Monthly Archives: January 2016

Some afternoon listening

During the summer months I usually help out my XYL in her shop on Saturdays/Sunday afternoons, so most of my listening is confined to the evening hours. However, during the winter months when trade is, should we say, slack, I get the weekend ‘off’. So today, after doing some household chores I settled in to do some listening. A lot of stations are on during the afternoon which I don’t normally get to hear, so it makes a nice change. Or the ones I can hear in the evening may have a stronger signal earlier in the day as they may be beaming more toward the UK. Also, during the winter months, the higher bands (17m, 19m and 22m) have shut down by the evening. So within the space of an hour I logged the following.

My listening sessions are usually confined to hour chunks, as I use a laptop for logging and frequency reference. My laptop has an extremely noisy SMPS, so I can only run it on battery power whilst listening, otherwise unless I am listening to one of the high power stations, everything is swamped by hash. Unfortunately, as the laptop is about 7 years old, the battery only lasts for an hour before requiring re-charging. Hence the hour chunks.

Logs:

17700 Khz Botswana VOA 15:25 UTC Hausa. Female announcer. ID at close out at 15:30 SINPO: 54455 2016-01-30

15140 Khz Oman R Sultanate of Oman 15:33 UTC Arabic. Discussion with a child followed by child reciting the English alphabet. SINPO: 54444 2016-01-30

15610 Khz USA WEWN 15:40 UTC English. Discussion about communications skills. SINPO: 43333 2016-01-30

13590 Khz Sri Lanka VOA Deewa Radio 15:45 UTC Pashto. Sounds like a radio drama. SINPO: 54444 2016-01-30

11670 Khz Phillipines VOA 16:10 UTC Tibetan. Male announcer. SINPO: 32233 2016-01-30

11655 Khz UAE IBRA Radio 16:15 UTC Afar. Male announcer SINPO: 43333 2016-01-30

11645 Khz North Korea V.O. Korea 16:17 UTC Music with announcements in Arabic. SINPO: 33333 2016-01-30

11680 Khz South Korea KCBS 16:22 UTC Korean. Music and chat. SINPO: 43333 2016-01-30

11730 Khz Belarus R Belarus 16:26 UTC Polish. Female announcer SINPO: 54444 2016-01-30

11860 Khz Saudi Arabia Yemen Radio 16:31 UTC Arabic. Music and chat SINPO: 32233 2016-01-30

The last one is a new one for me. Quite a good signal considering it is only a 50 KW transmitter.

RSGB propagation Report

Solar activity was a little more settled last week. The solar flux index was in the range 104-113 and the K index was mainly around one or two later in the week, after reaching four on Sunday.
This week the solar flux index is predicted to remain in the range 100-118, with lower activity on Friday the 5th and Saturday the 6th. The K index will be mostly settled, but possibly reaching four on Tuesday or Wednesday.
During this past week the noon critical frequency as measured by the Chilton Ionosonde reached 7.5MHz on Wednesday, offering a maximum usable frequency over 3,000km of about 27MHz. Ten and twelve metres have shown some activity with Bob, VP8LP on the Falkland Islands making an appearance at times.
Staying with the South Atlantic, the VP8SGI DXpedition should hopefully be on the air this week from South Georgia Island. On 7MHz and 14MHz, the best times for working them will be on 40m after midnight and 20m in the late evening and early hours of the morning.
During daytime, all the upper HF bands may offer opportunities, with even the possibility of a 10m opening from around 1000 to 1500 UTC. The optimum band, with a 90% probability of an opening, is 15m during late morning.
VHF and up propagation news:
The hoped-for tropo didn’t materialise last week and the charts look very unsettled again. Later in the week one of the weather models predicts a small high in the cold air over northern Britain, but others are less convinced and maintain a much larger high near the Azores. Any useful ridging from this extending into the continent to give some tropo across the Mediterranean, France and Iberia is sadly just out of reach from the UK.
The Moon reaches minimum declination on Friday so we will have short moon windows and low elevations with losses still quite high.
We are still in the early-year minimum of random meteor rates, so persistence and early morning activity is still the order of the day for meteor scatter operators.
Overall then, it is not looking promising for any significant tropo, but perhaps other modes will come to our rescue like rain scatter on the GHz bands or possibly aurora. This is perhaps a good week to try some satellite QSOs if you want to keep your VHF and up QSO rates ticking over.

The true story of the Yagi Antenna

From the DXZONE comes this interesting article on the development of the Yagi antenna.

Yagi antenna history

As many of you may already know, the full name of this antenna is Yagi-Uda Antenna.

The origin of this name is derived by the surname of two Japanese inventors that designed this antenna for the first time at the beginning of the 1920’s.

Yagi Antenna US Paten
Yagi Antenna US Patent Source http://www.uspto.gov
The two inventors were, Hidetsugu Yagi(1886-1976) and Shintaro Uda (1896-1976)  both professors at the Tohoku University Japan.

What not everyone knows is that the original concept of this antenna has to be attributed to Shintaro Uda(Yagi’s assistant professor) that in 1926, first described this antenna at Tohuku University in Japan,  in the IEEJ (Japan).

Hidetsugu Yagi , who worked in the UK, USA and Germany, applied for patents on the new antenna both in Japan and the United States.

The Japanese patent was immediately issued in 1926 with nr. 69115 while the U.S. patent 1,860,123filed in 1926 was issued later in 1932.

While the Japanese patent was properly attributed to both the inventors, the US patent was assigned tothe Dr. Yagi.

Japanes Patent 69115
Japanes Patent 69115 source aktuellum.com

Dr. Yagi is listed among the ten Japanese great inventors by the Japan Patent Office for this very invention, and has been president of Japan Amateur Radio League (JARL) in 1946.

Although no one can ever tell us how much authorship should be attribute to Professor Yagi rather than Professor Uda , certainly we should attribute the right authorship to this antenna by naming it always as Yagi-Uda.

A quick canter across the low bands

Some low-band loafing this evening. A quick canter across the lower bands gave the following (I haven’t included the multiplicity of CRI channels on these frequencies!)

4835 Khz Australia ABC Alice Springs 20:14 UTC English. Female announcer with ID at 20:14. Music and chat SINPO: 32222 2016-01-27

4920 Khz Tibet PBS Xizang 21:28 UTC Music and chat SINPO: 21122 2016-01-27

5885 Khz Vatican City VOA 21:38 UTC Bambara. Discussion prorgram SINPO: 54444 2016-01-27

5950 Khz Iran V.O. Iran 21:42 UTC Bosnian. Male announcer. Discussion. SINPO: 43344 2016-01-27

5960 Khz Albania CRI 21:44 UTC English. Discussion about making websites accessible to the visually impaired. SINPO: 54444 2016-01-27

5980 Khz Turkey V.O. Turkey 21:45 UTC Turkish. Middle-eastern music SINPO: 54455 2016-01-27

6195 Khz Singapore BBCWS 22:08 UTC English. News SINPO: 21122 2016-01-27

7380 Khz Romania RRI 22:12 UTC Spanish. Magazine program. SINPO: 54444 2016-01-27

Radio Inventors – J.C. Bose

With acknowledgements to both the SWLing Post and Hackaday for this. I have to admit, the only Bose I have heard of connected with electronics/radio is the American company who flamboyantly advertise the amazing properties of their equipment.

The gentleman who is the subject of this piece was an Indian scientist active at the turn of the 19th century. Marconi may have commercialised the use of radio, but it would appear J.C. Bose invented it way before. Anyway, here’s the article, I hope you enjoy it as much as I did.

The early days of electricity appear to have been a cutthroat time. While academics were busy uncovering the mysteries of electromagnetism, bands of entrepreneurs were waiting to pounce on the pure science and engineer solutions to problems that didn’t even exist yet, but could no doubt turn into profitable ventures. We’ve all heard of the epic battles between Edison and Tesla and Westinghouse, and even with the benefit of more than a century of hindsight it’s hard to tell who did what to whom. But another conflict was brewing at the turn of 19th century, this time between an Indian polymath and an Italian nobleman, and it would determine who got credit for laying the foundations for the key technology of the 20th century – radio.

Appointment and Disappointment

Jagadish_Chandra_Bose
Jagadish Chandra Bose

In 1885, a 27-year old Jagadish Chandra Bose returned to his native India from England, where he had been studying natural science at Cambridge. Originally sent there to study medicine, Bose had withdrawn due to ill-health exacerbated by the disagreeable aroma of the dissection rooms. Instead, Bose returned with a collection of degrees in multiple disciplines and a letter of introduction that prompted the Viceroy of India to request an appointment for him at Presidency College in Kolkata (Calcutta). One did not refuse a viceroy’s request, and despite protests by the college administration, Bose was appointed professor of physics.

Sadly, the administration found ways to even the score, chiefly by not providing Bose with any laboratory space, but also by offering him only 100 rupees a month salary, half of what an Indian professor would normally make, and only a third of an Englishman’s salary. Bose protested the latter by refusing salary checks – after three years his protest worked and he got his full salary retroactively – and worked around the former by converting a tiny cubicle next to a restroom into a lab. But in those 24 square feet, equipped with instruments of his own design and paid for at his expense, Bose would work wonders and begin to engineer the embryonic field of radio.

At around the time Bose joined Presidency College, Heinrich Hertz was confirming the existence of electromagnetic waves, postulated by James Clerk Maxwell in the 1860s. Maxwell died before he could demonstrate that electricity, magnetism, and light are all one in the same phenomenon, but Hertz and his spark gap transmitters and receivers proved it. Inspired by this work and intrigued by the idea that “Hertzian Waves” and visible light were the same thing, Bose set about exploring this new field.

2048px-Microwave_Apparatus_-_Jagadish_Chandra_Bose_Museum_-_Bose_Institute_-_Kolkata_2011-07-26_4051
Bose’s microwave apparatus. Transmitter on right, galena detector in the horn on the left of the experiment stage. By Biswarup Ganguly

By 1895, barely a year after starting his research, Bose made the first public demonstration of radio waves in the Kolkata town hall. Details of the apparatus used are vague, but at a distance of 75 feet, he remotely rang an electric bell and ignited a small charge of gunpowder. The invited guests were amazed by the demonstration that Adrisya Alok, or “Invisible Light” as Bose would summarize it in a later essay, could pass through walls, doors, and in a particularly daring feat of showmanship, through the body of the Lieutenant Governor of Bengal.

Bose’s wireless demonstration was remarkable for a couple of reasons. First, it took place two years before Marconi’s first public demonstrations of wireless telegraphy in England. Where Marconi was keenly interested in commercializing radio, Bose’s interest was purely academic; in fact, Bose flatly refused to patent nearly all of the inventions that would spring from his tiny workshop, on the principle that ideas should be shared freely.

The 1895 demonstration also used microwave signals instead of the low and medium frequency waves that Marconi and others were working with. Bose recognized early on that shorter wavelengths would make it easier to explore the properties of radio waves that were similar to light, like reflection, refraction, and polarization. To do so, he invented almost all the basic components of microwave systems – waveguides, polarizers, horn antennas, dielectric lenses, parabolic reflectors, and attenuators. His spark-gap transmitters were capable of 60GHz operation.

Coherent Thoughts

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Marconi Admiralty Pattern Coherer. Source: The Science Museum (UK)

Some of Bose’s most important work in radio concerned detection of electromagnetic waves. Early wireless pioneers had discovered that electromagnetic waves could be rectified by fine metal particles contained in a tube between metal conductors; the electrical energy would cause the particles to clump together and become conductive. The device was called a coherer because of the clumping action and was used as rectifiers in all the early practical wireless receivers, despite its operation being not well-understood. Experiments with coherers continue to this day.

Early coherers had a problem, though – the filings stayed stuck together after the signal had passed. The device needed to be reset by a tiny electromagnetic tapping mechanism that jiggled the filings back into a non-conductive state before the next signal could be detected. This had obvious effects on bandwidth, so the search for better detectors was on. One improvement invented by Bose in 1899 was the iron-mercury-iron coherer, with a pool of mercury in a small metal cup. A film of insulating oil covered the mercury, and an iron disc penetrated the oil but did not make contact with the liquid mercury. RF energy would break down the insulating oil and conduct, with the advantage of not needing a decoherer to reset the system.

Bose’s improved coherer design would miraculously appear in Marconi’s transatlantic wireless receiver two years later. The circumstances are somewhat shady – Marconi’s story about how he came up with the design varied over time, and there were reports that Bose’s circuit designs were stolen from a London hotel room while he was presenting his work. In any case, Bose was not interested in commercializing his invention, which Marconi would go on to patent himself.

The Father of Semiconductors?

Early Bose galena point-contact detectors. Source: National Radio Astronomy Observatory
Early Bose galena point-contact detectors. Source: National Radio Astronomy Observatory

Bose also did early work in semiconductor detectors. Bose was exploring the optical properties of radio waves when he discovered that galena, an ore of lead rich in lead sulfide, was able to selectively conduct in the presence of radio waves. He was able to demonstrate that point contacts on galena crystals worked as a better coherer, and in an uncharacteristic move actually patented the invention. Interestingly, the patent includes descriptions of substances that show either decreased or increased resistance to current flow with increasing voltage; Bose chose to describe these a “positive” and “negative” substances, an early example of the “P-N” nomenclature that would become common in semiconductor research. Decades later, William Brattain, co-inventor of the transistor, would acknowledge that Bose had beat everyone to the punch on semiconductors and would credit him with inventing the first semiconductor rectifier.

Inventions and innovations would flow from Bose’s fertile mind for many decades. He eventually turned his attention to plant physiology, studying the stress responses of plants with a sensitive device he invented, the crescograph, which could amplify the movements of the tips of plants by a factor of 10,000. Not surprisingly, he also did important work on the effects of microwaves on plant tissues. Bose also did work comparing metal fatigue and fatigue in physically stressed plant tissues. Bose is also considered the father of Bengali science fiction.

Bose is rarely remembered as a pioneer in radio, despite all he accomplished in engineering the wireless system that would eventually stitch together the world. Given his position on patents, that’s not surprising – his inventions were his gift to the world, and he seemed content with letting others capitalize on his genius.

Early 2016 listening conditions

My listening times since the start of the new year have been somewhat sporadic due to a number of factors. Some of the usual things such as work, family etc but also the many days of sub-par conditions. Even when the predictions from qrz.com and Solarham showed that conditions would be fair – good, I have noticed the bands to be very noisy. And this isn’t local noise from electrical gadgets, it’s solar/atmospheric noise. 31m appears, at least from this QTH, to be particularly  prone to poor conditions. I have some ‘marker’ stations on various bands which, when conditions are good, come booming in. These are VOA on 15580 in the 19m band, R Thailand on 9390 in the 31m band and R Farda on 5865 in the 49m band. These give a nice spread frequency-wise, over the busiest part of the HF spectrum. For a lot of days this year, reception of these, at the appropriate times of day, have been poor.

One surprise over a couple of days recently has been reception of ABC Alice Springs on 4835. On two consecutive days, reception was in the poor – fair range, when normally it is in the inaudible – poor range! A day later, it was back down in the noise. Ain’t propagation a wonderful and mysterious thing!

Talking of propagation, I received a great book for Christmas entitled: ‘Radio and Propagation Principles and Practice’ by Ian Poole G3YWX. I can highly recommend this book as it lays out the detail of radio propagation in an easy to follow style. It can be read from cover to cover, but it’s more of a dip-in-and-out book when you want info on something specific.

 

Here are the logs for the first 17 days of 2016:

9575 Khz Morocco Medi 1 17:55 UTC French/Arabic. Music and chat. SINPO: 44444 2016-01-01

11615 Khz Botswana Afia Darfur 18:25 UTC Arabic. male announcer. Loud buzzing noise. SINPO: 32333 2016-01-01

9610 Khz China CNR8 22:40 UTC Chinese. Music and chat SINPO: 32222 2016-01-05

9625 Khz Australia Reach Beyond Australia 22:44 UTC Indonesian. Religious broadcast, ending at 22:45 SINPO: 33333 2016-01-05

9525 Khz Java V.O. Indonesia 20:25 UTC French. Female announcer with music and chat. ID at 20:29 SINPO: 33333 2016-01-06

9690 Khz Nigeria V.O. Nigeria 20:45 UTC Hausa. Sounds like a heated discussion SINPO: 33333 2016-01-06

9840 Khz UAE KBS World Radio 20:59 UTC Arabic. Closing announcements and sign-off music SINPO: 54444 2016-01-06

9915 Khz Ascension Island BBCWS 21:02 UTC English. News SINPO: 33333 2016-01-06

9940 Khz Swaziland TWR 19:06 UTC Lingala. Male announcer. SINPO: 43333 2016-01-09

9780 Khz Ascension Island Afia Dafur 19:20 UTC Arabic. ID at 19:21, male announcer. SINPO: 43333 2016-01-09

5865 Khz Sri Lanka R Farda 19:35 UTC Farsi. Female announcer SINPO: 43333 2016-01-09

5875 Khz Phillipines VOA 19:41 UTC Korean. Male announcer. Sever QSB, only just audible at times. SINPO: 22222 2016-01-09

9500 Khz Swaziland TWR 18:58 UTC Swahili. Music followed by contact details before closedown at 19:02. SINPO: 43333 2016-01-12

9505 Khz Sudan V Africa 19:03 UTC Hausa. Music and chat. SINPO: 21122 2016-01-12

4835 Khz Australia ABC Alice Springs 19:08 UTC English. Discussion program. SINPO: 32222 2016-01-12

6195 Khz Singapore BBCWS 22:12 UTC English. World News SINPO: 32233 2016-01-12

4835 Khz Australia ABC Alice Springs 18:34 UTC English. World news followed by Australian weather and temps. ID at 18:35 SINPO: 32233 2016-01-14

4930 Khz Botswana VOA 18:56 UTC English. World news followed by ID at 18:57 SINPO: 32233 2016-01-14

5980 Khz Turkey V.O Turkey 19:04 UTC Turkish. Male announcer. Sounds like football match SINPO: 54444 2016-01-14

15325 Khz Guam KSDA 10:18 UTC Mandarin. Male announcer SINPO: 22222 2016-01-16

15465 Khz Taiwan R Taiwan 10:23 UTC Amoy. Female announcer SINPO: 33333 2016-01-16

15640 Khz Phillipines FEBC 10:28 UTC Close-out music. Off air at 10:30 SINPO: 21122 2016-01-16

15760 Khz Sri Lanka R Mashaal 10:57 UTC Pashto. Male announcer SINPO: 32233 2016-01-16

11615 Khz Botswana Afia Darfur Radio 18:20 UTC Arabic. Male announcer SINPO: 43333 2016-01-17

11735 Khz Zanzibar ZBC 18:25 UTC Swahili. Discussion program SINPO: 32233 2016-01-17

11760 Khz Cuba R Habana 18:30 UTC Spanish. ID at 18:31 followed by music and chat SINPO: 32222 2016-01-17

11900 Khz South Africa VOA 18:35 UTC Amharic. Music and chat. SINPO: 43333 2016-01-17

12075 Khz Botswana VOA 18:40 UTC French. Learning English program. SINPO: 43344 2016-01-17

9590 Khz Sao Tome VOA 19:38 UTC French. Soul music. SINPO: 33333 2016-01-17

5865 Khz Sri Lanka R Farda 19:48 UTC Persian. Ethnic music and chat. ID at 19:49 SINPO: 43344 2016-01-17