Not a lot happening...

Well, the propagation has been a little difficult the past few days.  Despite plenty of 14MHz WSPR monitoring, there haven't been any geomagnetic anomalies of any note, except for a series of spots early this morning from France.

Even though, at around 03UT, the dawn is approaching, astronomical twilight - and so the start of the greyline period - is still a good hour away.  

The OVATION auroral oval did predict weak, incoherent patches of auroral activity as far south as France overnight, and I think that, given I heard only two stations (apart from local groundwaves), both French, the spots must be considered anomalous and geomagnetically-related.  The field at the time was well into a period of relaxation after significant disturbances in the preceding couple of days.

14MHz WSPR reception.  F1JSC = 5W, F6EGX = 0.2W.  Long horizontal line is period of non-reception.

Otherwise, the only radio activity has been up in the air during periods of nice and unusually calm weather!

Radio stack and navigation instruments (not in use, as the red 'flags' indicate) in a PA-28-161.  One reason 144MHz has escaped French ideas of aviation expansion into that band was that channel spacing changed from 25kHz to 8.33kHz (AM) fairly recently.

Getting ready for an engine failure practice.

G2 Alert!

 

All turn north!

Ha ha, you are stupid!

I've been very interested - and surprised - with my recent ultra-low power WSPR activities.  As I speak, my home delta loop is running 100 microwatts - and getting spots - after an experiment at 500 microwatts earlier in the week.  From the beach, 50 microwatts is doing the trick.

Yesterday, I thought I might make a visit to the WSPRnet chat room to try and encourage more super-QRP experiments.  If you've never been there, it's a very strange place, populated over years and years by the same, very few handful of people, throwing aimless and often cryptic messages at one another.  It's a bit like a gang of kids, hiding under the stairs and talking about naughty things.

Here's how (in reverse time order) my comment was made, and the first comment (red) it attracted:

WA2ZKD rather threw me for a moment, until I realised the many - and entirely incorrect - assumptions he'd made in jumping to make me appear as though I was, well, a bit dim and/or dishonest (he later says this wasn't his intention - after the errors were pointed out to him.)

The wrong assumptions were:

(1) +7dBm is the power output report he saw when he looked my MW1CFN callsign up on some WSPR database or other.  But this wasn't the callsign I had used for the 50 microwatt experiment at the beach.  

(2) If he'd seen the words 'last night', this should have been enough to alert him as to his error, because he took WSPR results from the following afternoon to make his comment.

(3) A WSPRlite can only be set at fixed power levels down to 5mW.  With an attenuator fitted, there is no way to send the true power output to the world.  Even had WA2ZKD looked up MW6PYS - my daughter's callsign - instead, he still wouldn't have seen a true power report, but a value 30dB above what was actually feeding the antenna, because of this limitation.

(4) He assumed I was either incapable of understanding and calculating power, or else deliberately misleading people.  I am not known amongst those who know me for either of those two tendencies; quite the opposite.

So, in his rush to 'correct' my understanding of the world, WA2ZKD made a remarkable series of incorrect assumptions whilst also making himself, and not me, look silly.

Ah, well!  That's ham radio and angry old  men for you...

And now...even lower power!

Well, I couldn't resist the mathematics that said 50 microwatts should multiply up to around 500 microwatts at the beach, the latter being the level my delta loop showed could be heard across the Atlantic.  So off I went last night.

To put 50 microwatts into context, it's less than 1/1000th the power used by a single, typical LED indicator and resistor unit.  In other words, staggeringly low power: 0.00005W.

 

50 milliwatts out into a 30dB attenuator = 50 microwatts(!)

It wasn't the best evening for a test.  After a long period of very quiet geomagnetic conditions, the field was undergoing a moderate disturbance, bringing the auroral oval as far south as the central UK. 

Added to that was an unusual form of what appeared to be lightning, but had no accompanying thunder - possibly a result of being too far away - but rather oddly, also was not detected by lightning monitors anywhere.  This is in fact a culturally-recognised phenomenon, called 'dreigiau' (dragons) in Welsh.  This phenomenon passed quietly down the Irish Sea over a couple of hours. 

Even so, and perhaps even helped along a bit by these phenomena, my 50 microwatts at 14MHz from the usual elevated vertical with two elevated radials first made it to EA8BFK and then, an hour later to WA2TP (a per-Watt distance equivalent of 103,260,000km, or 70% of the Earth-Sun distance!)

Note: due to WSPRlite settings limitations, the reported power is 50 milliwatts, whereas the true output was 50 microwatts with the attenuator fitted.

With up to 9dB 'spare' in the EA8 spot before we reach the -34dB detection limit, this indicates that the lowest practical power that would be detectable from the beach under these geomagnetic conditions is roughly around the 5 microwatt level.

As a further indication of the low power in use, my delta loop and RSP1a SDR at home didn't hear any of the transmissions, despite being only 20km away.

The EA8 spot is coincidental with the start of a geomagnetic disturbance (here depicted as the D (deviation from true North) component), and the WA2 spot with a temporary relaxing of the field.  I've noted an enhancement to EA8 during such disturbances in the past.  It would have been nice to continue longer, but I was quite tired and had things to do the following day.

D-component geomagnetic field plot.  (Tromso Geophysical Observatory)

Forecast auroral oval mid-way between the two 50 microwatt spots. (NOAA)

QRPpppppppppppppppppppppppp...

Yesterday, with a lot of non-radio things to catch up on, I set the 14MHz vertical delta loop to work at the lowest power I've yet tried.

My WSPRlite units only go down to 5 milliwatts.  I used a 10dB attenuator to achieve 0.5 milliwatts (500 microwatts).

5mW out into a 10dB attenuator.

I thought I was doing quite well to be achieving 1676km to Italy during the afternoon.  As greyline approached,  I was very happy to be heard by EA8BFK at 2864km, well above the detection limit at -22dB.

I left the transmitter going overnight, and when I checked this morning, I was amazed to see 0.5 milliwatts had confidently crossed the Atlantic, to make -22dB at WA2TP!  This is a kilometres-per-Watt equivalent of 10,588,000 km!

Reception reports for my 500 microwatt 14MHz WSPR transmissions, 11:52UT - 06:34UT 22-23/9/2020

At these QRPpppp levels, the receiver has to be in a quiet environment.  So this experiment really does sort out the 'men from the boys' in terms of who really is operating an optimum receive station, and who isn't.  

Sample of reception reports.  Note: reported power is limited by WSPRlite parameters.  Actual power was 0.0005W (i.e. 10dB lower than reported)

 

At an achieved -22dB from home with this power level, there are 12dB 'spare'.  That indicates a power output of 32 microwatts would theoretically just be detectable across the Atlantic with my vertical delta.

But from the beach, there is an environmental gain of about 10dB available.  So the theoretical power output limit from this kind of omnidirectional antenna for detection in the US, ignoring any propagation enhancements, is about 4 microwatts. 

Inevitably, I will have to try this experiment at a west-facing beach this week, to see what happens there.  At least I have a well-defined time window, between 19 and 22UT, where propagation is strongest, to limit my standing around in the cold and the dark, unless the magnetic field changes!

 

 

Geomagnetic pathways

Over the past couple of weeks, during what has often been quiet geomagnetic conditions, the 5W, 14MHz WSPR signal from world-class VK3QN (beaming long path Europe) has been lost quite consistently between 22:50 and 23:10UT.

Last night, even though the magnetic field was only slightly disturbed (maximum Kp= 2), this was enough to make a very big difference to the received signal from VK3QN, which continued almost through the equinoctal night. 

VK3QN 14MHz WSPR received by MW1CFN, 2020 September 20-21.

 

On an entirely different subject, yesterday was also a reasonably good one for tropo propagation at 144MHz, where FT8 has really brought that band back into a large volume of activity - a good thing for a band that was, very recently, under threat:

My ~120W (into 8-ele) 144MHz FT8 signal across Europe yesterday morning.

WSPR: Signal strength is not the whole story

Yet another warm, sunny afternoon led me to think I might get 500 microwatts from the coast to somewhere today.

When you know the tide very well, you can do this (and beat the tourists to a car parking space!)

 

Sadly, propagation was such that it looked like I might get nowhere!

So, I took the 10dB attenuator off the WSPRlite unit, and sent 5mW instead.  Signals with this power clearly showed that 500 microwatts lay just below the detection limit at the time.  I probably would have achieved one or two spots, but I wasn't inclined to wait for several cycles of WSPR to find out if I ever did; each 2 minutes is a long time when you are standing in a strong wind at the beach!

The results with this extremely low power are very interesting.  I was also running the delta loop back home, with a second WSPRlite at 5mW.

The important message is that when we compare antennas, the plots below clearly show that simply comparing signal strength reports is not enough.  We also have to consider how many spots there were for each antenna.  

For example, if I used the median for EA8BFK's spots of my 5mW from each antenna, I could conclude that the coastal position was only 2dB better than the delta at home - although I would have to add about 3dB to that figure, to allow for the better 'inherent gain' that the delta has over the 1/4 wave vertical.

But this would be a very misleading conclusion, because the coastal antenna was heard by EA8BFK 12 times in just under an hour, whereas the delta was heard only three times.  The same was true with pretty much all other stations.

EA8BFK WSPR RX spots, 14MHz

OH8GKP RX hears the coastal antenna 13 times, but the delta only three times.

SM2HJJ's 7 spots for the coastal antenna, compared with only 1 spot for the delta.

The situation was even more critical for K9AN, R2ARX, LY3EC and WA9FIO, in that they heard the coastal antenna (even though the US stations were landward, though seawater was almost surrounding the antenna locally), but not the delta at all.  In the case of the US stations, the signal levels were all about -29dB, but LY3EC's reception was at -15dB, revealing a very good enhancement of about 20dB in that case, all factors considered.

So compare your antennas carefully!

Waiting for family, working the bands

Another round of waiting for teenagers to return from some crazy activities somewhere led to a brief opportunity to work 17m from the shore this afternoon.  Weather continues to be amazingly warm and sunny for the time of year, but with a moderate easterly wind that brought out the windsurfers.

I wondered if I could get JTDX to work on the Raspberry Pi 4B, so downloaded it using the mobile wi-fi.  Whilst the version listed for Linux wouldn't work, the version for the Pi 3 did.  

One thing to note if you download JTDX for the Pi is that, once installed, you must reboot to see the program listed under 'Sound and Video'.

 JTDX, up and running on the Pi 4 in the car.

From then on, it was easy going!  No more WSJT-X, which is far less capable than JTDX.  

Very happy to be the only station being heard on 17m WSPR by VU3KAZ (1W out), despite the simplicity of my /P station.  Of course, with the seawater, the effective signal is known to 'grow' to something between 10 and 25W typically. 

Just a shame K2IL started sending FT4 for quite a while, straight on top of ongoing WSPR transmissions.  In fairness, after sending him a polite e-mail, he moved a good distance down in frequency within a minute or two.

Sun, wind and kite surfers (and a weirdo doing something with a big antenna!)

I managed 19 FT8 QSOs using 6-8W, spanning the western US to Brazil and Indonesia.  Again, very pleasing results with such low power.

6-8W FT8 coverage at 18MHz from the beach.

Use your copper wisely.

Do you ever wonder, as you throw away old equipment or use yet another length of wire, what the real environmental impact of people like us, who depend on metals, is?

If so, then this is worth a watch.  I've seen similar mines in person in Peru, and they are not a pretty sight. 

Use your copper wisely, and recycle it as much as possible!

https://www.aljazeera.com/programmes/specialseries/2020/09/dark-side-green-energy-200906101945535.html

Wales finds life on Venus (maybe)

If, like me, you are Welsh, you are required, as a member of a small, mountainous and almost entirely rural nation, to have a good sense of humour, primarily so that you can laugh at your non-position in the world.

Yesterday, we suddenly all had to take ourselves very seriously, as Cardiff University made global headlines as they made known to the world their finding of phosphine in the temperate cloud regions of Venus - a potential inidicator of life floating around in that hellish planet's atmosphere.

Detection of phosphine needs further confirmation.  If it is confirmed, it might be a sign of bacterial life - or unknown chemistry that might take place in such a complex, extreme environment.
 

Of course, all the hype about life is very much premature.  The researchers have taken care to confirm their finding with two different telescopes, and tried hard - and so far failed - to explain the continuous presence of 20ppb of phosphine by various abiotic processes.  But there are still issues of weak signal levels and second-frequency identification yet to tackle before even the identification of phosphine, let alone life, can be fully accepted.

Living on top of an old copper mine, it comes as absolutely no surprise to me that bacterial life could be found in the clouds of Venus. Whilst that planet is much more severe than even the acidic waters of Parys Mountain, bacterial and even algal life is, nevertheless, abundant within the latter environment. 

In fact, extracting metals from low-grade metal ores using bacteria has been common practice for decades.

We have 'snottites', like those I photographed may years ago now - bacteria effectively protecting themselves from the harsh environment by producing copious quantities of biofilm.  Because the whole life cycle is based around sulphur, pH values in this environment are usually 1 or less.  When the acid emerges into daylight, algae start growing immediately in that water.

Bacteria also live freely in the blood-red acid water, deep pools of which you really wouldn't want to fall into!

Meanwhile, we have the amazing Russian Venera craft to thank for a lot of our knowledge about Venus - the only craft to successfuly make it to the surface and obtain data.  Note the lovely helical microwave antenna on Venera 9, below, making clever use of the aerobrake disk as a reflector. 

Venera 9.  Key features are: craft height of 2m.  Swirly 'top hat' microwave antenna (giving 512 bits per second upload to the orbiter, one camera on 122.8Mhz, the other on 138.6MHz).  Disk aerobrake, to slow the descent (without parachutes from 50km) to 7m/s on impact (entry speed was 10.7km/s) cushioned by the ring shock absorber, around which floodlights are arranged for the cameras.  The two tubes from the aerobrake to the body of the lander were for pre-cooling the instruments prior to detaching from the orbiter craft.  A gamma ray ('paint-roller') spectrometer is stowed beneath the ring, and would extend out on landing.  Despite temperaatures of 467 degrees Celsius and pressure of 93 bar, Venera 9 survived and took images for 50 minutes.

The alien world of Venus, as seen (perspective-corrected) by Venera 13.

 

                    Artist's impression of Venera craft on surface of Venus.

A dramatic impression of how Venera craft probably looked after not very long at all on the Venusian surface.

Has amateur radio lost the plot?

An interesting article from EI7GL about non-QSO QSL cards recently and, in particular, the following comment to it by another person, stopped to make me think:

The final sentence is the important one.  A contest seems like a decent enough idea.  Yet, precisely because they are competitive, they always lead to cheating, whether that is deliberate by some complex arrangement with other hams, or simply by using, as the comment says, a remote station.

It was exactly the use of remote stations - in this case, multiple remote stations - that led me to drop the idea of taking part in contests after my only attempt to do so in the 2019 RDRC JT9 activity day.  Even though that is not a contest in the very earnest manner of some competitions, it was still important enough to some that they resorted to using expensive access to an enormous array of Yagis across the world, tot up the points and coast to victory.  

Remote stations don't even need to be complex or expensive.  They just need to be within easier reach of that once-in-a-lifetime DX.  Today, there are loads of them around the world, just basic rigs, hooked up to the internet, that anyone can access. 

What point is there in me, or much of anyone else, sitting there for 48 hours, diligently working away with a wire antenna and semi-QRP power from one location?  Answer: none at all.

Being 'on top', 'the biggest', 'the loudest' is all part of the ham radio lexicon.  It's hardly surprising that, when a contest effectively asks: 'who's best?', some will run to use whatever method they can, fair or otherwise, to answer: 'me!'  

Anybody can win, if you pay dearly to access antennas and locations like this.  Image: remotehamradio.com

I suppose the majority of operators take part honestly, in the naive expectation that all is fair, with that fairness ensured by the often rather complex rules that apply.  But we only need one cheat - and there are certainly more of those around than we might expect - to spoil the game for everyone.

I don't follow the contesting world at all, but I do of course notice news about them in the magazines and online.  In this month's Practical Wireless, even avid contesters are now describing the number and timing of radio contests as "completely out of control".  I agree.  

Radio has long ago been hijacked on both sides of the Atlantic by over-competitive men whose entire life is dominated by being 'number 1'. They somehow get themselves elected to positions in national societies, where they set about manipulating how the hobby develops and is portrayed. Sadly, the hobby's whole purpose, if you believe these people and their many followers, becomes one of nothing more than contesting.

So, I'm glad I tried one contest in a serious fashion last year.  It confirmed to me what I already knew: it's a total waste of time, if only because radio is a hobby, not a measure of any worthwhile achievement that the rest of the world values and recognises.

A departure (non-ham)

With some warm weather this morning, my fuschia bushes were swamped by bees.  Because I've been managing the garden as a safe place for bees, this was very pleasing to me:

Mesospheric · Bees

Overnight anomaly

This past evening's anomaly at 14MHZ was my single spot reception of AA7FV at 01:56UT at -28dB, the only station outside the US, Latin America and the Pacific to do so, other than TF4AH - an often-seen situation with these unusual spots (TF4X only heard AA7FV at 04:40UT, just before the early greyline period, so is not of interest, likely being a long path signal.)

14MHz reception of AA7FV, 00UT-06UT

Kp rose to 6 around 00UT, and remained at Kp = 4 for several hours thereafter.  Once again, the single spot of AA7FV came as the magnetic midnight line was positioned midway between receiver and transmitter, the supposed great circle path making a tangent with the inner edge of the auroral oval.  The Icelandic stations gave three spots between 01:10 and 01:56UT, but nothing after that.

AA7FV uses a large, bidirectional rhombic antenna with one beam aimed at Europe, and the beamwidth is very narrow.  So we can be fairly certain that this very transient single spot had a very localised propagation mechanism.

Proppy 14MHz indicative (and not very accurate, given the unusual antenna in use) signal strength prediction at 02UT from AA7FV.

 

Tiny Watts

Rain was clearing from the west last evening, so I decided to try some WSPRlite transmissions from IO73RF, a local beach with an open aspect from south to NW.

Portable operating is as much about the scenery as it is about the radio.

Unfortunately, I had failed to realise two important things as I rushed to get out: I left my beach transmitter at its previous setting of 5mW, and was using the same callsign for it as I was with the WSPRlite operating back home (at 200mW).  So discerning which station was which was tricky, but not impossible, thanks to the reported power output differences.

Never mind.  It's really just an excuse to look at the sea and get some fresh air (well, lots of fresh air, given the wind!)

I did manage to extract some useful information from WA2TP's reception, where I have taken all other UK stations being heard by him at the time and converted them all into 5mW equivalent signals.  This sounds simplistic, but it is usually very reliable (last year, I could see that G0CCL's 5W and 1W signals were out of calibration by monitoring his reception at a station in the US - to an accuracy of 0.3dB!)

So, on the extreme left (MW6PYS) is my actual 5mW signal as received by WA2TP, and everyone else's 5mW equivalent signal.  The blue horizontal line is the -34dB SNR limit that can be decoded by current WSPR software (WSJT-X in this case):

It's yet another powerful piece of evidence that shows the enormous benefits of coastal operating.  Whilst my received signal was 14dB above the detection limit, all other signals are below it, with 7 of the signals significantly below that limit.  

Put another way, taking 14dB off my 5mW to still be detectable at the lowest decoding limit gives 200microwatts.  Think about that.  It's 0.0002W!

Powers used by others stations ranged from 0.2W to a staggering 10W (sadly, the latter station is MW0NAB, who is blasting everyone in the local area with his signal, yet serving only to demonstrate the uselessness of his antenna system).

 

VK7JJ

An overnight WSPR session at 14MHz produced a result that was quite unusual, thanks to extremely quiet geomagnetic conditions.

The band had been rapidly becoming quite dead well before midnight.  VK7JJ at the time was only hearing stations local to him, and from the US (mostly in daylight there).

At 22:26UT, VK7JJ heard my 1W at -28dB, but no other UK, or even European station, at all. Because these claims are often the subject of derision and disbelief by some quarters of the 'angry old man' ham community, I always present some proof, dull as it is (my call is near the middle):

It's difficult to know exactly (or even remotely) what mechanism leads to only one signal from essentially half the planet making it to a receiver on the other side of the world.  I understand my unique reception of others to be simply a low noise antenna (delta loop) in a low noise environment, when almost everyone else has significantly higher noise floors.  But my transmissions are not affected by such factors.

For now, the propagation from the UK to VK is clearly an evening long path, and antipodean focusing seems likely to be important, too:

Signal strength predicition for an indicative signal type, at 22UT (Proppy).

If you have good ideas, leave a comment!

Lab599 TX-500: stable, or not?

Regular readers of my blog will know that I am quite interested in using WSPR for checking antenna performance, evaluating different environments, and finding curious propagation effects.

In one way or another, at some time or another, WSPR is of use to just about all of us.  Whilst drifts of +/- 4Hz can still produce reliable decodes, drift of that degree is very unusual, generally indicates non-TCXOs, and in the WSPR community, is not really tolerated as acceptable.  Practically everyone produces zero drift, day in, day out.

Hence, as I look towards the next year, I am trying to find out as much as I can about, in particular, the Lab599 TX-500, which is not yet available in the UK.

This looks like a fine QRP transceiver.  But how good is its frequency stability?  I may have missed it, but I couldn't see any reference to the crystal stability anywhere for the TX-500; the manual's specifications pages (pp 28-29), accessed 10/09/20, has no reference to it.  

Frequency stability is, these days, quite an unusual thing not to shout about.  The forthcoming IC-705 from ICOM, in contrast, proudly announces its 0.5ppm stability.  

Even the cheap (but excellent) WSPRlite units have a TCXO, and the WSPR database is full of their zero drift transmissons.

An exchange broke out on Julian, OH8STN's Facebook page over the past day.  I was complaining that, despite several searches and requests, I still had no data on frequency stability for the TX-500.  

Julian started off by somewhat seeming to take my disappointment about the lack of data as a personal attack.  I replied that providing the stability data was as easy as someone - anyone - running a few minutes of WSPR transmissions.  But nobody has done it.  And nobody seems willing to try.

By now, Julian sounded less like an objective reviewer and more like someone trying to sell the TX-500.  He asserted that the TX-500 was stable enough to run various digital modes, which wasn't addressing my question.

Eventually, I had this, rather suprising response:

Again, this isn't providing any data.  It's merely someone's assertion.  And one where providing the data to back up that assertion, if it's true, is easy.  When I looked at Julian's call, with and without a /P extension over the past two weeks on the WSPR database, there were no entries.

A crystal stability of 2.5ppm is certainly not what we expect of a modern transceiver costing 890 Euro.  My FT-450, now an old rig, but still significantly cheaper new than the TX-500, produces zero drift in WSPR, regardless of any environmental changes.  

With the addition of a £15 generic, Chinese TCXO, my even older TS-480SAT also produces zero drift, regardless of working conditions.  And, if we believe the maker, even the Xiegu X5105 has +/- 1ppm stability - for 200 Euro less than the TX-500.

Oddly, I started out as a strong supporter of the TX-500, provided it comes to be sold in the UK directly.  But nobody seems willing to send some WSPR transmissions from it for five minutes, to which we can only submit the question: why?

Until I see someone demonstrate the actual frequency stability of a production TX-500, it will remain in the 'important questions not answered' category.

ZS4TX at dawn

Interesting to see how ZS4TX heard my 14MHz, 1W signal compared to the 0.2W sent by M0VIK/MM (he uses his 'MM' as a prefix, but I give it as a suffix, as it's meant to be).  The plot has adjusted M0VIK/MM's output to a 1W equivalent.

Despite being to the NE of me, and thus experiencing the day advance about 30 minutes ahead, I was heard by ZS4TX 30 minutes before M0VIK/MM this morning.  But I was quickly outstripped as the benefits of a boat on water, even when it's moored in a harbour, came into effect.  

Note how the difference at peak 'greyline' time was 6dB in favour of M0VIK/MM, whereas for the rest of the period, it becomes about 15dB in his favour.

 

WSPR anomalies return.

With fairly quiet geomagnetic conditions returning over the past day, I decided to run the RSP1a receiver overnight, to see what surprises might come in at 14MHz.

Sure enough, for just a few minutes around 02:20UT, KK6L's 5W was heard - quite weakly - where he was received by no other station in the dark hemisphere, other than TF4AH, who, being under the auroral oval, has markedly different propagation conditions than I do.  You might miss my reception on the plot - it's the short blue line (just three spots), right of lower centre.

I was interested to see that ZL stations were also hearing KK6L, and so I plotted ZL1ROT alongside myself and TF4AH, to see what that might reveal in relation to the opposite hemisphere.

14MHz reception of KK6L, 2020 September 07

As you can see - and remarkably clearly so - the signal response in the southern hemisphere is in a very good inverse correlation with TF4AH; when his signal is reducing to then hover around the -17dB level, ZL1ROT's received signal strength increases to much the same level.  

If this isn't immediately clear, then look at TF4AH's response, which is essentially a 'U' shaped curve, and then ZL1ROT's response, which is an upside-down U shape.  A 3-degree polynomial trend curve may make things a little clearer:

The sudden appearance of KK6L comes as the field restored from a southern deviation to a solar-quiet condition, although on this occasion, the field had been quiet for about an hour before KK6L was heard.

The reception also came, as I have seen many times before, as the auroral oval's midnight edge came to lie mid-way between KK6L and the UK.  At this time also, KK6L is just 10 minutes before sunset, so his D layer is rapidly starting to diminish. 

I expect the signal strength increase with KK6L that happens around this time briefly reaches detectable levels here in Wales due to the assistance of very localised ionisation, apparently within the inner edge of the auroral oval, if the path is assumed (probably simplistically) to be a great circle:

Terminator and auroral oval at time of KK6L reception by MW1CFN

 

Great circle path KK6L to MW1CFN at 02:20UT, assuming no skew.

Ha ha!

 

Well, though I did my best to set aside some time to take part in the recent RDRC JT9 event, I really couldn't be bothered to waste two whole days of my life gathering useless points.  

Accordingly, I ended up 90th, as opposed to last year's effort, where I received 10th place.

Rather pleased with that, as it is just too much like a pointless activity, nice though it is to see lots of JT9 signals.  If only people used it regularly, rather than just for activity days...

 

AA7FV rises in moderate geomagnetic disturbance.

A peak Kp of around 5 overnight, coupled with plenty of disturbances in the preceding day or two, brought a nice enhancement of AA7FV's 2W, 14MHz signal from his large rhombic, aimed at Europe.

I was quite surprised at the short period of reception for AA7FV on August 28th, which came to an abrupt end.  When I checked the entire reception record for that station, it was confirmed that he would disappear for everyone in the UK about 21-22UT each recent day, under quiet geomagnetic conditions.

But, with a bit of energy pumped into the ionosphere by the past 24 hours of HSS activity, AA7FV's pattern changes dramatically, to be heard throughout the night, until dawn here:

Brief G7 disturbance

Another nice example of a brief G7 geomagnetic disturbance bringing about a large enhancement of a local signal from G0CCL (14MHz) overnight. 

The peak occurs almost precisely at the most southerly deviation of the field, and when the Raspberry Pi transmitter had switched, as it is set up to do, from a series of 5W to 0.2W output, which (subject to checking with G0CCL) made this an even more remarkable enhancement:

It's perhaps tempting to think that this peak is just the passing of the greyline or some other effect.  But that is not seen on quiet days, as the results for 28-29 August 2020 show (the ~02:30UT peak is broadly coincident with a minor southerly deviation in the Z component):

G0CCL 14MHz WSPR reception on a low Kp day.

Meanwhile, W8AC comes in at a slowly increasing level, then undergoes a very dramatic slump in strength as the Z component southerly deviation strengthens, then restores as the field rebounds, before vanishing completely.  I checked various other receptions to see if this was repeated.  The result from G4ZFQ/Y, which is a Yagi pointing across the Atlantic, I think, seems to confirm it was a real effect, allowing for latitudinal differences in the stations:

14MHz reception of W8AC by MW1CFN

14MHz reception of W8AC by G4ZFQ/Y