Propagation charts updated through to March 2027

I have recently updated the propagation charts through to March 2027 with the new SSN figures.

Previously, these ranged from 120 to 999. But now they are:

October 2026: 74
November 2026: 72
December 2026: 69
January 2027: 66
February 2027: 63
March: 2027: 61

So they should be more accurate!

Regards, Steve G0KYA

Updated HF Propagation Charts from the UK

I have just updated my short-path propagation charts from the UK with the latest predicted smoothed sunspot numbers.

It takes about half a day to do - it took longer this time as I was using a new, faster laptop, but couldn't remember the log-in details for my server!

Anyway. they are done now. They are updated up to January 2027. Interestingly, the predicted smoothed sunspot numbers range from 120 for February 2026 to 96 for January 2027. These come from the Space Weather Prediction Centre in the US and are SIDC figures.

So it looks like we will have another good year of HF propagation, before the numbers star to slide further in late 2027. 

I still recommend both Proppy and VOACAP.com if you want detailed HF forecasts, or if you want to do long-path predictions. But for casual use my charts are fine, and produced using VOACAP.

Radials and Counterpoises

This is a talk I gave to Norfolk Amateur Radio Club at its annual Radioactive event. It looks at radials for ground-mounted verticals, including how many do you need and how long should they be. It references the excellent work done by Rudy Severns N6LF. Download the presentations in PDF format (760k). 

HF Propagation - what do the numbers mean?

This was the title of a talk and presentation I gave to the Nuneaton ARC in March 2025.

I have attached a PDF of the PowerPoint presentation, which can be downloaded here.

Without the talk, it may not make total sense, but it at least gives you a flavour of the talk and some insight into what some of the terms mean in HF propagation.

New worldwide 10m beacon list issued

RSGB’s Propagation Studies Committee (PSC) has released a new HF beacon list, with the 10m listings completely revamped.

The old list, which was started by Martin Harrison G3USF (SK), had been added to over the years, but was getting out of date. The only way to make it more accurate was to start again.

Use was made of the Reverse Beacon Network (RBN), which wasn’t available when the list was originally created, plus listeners’ contributions from around the world. 

I started by removing around 60 beacons that had not been heard for some time. Delving deeper it seems that a lot had been taken off the air, the owners had died, or their frequencies had changed.

Using the RBN gave a pretty good indication of what beacons are actually on air, plus help from a list compiled by Gary ZL2IFB filled in some of the gaps.

Beacons that are temporarily off-air have been left in, but marked in black.

While no list will ever be complete as changes take place around the world, I think the list is now far more useable. I’ll endeavour to make changes as and when they are needed.

The new beacon list can be found at:

https://rsgb.org/main/technical/propagation/propagation-beacons/

Help needed with Index Laboratories' QRP+ radio

I need your help! 

But first some background. The Index Laboratories' QRP+ is a 1990's 5W all-band QRP transceiver from the USA. I bought mine at a club sale and it was supposed to be working fine.

But it wasn't! Never mind, we all love a

challenge, don't we?

It seems that the SBL-1 mixer is a common failure point so a replacement was ordered.

The rig comprises four boards, which are stacked and have interconnecting leads.

It is relatively easy to pull apart, and the mixer is on the top board.

After a big desoldering struggle I fitted the new SBL-1 (U5), which brought the receiver back to life. Unfortunately, the TX still didn't work. Back to the drawing board.

The next stage was to replace the final PA transistor, which is on the lowest board. This is a IRF510 (Q9) and I ordered a few off Ebay. I fitted a new one and in tests I found that I could only get about 0.1W out! (on CW) with the gate bias backed off fully anticlockwise. 

Power out should be about 5W.

Anyway, that's as far as I have got. I have attached a link to the circuit diagram and would appreciate any suggestions.

Update

Well, some replacement IRF510s were sourced from the G-QRP club (thanks guys). Apparently, there are some "fake" IRF510s around that don't play well with RF.  After pulling the radio apart (again) and replacing the transistor, it was a little better - about half a Watt output. Anyway, to cut a long story short I have passed the radio to another G-QRP club member and I hope he has more luck than I did! 

Update to UK propagation charts

I'll freely admit that my UK propagation charts had been a bit neglected over the past year. But not any more!

I've now updated them until the end of 2024 with new predicted smoothed sunspot numbers.

I've also fixed a problem with the Kp graphs. They now appear, along with solar X-ray and proton flux graphs. This was because the US Space Weather Prediction Center had stopped the production of the previous Kp chart.

I still recommend both Proppy and VOACAP.com if you want detailed HF forecasts, or if you want to do long-path predictions. But for casual use my charts are fine, and produced using VOACAP.

Leave a comment if you find them useful (or not!).

Incidentally, the SSN charts I used show that the expected solar maximum is the middle of this year.

Preparing the GB2RS propagation report

Attached below is a PDF (14Mb) of the presentation I gave on 15th April 2023 after the RSGB AGM.

It looks at how we prepare the weekly propagation report for the RSGB's GB2RS news report. It contains a lot of useful URLs to sources, data and programs that people might find useful.

Steve G0KYA

Download GB2RS_Propagation.pdf

Ten metres (28MHz) beacon list updated

I've just spent two days updating the RSGB's 28MHz beacon list. I used the reverse beacon network and logged/updated the beacon list accordingly. This takes a lot of time as many of the "spots" are misread and have to be checked individually.

Beacons heard over the last three years are highlighted in red. I'm now happy that it is pretty up-to-date. The RBN has a beacon listing, but it is way out of date - GB3RAL is still listed and that hasn't been on for years.

I think this is the best way as it reflects beacons that are actually transmitting and not just listed. The full beacon list can be found on the propagation section of the RSGB website here: https://rsgb.org/main/files/2024/10/RSGBs-Worldwide-List-of-HF-Beacons.pdf

Change of freq/details:

28270.5 PY4MAB  Pocos de CaldasGG68      2W    

28193.1 LU2DT   Mar del Plata  GF12      5W 

28208   WD5GLO  Minco OK       EM15ah    3W 

28281   AG8Y    Middletown OH  EM79TL  7.5W   

28273.8 WI4L    Dalton GA      EM74MS                    

28243   AA1SU   VT             FN34KL    5W   

28209.5 N2UHC   St Paul KS     EM27JM    4W

28203.3 WB9OTX                 EN55      5W             

28280.4 KE4IFI  Lexington SC   EM9JV     7W 

Additions:

28297.9 K4JDR   Raleigh, NC    FM05     10W 

28255.8 WB4NCT  Athens, AL     EM64      5W  

28241.3 WW2BSA  Warren, NJ     FN20OU    7W   

28260.8 IQ8BB   Salerno        JN70JQ      

28178   IQ0GV   Sora           JN61TR    5W    

28236.3 F1ZTS   Rochefort      in97QI   10W     

28266.1 VK4RST  St George QLD  QG41HW   10W

28285.9 AJ4YN   Chesapeake, VA FM16UO    ? ?   

28215   GB3MCB  Cornwall, UK   IO70OJ    ? 

28252.6 WD8INF  Lebanon OH     EM79VK   10W

28258.8 AC5JM   Bartlesville OKEM16FT    ?

28209   N5TIT   Westminster, COEM12PX   10W 

28206.5 N4SO    Grand Bay, AL  EM50tk    6W   

28296.2 VE3IIM  Hanover, ON    EN94LD    4W 

28321.4 IZ1KXQ  La Spezia      JN44WC  0.1W

28230.8 NG7I    Ritzville WA   DN07TC    5W  

28202   WB7EUX  Joseph, OR     DN15JI   10W 

28233.5 K7RA    Seattle, WA    CN87UQ   11W  

28260   KC4QLP  Little Falls NYFN23OB   10W  

28245.3 K0WKT   Black Dia. WA  EN36WT    5W 

28226   K6KWS   Redwood City CA CM87VL  10W 

28240.1 W8EDU   Cleveland, OH  EN91EM   10W

28206.9 N4XRO   Burbank CA     DM04UE    5W 

28276   XE1JAL  Xalapa         EK19MM    5W

28230.3 W2MQO   Grand Island FLEL98dv   10W

73 de Steve G0KYA
Chairman, RSGB Propagation Studies Committee

Autumn 2022 HF popagation charts updated

 

I have just updated my propagation charts for October, November and December 2022 with new sunspot numbers. 

I will update the Spring 2023 charts when we get a little closer as they are likely to change as we head towards the maximum of solar cycle 25. 

Anyway, it is nice to see some good predictions of DX on 10 metres and if the past two weeks are anything to go by they are pretty spot on with very loud signals from the USA. 

ARRL's W1AW's CW practice files were romping in the other day on 28.0675MHz Nice to see 10 metres doing what it does best! 

Click here for the charts or use the link on the right-hand side.

Repairing a MFJ-1786 magnetic loop

I just wired up my MFJ-1786 magnetic loop, which hasn't been used for years. Unfortunately, it looked like the loop controller had gone U/S. 

The meter lit up, but pressing the loop buttons had virtually no effect. The amber lights flicked slightly, but they were not so bright as I remember them, and the motor didn't turn. I got hold of a schematic, but it is way more complex than I thought it would be. I first changed the only electrolytic capacitor in the unit as it was getting quite old, but it made no difference. 

I then stripped the antenna and made sure it was all OK. Connecting a 9V battery made the motor turn, so I sprayed the motor with grease and put it all back together. Turning to the controller again I first changed Q1, but that made no difference. Then I changed Q5, but nope! So I moved on to the U5 78L12 voltage regulator, which is fiddly job as it is an 8pin SMD. 

And low and behold it works! I just need to fix the power meter, which displays reflected power, but not forward, but that can wait until another day. Then finally I can mount it outside for final testing. I've attached the MFJ-1786 schematic as this was quite hard to track down - might come in handy for someone in the future.  Click on the image above to see a larger version.

Update

Well, it wasn't a diode that was stopping the meter from working, just a poor connection. 

So I now have some spare diodes for the future! I've uploaded a higher resolution version of the schematic too.

Steve G0KYA

HF propagation charts updated for 2021

I've now updated my propagation prediction charts for 2021 with the predicted smoothed sunspot numbers from NOAA/NASA.

So that's a chart for every hour, for every band and for every month, or more than 2,300 charts in total! The process is fairly automated, but it still fairly tedious and takes about a day to do.

The charts are useful as a quick guide to what parts of the world may be workable and which aren't. If you want more accurate charts then the ITURHFPROP-based predtest.uk or the VOACAP-based voacap.com websites are better.

I may need to update them as the year progresses as we get a better idea of how Solar Cycle 25 pans out. At the moment it isn't looking too good. December 2020 saw a sprinkling of SS25 sunspots with a corresponding rise in HF activity. But since January is has been pretty dire really with long periods of no spots 

Anyway, to avoid confusion, I have updated form February onwards. This means that January is actually for 2022. 

The charts are produced using Hamcap which is a VOACAP-based application and they are for short-path only.

VHF propagation video released on YouTube

As a result of the success of our HF Propagation video on YouTube, which has had 2,000 views in two months, the Propagation Studies Committee has now launched a 20-minute VHF propagation video as well.

The video was originally produced for club presentations, but with Covid-19 and the lockdown, it wasn't getting much use.

So if you have never heard what an auroral contact sounds like, for example, now's your chance!

See https://www.youtube.com/watch?v=5Yo4IFn6AAY&t=8s

Steve G0KYA
Chairman, RSGB Propagation Studies Committee

Understanding HF Propagation video released

I've just published a 40-minute video entitled "Understanding HF Propagation" on YouTube.

This presentation was originally produced for use with clubs around the UK and has been used by more than 100.

With the current Covid-19 restrictions in the UK, it looks like club meetings aren't going to be taking place any time soon, so I've released it on YouTube.

I may do some further videos over the next few months - it depends on how long the restrictions last!

See https://www.youtube.com/watch?v=DIAgzpdB67A&t=42s

Steve G0KYA

Range of HF propagation tools launched

There is now a range of online propagation tools available from the RSGB's Propagation Studies Committee, including Proppy for RadCom, VOACAP for RadCom, Predtest and Propquest. All very popular according to the feedback.

We highlighted these at the recent Newark Hamfest.

RSGB has now set up quicklinks to each of the tools, which will make it easier in the GB2RS audio bulletin. These are: 

Propquest
Shows real-time critical frequency and MUFs over various path lengths. Excellent tool for HF users.
See www.rsgb.org/propquest

Predtest
Designed by Gwyn G4FKH, calculates the probability of propagation over different paths and for different modes. Includes point-to-point and animated displays.
See www.rsgb.org/predtest

VOACap for RadCom
Shows the probability of propagation to 28 different locations around the world – the same locations used in the RadCom predictions. Can be tweaked for your particular station including mode, gain and power.
See www.rsgb.org/voacap

Proppy for RadCom
Uses the latest ITURHFPPROP tool to calculate the probability of propagation to the same 28 locations used in RadCom.
See www.rsgb.org/proppy

2019 Commonwealth Contest and QRP

My Yaesu FT-817 and Winkey

This weekend has seen the Commonwealth Contest 2019. I documented my 2018 attempt on the blog, and was keen to give another go this year.

Last year I used my Icom IC-756 Pro 3 wound back to 5W, but this year decided to use my Yaesu FT-817 for a real QRP approach. I bought a USB lead for it this year to give full computer control with N1MM and decided to use my Winkey for full auto CW .

This year I had a slight change to my antennas. Out went the end fed half wave (with 80 loading coil) and in came a 66ft OCFD with the apex at about 8m. Also new was a quarter wave vertical for 20m, erected for the weekend on a 10m fishing pole - more of that later.

The contest ran from 10am, but at 9.30am I was struggling with the computer and interface. Stupid me forgot to turn off the keyer on the FT817 - duh!. Soon we were under way.

The contest got off to slow start with my 5W struggling to break through. Many stations just couldn’t hear me. The quarter wave vertical for 20m turned out to be a noise magnet - almost S8. I  decided to abandon it quite quickly.

After an hour I had a few stations in the log - 5B4AGN (Cyprus) and 9H1CG am (Malta), but nothing better. 3B8XF Mauritius (G3TXF) was audible, but I couldn’t break through. Same with ZF2CA Cayman Islands (both 3B8 and ZF were worked last year).

The afternoon saw Canada romping in and I ended up doing an hour at about 10-11pm, clearing up the UK HQ stations.

Sunday started at about 5.30am and a few more Canadians on 40m were cleared up. I then had a big breakthrough - VK4CT on 40m. It wasn’t easy, as they needed three or four repeats on their serial number, but we got there eventually.

So there you go - 34 QSOs in total, which doesn’t sound much, but I didn’t take part for the full 24 hours and it is HARD work with only 5W. Peter M0RYB, a fellow Norfolk Amateur Radio Club member, cleaned up with 70 QSOs in the QRP section. Must find out his secret!

Note: The FT-817 isn't much of a contesting radio. I found it struggled with a nearby 400W station and also found the 500Hz filter a bit too wide. Might be back to the IC-756 Pro next year.

HF propagation charts updated

I have just updated my HF short-path propagation prediction charts for the UK (accessed via a link on the right).

I had to update them with the latest smoothed sunspot numbers for the next 12 months.

This is a little depressing as after May 2019 the predicted SSN falls to "one" and stays like that for the rest of the year! Sunspot minimum is currently thought to be later this year, but could spill over into 2020.

These charts are meant as a rough guide. Other tools that are available are:

1. The VOACAP RadCom prediction tool - this replicates the locations found in the monthly RSGB publication, but lets you choose your own mode, power and antennas to give more accuracy.

2. The Predtest.uk tool - this tool, developed by Gwyn Williams G4FKH, uses the latest ITURHFPROP prediction engine to let you produce point-to-point or area propagation predictions, again with full control over the input parameters.

3. Propquest - this is a near real-time tool, developed by Jim G3YLA, that shows the critical frequency and extrapolated maximum usable frequencies available over different path lengths. The critical frequency (the frequency at which a radio wave launched vertically stills gets returned to Earth) is derived from ionosonde data, mainly from Chilton and Fairford.

It should be your first port of call to see what conditions are like. In the summer it also has predictions for Sporadic E, courtesy of Jim.

Steve G0KYA
RSGB PSC Chairman

Yaesu FT-991A firmware update warning

I have owned a Yaesu FT-991A for about two years. I have to say that I really only use it on two metres. It isn't a bad radio, but it can be fiddly and you have to get used to going through lots of menus to do what you want it to do.

As such I tend to use my Icom IC-756 Pro 3 as my main HF rig (unless I'm using one of my QRP rigs like the Elecraft K1, YouKits HB1A, QCX, MTR etc). Use the QRP tag on the right if you are interested in reading about them.

Anyway, I recently tried to use Yaesu's Fusion mode as we have a new Fusion repeater (GB7NM) about 10 miles from me.

I wasn't impressed with the audio though. Half the time it was unintelligible and pretty awful to be honest. I did wonder if the signal strength is sufficient, but it is S9 +30db. Also, I live about half a mile from the police headquarters and do suffer some desensing on 2m if I use a cheap handheld like a Baofeng connected to my 2m antenna. Perhaps that's the problem.

However, I checked and found that the FT-991A's firmware (including C4FM) was out of date and thought that an update might improve things.

So, following the instructions, I first uploaded the main firmware - and this is where I came unstuck. Once I had completed it I rebooted the radio, but it wouldn't - all I had was the Yaesu screen.

Arrrgghh! Now what. Reading around the internet I found that you have to upload all four of the Yaesu firmware updates - the main, the TFT screen, the DSP and C4FM.

If you don't the radio won't work.

To be fair it does say in the instructions:

IMPORTANT NOTICE:
MAIN Ver. 02-01 also requires TFT Ver. 02-00; also DSP Ver. 01-11 and C4FM DSP Ver. 04-15.
If your FT-991A does not have them already, please update all firmware, they must be used together.

Once I had uploaded all four and reset it all was fine again - apart from I had lost all my settings.

Another quick hint. If you have memories loaded use VK2BYI's FTRestore software before you start the firmware update and make a copy of the memories. Once you have made the firmware updates you can then reload the memories and save yourself a lot of time.

Anyway, after two hours of messing around I had the radio back the way I wanted it.

So is Fusion better now? I still don't think the audio quality is that good, although it my be a bit better. But at least the radio isn't bricked!

Autumnal HF conditions show sunspots aren't everything

Click to enlarge

Don't you just love it when something works! I took down my multi-band end fed half wave (EFHW) antenna last weekend and replaced it with a home-made 40m off-centre fed dipole (OCFD).

The EFHW worked, but I was never happy with the performance. This may be due to the inverted L configuration or the compromise 49:1 ferrite-based Un-Un. Either way, I felt I was missing out on some DX and was keen to try something else for the Autumn/Winter.

The 40m Windom is about 66ft long and has a home-made 4:1 Guanella balun made with two ferrite cores. It is fed at the 41%/59% point so it covers 40, 20, 15 and 10m with an SWR below 3:1 and the other HF bands with an ATU.

The apex is at about 8m with the ends down to about two metres, so not ideal.

Nevertheless, in back-to-back WSPR tests it proved to be better than my W5GI dipole that goes over the roof by about 7dB on average. This was good as the EFHW was mostly down on the W5GI.

Anyway, I thought I would leave it running on 20m WSPR for 24 hours to see what it could pick up. This was with zero sunspots, but a Kp index of 1. I was delighted to see that I had been picked up as far afield as Japan, Australia, Alaska, Antarctica and Brazil. The furthest west I got in the US was Utah.

So, I'm a happier bunny. I might return to the multiband EFHW one day, perhaps looking at different ferrite mix configurations for the Un-Un, but for now I'll stick with monoband EFHWs with tuned iron toroid/capacitor matching units that work well.

The OCFD can stay up for a while - you know that the best antenna you can have is either the one you just took down, or the one you are going to put up, not the one you are using!

Predicting space weather – and how to get it wrong!

Space weather prediction is an inexact science. We still don’t fully understand the Sun or how it works.

This means that predicting what HF radio conditions are going to be like over the next seven days can be challenging – especially when you have to produce the forecast a couple of days before it is published.

This week was a perfect example of how to get it wrong!

I prepare the HF part of the RSGB’s GB2RS Propagation Prediction forecast on Thursday afternoon. Jim G3YLA looks at VHF and Sporadic E, before it is sent to John G4BAO who adds some more info on any microwave propagation such as rain scatter and also adds the EME report.

I then edit it, add my HF predictions and send it to RSGB HQ so it can be collated, published and sent to GB2RS readers on Friday.

Sunspots on Thursday 23rd August 2018.

At that point this week the Sun looked fairly innocuous with one tiny sunspot group, a solar flux index of 70 and a sunspot number of 15, representing one sunspot group with five tiny spots.

There were no obvious coronal holes and NOAA predicted the K index would likely be two all week due to a lack of geomagnetic disturbances. The US Air Force agreed.

So far so good!

At 04:45UTC on Monday 20th NOAA had reported:

“Region 2719 (S06, L=133, class/area Bxo/010 on 19 Aug)
developed in the SE quadrant on 19 Aug. No significant flare events
occurred from either region. Other activity included a filament
eruption centered near S11W04 observed lifting off the solar disk at
approximately 19/0538 UTC. An associated coronal mass ejection was
observed off the SW limb in SOHO/LASCO C2 imagery at 19/0812 UTC.
WSA/Enlil modelling of the event suggested the ejecta was primarily
directed westward of the Sun-Earth line and is not expected to cause
any significant effects.”

So the CME wasn’t earth-directed so shouldn’t be a problem – bear with me!

The NOAA report for Monday 20th August said there were no events.
The NOAA report for Tuesday 21st August said there was an RSP (a sweep-frequency radio burst) at 18:46UTC observed at Palahua, Hawaii, USA
The NOAA report for Wednesday 22nd August said there were no events.
The NOAA report for Thursday 23rd August said that at 20:23UTC on Thursday evening the older region 2719 emitted an an “A class” X-ray solar flare. “A class” flares are the weakest and it was after sunset in the UK so didn’t have any major impact for us according to the ionosonde data.

But there were further A class flares on Friday 24th August, which were at 12:47-12:50 UTC, 21:54-21:58 UTC and 21:57-22:01 UTC.

The Chilton and Fairford Ionosondes in the UK show Friday’s flare’s effect at 12:47 as there is a gap in the data.

You can see this at Jim G3YLA’s Propquest site at: http://www.propquest.co.uk/graphs.php?type=archive

But by Saturday 25th August a new large sunspot
group had appeared.

By Friday another new sunspot group (2720) had emerged, which grew rapidly and by Saturday it was quite large. Sunspot AR2720 is not only large, but also strange. Its magnetic polarity is reversed. The North and South ends of its magnetic field are backwards compared to the norm for sunspots in decaying Solar Cycle 24.

So could AR2720 be from the next solar cycle, Solar Cycle 25? We’ve already had one reverse polarity sunspot which has been attributed to Cycle 25, but that was last year. This is going to be discussed over the coming weeks.

Action on Friday 24th August continued.

From 02:00UTC a series of solar flares were recorded, mainly from the new region 2720. These were B-class solar flares.

By the early hours of Sunday morning, 26th August the K index had started to climb, peaking at Kp7 at 03:00 and 06:0UTC. The bands on Sunday were lousy with a lack of signals across the board in the UK as the ionosphere collapsed. The 14.100MHz IARU beacons were all inaudible.

The Kp index hit 7 in the early hours of Sunday
26th August 2018.

A sweep with my SDRPlay receiver and SDRUno software saw very few signals on 20m at all and virtually nothing higher in frequency. There were a few weak and watery CW signals from Germany on 40m.

So what was the cause?

NOAA now says there had been an earth-directed coronal mass ejection on Monday 20th August that no-one seemed to comment on at the time. NOAA’s own records don’t show any solar flares on Monday August 20th – see (ftp://ftp.swpc.noaa.gov/pub/indices/events/20180820events.txt)

So was it this CME or the one on the 19th that is now reported as causing the high-speed solar wind stream that brought about the Kp7 event and auroral conditions? The experts seem to think so – now!

Or was it a CME as a result of the solar flares on Friday 24th August? That to me would seem more likely and fit in with the roughly two-day solar wind transit time to Earth.

SpaceWeather.com described it as a “surprise geomagnetic storm” and I think that’s a pretty apt description as no-one predicted it.

If that is the case there is no way I could have known about it when I filed the copy to RSGB on Friday morning. This report predicted quiet geomagnetic conditions for the week commending Sunday 26th August – I don’t think so somehow!

Oh, the joys of space weather and HF radio propagation forecasting!