Sunday, August 16, 2020

Frequency problems with 28 MHz WSPR

 

My HF radio is monitoring the WSPR frequency of 28.1246 MHz most days and feeding the reception reports up to the WSPRnet website.

As 10 metres is the highest HF band in terms of frequency, it is also the band that is subject to the most drift.

This is illustrated in the screenshot taken above on the 16th of August 2020. You can see two signals that are outside the WSPR band which is 200 Hz wide. As might be expected, I didn't get any successful decodes from that particular two minute period.

I've checked my own reports against others and I think I am pretty much on the correct frequency.

I just thought it was a nice example of how important it is to make sure you are on the correct frequency on WSPR. If there is any doubt then you should aim to be in the centre of the WSPR band and not at its edges.

Friday, August 14, 2020

Reception of the EI1KNH beacon on 40 MHz via meteor scatter

 

The Irish 8-metre EI1KNH beacon on 40.013 MHz is located just to the south of Dublin and became operational in May of 2020.

Due to the nearby Dublin and Wicklow mountains, it is badly screened from the south west and even though I have a good take off in that direction, I am unable to hear it directly.

However, I tried listening for it during the Perseid meteor shower and even though I'm a bit close for meteor scatter, I thought 206 kms was far enough for it to work.

As you can see from the graphic above, I got several successful PI4 decodes on the 12th of August 2020.

The EI1KNH signal alternates between the digital PI4 mode, an identification in morse code and a carrier. The PI4 part of the transmission lasts about 24 seconds so a reasonable meteor burst is required to decode the signal. The 40 MHz band is excellent for meteor scatter so there are plenty of bursts available during major meteor showers.

The chart above shows the meteor bursts decoded on the 13th of August. Note that the signals were quite weak as they are in the range of -20dB to -26dB, below what can be heard by ear. This is probably the average signal for the duration of the 24 second PI4 transmission because I could certainly hear PI4 signals by ear at times.

Antenna... It's worth pointing out that I was only using a vertical antenna for 28 MHz for these tests. If I had a resonant antenna or a small directional beam then the results should have been even better.

If I can hear meteor burst from 206 kms away then anyone in the UK should certainly be able to hear it.

For EI1KNH, tune to 40.0122 MHz and listen on USB. For the OZ7IGY beacon in Denmark, try 40.0702 MHz USB.

Thursday, August 13, 2020

Video: IRTS Contests and Licence Exams in EI ...by EI7GY

 

The Mid-Ulster Amateur Radio Club are holding a series of lectures online and their most recent one was from Joe, EI7GY.

While the full video is 1 hour 44 minutes long, it can be broken down as follows...

00 to 04 mins - Introduction

04 to 34 mins - EI7GY talks about the IRTS contests and how they are organised

34 to 49 mins - Q&A session on the contest presentation

49 to 68 mins - EI7GY talks about the licence situation in Ireland (EI) and how the exams for the licence are held. There's a lot of work going on behind the scenes that many people won't be aware of

68 to 104 mins - Q&A on the exam presentation. Other items like 5 MHz operation and how to reach out to more people are also discussed.


Wednesday, August 12, 2020

Meteor Scatter signals on 143 MHz from GRAVES - the French radar system

 

As shown in the graphic above, the GRAVES radar system in France is used to detect satellites that go over France. The transmitter on 143.050 MHz near Dijon in the east of France runs huge power levels in the effective region of hundreds of kilowatts and reflected signals are picked up by special receiving station in a different part of the country.

One of the upsides of all this is that this 'radio curtain' over France will also interact with ionised trails of gas left by meteors as they enter the atmosphere.

On Stornoway on the Isle of Lewis in the far west of Scotland, there is a dedicated receiver that listens for the GRAVES signal on 143.050 MHz with a directional beam.

The online receiver with info can be found here... http://hebweather.net/meteor-echoes/

I had a listen during the Perseid meteor shower and got this good example of a meteor burst...

It's worth pointing that you can listen for meteor bursts regardless of the weather. It can make for an interesting alternative when the skies are cloudy.

The best time of day is usually during the morning peak at 06:00 UTC for stations in the UK & Ireland and obviously during major meteor showers.

GRAVES transmit antenna array

Tuesday, August 11, 2020

New 8m & 5m bands added to the popular PSK Reporter website...

The PSK Reporter website is used by nearly everyone on digital modes to see what is being heard by stations active on the HF and VHF bands.

Thanks to the efforts of Tim EI4GNB, the new 40 MHz (8-metres) and 60 MHz (5-metres) bands have been added to this hugely popular platform.

Tim writes...."After some emailing with Philip Gladstone, the coder behind the 'reverse beacon' system known as PSK REPORTER, it now officially supports 5m and 8m reporting and mapping, based on reports from [digital mode software] operating within the bandplan guidelines published on the IRTS website drafted by Dave Court."

Approx 40.0 to 40.7 MHz & 58.0 to 60.1 MHz

"This will mean anyone operating FT8/FT4/Digimode etc., or logging PI4 beacons, using supporting software with the 'psk reporter' option enabled, will now be correctly placed on the PSK Reporter map.

We nominated 2 new colours for this - 8m is to be Purple, and 5m is a Silver-Grey."

It's safe to say that the majority of radio amateurs in the world are still are not aware of the 8-metre and 5-metre bands. Even though this is just a small step, it will hopefully raise the profile of these two new VHF bands. 

Update: Example below of a FT8 contact between S50B and S59F on the 12th of August.


Monday, August 10, 2020

First Slovenia to Slovenia contact on 40 MHz - 9th Aug 2020

On the 9th of August 2020 at 10:14 UTC, Borut S50B and Ivo S59F managed to complete a contact on 40.680 MHz for the first contact on the new 8-metre band between two Slovenian stations.

Even though the distance between each of the stations was only about 20 kms, this was over a very poor path with a lot of high ground in the way. Signal reports of 5/3 and 5/5 were exchanged on SSB.

For this first S5 to S5 contact on 40 MHz, S59F was using an ICOM IC-7300 with 100 watts into a dual band 50 MHz / 70 MHz Yagi. It's probably safe to assume that this antenna had no gain on 40 MHz so would be no better than a dipole for the band.

S50B was also running 100 watts from an ICOM IC-7100 but into a dedicated SIRIO vertical for 8-metres.

Even though the Slovenian licencing authorities allocated a slice of spectrum at 8-metres back in 1998, it's only in 2020 that S5 stations have started up on the band. This is largely in response to the new 8-metre allocations in Ireland and Lithuania.

S50B had already worked EI4GNB and LY2YR for S5 firsts at 40 MHz so the contact with S59F was his third first for the band.

As can be seen below, the 8-metre allocation in Slovenia is from 40.660 to 40.700 MHz, the exact same as the ISM (Industrial, Scientific, Medical) band.

Sunday, August 9, 2020

Video: The history and appreciation of Morse... by GI4ONL

The Mid-Ulster Amateur Radio Club recently posted a video on their YouTube channel titled 'The history and appreciation of Morse...With Victor Mitchell GI4ONL'

The video can be broken down into three parts...

00 to 33 minutes - The first part deals with the the history of morse code and deals with the origins of terms like CQ, 73, 88, the various Q-Codes, SOS, Mayday and some terms that are still in use today on the marine bands.

33 to 47 minutes - How to learn morse code properly.

47 to 90 minutes - Questions & Answers

Thursday, August 6, 2020

New 2700km+ IARU Region-1 tropo record on 23cms between Ireland and the Canary Islands - 17th July 2020

On the 17th of July 2020, there was an opening between the Canary Islands and the UK & Ireland on the VHF & UHF bands. A remarkable contact was made on 1296 MHz between EA8CXN and EI2FG which turned out to be a new IARU Region-1 tropo record for the 23cms microwave band.

In a report on his website, Cesar EA8CXN reports that there was a good tropo opening on July 17, 2020,  between Ireland-England and the Canary Islands.

In the evening, EA8CXN completed contacts with G7RAU, G4LOH and EI20C (op. Mark, EI3KD) on 432 MHz. EI20C mentions that John, EI2FG is also active on 1296 MHz so tests begin.

G7RAU is the first to complete a successful contact on SSB on 1296.200 MHz using just 5 watts into a 56 element Yagi. G4LOH also completed a contact.

After a period of deep QSB, a successful SSB contact was completed with EI2FG on 23 cms with 5/1 and 5/4 reports exchanged. The distance was an amazing 2714 kms.

Not only was this the first ever contact between Ireland and Canary Islands on 1296 MHz but it was also a new IARU Region-1 tropo record for 23 cms.

The map above shows the limit of the new record. The old record of 2661 kms was set on the 14th of July 2017 between EA8AVI and M0VRL.

The map also suggests that there is plenty of scope for the record to be broken with sea paths further north to the west of Wales and up the Irish Sea.

Equipment... For the record SSB contact on 23 cms, EA8CXN was using 150 watts into a small parabolic dish which was 50 cms in diameter. The feed point for the dish was a 3-element horizontally polarized PCB Yagi.


EI2FG was using his EME station of 200 watts into a 3-metre parabolic dish. The feed point was Right-Hand Circular Polarization on transmit and Left-Hand CP on receive.


Propagation... The mode of propagation was via a maritime duct over the ocean.

This duct exists for long periods of the year between the Canary Islands and the western coast of Spain & Portugal and then gets extended sometimes further north to the UK and Ireland.

In conclusion.... To put this this record 2714 km contact on 1296 MHz, a microwave band into perspective, it's worth remembering that the distance across the North Atlantic from Ireland to Newfoundland is around 3000kms. 

It's also likely that the record distance could be exceeded further north to Wales or up the Irish Sea as outlined earlier. The biggest obstacle at the moment is probably the lack of stations on 23 cms.

If the D4VHF station on Cape Verde Islands off the coast of Africa ever became operational on 1296 MHz, the record could well be extended to about 4000 kms.

Links...

Tuesday, August 4, 2020

Slow Scan TV experiments from the International Space Station - 4th & 5th August 2020


On the 4th & 5th of August 2020, there will be Slow Scan TV transmissions from the International Space Station on 145.800 MHz.

See below....

MAI-75 SSTV activity planned for Aug 4 and 5, 2020

The final crew schedule for the week of Aug 3-9 was released recently and it showed a MAI-75 activity scheduled for Aug 4 and 5. This is soon after the Space X Demo-2 undock so changes to that event could impact the schedule.

This is the Moscow Aviation Institute SSTV experiment that is activate for orbital passes over Moscow, Russia. It has traditional been PD-180 or PD-120 and transmitting on 145.800 MHz.

**Update Aug. 3**
Looks like they made an adjustment to the schedule for Aug 5.
Aug 4 (12:25-18:10 UTC) is setup and day 1.
Aug 5 (08:15-18:25 UTC) is day 2 and close out of operations.

These are the passes for my location on the south coast of Ireland but they should be good for anyone in the UK or Ireland.

Tuesday 4th August 2020 (UK & Irish time which is UTC+1 hour)
15:21 to 15:27
16:57 to 17:04 (High pass)
18:34 to 18:41 (High pass)

Wednesday 5th August 2020
14:33 to 14:39
16:09 to 16:16 (High pass)
17:46 to 17:53 (High pass)

19:23 to 19:29

In a previous post HERE, I outlined how the European Space Agency had a series of video tutorials on how to decode SSTV signals from the International Space Station.


For a really simple set-up then just download the Robot36 app to your smartphone and hold it next to your 2-metre radio. See this post HERE

Updates on the ISS SSTV activity will be on this website... http://ariss-sstv.blogspot.com/

Updates... I lost two images as I wasn't used to the Robot36 app on the smartphone. Lots of controls in the programme but no instructions. I finally figured out that I needed to press the 'floppy disk' symbol to save the image as a photo as soon as the image was decoded. Need to be careful with the 'Play' / 'Pause' controls as this wipes out the previous photo. I also have the volume on the radio very high to get something showing in the green control bar.

Decoded at 17:40 UTC on the 4th. Not great but it's a start

Wed 5th Aug 2020... They seemed to have updated the format with more SSTV images sent on each pass.

Weak signal with two periods where the signal dived into the noise

Another image decoded on my phone

There was another pass at 5:50pm local time and I got two more decodes...



I would probably need to spend more time adjusting volume levels with some test signals to get things right. However, it's not bad for just holding a mobile phone next to the radio.

Monday, August 3, 2020

QSO TODAY Expo Virtual Talks - Sat 8th & Sun 9th Aug 2020


Normally at Amateur Radio conventions or expos, there are a series of talks which run alongside all of the other commercial business going on. With the COVID-19 restrictions, the QSO TODAY team have put on a virtual expo instead.

What is of particular interest are the sixty or so virtual talks and there is something there for everyone. Please note that these are free.

Speakers below begin at 1500 UTC on Saturday 8th and Sunday 9th of August in 5 parallel tracks.  Start on the hour with Q&A following each one. More info on how to register HERE

From the organisers...

All lectures are: 
fully live interactive with speaker during the session hour
completely downloadable
collateral materials are downloadable in PDF format
everything available up to 30 days beyond the presentation

The list of sixty or so talks are shown below....

List of talks...

How to Solder - Steve Johnston WD8DAS

The History of Heath Company, the G.I. Bill, and Economics of Restoration - Paul Topolski W1SEX

21st Century Transceiver Design: The K4 High Performance Direct Sampling SDR - Eric Swartz, WA6HHQ

3D Printing Microwave Antennas - Karen Ricker KG5GAK

Saturday, August 1, 2020

FT8 Experiment on 40 MHz - 1st to 15th August 2020


Between the 1st and 15th of August 2020, LY2YR & S50B will be experimenting with FT8 on the new 8-metre band.

Gintas, LY2YR in Lithuania will be transmitting on 40.220 MHz.

Borut, S50B in Slovenia will be transmitting on 40.680 MHz.

Both stations will be using the clone programme WSJT-Z in auto-replay mode. Both stations would welcome any reception reports.

S50B and LY2YR will be available for tests with EI stations from 10:00 to 21:00 UTC.

Info from LY2YR.... "Announcement. From 08.01 to 08.15 will work two FT8 Robots (auto-replay mode WSJT-Z),  LY2YR at 40.220 MHz and  the second S50B at 40.680 MHz. For EI / S5 tests during daytime from ~10 to 21 local time, no qsl. Only to CQ calls will be answered, multiple answers will also available. CQ mode by request via the messenger."

Friday, July 31, 2020

4000km plus opening on 144 MHz & 432 MHz from Cape Verde to NW Europe - 30th July 2020


30th July 2020 - There was another impressive 4000 km plus opening on the VHF & UHF today from Cape Verde Islands off the west coast of Africa to the north-west of Europe.

The map above from PSKReporter shows the FT8 signals being sent and received by D4VHF in Cape Verde. The mode of propagation was the usual marine duct but it was unusual to see the conditions extend into the midlands in England.

One of the most unusual reception reports was from PB0AHX in the Netherlands for two reasons.

1) The distance at 4680 kms is just 100kms short of the IARU Region-1 tropo record which was from D4VHF to the Isle of Skye in January of 2020.

2) The path from the Netherlands was over a lot of France and parts of Spain raising the possibility that perhaps there was another mode of propagation at work for the northern part of the path such as Sporadic-E or Meteor Scatter?

These are the FT8 reports on 144 MHz in order of distance for NW Europe...

Txmtr Rcvr Band Mode Distance Time (UTC)
D4VHF PB0AHX 2m FT8 4680 km 12:50:44
D4VHF M0CTP 2m FT8 4622 km 15:58:14
D4VHF G4BNM 2m FT8 4582 km 15:47:42
D4VHF GM3SEK 2m FT8 4562 km 14:29:44
D4VHF GD3YEO 2m FT8 4503 km 13:07:14
D4VHF G4CLA 2m FT8 4473 km 09:24:44
D4VHF G8VHI 2m FT8 4466 km 12:08:41
D4VHF G4KWQ 2m FT8 4462 km 16:36:11
G0CUZ D4VHF 2m FT8 4440 km 10:43:27
MW1CFN D4VHF 2m FT8 4438 km 11:04:57
G8TIC D4VHF 2m FT8 4411 km 12:15:27
D4VHF GW4SHF 2m FT8 4404 km 15:41:14
D4VHF M0BUL 2m FT8 4388 km 15:32:14
M0BUL D4VHF 2m FT8 4388 km 15:32:57
D4VHF G0JCC 2m FT8 4362 km 16:40:41
D4VHF GW7SMV 2m FT8 4317 km 16:52:44
D4VHF GW4HDF 2m FT8 4312 km 18:48:14
D4VHF GW4VXE 2m FT8 4280 km 09:55:41
D4VHF GW0KZG 2m FT8 4276 km 16:54:14
D4VHF GW1JFV 2m FT8 4264 km 10:16:41
D4VHF EI8KN 2m FT8 4230 km 13:29:11
D4VHF G4RRA 2m FT8 4211 km 16:44:14
D4VHF EI2FG 2m FT8 4182 km 19:11:41
D4VHF M0BKV 2m FT8 4181 km 18:49:44
D4VHF EI3KD 2m FT8 4170 km 19:26:14
G4ALY D4VHF 2m FT8 4160 km 12:07:57
D4VHF G8IXN 2m FT8 4110 km 13:30:44
D4VHF G4LOH 2m FT8 4098 km 19:43:14
M0AFJ D4VHF 2m FT8 4094 km 18:43:57
D4VHF G3NJV 2m FT8 4090 km 14:02:44
D4VHF G7RAU 2m FT8 4086 km 19:33:41
D4VHF F6DBI 2m FT8 4020 km 16:54:44
D4VHF F6KHM 2m FT8 3966 km 10:23:44
D4VHF F8DBF 2m FT8 3963 km 19:38:14

The tropo prediction map below from Pascal, F5LEN shows the sea path from Cape Verde... 

70cms... The sea path was also open at 432 MHz.

Rcvr Band Mode Distance Time (UTC)
EI3KD 70cm FT8 4170 km 10:12:14
G3NJV 70cm FT8 4090 km 13:03:14
G7RAU 70cm FT8 4086 km 19:16:11
F8DBF 70cm FT8 3963 km 22:08:44
EA1FBU 70cm FT8 3224 km 18:56:44
EA1YV 70cm FT8 3201 km 19:04:14
EA7SL 70cm FT8 2885 km 19:38:44
EA8CSB 70cm FT8 1562 km 19:15:14
EA8AR 70cm FT8 1546 km 11:12:11
EA8RH 70cm FT8 1512 km 20:45:11

It's always amazing to see a 4000 km plus path at 432 MHz.

Canary Islands... It's also worth mentioning that the sea path was also open from the Canary Islands to NW Europe...

G7RAU 432174.0 EA8CSB 18:15 30 Jul IN79JX IL18TL cq, gl Canary Islands
G7RAU 144485.0 ED8ZAA/B 17:48 30 Jul IN79JX IL18UM 599+10 Canary Islands
G7RAU 144320.0 EA8BPX 17:46 30 Jul IN79JX IL18SK 59++ gl Canary Islands
GM4FVM 144174.0 EA8CSB 17:39 30 Jul IO85WU IL18TL Hrd CQ -11dB Canary Islands
MM0CEZ 144174.0 EA8CSB 17:01 30 Jul io75xu IL18 FT8 -19 dB tnx Canary Islands
M1GSM 144174.0 EA8CSB 16:50 30 Jul IO94DR IL18TL RX -20 GL Canary Islands
G4RRA 144174.0 EA8CSB 16:02 30 Jul IO80BS IL18TL Canary Islands
F6FGQ 144485.0 ED8ZAA/B 10:52 30 Jul 529 stable in IN78QJ Canary Islands
G4ALY 144485.0 ED8ZAA/B 10:44 30 Jul IL18UM(TR)IO70VL 549 Canary Islands
EI3KD 144485.4 ED8ZAA/B 05:45 30 Jul IO51VW IL18UM 599+ Canary Islands

Let's have a look at the PSKReporter map for EA8CSB on 144 MHz for the 30th of July 2020...

Note that many of these paths are in excess of 3000kms,,,

Txmtr Rcvr Band Mode Distance Time (UTC)
EA8CSB GM0HBK 2m FT8 3287 km 15:50:14
EA8CSB GM4FVM 2m FT8 3248 km 19:01:41
EA8CSB MM0CEZ 2m FT8 3197 km 17:19:14
MM0CEZ EA8CSB 2m FT8 3197 km 17:17:29
EA8CSB 2M0ETJ 2m FT8 3135 km 17:58:44
2M0ETJ EA8CSB 2m FT8 3135 km 17:17:59
EA8CSB GM3SEK 2m FT8 3073 km 17:04:44
GM3SEK EA8CSB 2m FT8 3073 km 16:04:59
EA8CSB GI4SNA 2m FT8 3013 km 17:35:44
EA8CSB GI6ATZ 2m FT8 3002 km 17:56:41
EA8CSB G0SYP 2m FT8 3001 km 17:20:41

It's always worth remembering that the distance across the North Atlantic from Ireland to Newfoundland is about 3000 kms.

Links...
1) F5LEN Tropo Prediction

Wednesday, July 29, 2020

Article on using FT8 for Moonbounce on 1296 MHz...

Bacn in May of 2020, I had a post up about the first Moonbounce /EME (Earth-Moon-Earth) contact on 432 MHz by using the FT8 digital mode.

I recently came across another detailed article by KA1GT on using FT8 for Moonbounce on 1296 MHz.


Besides the very weak signals, one of the problems that FT8 has to deal with is the time delay of about 2.4 to 2.8 seconds for the signal to go from the Earth to the Moon and back to the Earth again. Signals on the HF bands by comparison are almost instantaneous.

As you can see from the waterfall display above, the signal from the Moon is delayed and falls outside the usual 15 second window for decoding.


The article covers how this delay is dealt with and concludes that the FT8 digital mode is suitable for strong signals on 1296 MHz and allow a contact to be completed up to four times faster than using the more usual JT65C mode.

You can view the article HERE

Monday, July 27, 2020

Videos about VDSL Broadband interference

VDSL (Very-high-bit-rate Digital Subscriber Line) is currently the main way to deliver broadband to  residential customers in the UK. A similar ADSL system is used in Ireland.

VDSL uses the existing twisted-pair traditional telephone cables to carry high speed broadband data signals between the network provider’s “cabinet” (typically an above ground street-furniture box) and the customers premises.

The frequencies used in the UK are shown below...


The problem however is that the existing telephone cables were only supposed to carry a simple telephone signal in the audio spectrum up to several kHz and not signals of several MHz. As a result, VDSL broadband signals can cause widespread interference as seen in the plot below...

VDSL interference to the 7 MHz (40m) & 10 MHz (30m) bands
Videos... Two videos featuring presentations by John Rogers, M0JAV have been uploaded to YouTube recently.

The first one on the Mid-Ulster Amateur Radio Club account outlines what VDSL is and ways to deal with interference...



The second one on the Radio Society of Great Britain (RSGB) account describes VDSL and how people in the UK can complain to OFCOM, the UK regulator...



For further reading, RSGB have provided some additional information...

RSGB Frequently Asked Questions about interference

VDSL Interference Reporting

VDSL Interference Advice Leaflet

Saturday, July 25, 2020

144 MHz Weak Signal Ionosphere Scatter


One of the more unusual propagation modes on the VHF bands is Ionosphere Scatter or 'Ionoscatter' for short.

To establish contact, both stations at either end of a link usually run very power into very large antenna systems with a lot of gain and beam at a common point in the D layer of the ionosphere which is about 85 kms above the earth.

It is similar in many ways to troposcatter except the greater height allows a much greater range. With troposcatter, the scatter point in the troposphere may be in the region of several kms above the earth e.g. 9kms for a 500 km path.


For ionoscatter, the radio signal is scattered forward by small changes in the ionization density in the ionosphere at a height of about 100kms or below with a peak at 85 kms. This gives a typical range of about 800 kms to 2000 kms with a peak around 1300 kms.

Ionoscatter works best at the low VHF part of the spectrum (30-50 MHz) although under the right conditions, it can be used at 144 MHz as well.

RSGB Video... Traditionally, ionoscatter contacts were the preserve of stations running very high power to large antenna arrays and using CW.

Now with the advent of new digital modes, the entry level for this mode of propagation is lower and it's possible that many people have already made ionoscatter contacts and were not even aware of it.

At the 2019 RSGB Convention, Richard, G4CDN gave a talk titled "2m Weak Signal Ionosphere Scatter". In it, he gives an outline of his experience of ionoscatter and advocates the use of the QRA64 digital mode.



Additional info...
1) Ionoscatter lecture from 2002 by OZ1RH

Thursday, July 23, 2020

4000km VHF opens up from NW Europe to Cape Verde Islands - 22nd July 2020


Over the last few days, there have been another opening from the north-west of Europe on the VHF and UHF bands to Cape Verde Islands off the west coast of Africa. The map above shows the opening on 144 MHz on the 22nd of July 2020 with many of the FT8 signals from D4VHF around the 4000 km mark.

xmtr Rcvr Band Mode Distance Time (UTC)
D4VHF GW4VXE 2m FT8 4280 km 19:01:11
D4VHF GW1JFV 2m FT8 4264 km 21:31:14
D4VHF GW6TEO 2m FT8 4249 km 20:44:14
D4VHF EI8KN 2m FT8 4230 km 20:57:11
D4VHF EI2FG 2m FT8 4182 km 19:51:41
D4VHF M0BKV 2m FT8 4181 km 22:49:14
D4VHF EI3KD 2m FT8 4170 km 22:22:14
D4VHF G4LOH 2m FT8 4098 km 23:26:14
M0AFJ D4VHF 2m FT8 4094 km 19:52:26
D4VHF G3NJV 2m FT8 4090 km 21:34:14
D4VHF G7RAU 2m FT8 4086 km 23:25:11
D4VHF F6KHM 2m FT8 3966 km 22:25:14
D4VHF F8DBF 2m FT8 3963 km 22:39:14
F6DRO D4VHF 2m FT8 3870 km 15:30:26

The path was also open on 432 MHz...


As with previous openings of this type, the path is marine ducting. There seems to be almost a permanent 3000 km path from Cape Verde to Spain & Portugal at certain times of the year and this pushes northwards towards the UK and Ireland from time to time.


Just to give an idea of how good this opening was, Tim GW4VXE in the far SW of Wales reports hearing D4VHF on 70cms with a vertical!

It would be really interesting to see if this path extends up into the microwave bands, especially on 1296 MHz.

Wednesday, July 22, 2020

Articles about using Ferrite Cores as RF chokes


Ferrite cores are used everywhere in radio from RF transformers to filters to chokes. They are often made from different materials that will have different properties at different frequencies and they are often seen as a bit of a Black art.

I came across some recent articles on using ferrite cores as RF chokes and I'm posting the links here so I don't lose them.

1) QRM GURU : The truth about ferrites... This website looks at a selection of ferrite cores and how they can be use to prevent interference at HF & VHF.

2) K9YC ... This website has a detailed PDF on using ferrite cores as RF chokes.

Monday, July 20, 2020

Australian authorities turn down request for 70 MHz allocation

There was a news item on the Internet recently about how the Australian regulator was not considering an allocation at 70 MHz for radio amateurs.

“We note the continued interest in this band from the amateur community. The ACMA will not be further investigating this matter at this time.

The ACMA considers that operating amateur services in this frequency range is not feasible as it would be inconsistent with ITU Radio Regulations and existing services are already operating in the frequency range. 

This frequency range is used by a variety of fixed and land mobile services as supported under the VHF mid band (70–87.5 MHz). Class licensed devices authorised under the LIPD Class Licence operate in the frequency range 70–70.24375 MHz.”

This was the reply to a submission to an earlier submission by the Wireless Institute of Australia (WIA) to the ACMA which essentially consisted of a single sentence... "10. The WIA still has an interest in an allocation at 70 MHz."

ITU Region 3... As can be seen from the map below, Australia is in ITU Region 3 while nearly all of the 70 MHz allocations are in Region 1 countries.


It's a pity that something like a 4m beacon couldn't be established in Australia or even a or a few experimental licences for the band.

It would be interesting to see if say someone in Perth on the west coast (VK6) could investigate if there is a multi-hop Sporadic-E path across the Indian Ocean to South Africa or up to the Middle East.

What would be good is for one of the smaller countries in Region 3 to give a small allocation for the 4m band which would then set a precedent. Even a 200 kHz wide segment of spectrum dedicated to weak signal modes would satisfy most requirements.

Saturday, July 18, 2020

Video: Transceiver performance for the HF - VHF - UHF operator... by NC0B


The Sutton and Cheam Radio Society recently uploaded a video on YouTube titled Transceiver performance for the HF - VHF - UHF operator.

No matter what bells and whistles a radio has, the most important parameter is how it performs on the air in terms of reception and transmission of signals.

The presentation is given by Rob Sherwood, NC0B and it goes into quite a bit of technical detail on how to judge the RF performance of a transceiver on the HF or VHF bands.

Some key points...

  • Sensitivity isn't the most important parameter on HF
  • Low signal performance is often determined in modern times by urban noise
  • While a dynamic range of 100dB is common on HF, it's usually a lot worse on 2-metres and above
  • 2m & 70cms tranceivers are 10-25 years behind HF versions

If you are serious about getting the most from your station then it's well worth watching.

Fast forward to 2:45 for the start of the presentation...



Link...
1) http://nc0b.com/

Friday, July 17, 2020

What is the IARU??


The IARU is the International Amateur Radio Union and it represents the interests of radio amateurs worldwide at international conferences and with national regulators through the various national societies.

A 3-minute promo video outlining their work can be seen HERE

The national society for radio amateurs in Ireland is the IRTS - the Irish Radio Transmitters Society.