Watching Shortwave Broadcast Stations on the TinySA Spectrum Analyser
by Bill Meara
November 18, 2022 1244 UTC. I was using a TinySA spectrum analyzer to look at noise levels on the 40 meter ham radio band. I also wanted to take a look slightly above the band (in frequency) to see Radio Marti at 7355 kHz. As I was doing this I remembered that Vatican Radio was on the air at 7305 kHz from 1230 UTC to 1245 UTC. So was just going to catch the last moments of that day’s transmissions. Sure enough, I caught it, and watched it disappear from the TinySA screen. See the video below:
Radio Marti continued on. In the morning we can hear the rooster recordings from that station. We are using it to test how well our homebrew Direct Conversion receivers avoid AM detection. In the video I mistakenly said these two transmitters were on the air with 250 megawatts. The correct power is 250 kilowatts. Both transmit from Greenville NC. I think the signal from Vatican Radio is stronger here because they are using a different antenna pattern — Radio Marti is aimed at Cuba.
NATE, in collaboration with Storybuilt Media, has created a feature-length documentary titled “Vertical Freedom,” which highlights the professional and personal lives of six communications infrastructure workers in the United States.
Throughout the film, these cellular and broadcast tower climbers share what compels and excites them about their line of work. Plus, how to overcome every-day danger in order to connect us all.
Ky Nguyen is just one of the climbers featured in the film. He has worked with RIO Steel and Tower out of Alvarado, Texas for the last 10 years.
After the Great Recession, Nguyen wanted to move away from his job in construction and — while he is skilled at his craft now — he was initially hired onto the tower communication service’s team with zero experience.
“I started as a climber and then just kept working my way up,” he said. “Then I became foreman and began project managing. I’m one of those types of guys where, if you want it done a certain way, you have to be with them, showing them, leading by example – so I’m climbing every day.” [Continue reading…]
Ten years ago, my friend John gave me this tiny Sony receiver. It wasn’t working. I tried to fix it but quickly discovered that the tiny size of the device made repair difficult. All you needed to do was to swap out some leaking electrolytics, but they are surface mount electrolytics — replacing them is not for the faint of heart. Kits are available, but again, this is not easy.
In 2020 I got one of the kits, but didn’t try to use it until yesterday. It only supplied six of the electrolytics. In the video above, they discuss replacing seven electrolytics, including the one that seems to be placed in the round black holder. C-625. Why didn’t my kit include a replacement for that one? Could it be that this capacitor was not one of the leaky SMD caps?
Replacing these caps really wasn’t easy. At one point I inadvertently removed not just the bad cap, but also a nearby surface mount resistor. Luckily the schematic showed it to be 0 ohms. That was easily replaced. I lifted one of the pads on one of the other caps — I just slid it back into place and hoped for the best. [Continue reading at Soldersmoke…]
The FCC has introduced a proposal for rulemaking to determine whether to permanently approve the use the spectrum of television channel 6 for analog radio service on 87.75 MHz and will vote on whether to proceed with it at its June meeting.
In July 2021, all of the remaining analog low-power television stations were required to convert to digital, which would then lead to thirteen of them resuming analog audio transmission within their ATSC 3 broadcasts on an experimental basis. The rulemaking proposal seeks comments whether FM on channel 6 operations server the public interest and should be authorized to continue, whether they should be authorized as ancillary or supplementary services and if so subject to a new rule that permits their operation subject the certain technical and operational requirements, whether they can limit future channel 6 FM operations to those stations with active STAs, whether to consider a proposal to license additional non-commercials FMs on 82-88 MHz in areas where no television stations are operating, and whether to eliminate or revise the distance separation rules between television stations on channel 6 and radio licenses in the non-commercial band.
The petition by Educational Media Foundation and antenna manufacturers Dielectric, Jampro Antennas, Radio Frequency Systems, and Shively Labs to allow FM antenna directional pattern verification by computer modeling was approved at the FCC’s monthly open meeting. [Click here to read the full article at Radio Insight…]
The Marconi Van exhibition tells the story of Marconi’s pioneering work and its scientific legacy in radio and microwave physics. The exhibition combines:
Engaging exhibits and interactive activities exploring the past, present, and future of radio and communications physics.
An exploration of historical objects from the History of Science Museum’s Marconi collection.
Virtual experiments you can try yourself. As restrictions ease we shall be inviting you to have a go in the laboratory!
The exhibition is housed inside a 1968 Morris Motor Traveller van built at the iconic Morris Motors plant in Cowley, Oxford. The objects an information available inside the van will evolve as the exhibition progresses… so just because you’ve seen it once doesn’t mean there isn’t more to see.
Bill Meara, producer of the popular SolderSmoke Podcast, recently recorded audio echoes on a couple of his home brew regenerative receivers. Bill posted the following video, of his regen receiver tuned to China Radio International:
The fact that Bill measured a .133 second delay (the amount of time it would take for a signal to circle the globe), makes me believe he’s hearing an echo similar to Lyle. But I must admit, I’m a bit amazed that a faint AM echo could penetrate blowtorch signals like CRI and Brother Stair’s relay generate State side.
Readers:What’s going on here? Is Bill catching rare propagation openings–or perhaps ducting in the Earth’s magnetosphere and ionosphere–or is there another explanation?
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