Radio Waves: Stories Making Waves in the World of Radio
Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!
Many thanks to SWLing Post contributors Andrea Borgnino, Paul, and Dennis Dura for the following tips:
BBC World Service announces Emergency Radio Service for Gaza (BBC Media Centre)
It will provide listeners in Gaza with the latest information and developments as well as safety advice on where to access shelter, food and water supplies
BBC News Arabic has today (1 November) announced an Emergency Radio Service for Gaza in response to the conflict in the region.
The emergency service – Gaza Daily – will broadcast vital news daily to the people of Gaza during this time of urgent need.
It will provide listeners in Gaza with the latest information and developments as well as safety advice on where to access shelter, food and water supplies.
Produced in Cairo and London and broadcast on medium wave, the service will initially run one programme a day at 1500 GMT from Friday 3 November. A second daily update will be broadcast at 0500 GMT from Friday 10 November.
The BBC World Service has a history of responding to emergency situations globally. Most recently, in May 2023 during the conflict in Sudan BBC News Arabic began an emergency radio service. In February 2022, the BBC News Ukraine service began extended TV bulletins following the invasion of the country. The BBC also previously launched a service for Gaza in 2014 following a summer of conflict.
Liliane Landor, Director, BBC World Service, says: “BBC News Arabic are extremely well-placed to offer this vital service for the people of Gaza at a time of greatest need. Their expertise and specialist knowledge of the region alongside the BBC’s reputation as the most trusted news provider, means we can reach civilians in Gaza with the information they need.”
RM3
Notes to editors: The Gaza service will be broadcast on MW 639kHz for morning and evening episodes.
FCC Wants to Bolster Amateur Radio (Radio World)
Commission will vote in November on plan to remove outdated technical restrictions
FCC Chairwoman Jessica Rosenworcel says the FCC plans to “incentivize innovation and experimentation in the amateur radio bands” by getting rid of outdated restrictions and providing licensees with the flexibility to use modern digital emissions.
The commission at its November meeting is expected to take action on a Report and Order that would eliminate the baud rate limitation and establish a bandwidth limitation in the amateur radio bands below 29.7 MHz.
The order being circulated for tentative consideration by the commission would remove the baud rate limitation — the rate at which the carrier waveform amplitude, frequency and/or phase is varied to transmit information — for data emissions in the amateur radio bands, the FCC says. The current baud rate limits were adopted in 1980.
The order would implement a 2.8 kilohertz bandwidth limitation in place of the baud rate in amateur radio bands. The 2.8 kHz limitation is consistent with the commission’s treatment of other wireless radio services, the FCC says.
The current rules limit the baud rate for high-frequency amateur radioteletype/data transmissions to 300 baud for frequencies below 28 MHz (except in the 60-meter band), and 1200 baud in the 10 meter (28-29.7 MHZ) band. [Continue reading…]
Ham Radios Crowdsourced Ionospheric Science During Eclipse (EOS.org)
Amateur radio operators who study space physics and the upper atmosphere probed the ionosphere’s response to the 2023 annular solar eclipse using shortwave transmissions.
On 14 October, millions of people in North, Central, and South America peered through safety glasses and other viewing aids at the partially obscured Sun. Simultaneously, thousands of folks experienced the annular solar eclipse in a different way: through transmissions sent and received over amateur radios.
Before, during, and after the eclipse, ham radio operators pinged signals off the ionosphere and connected to people hundreds or thousands of kilometers away. The experiment, part of the Ham Radio Science Citizen Investigation (HamSCI), is gathering hundreds of thousands of those contacts to investigate how the ionosphere responds to the temporary loss of sunlight during an eclipse. [Continue reading…]
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FCC regulations for Amateur Radio.
The faster the data rate in general, the wider the bandwidth required to transmit the signal. The bandwidth is also affected by the type of modulation used. For example Quadrature Amplitude Modulation is essentially a pair of independent signals on the same centre frequency but are 90 degrees of carrier apart allowing for them to be separated on reception. Coded Frequency Division Multiplex allows a QAM signal to be converted from a pair of independent signals to hundreds of very closely spaced signals which can increase the data rate. However in the real world signals are also reflected from the ionosphere, objects etc. This causes corruption of the signal. As a result the higher data rate is used but the signal is sent in bursts, to allow time for the reflections to dissipate making the transmission reliable.
Forward Error Correction can be added prior to transmission. This is the addition of extra signal related data so the receiver can correct for data errors provided there is not too many. This means perfect reception until there is more than 1 error in 10 000 bit and then the signal is often muted because it breaks up and can make annoying noises. The extra data has to be included in the transmission data rate going out of the antenna.
For sound, images and data compression algorithms are used prior to modulation to reduce the data rate by leaving out information which is redundant. At the receiver the algorithm is reversed to restore the original data. Typical examples from broadcasting are xHE-AAC which is the most efficient compression for speech and music, and High Efficiency Video Coding for images.
I do commend the FCC for lifting their restrictions but they must limit the bandwidth of signal so there is enough space for each individual simultaneous user. They must also keep in mind that the high frequency bands can mean that signals can cover multiple countries so interference must not increase between users.
You didn’t read it completely: the bandwidth will be 2,800 KHz, pretty much the same as elsewhere in the world with legal ham radio. I haven’t read the proposal but I’m guessing the spread spectrum restriction will still be in place keeping some modes illegal.
Basically everything you mentioned is base tech and lots of fancy stuff is done especially on military waveforms. For instance the current WiFi, LTE, and New Radio standards use QAM constellations of 1024 and above for strong connections; this is too much for HF usually, though. They all fall back to QPSK (rarely even BPSK) for very poor connections but PSK is too spectrally inefficient compared to QAM.
In any case, the point here is that by removing the restrictions you can put even the most modern modes on the air as long as they fit within the channel, just like everyone else. It’s been too long coming!
While they’re at it, I think the FCC band plans separating phone from data should be scrapped. There absolutely need to be QRP holes but this segment separation is nonsense! (As I said, I haven’t read it yet so that could be in there already.)
Along the same lines I think the restriction on CW-only on the first 100 KHz of the VHF bands needs to be scrapped as well to get more usage from other extremely narrow weak signal modes; if necessary, a power restriction could be implemented, but many hams ignore that anyway. 🙁