40 MHz signals from South Africa heard in Europe - 5th Nov 2021

Friday 5th November 2021: This was an interesting day for the 40 MHz band with signals from South Africa reaching Europe and a big Sporadic-E opening in Europe.

The map above shows the reports from the PSK Reporter website...

 Rcvr Band Mode Distance Time (UTC)
SV1DH 8m FT8 6898 km 15:02:56
9H1TX 8m FT8 6828 km 15:02:29
G7PUV 8m FT8 8798 km 15:01:30

TEP Reports: Paul, G7PUV on the SE coast of England (JO00AU) writes... "Willem ZS6WAB has been on 40.675MHz today using FT8 but I was surprised to get some decodes from him around 1500UTC. The path length is around 8800KM and his peak signal was -10dB although I've listened back to my IQ recording and it was strong enough to hear quite clearly.

I think it's the first FT8 reception from South Africa in the UK on 40MHz, and presumably all TEP as I had no reception towards EA/CT/I on 10 or 6 to suggest mixed mode."

Reception of ZS6WAB by G7PUV

Thomas, DF6HT in the NE of Germany (JO63BT) writes... "Hi all, today received for the first time a signal on 40.675, around 8minutes long was the call from ZS6WAB who called there CQ, received here on a 15m sw vertical For me a sign to check sometimes this qrg for some action, and also a sign that North DL also have a chance to work on that interesting band! 73s from Thomas, DF6HT"

TEP Analysis: Paul is using a log periodic antenna for the low VHF bands. I suspect that there may have been one Sporadic-E hop from G7PUV to the north of Africa where the signals were coupled into the TEP (Trans-Equatorial Propagation) path to ZS6WAB.

It was probably the same for Thomas in Germany with one Sporadic-E opening to the south.

The problem in Europe is that there can be an excellent Sporadic-E opening to the south but as there are no stations in the north of Africa ,we hear nothing and think the band is closed.

Sporadic-E in Europe: There was also a very good Sporadic-E opening in Europe on the day as can be seen from the report below and the report from 

Report from Borut, S50B... "Very good prop on 8m today in EU. As far, EI1KNH have the strongest signal....599+++ on CW ever on my side. Hrd EI7HBB on SSB too.
Hrd also EI1CAH/b and OZ7IGY/b. I forgot to monitor ZS beacon. Tomorrow....
I was also on 40662, but every time I was on this freq I have strong qrm from some device only in dir of EI and US. I hope that till next year, qrm will be lower/disappeared.
 IC-7100...80W.....4 EL YAGI (YU7EF) 10m high."

DX-Cluster Spots for the day...

Spotter Freq. DX Time Info Country
G7PUV 40675.0 ZS6WAB 15:08 05 Nov JO00AU<TEP>KG46RB CQ FT8 -10dB South Africa 
EA3ERE 40016.0 EI1CAH 13:44 05 Nov JN11CX<ES>IO53CK cw 419 Ireland
EA3ERE 40013.0 EI1KNH 13:42 05 Nov JN11CX<ES>IO63VE cw 559 Ireland
EI7GL-@ 40016.0 EI1CAH 13:29 05 Nov PI4 -25 dB Q=50 Ireland
S50B-@ 40670.0 S55ZMS/B 13:07 05 Nov PI4 -20 dB Q=48 Slovenia
F4CXO 40013.0 EI1KNH/B 13:03 05 Nov JN26PP<ES>IO63VE 519 Ireland
F4CXO 40016.0 EI1CAH/B 13:01 05 Nov JN26PP<ES>IO51CK 519 in CW Ireland
S50B 40070.2 OZ7IGY/B 12:50 05 Nov Denmark 
F4FRQ 40016.0 EI1CAH 12:44 05 Nov JN37KQ<>IO53XK CW 559 Ireland
F4FRQ 40013.0 EI1KNH 12:40 05 Nov JN37KQ<>IO63VE CW 559 Ireland
S50B 40680.0 EI7HBB 11:38 05 Nov Ireland
S50B 40013.0 EI1KNH/B 11:32 05 Nov Ireland
EI7HBB 40670.0 S55ZMS 11:18 05 Nov 529 Slovenia

Link....
1) As always, there is plenty of information about the 8m band on my 40 MHz page HERE

Danish OZ7IGY 40 MHz beacon now back on air - Nov 2021

5th Nov 2021: Back at the end of August 2021, the OZ7IGY 8m beacon on 40.071 MHz had to be turned off due to a faulty trimmer in the power amplifier stage.

At the end of October 2021, it was turned back on after the faulty part was replaced.

It has since been reported on the DX Cluster...

 Spotter  Freq.  DX  Time  Info  Country

OZ1BNN-@ 40071.0 OZ7IGY 15:51 02 Nov PI4 16 dB Q=100 37 km Denmark
EA3ERE 40070.2 OZ7IGY/B 11:37 31 Oct JN11CX<ES>JO55WM CW-PI4 Denmark
EA3ERE 40070.2 OZ7IGY 10:21 31 Oct JN11CX<ES>JO55WN cw pi4 -5db Denmark

As can be seen from the reports, EA3ERE near Barcelona heard the beacon via Sporadic-E propagation at a distance of about 1660 kms.

The website for the beacon is here... http://www.oz7igy.dk/

Openings on the 40 MHz band - 1st & 2nd Nov 2021

Monday 1st November 2021: The was a nice Sporadic-E opening on this day and extended in frequency at least as high as the 40 MHz band.

Christian, F4CXO in the east of France heard the two Irish 40 MHz beacons and managed to complete a 40 MHz to 50 MHz crossband contact on SSB with Lloyd, EI7HBB.

  Spotter Freq. DX Time Info Country
G7PUV 40670 S55ZMS/B 19:54 01 Nov 21 JO00AU<ES>JN86CR weak Es Slovenia
F4CXO 40016 EI1CAH/B 15:20 01 Nov 21 JN26PP<ES>IO53CK 529 QSB Ireland
F4CXO 40680 EI7HBB 15:14 01 Nov 21 JN26PP<ES>IO53SQ 50140 X Band Ireland
F4CXO 40680 EI7HBB 15:05 01 Nov 21 JN26PP<>IO53SQ 52 Ireland
F4CXO 40013 EI1KNH/B 14:47 01 Nov 21 JN26PP<ES>IO63VE 539 QSB Ireland

As the DX cluster spots above show, Paul G7PUV in the SE of England heard the 40 MHz beacon in Slovenia.

The two Irish beacons were also heard by a listener in Belgium.

Tuesday 2nd November 2021: There are reports that the ZS6WAB beacon in South Africa on 40.675 MHz was heard by 9H1TX in Malta and SV8CS in Greece. The propagation mode is believed to have been TEP.

G7PUV also reports hearing the ZS6WAB beacon a week earlier when there was a Sporadic-E extension allowing the TEP signals to reach that far north.

Joan, EA3ERE near Barcelona (JN11CX) reports hearing the OZ7IGY beacon in Denmark on 40.071 MHz on the 31st of October at 09:20 UTC. Joan also reports hearing the ZS6WAB beacon on the 30th of October using just a dipole for the HF bands and an ICOM IC7300.

Links...

1) Lots of info about the 8m band on my 40 MHz page HERE

TEP opening on 40 MHz between South Africa and Europe - 23rd Oct 2021

Saturday 23rd October 2021: This seemed like a particularly good day for TEP (Trans-Equatorial Propagation) with signals on the 40 MHz (8m) and 50 MHz (6m) from South Africa reaching Europe. In this post, we'll just look at the 40 MHz opening.

The map above shows the reports from the DX-Cluster with several stations across the south of Europe hearing Willem, ZS6WAB on 40.675 MHz.

Spotter Freq. DX Time Info Country
SV8CS 40675.0 ZS6WAB 14:04 23 Oct FT8 Beacon South Africa
I0YLI 40675.0 ZS6WAB 13:28 23 Oct JN61HU<TEP>KG46RB Calling CQ . South Africa
EA3ERE 40675.0 ZS6WAB 13:18 23 Oct JN11CX<ES>KG46 +2db cq South Africa
IZ0CBD 40675.0 ZS6WAB 13:00 23 Oct JN61FP<TEP>KG46RB Rx 589 South Africa
IK0OKY 40675.0 ZS6WAB/B 12:52 23 Oct JN61ES<TEP>KG46RC 559 South Africa

Most of the distances seem to be in the region of 7000-8000kms.

SV2DCD in Greece and 9H1TX on Malta also report hearing ZS6WAB.

Report 1: Francesco, IZ0CBD in JN61FP near Rome reports hearing the ZS6WAB beacon on 40.675 MHz with a Kenwood TS2000 transceiver and a 6-element Yagi for the 50 MHz band.

Here is a nice video from Francesco showing his reception of the 8m beacon...

Report 2: Emilio, IK0OKY writes to say that he and Pino, IK0SMG both heard ZS6WAB/B on 40.675 MHz from JN61 Square. IK0OKY writes... "Signals were very good with peaks up to 559 on a FT 847 and 2 element quad fractal antenna for the 6 meter band. Pino uses an IC7300 plus a 2 el HB9CV for 6m as well. After a nice 50 Mhz opening to South Africa and Namibia took place as well with ZS6 and V51 stations coming in."

Video 1 from IK0SMG shows how strong the signal was...

Video 2 from IK0OKY shows reception of the 8m beacon on a Yaesu FT-847...

Propagation Mode: It seems to be assumed that the propagation mode for these low band VHF signals near the bottom of the sunspot cycle are TEP (Trans-Equatorial Propagation). However as the solar flux rises, there will be a stage where North-South paths on the low VHF bands are possible via F2 layer propagation.

Considering this opening reached 50 MHz as well, I suspect it was due to TEP but as the solar flux rises, I don't think we can always assume it is. It could well be that paths that cross the equator like this will be a mixture of both.

Links...

1) As always, there is plenty of information about the 8m band on my 40 MHz page HERE

First contact between Slovenia and South Africa on the new 40 MHz band - 17th Oct 2021

Sunday 17th October 2021: A little bit of radio history was made today when there was a successful two way contact between S50B in Slovenia and ZS6WAB in South Africa on the new 40 MHz band.

Not only was this the first contact between Slovenia and South Africa but it was also the first contact between Europe and Africa on the new 8-metre band.

Borut, S50B reports that he worked Willem, ZS6WAB on 40.680 MHz using the FT8 digital mode...

As can be seen, the signal was quite weak at -8dB and -10dB which suggests that a contact on CW might have been possible but unlikely on SSB.

S50B writes... "I'd like to announce the first 8m, 40mhz, FT8 qso between AF-EU and South Africa and Slovenia. Mny tnx to ZS6WAB.....Juupii 🙂 73 de Borut s50b"

The key point about this contact is that it shows the 40 MHz path between Europe and South Africa is possible and in future, CW and SSB contacts may follow.

Distance: The contact was in the region of 7925kms which means by default, it also sets a new distance record for the new 40 MHz band.

Propagation Mode: If this contact was on 50 MHz, I'd probably be saying it was TEP - Trans-Equatorial Propagation. At the moment, we're getting modest East-West openings at 28 MHz further north in Europe. It stands to reason that openings from the south of Europe on paths to the South must extend well up into the low VHF region above 30 MHz.

Does the F2 MUF to the south extend up as far as 40 MHz? I really don't believe anyone can say with 100% certainty that this opening was only F2 layer or it was only TEP. The solar flux today was just 78 which isn't all that high.

Equipment: Subject to confirmation, I think S50B was using 100 watts from an ICOM IC-7100 into a 4-element Yagi as shown above. 

ZS6WAB uses an old ICOM IC-706 for the 8m CW beacon with a 5-element YU7EF designed Yagi so I presume that is what was used.

Antenna stack at ZS6WAB with the 40 MHz Yagi at the top

Hopefully, this contact will encourage more experiments on the 40 MHz band. There is a number of new 40 MHz experimental stations in the USA and an 8m contact contact between South Africa and North America would be really interesting.

As always, if you want more information on the new 8m band then check out the links in my 40 MHz page.

South African 8-metre beacon on 40.675 MHz heard in Greece - 6th October 2021

In a report by email, Leonidas SV2DCD in Greece informs me that he heard the ZS6WAB 8-metre beacon in South Africa on 40.675 MHz.

"Hi there John. TEP is back again on 8m band. Today me and SV8CS had copy from ZS6WAB/B 40.675mhz with peak around 16:50z best copy 539 qsb

Here is a video of my copy ZS6WAB/B @ SV2DCD via TEP 6/10/2021 16:40z 40.675mhz "

You can see a video of the reception below...

As outlined in the video title, Leonidas feels that the propagation mode was TEP (Trans-Equatorial Propagation). I have shown the Geomagnetic Equator in the map above and it seems to be roughly equidistant from both stations.

The distance was approximately 7,220 kms. Leonidas was using an 8-element Yagi for 50 MHz to listen to the beacon on 8m.

I also understand that the South African 40 MHz beacon has been heard in the south of Portugal in the last few days as well.

SV2DCD also reported hearing the same 40 MHz beacon in April of 2021. See previous post HERE

Now that we have concrete evidence of the 8m South African beacon being heard in Europe, hopefully others will try to have a listen and report it.

Analysis... This new 40 MHz beacon could prove very useful for serious 6-metre operators in Europe checking to see if there is a propagation path to South Africa. There is quite a jump from say 28 MHz to 50 MHz where as if the band is open at 40 MHz then 50 MHz may not be far behind.

Links...

1) My previous post about the ZS6WAB beacon

2) My 40 MHz page

EI1KNH 40 MHz beacon heard in Lincoln, England - Oct 2021

I got a recent email from Keith, G0RQQ to say that he was hearing bursts of the Irish EI1KNH beacon on 40.013 MHz recently. The distance is approximately 370 kms.

Keith, who is in the city of Lincoln, England heard the 15-second burst with a signal of S5 at around 08:15 UTC on the 13th of October 2021. He was unable to listen to the PI4 signals as he didn't have the software installed. 

Keith is using a Yaesu FT-817ND wide-banded, and the antenna is an end-fed wire 20m long and about 1.5m above ground.

It's just a reminder that it is very easy for anyone in the UK to listen to the Irish 40 MHz beacons during the early morning (~6-7am) when meteor scatter conditions tend to be best.

For EI1KNH/B, just leave your receiver on SSB about 800 Hz lower on 40.0122 MHz and you should hear the CW and PI4 tones eventually.

For more information on the 40 MHz band, check out my 40 MHz page.

Guidelines for US stations applying for an experimental 40-MHz permit

In the last few months, two US amateur radio stations have applied for and received special experimental callsigns for the 40-MHz band. Lin, NI4Y near Atlanta got the call WL2XUP while John, AE5X in Houston got the call WL2XZQ.

The application form 442 from the FCC is called an Experimental Radio Station Authorization and it costs €125 for two years.

AE5X has a page up on his blog now with guidelines for US stations interested in applying for a permit. Go to http://ae5x.blogspot.com/p/operating-on-40-mhz.html

While the Summer Sporadic-E season is pretty much over for now, there is plenty of time to get ready for when it starts again in May of 2022.

For more information on the 8-metre band, see my 40 MHz page HERE

FCC issue another experimental permit for the 40 MHz band in the USA (WL2XZQ)

On the 19th of August 2021, the FCC in the USA allocated the callsign WL2XZQ for experiments on the 40 MHz band from Houston in Texas. This was allocated to John, AE5X in the EM20 grid square.

This is I believe the second experimental permit for the 40 MHz band in the USA with the first one WL2XUP going to Lin, NI4Y near Atlanta, Georgia.

The permit for WL2XZQ allows for experiments in the frequency range of 40.660 to 40.700 MHz which is the 40 MHz ISM band (Industrial, Scientific, Medical).

The permit allows a maximum ERP of 100-watts and the license expires on the 1st of September 2023.

Propagation & Range - What to expect: The band is affected by several propagation modes. Let's have a look at them...

a) Tropo: It's likely that it will have a range of up to 200kms locally but it's unlikely that there will be many listening from that small area.

b) Sporadic-E: This will be main propagation mode from April to August every year and it WILL be heard all over most of the United States. The map above shows the likely range being in the range of 500kms to 2200kms. The most consistent signals should be in the 1200 to 1800km range.

In terms of double hop Sporadic-E, there may be a skip zones in the NE of the USA near New Hampshire and in the NW in the north of California and Oregon. The one issue for the western states may be interference from SNOTEL stations on the same band.

Looking further afield, there will also be times in June and July when there will be multi-hop Sporadic-E to Europe, a distance of about 6000-8000kms.

Trans-Equatorial Propagation (TEP): The experimental station is also well placed for tests to South America in May and November. While it is too far north for TEP, just one Sporadic-E hop is required to the south to open up the path to Argentina (LU), Uruguay (CX) and Brazil (PY).

F2 Propagation: The 40 MHz band will be certainly be impacted by the rising solar flux as we approach the peak of the next sunspot cycle. The 40 MHz band will open a lot earlier than say 50 MHz and it could prove to be a useful resource for European stations monitoring the trans-Atlantic path.

In Conclusion: This second experimental 40 MHz station is a very welcome development and it should mean that there is some amount of activity on the band in the Summer of 2022. This should raise awareness among the amateur radio community in the USA and perhaps more will apply for permits.

Links...
1) AE5X blog
2) See my 40 MHz page for more info about the band

US Experimental 40 MHz Station WL2XUP is heard across the Atlantic in England - 22nd July 2021

On the 18th of July, I had a post up about the new US experimental station WL2XUP on the 40 MHz band. Just four days later on the 22nd of July, a WSPR signal from WL2XUP was heard across the Atlantic in England.

The owner of the experimental station WL2XUP is Lin, NI4Y and in a message he writes... 

"I can report that VE3QC and VE2DLC received my station via Eskip on July 22nd. Shortly after VE3QC received my signal G7PUV received WL2XUP via multi hop Eskip. The following Day KI4RVH received the WSPR signal via what was likely tropo ducting. 

VE3QC also reports hearing my FT8 signals transmitted later in the day on July 23rd. 

2021-07-22 19:00 WL2XUP 40.663508 -26 -1 EM73vv 20 VE3QC FN25fk 1557 29 2 

2021-07-22 20:42 WL2XUP 40.663488 -34 0 EM73vv 20 VE2DLC FN58rk 2155 35 2 

2021-07-22 19:40 WL2XUP 40.663514 -26 -1 EM73 20 G7PUV JO00au 6869 46 2 

2021-07-23 14:08 WL2XUP 40.663536 -13 -2 EM73 20 KI4RVH EM95 429 58 2"

Paul, G7PUV is located in the SE of England and was using an SDRPlay RSP1A SDR and a W4KMA 18-100MHz Log Periodic on a 6.2M boom up at 15M AGL.

Paul heard seven WSPR transmissions from WL2XUP between 19:40 and 20:42 UTC and the strongest signal was -16dB. 

The 40 MHz trans-Atlantic opening coincided with a big opening on 50 MHz between Europe and North America.

Analysis: As NI4Y points out, this was very likely to be a multi-hop Sporadic-E opening across the North Atlantic with maybe 3-4 hops involved. What is significant about this reception report is not so much the distance but the fact that this is the first crossing of the Atlantic on the 40 MHz band.

During Sporadic-E openings on 50 MHz, it's very likely that paths on lower frequencies like 40 MHz will be open as well. It's just a question of more people listening on the band and reporting what they hear.

This new experimental 40 MHz station has already sparked some interest in the 8m band in North America so hopefully it will encourage activity on the band.

Update: The exact frequency was 40.662 MHz USB with the WPSR signals roughly 1.5kHz higher.

Link...

1) See my 40 MHz page for more info on the band

New US experimental station WL2XUP now operational on the 40 MHz band

In June of 2021, the FCC in the USA issued the experimental call sign WL2XUP to conduct tests on the 40 MHz band. The owner of the call, Lin Holcomb (NI4Y) reports that the station is now on air.

The license allows for operation between 40.660 MHz to 40.700 MHz with a maximum output of 400-watts ERP. The license was issued on the 17th of June 2021 and it lasts until the 1st of July 2023.

As of mid July 2021, WL2XUP is intermittently transmitting WSPR on 40.662 MHz (1500Hz). It transmits for 2 minutes out of every 10 with an output power of 20-watts ERP into an omni-directional antenna. For FT8 skeds and tests, an ERP of 100-watts can be used.

It is hoped in time to upgrade to a log-periodic antenna pointing at Europe.

Location: The experimental WL2XUP station is located near the city of Atlanta in Georgia in the SE of the USA. It is in the EM73 locator square.

Propagation & Range - What to expect: The band is affected by several propagation modes. Let's have a look at them...

a) Tropo: It's likely that it will have a range of up to 200kms locally but it's unlikely that there will be many listening from that small area.

b) Sporadic-E: This will be main propagation mode from April to August every year and it WILL be heard all over the eastern half of the United States. The map above shows the likely range being in the range of 500kms to 2200kms. The most consistent signals should be in the 1200 to 1800km range.

In terms of double hop Sporadic-E, there may be a skip zone out going from Arizona to Montana but anyone in California to Washington should get signals in June and July. The one issue for the western states may be interference from SNOTEL stations on the same band.

Looking further afield, there will also be times in June and July when there will be multi-hop Sporadic-E to Europe, a distance of about 6000-8000kms.

Trans-Equatorial Propagation (TEP): The experimental station is also well placed for tests to South America in May and November. While it is too far north for TEP, just one Sporadic-E hop is required to the south to open up the path to Argentina (LU), Uruguay (CX) and Brazil (PY).

F2 Propagation: The 40 MHz band will be certainly be impacted by the rising solar flux as we approach the peak of the next sunspot cycle. The 40 MHz band will open a lot earlier than say 50 MHz and it could prove to be a useful resource for European stations monitoring the trans-Atlantic path.

In Conclusion: This new experimental station is a very welcome development and it establishes a presence on the 40-MHz band in North America. It may also allow for more US stations to follow this lead and apply for similar permits.

The really big challenge now is trying to raise awareness amongst the amateur radio community in North America and making them aware of the 40 MHz band and the activity on it. 

South African 8-metre beacon on 40.675 MHz heard in SE England - 13th July 2021

On the 13th of July, there was a good opening on the 50 MHz band from Europe to South Africa. During this opening at about 13:50 UTC, Paul G7PUV in the south-east of England managed to hear the South African 8m beacon ZS6WAB/B on 40.675 MHz.

This beacon was heard in the Mediterranean area several times during the month of April 2021 and this is the first time that it has been heard so far north. The distance is around 8,800kms.

For the reception, Paul was using a custom made W4KMA Log-Periodic antenna covering 26-100 MHz at 15-metres above ground level.

Paul reports that the beacon which transmits only on CW peaked at S2.

Propagation Mode: It's probably one of two options.

a) Multi-hop Sporadic-E which would require 4-5 hops and crossing the equator to the southern hemisphere where it's their winter season.

b) A combined TEP (Trans-Equatorial Propagation) and Sporadic-E opening. TEP from South Africa to the Mediterranean area and then via a Sporadic-E hop from there to England.

I suspect it may have been TEP + Sp-E even though we are not near the Equinox and the peak of the TEP season.

Info: For more information of the ZS6WAB beacon and previous reception reports, see my 40 MHz page.

First 9A to 9A contact on 40 MHz - 25th May 2021

25th May 2021: A little bit of history was made on the 40 MHz band on the 25th of May when the first contact between two stations in Croatia took place.

At 06:00 UTC, Patrik, 9A5CW and Zeljko, 9A2EY completed a successful FT8 contact on 40.680 MHz.

The distance was 24.5kms between the two stations over an obstructed path and both stations were using vertical non-resonant HF antennas.

One of the antennas was a vertical for the 60m HF band without a tuner and the radio was an ICOM IC706 Mk2.

Hopefully this will encourage more 9A stations to experiment with the band.

Solar Noise detected at 40 MHz - 22nd May 2021

Early on the morning of the 22nd of May 2021, I was listening for some aircraft scatter signals on the 40 MHz band when I noticed a sudden onset of solar noise as shown above.

This sounds just like a hissing sound but the intensity comes in waves. It's not like say interference you might get from an electrical source which is very much on or off. Solar noise is a gentle hiss that rises and falls in intensity, a bit like waves would do as they crash on a beach.

The waterfall display above shows the event starting around 06:48 UTC and finishing at 06:54 UTC. As soon as I was sure it had finished, I checked the Space Weather Prediction Center website and sure enough, there was a solar flare that matched what I had heard.

I later heard the same effect on 28 MHz while I was listening for WSPR signals and my Twitter feed had lots of tweets about solar flares and solar storms.

It seems to me that the 40 MHz band is a good choice for monitoring noise from the sun. It's high enough in frequency that it's above all of the usual F2 layer propagation and the antennas can be large enough to capture a lot of noise.

Aircraft Scatter on the 40 MHz band

 A few days ago during the Sporadic-E backscatter tests on the 40 MHz band, I noticed some curious little ticks on the waterfall display. These short lines were moving slowly downwards in frequency and lasted for about 30 seconds, a tell tale signature of aircraft scatter.

On the 21st of May, the band seemed to be quieter with less Sporadic-E about so I tried some aircraft scatter tests with both of the Irish 40 MHz beacons (EI1KNH 40.013 MHz & EI1CAH 40.016 MHz).

Both beacons are about 200kms from my location and I used the FlightRadar24 website to track the various flights. This was the strongest signal that I got...

The image above shows the carrier & CW portion of the signal appearing at about 11:06 UTC (12:06 Summer time). As the aircraft was moving at several hundred kph, there was some doppler shift in the received signal and this can be seen in the signal slowly drifting downwards in frequency.

There is a gap at around 11:07 UTC when the beacon was sending out PI4 signals and it then returns again.

This was one of the longest signals I got as the vast majority last maybe 20-30 seconds.

The image below shows what happened....

The EI1KNH beacon is about 200kms from my location. A Delta Airlines plane heading from London to Seattle crossed over the mountains to the south-west of the beacon and it reflected the signal.

While the beacon has an excellent take off to the East, it is badly blocked to the West by the local mountains. I have a pretty good take off in that direction which means I am probably close to line of sight to planes at an altitude of 35000-40000 feet (7-8kms) over the mountains near the beacon.

Despite the doppler shift, I managed to get a successful PI4 decode during this crossing and a small number of other ones.

Using the FlightRadar24 site as a reference, I could correlate a lot of the doppler tracks seen with passing aircraft near both of the beacons. Nearly all of the signals were incredibly weak and were not audible to the ear. Most of the tracks were also about 10-30 seconds in duration. 

It's also worth noting that not all passing aircraft resulted in me hearing a signal. One large airplane went right over the EI1KNH beacon and I saw nothing. Obviously the orientation of the aircraft with respect to the beacon and my location are a factor here. It needs to be close but not too close.

I also got some reflections from aircraft that were on the far side of the beacon. I got one trail from a Ryanair flight just off the coast of Wicklow and heading north for Dublin as well as tracks from trans-Atlantic aircraft passing just north of the EI1CAH beacon in the west of Ireland.

FT8: Considering how often I was seeing these little doppler tracks at 40 MHz, I suspect a lot of people are getting FT8 decodes on the 28 MHz and 50 MHz bands from stations in the 100km to 250km range via aircraft scatter without even really realising it. I often see this, I get one FT8 decode from a station and get nothing else.

Other bands: Needless to say, aircraft scatter isn't confined to the 40 MHz band. If you or a distant beacon or station are blocked by a local hill then you might see aircraft scatter on 28 MHz or any of the VHF and UHF bands.

In the tests that I carried out above, I was 200kms away from the distant beacons and aircraft and the signals were weak as a result. If you try this and the distance are much shorter then you may experience much stronger reflections and signals.

Backscatter on 40 MHz - 19th May 2021

Wednesday 19th May 2021: The day started with a comment by Joe, EI3IX on a Facebook post that he wasn't hearing the new EI1CAH 40 MHz beacon even though he is only 64kms from it. That set me off checking why that was the case and I ended going down a rabbit hole that saw me on the 8-metre band for most of the day!

Both the EI1CAH (40.016 MHz) and the EI1KNH (40.013 MHz) beacons are about 200kms from my location with plenty of hills and mountains in the way. I listened early on the morning of the 19th and I couldn't hear either beacon although I did get a meteor burst from EI1CAH so I knew that it was still operational.

A few hours later, I tried listening again and I found I could now hear EI1CAH all of the time! What had changed? As the signal was buried in the noise with a Signal to Noise ratio of -26dB, my initial thought was that it might be tropo? However, I couldn't rule out that it may have been to Sporadic-E backscatter either.

It was only later when I saw the signal improve to -6dB over the space of a few minutes then I knew it was Sporadic-E related. While there are no doubt slight tropo enhancements at 40 MHz, large changes like this are almost certainly due to Sp-E.

Later when I checked the EI1KNH beacon near Dublin, I could that as well. At that stage, I was 100% sure it was backscatter. Lloyd, EI7HBB reports hearing both beacons by backscatter as well.

Backscatter Sporadic-E: What is it? Refer to the diagram below...

The signal from the EI1CAH beacon (TX) is being propagated forward by an intense Sporadic-E region about 100-110kms above the Earth. The signal is then being reflected off something maybe 500kms or so away... maybe a range or mountains? The signal then returns by pretty much the same path and I hear it at my location (RX).

I've heard backscatter via Sporadic-E several times before on 10m and 6m. Back in the 'old days' when everyone was on either on SSB or CW, I remember beaming South to work stations in the UK on 50 MHz.

The signals seem to have a certain characteristic in that they are pretty constant but just at a very low level. This is what I was hearing... EI1CAH was a weak but constant signal for most of the time with the occasional jump.

The truth is that backscatter is probably there all of the time during Sporadic-E openings but we're not aware of it as the signals are so weak. When there is an intense Sporadic-E with the skip distances much shorter (e.g. <700kms), signals get a LOT stronger.

Imagine a signal being reflected off a distant mountain range which is 1500kms away which is a pretty normal skip distance for Sporadic-E at 40 MHz. Now imagine the range reduces to 500kms under intense Sporadic-E like there was on the 19th of May. Obeying the inverse square law, the transmitted signal at the mountain range would appear 9.5dB stronger. But crucially, this also applies to the reflected path resulting in an additional 9.5dB enhancement. This adds up to a 19dB improvement overall in signal which is a really big jump. 

Back in the 'old days' with SSB/CW, backscatter via Sporadic-E was something that was observed on an occasional basis. Now that we have digital modes like FT8 and PI4, we are 'hearing' signals that are much much weaker.

Assumptions about Propagation: It is for me a reminder that we should always question our assumptions about a propagation mode when we hear a weak signal. Is a weak signal from someone say 200-400kms away on 28/40/50 MHz really tropo, short skip Sporadic-E or via Sporadic-E backscatter?

When we look at those FT8 or WSPR maps at the end of the day, how were we hearing all of those stations in the 200km-500km skip zone? Meteor Scatter? Tropo? Back-Scatter? I think the real picture is a lot more complicated than we assume.

Practical Application: It's all very well wondering about the propagation mode but most people will want to know what is the practical application? Imagine say you are a serious 50 MHz station and you want to work a new country which is only 400kms away and there are mountains in the way. You should never assume that just pointing your beam at a wanted station will always result in a stronger signal. If the signal is weak but constant then it may be via backscatter and you'll have to look for the direction which gives the strongest signals.

Addendum

For Reference: This map from DXMaps shows the suggested maximum usable frequency (MUF) at around 12:00 UTC on the 19th of  May.

It clearly shows one area over the south of England. Note however that this map is generated by users reports and areas of Sporadic-E out over the ocean are not shown. There could be an intense area to the west of Ireland and it would go unreported.

This was the Jet Stream at the time...

Changes in the direction of the Jet Stream are associated with Sporadic-E openings.

Data: Just for my own benefit, I've kept a list of the PI4 decodes below.

Updated Beacon list for the 40 MHz and 60 MHz bands... May 2021

I have now updated the beacon list for the 40 MHz and 60 MHz bands.

If you hear them then please spot on the DXMaps website or DXSummit DX Cluster.

For more information on the 40 MHz band, go to https://ei7gl.blogspot.com/p/40-mhz.html

New 40 MHz propagation beacon in the West of Ireland - EI1CAH

17th May 2021: There is now a new 8-metre propagation beacon in the west of Ireland using the callsign EI1CAH and it is operating on 40.016 MHz. The locator square is IO53CK.

This new beacon is designed to compliment the existing EI1KNH beacon which is situated near the east coast of Ireland. While EI1KNH has a superb take off the East, it is blocked by mountains to the West. By contrast, the new EI1CAH beacon has a good take off to the West and is poor to the East.

The EI1CAH beacon runs PI4 every second minute as well as CW. Its power is approximately 25 watts and the antenna is a horizontal dipole running roughly NW/SE.

The beacon keepers are using a QRPLabs Ultimate 3 (previously used on EI0SIX) to generate the 40 MHz signal and it has a matching internal QRPLabs 6m low pass filter which was modified to cut in closer to the 8-metre band.

They are using a NXP MRF101 based power amplifier to generate the required output power.

Analysis: This new 8-metre beacon is an excellent addition to the European suite of 40 MHz beacons and will be very useful in exploring Sporadic-E and F2 propagation paths across the Atlantic.

Site Profile: The graphic below shows the elevation profile for the EI1CAH beacon site.

There are some serious hills to the East which will block off a lot of low angle propagation paths. A typical Sporadic-E signal may be down around 5 degrees which as the image shows will be blocked by the local hills.

This is the likely maximum range due to one hop Sporadic-E...

As you can see, under short skip Sp-E conditions, reception of this beacon may be possible in say the SE of England, Belgium, Netherlands, N France and the fast west of Germany. As the antenna is running NW-SE, the signal towards Spain will be poor.

What is key however is the low elevation to the West ...towards South America, the Caribbean and North America.

Under multi-hop Sporadic conditions, this 8-metre beacon will be heard across the Atlantic and the most likely people to hear it are those out around the 4000km mark in Nova Scotia and Maine. There is also the potential that it will be heard anywhere in the eastern half of the USA.

Likewise, it will reach the Caribbean at times and will certainly make it down to Brazil and Argentina.

Solar Maximum: Around the time of the Solar Maximum, there should be some East-West openings and this 8-metre beacon could be heard anywhere in the Americas.

Value of a 40 MHz beacon: The real value of this beacon is that there is a huge 20 MHz gap between the 28 MHz and 50 MHz bands. As the maximum usable frequency (MUF) for Sporadic-E and F2 propagation rises, it can be very difficult to know where exactly or how high it is.

By having a beacon at 40 MHz, it will allow serious 50 MHz stations to monitor the rising MUF and be ready for any potential 6-metre opening. 

I think this beacon will be of real value as we get close to solar maximum and North American stations are checking for a 6-metre opening to Europe.

Thanks to Tim, EI4GNB and Tony, EI7BMB in getting this beacon up and running.

For more information on the 40 MHz band, see the information on my 40 MHz page... https://ei7gl.blogspot.com/p/40-mhz.html

Contact between Ireland & Croatia on 40 MHz - 7th May 2021

Tim, EI4GNB reports making a FT8 contact on 40.680 MHz with 9A5CW in Croatia during the big Sporadic-E opening on the 7th of May 2021.

The screen composite below shows the FT8 contact from Tim's station.

While this wasn't the first 40 MHz contact between Ireland and Croatia, I think it may have been the first time 9A5CW has worked Ireland on this new amateur radio band.

This is the screen from 9A5CW...

It's good to see activity on the increase on 40 MHz from Croatia.

For more information on the 40 MHz amateur radio band, go to https://ei7gl.blogspot.com/p/40-mhz.html

Report on 40 MHz activity on the 8th of May 2021 ...by EI7HBB

Lloyd, EI7HBB reports that he was active on the 40 MHz band on the 8th of May and caught the extensive Sporadic-E opening. He managed to work S50B in Slovenia twice on SSB during the day as well as hearing S57RW and S5/M0MPM on FT8.

LLoyd also reports managing to complete a 40 MHz / 50 MHz crossband SSB contact with Hugo, ON6ID in Belgium at a distance of about 900kms. ON6ID was on 50.145 MHz and EI7HBB was on 40.680 MHz and the contact took place at 15:22 UTC. He also wonders if this was a first EI-ON crossband contact for 8-metres?

LLoyd was also heard in the Netherlands at a distance of about 1000 kms.