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Many thanks to SWLing Post contributor, Kris Partridge, who writes:
Last night I sent the link to the SWLing Droitwch item to a former colleague. He replied this morning, reply below, and includes a couple of useful links. I’m very sure the SWLing Post knows about MB21.
Thinking that maybe the item on Crowbourgh will be of interest to SWLing readers. It contains the ‘magic’ word “Aspidistra” ! Lot of SW history there.
Many thanks to SWLing Post contributor, Dave Porter, who writes:
This picture [above] has just emerged, photographer unknown but most likely a rigger from the top of one of the 700′ masts there!
This was taken at Droitwich sometime after colour photography came in (late 1960’s) and before 1986 when the four wire Tee was replaced by a new design developed by BBC Antenna Engineer Tony Preedy, G3LNP that improved upon the 11-j85 Ohms driving point impedance giving a few more ohms and less capacitive reactance for the 2 x 250kW B6042 transmitters and a greater radiation efficiency.
Tony’s present LF array does not look so symmetrical as it comprises four separate Tee wires with the drops as a square box rather than the centre-joined drops of this one.
Tony also developed a low profile Tee antenna over 3 x 17m wooden telegraph poles for MF at up to 1 kW that was used when planning restrictions were enforced. Efficiencies were up to 40% at the 1500 kHz end of the band. However, if used by birds as an overnight roost it could provoke VSWR trips on solid state transmitters, the fix was to use a sliding reduced power detector that wound down the power to a level that did not trip the VSWR monitoring. Old tube transmitters were not affected!
The operating frequency for this LF Tee was 200 kHz at that time, now the antenna is on 198 kHz
Wow–thank you, Dave, for sharing this photo. We truly appreciate your impressive knowledge of UK broadcasting and history! And, wow! The views those riggers took in!
Radio Waves: Stories Making Waves in the World of Radio
Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers. To that end: Welcome to the SWLing Post’sRadio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!
Many thanks to SWLing Post contributors Ron, John (K5MO) and the Southgate ARC for the following tips:
Did a broken random number generator in Cuba help expose a Russian espionage network?
I picked up the new book Compromised last week and was intrigued to discover that it may have shed some light on a small (and rather esoteric) cryptologic and espionage mystery that I’ve been puzzling over for about 15 years. Compromised is primarily a memoir of former FBI counterintelligence agent Peter Strzok’s investigation into Russian operations in the lead up to the 2016 presidential election, but this post is not a review of the book or concerned with that aspect of it.
Early in the book, as an almost throwaway bit of background color, Strzok discusses his work in Boston investigating the famous Russian “illegals” espionage network from 2000 until their arrest (and subsequent exchange with Russia) in 2010. “Illegals” are foreign agents operating abroad under false identities and without official or diplomatic cover. In this case, ten Russian illegals were living and working in the US under false Canadian and American identities. (The case inspired the recent TV series The Americans.)
Strzok was the case agent responsible for two of the suspects, Andrey Bezrukov and Elena Vavilova (posing as a Canadian couple under the aliases Donald Heathfield and Tracey Lee Ann Foley). The author recounts watching from the street on Thursday evenings as Vavilova received encrypted shortwave “numbers” transmissions in their Cambridge, MA apartment.
Given that Bezrukov and Vaviloa were indeed, as the FBI suspected, Russian spies, it’s not surprising that they were sent messages from headquarters using this method; numbers stations are part of time-honored espionage tradecraft for communicating with covert agents. But their capture may have illustrated how subtle errors can cause these systems to fail badly in practice, even when the cryptography itself is sound.[…]
From today, Thursday, Sept 24, the RSGB are allowing Full amateur radio online exams to be booked. All 3 levels of exam required to get a HAREC certificate can now be done completely online
Potentially this could mean amateurs in other countries could take the RSGB online exams, get their HAREC certificate and then apply for an amateur licence in their own country. This would be beneficial in those countries where provision of local exams is virtually non-existent.
Currently there is a 4-5 week backlog for amateur radio exams, the next available exam slots that can be booked are at the end of October.
The wartime BBC was involved in a range of top secret activities, working closely with the intelligence agencies and military.
by Professor David Hendy
As well as making programmes for the public, the wartime BBC was involved in a range of top secret activity, working with closely with the intelligence agencies and military. Here, newly-released archives lift the veil on the broadcaster’s role in this clandestine world of signals, codes, and special operations.
It’s always been known that just before the war began in September 1939, the BBC’s fledgling television service was unceremoniously shut down for the entire period of the conflict.
What’s less well-known is that, far from being mothballed, the television facilities of Alexandra Palace were carefully kept ticking-over by a small team of engineers – and that the transmitter which had supposedly been silenced for reasons of national security was soon sending out its signals again.
From May 1940, Alexandra Palace’s ‘vision’ transmitter was being tested for its ability to jam any messages passing between tanks in an invading German force. The following year, its sound transmitter was being deployed for something called ‘bending the beam’. One of the BBC’s engineers who remained on site was Tony Bridgewater:[…]
Thank you for sharing this, Jeremy. I can guarantee that if the TV was emitting enough noise to interfere with broadband, it likely also affected the HF, MW, and LW radio bands!
What baffles me is the amount of time it took for the engineers to track down the source in such a small community. A skilled RFI engineer would have likely discovered what was causing the noise by looking at the spectrum analyzer–quite often the signal shape and frequency are indicators. In addition, a little signal “fox hunting” could have proven useful. With that said, noises aren’t always easy to locate and can travel along unexpected paths.
I certainly don’t blame the resident for remaining anonymous!
Radio Waves: Stories Making Waves in the World of Radio
Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers. To that end: Welcome to the SWLing Post’sRadio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!
Many thanks to SWLing Post contributors Mark Hist, Kris Partridge, John Palmer, and the Southgate ARC for the following tips:
Radio reporters to be axed by BBC and told to reapply for new roles Critics fear end of an era because of plans to make audio journalists work across media platforms
BBC radio voices have described and defined modern British history. Live reports from inside a British bomber over Germany during the second world war, or with the British troops invading Iraq in 2003, or more recently from the frontline of the parent boycott of a Birmingham school over LGBT lessons have also shaped the news agenda.
But now the BBC plans to axe all its national radio reporters and ask them to reapply for a smaller number of jobs as television, radio and digital reporters, rather than as dedicated audio journalists. Many fear it is not just the end of their careers but the premature end of an era for the BBC.
“Radio reporting is a different job. Of course, you can do both, but a report designed for television starts from a completely different place. Radio is also more agile and also a lot less expensive,” said one experienced broadcast journalist. “I am pretty sure most of us will not be given new TV roles. It seems sad to lose all that specific radio expertise.”
Among the well-known voices likely to be affected are Hugh Sykes, Andrew Bomford – who has just completed a long feature on the child protection process for Radio 4’s PM show – and the award-winning and idiosyncratic Becky Milligan, as well as a wider team of expert correspondents.[…]
A high-altitude balloon experiment, launched by Warsaw University of Technology, is planned to lift off September 12, carrying a VLF 210-m-long fully-airborne antenna system, transmitting on 14.2 kHz
14.2 kHz is the former frequency of the Babice Radio Station in Poland.
The project is delivering very important data for a doctoral dissertation – any and all feedback on the reception of the signal (reception location, SNR, bandwidth etc.) is extremely important; your help with the listening to the transmission would be invaluable!
The balloon will also be transmitting APRS on 144.800 MHz FM, callsign SP5AXL.
Invented for the first time in 2014, in 2020 it will finally be implemented – the idea of „restoring” the TRCN, but in the stratosphere, where there are no mechanical limitations at the height of the antennas, and the achieved range can be gigantic.
The launch of a stratospheric balloon from the Przasnysz-Sierakowo airport of the Warsaw University of Technology is planned for September 12, 2020, in order to perform atmospheric tests – measuring UV radiation, recording the cloudy surroundings with a high-speed camera and conducting an inductive experiment at 14.2 kHz using a special antenna system.
The inductive system uses a modified long-wave transmitter (A1 emission, unkeyed) from the GLACiER project of the Warsaw University of Technology, implemented as part of the IGLUNA – a Habitat in Ice programme (ESA_Lab / Swiss Space Center). The power of the transmitter, due to the emission limits for this type of inductive devices, shall not exceed a few watts. The antenna system is a centrally fed (35: 1) dipole with capacitive (Hertzian) elements and a vertical axial coil. The electrical length is between 400 and 500 m, with a total system length of 210 m. The antenna is equipped with metalized radar reflectors.
The entire balloon mission will use 144.8 MHz (as SP5AXL) and 868 MHz (as part of the LoVo system) for navigation. Flight information will be available in advance in NOTAM (EPWW).
Planned balloon launch (even if the sky is full of ‘lead’ clouds) at 12.00 UTC (14.00 CEST, local time). The 14.2kHz experiment will be switched on on the ground, with the antenna initially folded in harmony. The predicted total flight time is 3 hours – around 13.30-14.00 UTC / 15.30-16.00 CEST it is planned to reach the maximum altitude of 30 km above sea level.
How can you help with the experiment? By recording as much as possible! Every parameter is valuable – from the spectrum / screenshot with the spectrum, to the EM field strengths, SNR and bandwidth, to the change of the EM field strength over time. The collected data can be sent to our e-mail address: stowarzyszenie@radiostacjababice.org. On the day of launch, we plan to post updates on the launch, flight and the experiment itself via our Facebook page: facebook.com/radiostacjababice.
Stay tuned!
We answer your questions about the BBC World Service’s plans for shortwave. With many tens of millions still relying on it to listen every day, what does the future hold?
Plus: earlier this year it was “temporarily suspended” due to Covid – but now Weekend is back. We get your reaction.
Many thanks to SWLing Post contributor, Jason W, who writes:
You might be interested in this episode of the BBC series tomorrow’s world from 17th Feb 1993 on YouTube:
10:23 to 14:50 has a introduction and demonstration of digital radio in the UK and concluding with “the experts say we will be fully digital by 2020 it’s a long wait” (referring to the switch from fm to digital radio in the UK which is yet to happen).
I thought it might be interesting to highlight this on the blog in 2020.
We can forgive the bit where she suggests digital radio will operate alongside analogue FM in the same frequency band. This Wikipedia on the history of digital broadcasting in the UK shows the UK adopted the DAB Eureka 147 standard in a SFN (single frequency network) from the start of test transmissions in 1990. https://en.m.wikipedia.org/wiki/Digital_radio_in_the_United_Kingdom
The same episode has a later piece on wide-screen digital television. (20:18 to 23:41) ending with the line “like digital radio, it is a few years away”
This is fantastic! I love watching vintage Tomorrow’s World episodes. It’s great to see how well they predicted the future and what they considered to be meaningful future innovations at the time. Thank you for sharing, Jason!
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Many thanks to SWLing Post contributor, Kris Partridge, who writes:
