DRM or Digital Radio Mondiale has long been touted as the digital solution for Medium Wave and Short Wave broadcast radio with higher efficiencies and less noise. There have been tests for well over a decade but very few adopters until now.
India now has 35 DRM transmitters covering the sub-continent with a potential audience of about a billion people. There is however still a serious issue regarding the high cost of receivers.
A company called Cambridge Consultants have now announced a prototype of a DRM design which will cost $10 or less. If they are successful, it could be a game changer for digital radio.
This is from their press release... "Cambridge Consultants has just held its annual Innovation Day, where we throw open our doors to industry leaders and reveal future technology. One of our highlights was the prototype of a DRM design that will cost ten dollars or less to produce, addressing that vital need for information by the 60-ish per cent of our global population that doesn’t have internet or TV. It’s low power, so can run from solar or wind-up. This design will be ready in 2020, available for any radio manufacturer to licence and incorporate into its own products. "
I heard both of these stations most days on 28 MHz. i.e. there is usually some sort of propagation on the band but it's just that there aren't enough people active.
The one unusual signal was K6ND in Pennsylvania. He was the only US station that I heard and I was the only person in Europe to hear him.
The QCX cw transceiver from QRP-Labs is one of the most popular kits for radio amateurs on the market and sells for just $49. It comes in single band versions from 80m to 17m. Earlier in 2019, they sold their 8,000th kit which just testifies how popular this little 5 watt radio is.
QRP-Labs have now announced that they are releasing an accompanying amplifier which is capable of 50 watts.
Some of the key features... Designed for the QCX CW transceiver kit
Up to 50W power output on 40m with 20V supply, falling to around 25W at 13.8V supply 50-ohm input and output Fast clean solid-state Tx/Rx switching provides full break-in operation (QSK) Can be built for one of 40, 30m or 20m bands with the supplied components (or other bands with suitable choice of Low Pass Filter components) Uses two low-cost IRF510 transistors as the power amplifier in push-pull configuration Recommended amplifier operation in Class C (Not suitable for SSB) On-board 7-element Low Pass Filter for harmonic attenuation Standard inexpensive components throughout (easy to replace)
The chart below shows how the output power is dependent on the supply voltage and the frequency.
The price of the amplifier is just $29.50. There is also an optional enclosure for an additional $16.
An international panel of scientists co-chaired by NOAA and NASA release reports every few months on the state of the sunspot cycle. This is probably the most accurate source in terms of what is likely to happen.
Back in April of 2019, the previous report predicted that the solar minimum would likely happen between July 2019 and September 2020. In the most recent report dated December 2019, they are predicting that the minimum has been pushed back. They predict that it will now occur sometime between November 2019 and October 2020.
As for the upcoming Solar Cycle 25, they are still predicting that it will be similar in intensity to the last solar cycle with a smoothed sunspot number (SSN) of 115. The peak is predicted to occur between November 2024 and March 2026.
Original press release... SOLAR CYCLE 25 FORECAST UPDATE
published: Monday, December 09, 2019 22:30 UTC
The NOAA/NASA co-chaired, international panel to forecast Solar Cycle 25 released their latest forecast for Solar Cycle 25. The forecast consensus: a peak in July, 2025 (+/- 8 months), with a smoothed sunspot number (SSN) of 115. The panel agreed that Cycle 25 will be average in intensity and similar to Cycle 24.
Additionally, the panel concurred that solar minimum between Cycles 24 and 25 will occur in April, 2020 (+/- 6 months). If the solar minimum prediction is correct, this would make Solar Cycle 24 the 7th longest on record (11.4 years).
On the 1st of December 2019, there was an extensive Sporadic-E opening on 144 MHz in the south-eastern part of Australia. While this allowed contacts on the 2-metre band between various Australian regions, the most remarkable opening was probably between Adelaide (VK5) and the northern tip of New Zealand.
Both VK5GF and VK5AKK managed to hear the WSPR beacon ZL1SIX, a distance just over 3,170 kms and a remarkable distance for 2-metres. To explain that from a European perspective, that is the same as say London to Cyprus or across the North Atlantic from Ireland to Newfoundland.
Mode of Propagation???... Normally the maximum distance for one Sporadic-E hop is about 2,300 kms so this alone cannot account for the 3,174 kms covered.
There were other reports of some double hop Sporadic-E on 50 MHz between Australia and New Zealand so perhaps it reached as high as 144 MHz as well? While it is not impossible, it would be highly unusual.
Another possibility was that there was a single hop Sporadic-E hop from Adelaide to the east and then the rest of the path was via a tropo duct to the North of New Zealand. It's impossible to tell though.
ZL1SIX Beacon... This WSPR beacon is located 370 metres above sea level and runs 10 watts into four stacked 3-element beams pointing west towards Australia (pictured on the left).
Beacon Info) Two metre WSPR transmitter: QTH: Manginangina, 13km (8 miles) west of Kerikeri at 370m (1200 feet) ASL overlooking the Bay of Islands, New Zealand Frequency: 144.490540 MHz (GPS calibrated) Ident: Standard WSPR transmission followed by ZL1SIX RF64VT in Morse code. Current operating conditions: 10W RF output into 4 x 3 element Yagis facing West (13dBi). EiRP = 200W Equipment: QRP-Labs U3S with a TCXO on the synthesizer board, Tait T198 PA module, QRP-Labs QLG1 GPS unit More info here... https://www.qsl.net/zl1rs/bcn_ant.html
Extract from the report on Facebook by VK2KRR... "Yesterday we had the BRILLIANT situation, where we saw a high MUF sporadic E area highlighted on 6m WSPR, which quickly escalated to showing 2m sporadic E paths going north and south across this area, also initially detected on 2m WSPR between VK7 stations and VK2, which is quite a high MUF down to 1000 km distance for some of the paths. Since the first 2m Sporadic E opening found just over a week ago, we have found an opening on 2m almost every day! At this stage I am not sure if its because of all the signals and data being shown by WSPR operations that we have been able to better locate areas of high MUF sporadic E and make use of it, or if it's just an extraordinary series of events that's been going on. I don't recall seeing such regular E openings on 2m here in the past, they are usually quite a rare thing." ... VK2KRR on Facebook.
Video... This video from VK7HH in Tasmania shows some of the openings on 50 MHz and 144 MHz. (The 2m opening starts around the 4 min mark)...
Addendum... It looks as if another 3000km plus path opened up again on the 6th of December 2019 in Australia.
This time, the WSPR signal of VK2DVM in Sydney was heard in the south-west corner of Australia, a distance of some 3,102 kms.
Note the signal... -27dB! This shows the value of WSPR in that it allows the discovery of paths on the VHF bands which would have gone unnoticed before.
As for how, it was most likely a mixed Sporadic-E and tropo signal. i.e. One Sporadic-E hop from VK2DVM so that the signal reached the Great Australian Bight and then via a maritime tropo duct to VK6NI.
Truth be told, conditions weren't all that good on 28 MHz on Monday the 9th of December 2019. There were a few signals from around Europe which were either Sporadic-E, meteor scatter or a mixture of the two.
There was also a distinct lack of stations on the band with most probably opting for the lower HF bands where things are much easier.
The one interesting signal was from ZD7JC in St Helena Island in the South Atlantic. This is about 7,500kms from my location.
As per usual, I'd suspect the first hop to the south was via Sporadic-E from here and then via F2 from there.
The solar flux was 70 today so we're still well and truly at the bottom of the sunspot cycle.
Early on the morning of the 5th of December 2019, there was a remarkable tropo contact between Leigh, VK2KRR and Peter, VK6KXW on 70cms across the Australian continent. The distance was 2,806 kms and crossed over the Great Australian Bight, a part of the ocean well noted for tropospheric ducting.
This was a new Australian record for a digital contact on 432 MHz as both stations were using the FT8 mode. The previous record was 2,793 kms which was set back in December of 2016.
VK6KXW was running 75 watts from an IC9700 into a single yagi. VK2KRR was also running 75 watts from an IC9700 but his antenna was a box of four yagis.
VK2KRR's box of four yagis used for the contact. Source: VK2KRR on Facebook
The time of the contact was probably also a factor as tropo ducting is often at its best very early in the morning when the atmosphere has settled down and the sun hasn't risen yet.
The current non-digital record for the 70cms band in Australia is just a bit further at 2,862 kms. This was set between VK6KXW and VK7AC on the 17th of January 2019.
While examining both of these contacts, it can be difficult to relate to the distance of 2,806 kms and just how far it is. It might be useful for stations in Europe to remember that the distance from the west coast of Ireland to Newfoundland in Canada is 3,000kms, just an extra 200 kms.
Normally news items about DRM (Digital Radio Mondiale) tests on the short wave bands are of little interest to me except that this one is unusually at 26 MHz!
Avion DRM receiver
The Budapest University of Technology started a 1-year DRM test on the 1st of June 2019 and it will run until the end of May 2020.
The transmitted content is a 24-hour program, played out in a loop, compiled by the media partner of the project, Radio Maria.
They are transmitting on a frequency of 26.060 MHz with 100 watts into a 5/8 vertical.
Additional info..."The current short wave DRM transmission performed from the university has two main objectives: partly to demonstrate the value-added possibilities of DRM (xHE-AAC coding, slideshows and Journaline advanced text services accompanying the audio content), and partly to provide an opportunity for receiver manufacturers to test their products in real life. Since this is not a public or commercial service, the modulation parameters (transmission mode, SDC and MSC constellations, interleaving depth, etc.) can be freely changed at any time. Developers are, therefore, welcome to perform field tests with their devices in Budapest working in close co-operation with the broadcasting team of the Department of Broadband Infocommunications Systems and Electromagnetic Theory of the Budapest University of Technology.
The landscape of the Hungarian capital is particularly interesting because the town is partly built on a flat area, partly on hills. The two sides are separated by the river Danube and are exhibiting various interesting wave propagation phenomena."
Looking at the display above, it looks as if the DRM signal is about 6 kHz wide.
The technical parameters of the demonstration broadcast in Budapest, Hungary, are as follows:
Frequency: 26060 kHz
EIRP: approximately 100 W
Antenna: 5/8 l monopole
Transmission time: 24/7
Thoughts.... Under Sporadic-E conditions, this should be heard around Europe. It has been heard already in the Netherlands so it should be possible.
As most people don't have DRM receivers, have a listen to Radio France Internationale on 3.965 MHz at night and you will hear a good strong DRM signal. If you listen on AM or SSB, you will get a good idea of what a DRM signal sounds like. If you hear the same type of signal on 26.060 MHz then it is very likely to the the test transmission from Hungary.
Conditions on 28 MHz in Europe on Wednesday the 4th of December 2019 were generally very poor with very little propagation by way of Sporadic-E on the band. As can be seen from the map above, it did open to the NE of the USA.
Looking at the PSKReporter website, there did by contrast seem to be plenty of Sporadic-E in the eastern part of the USA today. Did this extend out over the North Atlantic as well?
In total, I heard four US stations and the decodes are shown below. The W1SSN and NF1G reports did not appear on the PSKReporter website.
When I checked the heard/receive maps for each of the four stations that I heard, the trans-Atlantic path seemed to be confined to just a few stations in the UK and Ireland.
The distance for me was about 5,000kms which suggests either 3 x Sp-E hops or some F2 enhancement. With the solar flux down at 71 and no sign of anything special happening on the sun today, I'd suspect the multi hops E's but you can never be really certain at 28 MHz.
There was a pretty good mid-Winter Sporadic-E opening on 28 MHz on Sunday the 1st of December 2019 with the band open to most of Europe. A total of 291 stations in 26 countries were heard which is on par with a good day in the middle of the Summer.
It looks as if most of the signals were single hop Sp-E although the one in Bulgaria and the three in Russia were probably double hop.
The most interesting signal was the one that didn't get uploaded to the PSKReporter website and hence, isn't on the map.
151445 -18 -0.4 2042 ~ KN4MKX AK4QR R-14
AK4QR is in Alabama and it looks as if there was a Sp-E opening from his location to the NE of the USA. There is no sign of any other European station hearing him, just me.
As for the propagation mode for that one signal I heard? Multi-hop Sp-E? Was there some F2 involved?
Dave, EI3IO, reports that the Falkland Islands Telecoms Regulatory Body has granted access for radio amateurs to the 4-metre band from 70.000 MHz to 70.500 MHz using a maximum power of 1 kW on a secondary basis since 15 November 2019.
The Falkland Islands (VP8) is now one of the few countries in the southern hemisphere with access to this unique VHF band. The map below shows the countries that have some form of access to the 4-metre band.
Red & Blue = Countries with some form of access on 70 MHz
What is perhaps unique about the 70 MHz allocation in the Falkland Islands is the sheer isolation of the location. There are no countries within a normal one-hop Sporadic-E range of the islands and indeed, the closest other radio amateurs on 70 MHz are probably in South Africa, a distance of some 6,200 kms!
This raises the very real possibility that contacts outside of the Falkland Islands may not be possible on the band.
The most likely possibility if at all would be a multi-hop Sporadic-E link across to South Africa but it would probably require 3 hops at 70 MHz which isn't easy. The other possibility is St.Helena in the South Atlantic but this is almost as far.
There may be a remote possibility of Sporadic-E link to some Trans-Equatorial Propagation (TEP) to the north but this seems unlikely.
On the fourth Tuesday of every month, we have a local net on 70cms about digital radio. While its primary purpose is to generate some activity on the local DMR repeater and talk groups, the conversation this month turned to the subject of digital voice on the HF bands. It was then that the digital mode FreeDV was mentioned and I have to admit it was the first time I had heard of it.
Perhaps I had come across it before in a news item and I didn't take much notice but it sounds like an interesting mode. It seems that while it started back in 2012, it's only in more recent years that the performance has surpassed that of SSB when the signals are very weak and in the noise.
I thought it might be an idea to put up a blog post so that perhaps a few more people might be interested in trying out this new mode.
My first question I had about this digital mode was how could it possibly work on the HF bands with all of the multi-path interference and fading? Well, it seems as if it's not a case of all or nothing. The signal is broken up into separate sub-carriers and the information is modulated on these by phase shifting.
The modulation mode is OFDM which stands for Orthogonal Frequency Division Multiplexing. The spacing is chosen so that the subcarrier nulls coincide with the peaks of other subcarriers. By doing this, the subcarriers don't interfere with each other.
It works on the principle that even if there is some selective fading on some of the subcarriers, enough information is getting through on the others to allow a conversation to be held.
Waterfall display of a FreeDV signal showing selective fading
FreeDV... What it is and what it's not
First of all, what it's not. It's not for DX-ing, chasing DXCC countries, contesting, chasing squares or awards. It's not there to replace SSB or even your local net on HF.... (for the moment ;o)
COMREG, the Irish licencing authority defines Amateur Radio as follows..."The amateur service is defined by the International Telecommunication Union (ITU)1 as: A radiocommunication service for the purpose of self training, intercommunication and technical investigations carried out by amateurs, that is, by duly authorised persons interested in radio technique solely with a personal aim and without pecuniary interest"
The self training and technical investigation aspects are what FreeDV and digital voice are really about. It's a new technology that is evolving and will appeal to people who want to learn about new developments and how they might be implemented.
The big advantage of FreeDV is that you can use it with existing HF radios with SSB. It's not like DMR, C4FM or D-STAR which require a completely new radio to be bought. If someone is set up for digital modes like FT8 then they have the equipment already. As such, it can be used on any band where there is SSB... HF or VHF.
An interesting feature is that FreeDV demodulator can automatically acquire signals with a frequency offset of up to ±200 Hz. This means that you don't have to be the exact same frequency as the other station. You can see how this might be of value in say a net on SSB where everyone is trying to get on the correct frequency.... and there's always one who is off a bit :o)
Modes...
It's also worth mentioning that there are several FreeDV modes as well. 700D... This is for weak signal work on the HF bands and is claimed to work down as far as a signal to noise ratio of -2dB. The 700C version was introduced in 2017 and was replaced by the better 700D mode in 2018. 800XA... Similar to C4FM except over FM radio. Designed for VHF work. 1600... This is for a higher quality audio signal. 2020... 8 kHz of audio bandwidth is fitted in just 1.6 kHz of RF bandwidth. Delivers high quality audio when the signal are strong. Introduced in 2019.
Video... The video below from the 2018 RSGB Convention gives a good outline of FreeDV and its use. Even if you have only a passing interest in digital voice, it's worth a watch.
Regular visitors to the blog will know that I try to promote more interest in the low-VHF part of the spectrum by having a dedicated page related to the new 40 MHz / 8 metre band. If I come across anything of interest that might be related to the band then I post it here on the blog and link to it from the 40 MHz page. The Clansman is an ex-British army radio that can operate on FM on the low VHF spectrum from 30 to 76 MHz. As such, it is one of the few radios available on the second hand market that can operate at 40 MHz, 50 MHz, 60 MHz or 70 MHz. Thanks to Steve EI5DD for his permission to post this guest post here....de EI7GL
The Clansman PRC-3512 is an intra-platoon level backpack VHF FM transceiver. The PRC 351 has 4 watt RF power output, and operates in the 30–75.975 MHz range with a possible 1840 channels spaced 25 kHz apart.
This radio is also capable of being mounted on a vehicle in conjunction with the TUAAM (Tuning Unit Automatic Antenna Matching). The PRC 352 is identical, with the addition of a 20 watt RF amplifier and can be used as a ground station also.
The Clansman RT-351 / VRC-351 Back-Pack 4 Watt portable VHF (FM) Radio was made by RACAL BCC Ltd. in England. The PRC-351 was designed to provide command communications at battalion and company level for dismounted troops. It was also used in vehicles by mounted troops. The PRC-351 replaced the older A41 and A42 British VHF radios.
The frequency Range 30 to 76.000 MHz in 25 Khz steps giving a total of 1841 programmable channels. The desired frequency is set by four knobs on the side of the radio which can be operated even while the operator is wearing Arctic mittens, or in the dark by counting clicks from the end-stops.
The World Radio communication Conference WRC-19 has just approved an allocation in the 50 MHz band for radio amateurs in Region 1 which includes Europe, Africa and the Middle East.
The entire region will now have an amateur secondary allocation of 50-52 MHz. This is usually granted on basis that secondary users do not cause interference to primary users of the band.
The exception is the Russian Federation, whose administration opted for only 50.080-50.280 MHz on a secondary basis.
This change should make a big difference in areas like Africa where only 11 countries have a primary allocation at present. The secondary allocation now opens the door for more activity from the continent.
According to a press release from the IARU, they state..."The exact manner in which the allocations will be implemented in Region 1 countries will be determined by each administration and may be either more generous or less, depending on national considerations."
So what does this mean??
While 26 countries in Region 1 currently have primary access to 50-54 MHz, the fact is that the vast majority of all 6-metre activity happens between 50 and 52 MHz. By having an official secondary allocation, radio amateurs in countries in Africa, Russia or the Middle East will now have a more valid reason for access to the band. This should result in more activity from those regions and this will be of interest to radio amateurs in western Europe.
It means that there is likely to be more DX related activity on the band which should encourage more activity. Every Summer, there will be multi-hop Sporadic-E from Europe to some of those potentially new countries on the band.
While the current predictions for the next sunspot cycle in a few years time aren't great, it should still result in good north-south paths. For stations in western Europe, this should result in openings to new countries in the Middle East and Africa.
Sunday the 17th of November 2019 was an interesting day on 28 MHz. In the morning, there was a modest Sporadic-E opening in Europe with a number of stations being heard on FT8.
The two signals of note were...
5R8VX in Madagascar at 9050 kms. Anything from the Indian Ocean is always of interest on 28 MHz.
F5MYK/MM in the South Atlantic. These are the FT8 signals that I heard...
It looks as if the strange call was enough to stop it being accepted by the PSKReporter website, hence the lack of a line on the display. An unusual one to hear on the band.
Galway Radio Club in the west of Ireland have recently launched a new 48 page newsletter which covers some some recent club activities as well as a number of items which may be of interest to a wider audience.
These include... 1) An overview of how an amateur radio digital network was developed in the west of Ireland. 2) An overview of the experimental 5 MHz / 60m band. 3) Antennas for portable operation. 4) Understanding the Ionogram. 5) 160m top band operation. 6) G4HOL multi-band HF horizontal loop. 7) Operating the DVstick 30 - How to communicate on D-Star and DMR without a radio.
Monday the 11th of November 2019 was a pretty quiet day on 28 MHz for the most part. Other than a handful of European stations, the best DX to the south on FT8 was ZD7MY on St.Helena. The three exceptional signals however were WU1ITU, K0TPP and KC4QX in the USA.
On the lower bands like 18 MHz, 21 MHz or even 24 MHz, it's no big deal to hear an East-West signal outside of the Sporadic-E season. On 28 MHz and at the bottom of the sunspot cycle, it is.
When the solar flux is very low at the bottom of the sunspot cycle, propagation on 28 MHz via the F2 layer in the ionosphere is usually via North-South paths. As a result, hearing South Africa or South America from Europe on 28 MHz at the moment is nice but not exceptional. Hearing North America is unusual though.
I got just two FT8 decodes today from K0TPP in Missouri. He was 6,267 kms from here which is more than one F2 hop so perhaps there was some Sporadic-E helping to extend the path at one end or the other?
WU1ITU by contrast was much stronger and was at least +14dB here. That's a kind of level where a CW or SSB contact should be easily possible. It was a bit strange that these were the only two US stations that I heard.
KC4QX in Florida was heard much later at 18:43 UTC, about two hours after local sunset. Looking at the PSK Reporter website, it seems as if I was the only one in Europe in Europe to hear him.
Some of the my FT8 decodes are shown below. As you can see, WU1ITU was working Greece, France, Denmark and Spain.
Sunday the 10th of November 2019 was a pretty quiet day on 28 MHz with only one South African station being heard on FT8 here as well as a handful of Europeans.
I did a check of all the FT8 stations on 28 MHz from 9am to 9pm on the 10th of November and the map is shown above. I'm not sure if all the stations are shown but you can see very clearly where most of the activity is located.
It just highlights the fact that while there is plenty of activity from Europe, there is nobody active in most of Africa. This means that the 10-metre band may well be open from Europe to Africa at times but we can't tell.
An interesting day on 28 MHz with some mixed propagation on the band. There seems to have been some Sporadic-E between Ireland and Spain to the south. This then linked to what was probably F2 propagation from the latitude of Spain down to South Africa and Mauritius in the Indian Ocean.
