ICOM recently posted this video on their YouTube channel showcasing some of the radios that they have released down through the years...
Thursday, December 26, 2019
Monday, December 23, 2019
The Five-Metre Story ... Article from the Short Wave Magazine in 1949
After the Second World War, some radio amateurs in Europe were allowed to use the 5-metre band (58.5 MHz to 60.0 MHz) until 1949-1951 when this part of the VHF spectrum was cleared for TV transmissions.
The following article written by E.J. Williams (G2XC) appeared in the April 1949 issue of the Short Wave Magazine. It covers a period of time when radio amateurs in the UK were about to lose the band.
* * * * *
SHORT WAVE MAGAZINE - APRIL 1949
VHF BANDS
By E. J. WILLIAMS, B.Sc. (G2XC)
The Five -Metre Story- Summary of Results on Five-Metre Activity
To summarise the results obtained on Five Metres since the band was first operated, and the experience it has given all VHF workers in this country, is not the easiest of tasks-apart from which, we are all bidding farewell to an old friend. Operations on Five Metres find a unique and lasting place in the history of Amateur Radio in this country. In the amateur field, they made possible some remarkable developments in VHF technique ; every VHF operator, known or unknown, has benefited directly from the collective progress made by British amateurs on Five Metres ; and most operators cut their VHF teeth on the problems (which seem so easy now) posed by the Five Metre Band.
It will probably be agreed that the story of Five Metres divides itself into two well-marked periods. The first, the years up to about 1936, when self-excited transmitters and super regenerative receivers were the order of the day ; and the second, from 1938 onwards, when crystal control and either straight or superhet receivers became the standard equipment. The years between were a transition period when the need for stabilised apparatus was becoming generally recognised, with the DX possibilities of the band gradually assuming a greater importance.
Pre -War Era
For those who did not know the pre -crystal control period, we should like to paint a picture of five metres as it was then. The experience of your conductor started in 1933, but others knew the band long before that. That long distances might be covered on rare occasions had been proved by one or two reports of 100-mile (160kms) reception several years before, but in general, anything over 10 miles was considered DX and worth reporting. Transmitters were often of the push-pull tuned anode resonant grid type, feeding into long wire aerials.
Such was the transmitter at, for instance, G6NZ in Southsea. In common with other local enthusiasts, we built a super -regenerative receiver, but being on the opposite side of a 300-ft. hill from G6NZ, we failed to hear anything but ignition QRM. Nothing daunted, we persuaded a neighbour to spend Sunday mornings taking us round the district in his car, so that we could log G6NZ's signals in more favourable locations.
Other groups up and down the country were doing the same sort of thing. Portable work became the great thing. One Sunday in each month was set apart in the South of England as a 5-metre field day. Transceivers, each smaller than the last, were built by every- one and provided much fun, even if they did not add much to the sum total of radio knowledge. We remember a contact between G2XC and G6NZ while the latter was on a moving bus, and other similar novel contacts were made elsewhere.
In 1934, G6QB took his five -metre gear to the top of the Crystal Palace, while G5CV went aloft in an aircraft and obtained air-to- ground ranges of 130 miles (209 kms). G5BY went to the top of Snowdon, a venture repeated by G5CV, G6YQ, GW6AA and others later. Signals from Snowdon were heard as far away as Essex.
But by 1936, many of us were realising that so far we had only been playing at 5 metres and that if the full possibilities of the band were to be explored, both transmitters and receivers must be improved considerably. CW reception should be made possible, and that meant frequency stability at both Tx and Rx ends. Really good valves for use on 60 mc were still scarce and expensive, and in spite of the general acceptance that CC transmitters and straight or superhet receivers were desirable, progress was slow. Gradually, however, stabilised transmissions increased in number as news spread of the possibility of European DX ; commercial harmonics had been logged during the summer of 1936 and G2FA worked F8NW across the Channel, while G5BY (then at Croydon) was reported heard at W2HXD (trans-Atlantic).
But the first European QSO was delayed until July 2, 1938, when G5MQ worked I1IRA. About this same time, inter -G con- tacts over distances up to 100 miles (160 kms) or so were becoming commonplace, as a result of the improved Tx, Rx and aerials in use. In fact, we find A. J. Devon saying in the Short Wave Magazine for October, 1938, " 56 mc contacts are of little value as news items when the distances involved are less than 50 miles. (80 kms)" In the latter half of the same year, G5BY-G6FO obtained regular schedule contacts over the 126-mile (202 km) path between Croydon and Newport, Mon., for the first reliable ground -to -ground GDX, and G6FO also logged G6DH at 180 miles (290 kms). The G5BY-G6FO contacts stood for many months as the GDX record.
Early 1939 found G6DH striving to work ON4DJ across 85 miles of sea. And so came the summer, when in 8 days of June, G6CW made 13 contacts over 100 miles. Contacts between G and I were made on June 1, 13, 24 and 25, and G2ZV and G6CW set up a new inter -G record of 150 miles (240 kms). The Snowdon tests of that same summer were, however, not so successful as a result of a severe gale which reduced all the expectations of GW6AA and his helpers to nothing. In spite of that 25 stations were worked, including G6CW at 137 miles (220 kms). In August, 1939, the GDX record advanced another stage, when the late G2OD (Worthing) contacted GBKD (Sheffield) over a 190 -mile (306 km) path, while G2AO (Eastbourne) worked PAOPN. When, on the outbreak of war, activity ceased on September 3, 1939, not only had the GDX record been brought to a figure which would have been considered incredible only a few years previously, but contacts had been made between G and EI, F, I and PA.
Post -War Results
And so to 1946, when with the return of amateur licences the Five -Metre Band was one of the two bands made available, but shorn now of its LF end. With better and cheaper valves, and a general trend towards beams in place of long wires and simple dipoles, GDX was soon being worked. By June, A. J. Devon, in his feature "Five Metres" in the Magazine, was beginning to run out of superlatives ! G5BY made the first inter -European contact on May 19, working I1FA. About the same time G5MQ and G6VX were maintaining a 184 -mile schedule for 15 evenings in succession, while G5BY worked G5MQ on May 13 over a 215 -mile path. As A.J.D. said that month, "Inter -G working up to 200 miles is passing from the very uncommon and exciting". During June, the band opened to Europe on six occasions, G2XC, 5BD, 5BY, 5LL, 5MP and 6CW being there is take advantage of it. G5BY and G6LK started a regular schedule over 156 miles with remarkably consistent results. The GDX record passed to G5BY/ G8UZ. July 23, 1946, was an outstanding evening for inter -G work, while August 22 provided the best European evening of the year with the first HE contacts being made. Early October brought a fortnight of excellent conditions for GDX working, the evening of October 11 surpassing anything previously experienced. Complaints were coming in of congestion at the LF end of the band, and of weak, unindentifiable 'phones who failed to sign on CW.
In November came the first Short Wave Magazine Five -Metre Contest, lasting a fortnight. From the point of view of GDX, the event was a failure, conditions being far below normal, but all participants enjoyed it and activity was outstanding. G6VX (Hayes) was the easy winner of this Contest, with G5MA his runner up. There was a total entry of 44, and A. J. Devon estimated that about 300 G's were active on the band during the period.
Aurora Openings
March 8, 1947, was the date of the first major Aurora opening on 58 mc, GDX signals being received from the North irrespective of great -circle directions and with fuzzy notes. During a further auroral display on April 17, G5MA (Ashstead) was logged by GM3BDA (Airdrie). In April, 1947, A.J.D., in the Magazine, Iaunched "Counties Worked" as a method of assessing collective progress, com- menting that there was known to be activity in 30 G counties. G5MA became first leader in the table with 22 counties worked. The EDX season opened on May 14 with the GM's receiving I's, while at G2XC we worked 21 counties in a month! The table of Five Metre Firsts was growing rapidly, and by the end of the summer 11 different European countries had been worked from the U.K. W5BSY/MM added to the excitement of that summer of 1947 by operating on 5 metres from the Mediterranean area, and a new GDX record was set up on June 1, 1947, over 285 miles (458 kms) between G5BY and G5GX.
Personality Note
In November, 1947, your present conductor took over from A. J. Devon, who for years had contributed this feature. As many may have guessed, it might now be disclosed that A.J.D. was the pseudonym of the Editor of the Short Wave Magazine.
Five metre news was temporarily eclipsed by the DX openings on 6 metres. A second Five -Metre Contest in January, 1948, attracted a good entry, although again we were unlucky with conditions. G6VX and G5MA repeated their former success and, as in the previous contest, occupied the first two places. The idea of the " Fiveband Club" was born on February 21, and was immediately well supported by VHF enthusiasts.
Rise-
Activity Week -Ends provided a valuable incentive during the summer of 1948. By a remarkable coincidence, all these week-ends produced unusually fine weather, and we were inundated with requests to make every weekend an "activity" one ! GM3OL and the Newcastle group broke through to the Midlands in May, and several new counties, notably Dorset, Somerset and Suffolk, appeared on the 5-metre map.
The Counties table now showed several stations at the 31 level. Excitement grew as in June GM3OL and G3BW were heard in the London area, and on June 13 a new GDX record was achieved by G3BLP and GM3OL, the distance being 296 miles (496 kms). On June 9 a tropospheric contact between G2XC and PAWL, 370 miles (595 kms), also set a new record. In fact, some 19 contacts during June of over, 200 miles (320 kms) via the troposphere were recorded in our columns. June 4 saw an excellent European opening, as many as eight different countries being heard.
With greatly increased activity in GI and GM the stage was well set for August 7, when an amazing spell of "aurora conditions" opened the band for working between Southern G and GM's and GI's. Record contact was that by G5MA and GM2DAU, a distance of 363 miles (584 kms). A further outcome of this occurrence was a rapid rise in the counties worked, G5WP reaching 41, and G6LK making his total 16 countries.
-And Fall
On September 1, 1948, the two -metre band became available for amateur use and from that date five -metre activity started on a steady decline. A contest organised by the R.E.F. on October 23-24 produced a brief burst of activity and enabled G3HWJA and G3CQC to make 460 -mile (740kms) contacts with F8YZ, thus raising the tropospheric record to an even higher figure. A second break in the general lull came as a result of our own Magazine VHF Contest in mid -November. This time conditions were excellent and numerous over-200-mile (320 kms) contacts were made, G5BY and G3HW/A being the outstanding stations.
To round it all off, we reproduce herewith the last set of Five -Metre Achievement Tables, based upon all the available information. Some of the figures are interesting : No less than 43 counties worked, 42 of them by a station in the South London area; nearly 100 stations figuring in the Counties Worked list, for which the qualifying standard is 14 counties ; 17 European countries worked by one station, followed by two operators with 15 countries each ; a total of 88 stations shown in the Countries Worked list ; 11 European countries worked first time on 58 me post-war, three of them-North Africa, Switzerland and Czechoslovakia-by the same operator ; an estimated total of not less than 600 G stations which have appeared on the band ; and some distance records which will stand as a monument to the operators who made them.
British VHF Records
58 mc (58 MHz)
GDX (Tropo), G3BLP/GM3OL, 296 miles (476 kms)
GDX (Aurora), G5MA/GM2DAU, 363 miles (584 kms)
Tropo (European), G3CQC/F8YZ, 460 miles (740 kms)
The following article written by E.J. Williams (G2XC) appeared in the April 1949 issue of the Short Wave Magazine. It covers a period of time when radio amateurs in the UK were about to lose the band.
* * * * *
VHF BANDS
By E. J. WILLIAMS, B.Sc. (G2XC)
The Five -Metre Story- Summary of Results on Five-Metre Activity
To summarise the results obtained on Five Metres since the band was first operated, and the experience it has given all VHF workers in this country, is not the easiest of tasks-apart from which, we are all bidding farewell to an old friend. Operations on Five Metres find a unique and lasting place in the history of Amateur Radio in this country. In the amateur field, they made possible some remarkable developments in VHF technique ; every VHF operator, known or unknown, has benefited directly from the collective progress made by British amateurs on Five Metres ; and most operators cut their VHF teeth on the problems (which seem so easy now) posed by the Five Metre Band.
It will probably be agreed that the story of Five Metres divides itself into two well-marked periods. The first, the years up to about 1936, when self-excited transmitters and super regenerative receivers were the order of the day ; and the second, from 1938 onwards, when crystal control and either straight or superhet receivers became the standard equipment. The years between were a transition period when the need for stabilised apparatus was becoming generally recognised, with the DX possibilities of the band gradually assuming a greater importance.
Pre -War Era
For those who did not know the pre -crystal control period, we should like to paint a picture of five metres as it was then. The experience of your conductor started in 1933, but others knew the band long before that. That long distances might be covered on rare occasions had been proved by one or two reports of 100-mile (160kms) reception several years before, but in general, anything over 10 miles was considered DX and worth reporting. Transmitters were often of the push-pull tuned anode resonant grid type, feeding into long wire aerials.
Such was the transmitter at, for instance, G6NZ in Southsea. In common with other local enthusiasts, we built a super -regenerative receiver, but being on the opposite side of a 300-ft. hill from G6NZ, we failed to hear anything but ignition QRM. Nothing daunted, we persuaded a neighbour to spend Sunday mornings taking us round the district in his car, so that we could log G6NZ's signals in more favourable locations.
Other groups up and down the country were doing the same sort of thing. Portable work became the great thing. One Sunday in each month was set apart in the South of England as a 5-metre field day. Transceivers, each smaller than the last, were built by every- one and provided much fun, even if they did not add much to the sum total of radio knowledge. We remember a contact between G2XC and G6NZ while the latter was on a moving bus, and other similar novel contacts were made elsewhere.
In 1934, G6QB took his five -metre gear to the top of the Crystal Palace, while G5CV went aloft in an aircraft and obtained air-to- ground ranges of 130 miles (209 kms). G5BY went to the top of Snowdon, a venture repeated by G5CV, G6YQ, GW6AA and others later. Signals from Snowdon were heard as far away as Essex.
But by 1936, many of us were realising that so far we had only been playing at 5 metres and that if the full possibilities of the band were to be explored, both transmitters and receivers must be improved considerably. CW reception should be made possible, and that meant frequency stability at both Tx and Rx ends. Really good valves for use on 60 mc were still scarce and expensive, and in spite of the general acceptance that CC transmitters and straight or superhet receivers were desirable, progress was slow. Gradually, however, stabilised transmissions increased in number as news spread of the possibility of European DX ; commercial harmonics had been logged during the summer of 1936 and G2FA worked F8NW across the Channel, while G5BY (then at Croydon) was reported heard at W2HXD (trans-Atlantic).
But the first European QSO was delayed until July 2, 1938, when G5MQ worked I1IRA. About this same time, inter -G con- tacts over distances up to 100 miles (160 kms) or so were becoming commonplace, as a result of the improved Tx, Rx and aerials in use. In fact, we find A. J. Devon saying in the Short Wave Magazine for October, 1938, " 56 mc contacts are of little value as news items when the distances involved are less than 50 miles. (80 kms)" In the latter half of the same year, G5BY-G6FO obtained regular schedule contacts over the 126-mile (202 km) path between Croydon and Newport, Mon., for the first reliable ground -to -ground GDX, and G6FO also logged G6DH at 180 miles (290 kms). The G5BY-G6FO contacts stood for many months as the GDX record.
Early 1939 found G6DH striving to work ON4DJ across 85 miles of sea. And so came the summer, when in 8 days of June, G6CW made 13 contacts over 100 miles. Contacts between G and I were made on June 1, 13, 24 and 25, and G2ZV and G6CW set up a new inter -G record of 150 miles (240 kms). The Snowdon tests of that same summer were, however, not so successful as a result of a severe gale which reduced all the expectations of GW6AA and his helpers to nothing. In spite of that 25 stations were worked, including G6CW at 137 miles (220 kms). In August, 1939, the GDX record advanced another stage, when the late G2OD (Worthing) contacted GBKD (Sheffield) over a 190 -mile (306 km) path, while G2AO (Eastbourne) worked PAOPN. When, on the outbreak of war, activity ceased on September 3, 1939, not only had the GDX record been brought to a figure which would have been considered incredible only a few years previously, but contacts had been made between G and EI, F, I and PA.
Post -War Results
And so to 1946, when with the return of amateur licences the Five -Metre Band was one of the two bands made available, but shorn now of its LF end. With better and cheaper valves, and a general trend towards beams in place of long wires and simple dipoles, GDX was soon being worked. By June, A. J. Devon, in his feature "Five Metres" in the Magazine, was beginning to run out of superlatives ! G5BY made the first inter -European contact on May 19, working I1FA. About the same time G5MQ and G6VX were maintaining a 184 -mile schedule for 15 evenings in succession, while G5BY worked G5MQ on May 13 over a 215 -mile path. As A.J.D. said that month, "Inter -G working up to 200 miles is passing from the very uncommon and exciting". During June, the band opened to Europe on six occasions, G2XC, 5BD, 5BY, 5LL, 5MP and 6CW being there is take advantage of it. G5BY and G6LK started a regular schedule over 156 miles with remarkably consistent results. The GDX record passed to G5BY/ G8UZ. July 23, 1946, was an outstanding evening for inter -G work, while August 22 provided the best European evening of the year with the first HE contacts being made. Early October brought a fortnight of excellent conditions for GDX working, the evening of October 11 surpassing anything previously experienced. Complaints were coming in of congestion at the LF end of the band, and of weak, unindentifiable 'phones who failed to sign on CW.
In November came the first Short Wave Magazine Five -Metre Contest, lasting a fortnight. From the point of view of GDX, the event was a failure, conditions being far below normal, but all participants enjoyed it and activity was outstanding. G6VX (Hayes) was the easy winner of this Contest, with G5MA his runner up. There was a total entry of 44, and A. J. Devon estimated that about 300 G's were active on the band during the period.
 |
| G2WS/P in 1946 |
Aurora Openings
March 8, 1947, was the date of the first major Aurora opening on 58 mc, GDX signals being received from the North irrespective of great -circle directions and with fuzzy notes. During a further auroral display on April 17, G5MA (Ashstead) was logged by GM3BDA (Airdrie). In April, 1947, A.J.D., in the Magazine, Iaunched "Counties Worked" as a method of assessing collective progress, com- menting that there was known to be activity in 30 G counties. G5MA became first leader in the table with 22 counties worked. The EDX season opened on May 14 with the GM's receiving I's, while at G2XC we worked 21 counties in a month! The table of Five Metre Firsts was growing rapidly, and by the end of the summer 11 different European countries had been worked from the U.K. W5BSY/MM added to the excitement of that summer of 1947 by operating on 5 metres from the Mediterranean area, and a new GDX record was set up on June 1, 1947, over 285 miles (458 kms) between G5BY and G5GX.
Personality Note
In November, 1947, your present conductor took over from A. J. Devon, who for years had contributed this feature. As many may have guessed, it might now be disclosed that A.J.D. was the pseudonym of the Editor of the Short Wave Magazine.
Five metre news was temporarily eclipsed by the DX openings on 6 metres. A second Five -Metre Contest in January, 1948, attracted a good entry, although again we were unlucky with conditions. G6VX and G5MA repeated their former success and, as in the previous contest, occupied the first two places. The idea of the " Fiveband Club" was born on February 21, and was immediately well supported by VHF enthusiasts.
Rise-
Activity Week -Ends provided a valuable incentive during the summer of 1948. By a remarkable coincidence, all these week-ends produced unusually fine weather, and we were inundated with requests to make every weekend an "activity" one ! GM3OL and the Newcastle group broke through to the Midlands in May, and several new counties, notably Dorset, Somerset and Suffolk, appeared on the 5-metre map.
The Counties table now showed several stations at the 31 level. Excitement grew as in June GM3OL and G3BW were heard in the London area, and on June 13 a new GDX record was achieved by G3BLP and GM3OL, the distance being 296 miles (496 kms). On June 9 a tropospheric contact between G2XC and PAWL, 370 miles (595 kms), also set a new record. In fact, some 19 contacts during June of over, 200 miles (320 kms) via the troposphere were recorded in our columns. June 4 saw an excellent European opening, as many as eight different countries being heard.
With greatly increased activity in GI and GM the stage was well set for August 7, when an amazing spell of "aurora conditions" opened the band for working between Southern G and GM's and GI's. Record contact was that by G5MA and GM2DAU, a distance of 363 miles (584 kms). A further outcome of this occurrence was a rapid rise in the counties worked, G5WP reaching 41, and G6LK making his total 16 countries.
-And Fall
On September 1, 1948, the two -metre band became available for amateur use and from that date five -metre activity started on a steady decline. A contest organised by the R.E.F. on October 23-24 produced a brief burst of activity and enabled G3HWJA and G3CQC to make 460 -mile (740kms) contacts with F8YZ, thus raising the tropospheric record to an even higher figure. A second break in the general lull came as a result of our own Magazine VHF Contest in mid -November. This time conditions were excellent and numerous over-200-mile (320 kms) contacts were made, G5BY and G3HW/A being the outstanding stations.
To round it all off, we reproduce herewith the last set of Five -Metre Achievement Tables, based upon all the available information. Some of the figures are interesting : No less than 43 counties worked, 42 of them by a station in the South London area; nearly 100 stations figuring in the Counties Worked list, for which the qualifying standard is 14 counties ; 17 European countries worked by one station, followed by two operators with 15 countries each ; a total of 88 stations shown in the Countries Worked list ; 11 European countries worked first time on 58 me post-war, three of them-North Africa, Switzerland and Czechoslovakia-by the same operator ; an estimated total of not less than 600 G stations which have appeared on the band ; and some distance records which will stand as a monument to the operators who made them.
The detail of all this achievement, over a period of years, is contained in the pages of the Short Wave Magazine, which from the beginning has devoted much space, time and energy to the VHF bands. No other record can be so complete nor so accurate. It is with pride that we look upon their results in the VHF field and the vast accumulation of technical knowledge and experience gained by so many of our readers for still further VHF exploration. But unless they had taken the time and the trouble, not only to record their results but also to report them to us, this all - too -brief Summary would not have been possible, and much of the history of VHF achievement would have been lost.
And so we come to the close of the story. Among the thoughts which pass through one's mind is the remarkably persistent attraction the band was held for so many operators. Many of the calls that were in the five-metre news in 1933 still hit the headlines in 1948. Among its regular habitués existed a unique spirit of friendly rivalry, an amazing willingness to help the other man, even to break one's own records.
From the technical point of view the Five - Metre Band laid the foundations of British VHF technique and provided a grand opportunity to investigate sporadic -E propagation ; the Summaries of European Activity and EDX contacts which we prepared from readers' reports have been acknowledged by research laboratories in several countries as a valuable contribution to the study of VHF propagation problems.
Most of the well-known 5-metre call -signs can now be heard on two metres-or if not there, then on 70 cms. The experience of Five - Metre operation enabled excellent two -metre records to be set up within a few months. On 70 cm. technique is somewhat different, but we have no doubt that the persistence and endeavour which brought success on "five" will prevail on 70 cm. as well and that in due course a story of great achievements will be written for this new band. Five has gone ! Here's to Two and Seventy !
58 mc (58 MHz)
GDX (Tropo), G3BLP/GM3OL, 296 miles (476 kms)
GDX (Aurora), G5MA/GM2DAU, 363 miles (584 kms)
Tropo (European), G3CQC/F8YZ, 460 miles (740 kms)
Saturday, December 21, 2019
Radio Netherlands TV documentary on 70 years of international broadcasting
Back in 1997, Radio Netherlands produced a TV documentary about the history of radio broadcasting on the short wave bands during the 20th century. The programme was put up on the Vimeo platform recently.
Anyone with an interest in short wave broadcasting might find it of interest...
Note that the video is 48 mins long.
Anyone with an interest in short wave broadcasting might find it of interest...
Note that the video is 48 mins long.
Monday, December 16, 2019
Winter 2019 QRSS Compendium
QRSS is a CW mode in which the receiver bandwidth is drastically reduced and the rate at which code is sent is slowed beyond that which would be normally be readable by ear. A typical signal has a dot length of three seconds and a dot length of nine. The signal is 'decoded' by looking at the trace on a computer monitor rather than by ear.
There is a dedicated group called the QRSS Knights promoting the mode and are very active during the Summer months on 28 MHz.
Andy, G0FTD has compiled a Winter 2019 Compendium and it can be viewed in PDF format HERE
Opening to Africa on 28 MHz - Sun 15th Dec 2019
The ARRL 10-metre contest was held last weekend and it usually generates quite a bit of activity if the band is in good shape.
On Saturday the 14th of December, conditions on the band were poor and I just heard a few stations on FT8 from around Europe. I scanned the CW and SSB portion of the band once and I heard just one very weak German station on CW.
I wasn't around on Sunday the 15th of December but I left the radio on monitoring the band. It seems as if the band was much better with plenty of Sporadic-E signals from Europe.
The really interesting signals are the ones from further away. For example, I heard Greece and Turkey... double hop Sporadic-E or F2 propagation?
In Africa, I heard TT8SN in Chad as well as three in South Africa. 3B8CW on Mauritius in the Indian Ocean was also heard.
Considering it's December and we're at the bottom of the sunspot cycle, it was a reasonable opening.
(Solar Flux: 71 / Sunspot number 0)
On Saturday the 14th of December, conditions on the band were poor and I just heard a few stations on FT8 from around Europe. I scanned the CW and SSB portion of the band once and I heard just one very weak German station on CW.
I wasn't around on Sunday the 15th of December but I left the radio on monitoring the band. It seems as if the band was much better with plenty of Sporadic-E signals from Europe.
The really interesting signals are the ones from further away. For example, I heard Greece and Turkey... double hop Sporadic-E or F2 propagation?
In Africa, I heard TT8SN in Chad as well as three in South Africa. 3B8CW on Mauritius in the Indian Ocean was also heard.
Considering it's December and we're at the bottom of the sunspot cycle, it was a reasonable opening.
(Solar Flux: 71 / Sunspot number 0)
Sunday, December 15, 2019
Experiments continue on the 40 MHz band in the west of Ireland
Back in early 2018, the 40 MHz (8-metre) band was allocated to radio amateurs in Ireland (EI) on a secondary non-interference basis. Since then, interest in experimenting on the band has increased and there are now a number of EI stations carrying out tests.
The latest EI station on the band is Stefan, EI4KU in Co.Clare in the west of Ireland. Stefan has kindly forwarded on some details and photos of his latest tests.
Equipment... Stefan has built a small 1-watt beacon running on 40.013 MHz and is carrying out propagation tests. The photo below shows the home made beacon and the associated antenna tuning unit (ATU).
The beacon is using a crystal running at about 13 MHz and this is modulated by a varactor diode (FSK - Frequency Shift Keying). This is then tripled up to 40.013 MHz and is then buffered and amplified. The output transistor is a 2SC1970 running in Class-C with one watt after the low pass filter.
The signal is then fed into a home made Z-match ATU as shown below.
Unusually, 100-Ohm balanced coax cable is used on the output. This however provides a very good match to the antenna which is a single quad loop which would have an impedance of about 100 ohms.
The photo above shows the quad loop. The sides are about 2 metres each and it is shown being fed at the bottom so it is horizontally polarised.
This photo below shows the view to the north from Stefan's location so it looks as if he is in a good spot for VHF.
Stefan is currently in the process of building a transverter for the band. If anyone would like to carry out some tests on the 40 MHz, EI4KU can be contacted via QRZ.
Tests... In November of 2019, Stefan carried out some tests with Phil EI9KP and Michael EI3GYB in Co.Mayo with the equipment shown above and both heard the CW beacon.
The distances covered were about 125 kms for EI9KP and 100 kms for EI3GYB.
The waterfall display below shows the slow cw signal as received by EI9KP in Mayo.
Interestingly, the signal over the 125 km path wasn't always steady. This second screenshot from EI9KP shows some multi-path distortion on the signal.
In an email, Phil EI9KP described it like this..."Screenshot attached showing reception of the beacon signal showing diffracted signal (wavey pattern). The signal diffraction is actually audible on the long carrier and it sounds like a wave building."
Phil also reports that he was using a horizontally polarised 2 element Yagi beam 5m above ground level for reception of the signal and it was RST 519.
EI3GYB... Michael, EI3GYB also reports that he heard Stefan's beacon from a distance of about 100 kms. Interestingly, Michael reports that there was a very slow fading on the band at times with the signal going from nothing up to 519. Most of the time, it was around 319 when the band was stable.
This mix of steady and fading signals would seem to concur with some of the reception reports that EI9KP experienced.
Michael doesn't have a dedicated antenna for the 8 metre band but instead was switching between a Sandpiper Moxon for 2/4/6 in horizontal position and a Windom antenna for 160 to 6 metres. According to Michael..."The Moxon was the best, although I had a period where I received nothing via the Moxon, but a 5/1 signal on the Windom."
It seems like that the 6m part of the Sandpiper Moxon was probably acting as a shortened dipole on 40 MHz so the gain would be somewhat reduced.
Michael also reports having several contacts with Phil, EI9KP on SSB who is 25 kms distant.
Thanks to Phil, EI9KP and Michael, EI3GYB for their reception reports... de EI7GL
The latest EI station on the band is Stefan, EI4KU in Co.Clare in the west of Ireland. Stefan has kindly forwarded on some details and photos of his latest tests.
Equipment... Stefan has built a small 1-watt beacon running on 40.013 MHz and is carrying out propagation tests. The photo below shows the home made beacon and the associated antenna tuning unit (ATU).
The beacon is using a crystal running at about 13 MHz and this is modulated by a varactor diode (FSK - Frequency Shift Keying). This is then tripled up to 40.013 MHz and is then buffered and amplified. The output transistor is a 2SC1970 running in Class-C with one watt after the low pass filter.
The signal is then fed into a home made Z-match ATU as shown below.
Unusually, 100-Ohm balanced coax cable is used on the output. This however provides a very good match to the antenna which is a single quad loop which would have an impedance of about 100 ohms.
The photo above shows the quad loop. The sides are about 2 metres each and it is shown being fed at the bottom so it is horizontally polarised.
This photo below shows the view to the north from Stefan's location so it looks as if he is in a good spot for VHF.
Stefan is currently in the process of building a transverter for the band. If anyone would like to carry out some tests on the 40 MHz, EI4KU can be contacted via QRZ.
Tests... In November of 2019, Stefan carried out some tests with Phil EI9KP and Michael EI3GYB in Co.Mayo with the equipment shown above and both heard the CW beacon.
 |
| EI4KP (IO52OW), EI9KP (IO54MB) & EI3GYB (IO53OT) |
The distances covered were about 125 kms for EI9KP and 100 kms for EI3GYB.
The waterfall display below shows the slow cw signal as received by EI9KP in Mayo.
Interestingly, the signal over the 125 km path wasn't always steady. This second screenshot from EI9KP shows some multi-path distortion on the signal.
In an email, Phil EI9KP described it like this..."Screenshot attached showing reception of the beacon signal showing diffracted signal (wavey pattern). The signal diffraction is actually audible on the long carrier and it sounds like a wave building."
Phil also reports that he was using a horizontally polarised 2 element Yagi beam 5m above ground level for reception of the signal and it was RST 519.
EI3GYB... Michael, EI3GYB also reports that he heard Stefan's beacon from a distance of about 100 kms. Interestingly, Michael reports that there was a very slow fading on the band at times with the signal going from nothing up to 519. Most of the time, it was around 319 when the band was stable.
This mix of steady and fading signals would seem to concur with some of the reception reports that EI9KP experienced.
Michael doesn't have a dedicated antenna for the 8 metre band but instead was switching between a Sandpiper Moxon for 2/4/6 in horizontal position and a Windom antenna for 160 to 6 metres. According to Michael..."The Moxon was the best, although I had a period where I received nothing via the Moxon, but a 5/1 signal on the Windom."
It seems like that the 6m part of the Sandpiper Moxon was probably acting as a shortened dipole on 40 MHz so the gain would be somewhat reduced.
Michael also reports having several contacts with Phil, EI9KP on SSB who is 25 kms distant.
Thanks to Phil, EI9KP and Michael, EI3GYB for their reception reports... de EI7GL
Friday, December 13, 2019
Cambridge Consultants announce low cost DRM receiver design
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. "
More info HERE
Lone signal from the USA heard on 28 MHz - Thurs 12th Dec 2019
The 12th of December 2019 seemed pretty poor for propagation on 28 MHz.
First off, there was a distinct lack of stations. I noted the following two however...
103130 -1 -0.1 1494 ~ CQ G0OYQ IO93
103200 -3 -0.1 1495 ~ CQ G0OYQ IO93
110000 -14 -0.2 1364 ~ CQ RA2FL KO04
110415 -3 -0.3 1365 ~ CQ RA2FL KO04
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.
134630 -12 -0.2 1331 ~ CQ K6ND FN10
134700 -9 -0.2 1331 ~ CQ K6ND FN10
134730 -13 -0.2 1331 ~ CQ K6ND FN10
134800 -13 -0.2 1331 ~ CQ K6ND FN10
Thursday, December 12, 2019
QRP-Labs release a 50 watt amplifier for their CW QCX Transceiver
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.
For more info, go to https://qrp-labs.com/50wpa.html
Wednesday, December 11, 2019
Latest forecast for the next Solar Cycle - Dec 2019
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).
Monday, December 9, 2019
Recent 3000km+ opening on 144 MHz between New Zealand and Australia reported
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.
2019-12-01 04:12 ZL1SIX 144.490539 -18 1 RF64vs 10 VK5AKK PF94ix 3174 kms
2019-12-01 03:52 ZL1SIX 144.490540 -14 0 RF64vs 10 VK5GF PF94hk 3171 kms
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.
2019-12-06 04:06 VK2DVM 144.490524 -27 1 QF56og 10 VK6NI OF85pa 3102
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.
Conditions on 28 MHz - Mon 9th Dec 2019
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.
Saturday, December 7, 2019
Australian 70cms digital record extended to 2,806 kms
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 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.
Leigh VK2KRR has a nice website with plenty of VHF info, visit https://www.vk2krr.com/
Friday, December 6, 2019
DRM tests from Hungary on 26 MHz - June 2019 to June 2020
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!
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.
Links...
1) https://www.drm.org/
Addendum...
1) In response to this blog post, Rob PE9PE suggests the use of an online SDR to listen to the 26 MHz frequency... http://websdr.ewi.utwente.nl:8901/ and https://sdr.hu/
I wonder if there is an online DRM receiver in Europe???
2) Thanks to Bas PE4BAS for the info about the DREAM programme which can decode DRM signals. Info... https://www.drm.org/pc-based-receivers-and-software/
3) Info on 26 MHz from the DRM Handbook (Feb 2019)...
 |
| 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.
Links...
1) https://www.drm.org/
Addendum...
1) In response to this blog post, Rob PE9PE suggests the use of an online SDR to listen to the 26 MHz frequency... http://websdr.ewi.utwente.nl:8901/ and https://sdr.hu/
I wonder if there is an online DRM receiver in Europe???
2) Thanks to Bas PE4BAS for the info about the DREAM programme which can decode DRM signals. Info... https://www.drm.org/pc-based-receivers-and-software/
3) Info on 26 MHz from the DRM Handbook (Feb 2019)...
Wednesday, December 4, 2019
Opening to the USA on 28 MHz - Wed 4th Dec 2019
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.
143800 -12 -0.2 1327 ~ G0OYQ W1SSN -12
143830 -6 -0.2 1327 ~ G0OYQ W1SSN -12
143930 -11 -0.3 1328 ~ G0OYQ W1SSN -12
144000 -14 -0.3 1328 ~ G0OYQ W1SSN -12
144300 -12 -0.3 1328 ~ G0OYQ W1SSN -18
145700 -18 -0.2 1112 ~ KN4CNX W2MGF 73
145830 -18 -0.2 1111 ~ G4HZW W2MGF FN30
150400 -10 -0.6 973 ~ CQ WA2HMM FN30
150430 -8 -0.6 973 ~ CQ WA2HMM FN30
150500 -6 -0.6 972 ~ CQ WA2HMM FN30
150530 -12 -0.6 973 ~ CQ WA2HMM FN30
150600 -12 -0.8 1520 ~ G4HZW NF1G R-14
150630 -10 -0.8 1520 ~ G4HZW NF1G 73
Sunday, December 1, 2019
Good Sporadic-E opening on 28 MHz - Sun 1st Dec 2019
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?
Saturday, November 30, 2019
Falkland Islands gain access to 70 MHz band
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 |
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.
Link...
1) https://www.regulatorfi.org.fk/spectrum/national-frequency-allocation-table/60-fi-spectrum-allocation-table-v2-0-full-table-public-pdf/file
Friday, November 29, 2019
FreeDV: A digital voice mode for the HF bands
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 |
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.
Timeline...
2009 - Codec 2
2012/2013 - FreeDV 1600
2015 - SM1000 FreeDV hardware
2018 - FreeDV 700D low SNR > SSB
2019 - FreeDV 2020 8 kHz audio
2019 - SM1000 700D port
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.
Link...
1) FreeDV... https://freedv.org/
2) Demo of 2020 mode
Friday, November 22, 2019
Guest post: A look at the Clansman PRC-3512 Low Band VHF Radio...by EI5DD
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 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
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.
Thursday, November 21, 2019
More countries in Europe & Africa gain access to 50 MHz
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.
Links...
1) IARU news item dated 21st Nov 2019
2) RSGB News
Subscribe to:
Posts (Atom)