant to represent operators for their annual membership fee.

(11) EURAO are the only ones who have understood this problem, recently publishing bandplan guidance that makes the importance of modes like WSPR very much more clear to everyone.

Reflections on a reflector.

WSPR operations continue apace at the Copper Mountain station!

With the winter winds gone for a while, and good conditions across to the western US, I decided to throw up a reflector for my 20m delta.  The spacing between elements is exactly 5m, or a 1/4 wave at 14MHz.  This was simply because it favoured fixing a post at that point.  The ideal spacing is more like 3.5 to 4m.

I did this many years ago, but didn't really get around to using WSPR.

Beaming the USA (reflector at right).

 
I seem to have run out of good wire these days, so some very lightweight equipment wire bits were soldered together, amounting to a total of 23m.  The light weight of the wire was actually a benefit, as I had to use every last mm of the top, weak section of an elderly 10m fishing pole - which are usually a bit shorter than this - to support it at the correct height.

A quick look with the SARK analyser showed the system was very well behaved, at 1.28:1 SWR at the WSPR frequency:

A walk around what is now a two element vertically polarised 'quad' system confirmed the modelled expectation of modest front to back ratio, the rear lobe being very clearly 'seen' in my simple RF meter.

Generalised, but accurate azimuth pattern for a 2 ele loop system.

How did it work out?  Well, conditions on 14MHz were quite poor due to a situation where a very strong sporadic E propagation was present across HF and into VHF.  This was strongly inhibiting propagation across the Atlantic for most users.

I found very many stations were unique in being heard by my 2 ele loop system.  There were enough of these, a few of which I present as independent evidence below, to conclude that the system works exceptionally well.  Even into the early morning, when west coast US stations would not be expected to be reaching the EU at 14MHz under those propagation conditions, I was hearing a couple out in the far western coasts of America.

K7KRR unique spot in the hour (evening of May 04, 2018)

K6MCS, a highly unusual spot for the early-to-mid morning period in the UK.

VE3XIX, unique spot in the hour (evening of May 04, 2018)

WA1DLZ, heard only by me and the globally-number 1WSPR RX station, EA8BFK.  Morning of May 05, 2018.

AE7YQ, hour to 15:25UT, 05/5/2018.

Very curiously, AA7FV wasn't coming through quite as often or as strongly as previous nights.  It may well be that either propagation conditions didn't favour the path or, more likely, that my beam was slightly less than ideal for him. 

AA7FV - new WSPR record

Yesterday saw some strong sporadic E on the upper HF and lower VHF frequencies.  Skip was particularly strong and short on 12m, where PA stations were bounding in on FT8.  10m was more subdued and patchy, but still open to medium distances.  6m also had short skip, with stations only a couple of hundred miles away being worked.

Geomagnetic conditions were fairly quiet, with a small disturbance in the later evening.

But the reception of AA7FV broke all records last night.  In fact, the record (+0dB S/N) was broken at 16:14UT, just after I turned the rig to listening operations, but it got a lot better later:

Wow!

A S/N report of +5dB S/N at 23:14UT from 8154km is just stunning - even from a rhombic with 15dBi gain taking 2W output to about 63W effective output!

Usefully, AE7YQ is just a few miles away from AA7FV and using 5W from a more typical antenna - an email confirmed it is a folded dipole  His signal reached a steadyish -3dB S/N between 23:34 to 23:50UT.  The slight but real difference in timing of strongest signal from each station is most likely attributable to the very narrow beamwidth of the rhombic.

The timing of strongest signal is fairly typical from this region of the US, but the strength is a good 8dB or so above usual quiet geomagnetic conditions.  The enhancement seems to correlate with the field restoring to calm conditions after a minor disturbance - something I've noticed with other enhancements in the past.

I also, incidentally, managed to get to position number 4 in the daily WSPR listening challenge.  I don't take this as a contest, but an indicator of my system performance.  In the past, I've tended to come in at around position number 9 or so.  Last night, even with the rig off for a number of hours, I managed to get to position 4, with which I'm quite impressed!

With the weekend upon us and the careless use of other digital modes, it's unlikely that listening over the next couple of days will be worthwhile.  We'll see...