Target moving ainakin sanottiin. Mitä mahtaa meinata en tiedä.Desantteja. Mitä ne sanoi?
ja heräsit rajuun tulitukseen..Target moving ainakin sanottiin. Mitä mahtaa meinata en tiedä.
Sitten tällainen pidempi keskustelu:
Company leader to identify Baker Team – Rambo, Messner, Ortega, Coletta, Jurgensen, Barry, Krakauer confirm! This is Colonel Trautman.
Homma noilla käsivehkeillä on että etäisyys ei ole kummoinen ja suomessakin on näitä vakoilutapauksia. Tuo ketju kyllä kuulostaa täysin fiktonaaliselta. Olisiko jonkun radiosta vuotanut yöllisiä katselmuksia kuin mitään tositapahtumaa. Miksi joku eversti paljastaisi sen olemassa olon salaamattomalla kanavalla?Company leader to identify Baker Team – Rambo, Messner, Ortega, Coletta, Jurgensen, Barry, Krakauer confirm! This is Colonel Trautman.
https://youtu.be/r17b6IuyakwHomma noilla käsivehkeillä on että etäisyys ei ole kummoinen ja suomessakin on näitä vakoilutapauksia. Tuo ketju kyllä kuulostaa täysin fiktonaaliselta. Olisiko jonkun radiosta vuotanut yöllisiä katselmuksia kuin mitään tositapahtumaa. Miksi joku eversti paljastaisi sen olemassa olon salaamattomalla kanavalla?
https://hackaday.com/2018/07/11/ham-designed-gear-used-in-thailand-cave-rescue/Unless you live in a cave, you’ve probably heard a little about the thirteen people — mostly children — trapped in the Tham Luang Nang Non cave in Thailand. What you may have missed, though, is the hacker/ham radio connection. The British Cave Rescue Council (BCRC) was asked for their expert help. [Rick Stanton], [John Volanthen] and [Rob Harper] answered the call. They were equipped with HeyPhones. The HeyPhone is a 17-year-old design from [John Hey, G3TDZ]. Sadly, [G3TDZ] is now a silent key (ham radio parlance for deceased) so he didn’t get to see his design play a role in this high-profile rescue, although it has apparently been a part of many others in the past.
The HeyPhone is actually considered obsolete but is still in service with some teams. The radio uses USB (upper sideband, not universal serial bus) at 87 kHz. The low frequency can penetrate deep into the ground using either induction loop antennas like the older Molephone, or — more commonly — with electrodes injecting RF energy directly into the ground.
You can find a very detailed article about the radio from 2001 if you want more details. The system is somewhat dated, but apparently works well and that’s what counts.
What we find interesting is that in today’s world, people take wireless communications for granted and don’t realize that cell phones don’t work underground or in the face of widespread disasters. We would imagine most Hackaday readers know how cell phone towers use “cellular reuse” to support more than a handful of phones. Ask some non-technical friend if they know how a cell phone works and you’ll be surprised how few people understand this. Ham radio operators and hackers are vital to building and deploying specialized radio systems in times of disaster or — in this case — where people need rescuing from an odd environment.
We were glad to see a nod to some hacker gear in the popular press. But we almost wish there had been more reporting on the volunteer divers and their hacked radio gear.
We’ve talked about VLF radios before, but not for caving. Of course, in the old days, all radio was VLF and it might have even had some unintended consequences.
https://hackaday.com/2018/07/16/global-radio-direction-finding-in-your-browser/Radio direction finding is one of those things that most Hackaday readers are likely to be familiar with at least on a conceptual level, but probably without much first-hand experience. After all it’s not everyday that you need to track down a rogue signal, let alone have access to the infrastructure necessary to triangulate its position. But thanks to the wonders of the Internet, at least the latter excuse is now a bit less valid.
Mielenkiintoinen tuo juttu radioiden paikannuksesta. Signaalin saapumisaikaan perustuva menetelmä on tarkkojen kellojen ansiosta parempi kuin suunnan mittaukseen perustuva paikantaminen.
https://hackaday.com/2018/07/18/harley-hardened-wire-helps-high-gain-antenna-hack/What does a Harley-Davidson motorcycle have to do with building antennas? Absolutely nothing, unless you happen to have one and need to work-harden copper wire to build a collinear antenna for LoRa.
https://hackaday.com/2018/09/27/antennas-that-you-install-with-a-spray-can/With the explosion in cell phones, WiFi, Bluetooth, and other radio technologies, the demand for antennas is increasing. Everything is getting smaller and even wearable, so traditional antennas are less practical than ever. You’ve probably seen PCB antennas on things like ESP8266s, but Drexel University researchers are now studying using titanium carbide — known as MXene — to build thin, light, and even transparent antennas that outperform copper antennas. Bucking the trend for 3D printing, these antennas are sprayed like ink or paint onto a surface.
A traditional antenna that uses metal carries most of the current at the skin (something we’ve discussed before). For example, at WiFi frequencies, a copper antenna’s skin depth is about 1.33 micrometers. That means that antennas have to be at least thick enough to carry current at that depth from all surfaces –practically 5 micrometers is about the thinnest you can reasonably go. That doesn’t sound like a lot, but when you are trying to make something thin and flexible, it is pretty thick. Using MXene, the researchers made antennas as thin as 100 nanometers thick — that’s 10% of a micrometer and only 2% of a conventional antenna.
There are other materials that wind up in thin antennas, but they all have challenges either because they are not very conductive or are difficult to fabricate. MXene is a fairly new family of materials developed at Drexel University. To produce it you start with MAX which is a combination of titanium, aluminum, and carbon. The aluminum is removed in a process that requires acid and stirring for 24 hours, lithium chloride, and a centrifuge. The hydrofluoric acid is nasty to work with, but not beyond the reach of a careful home lab. You can see a Drexel video about making MXene, below. The researchers sprayed the antennas on a thin plastic substrate.
The only thing that looked tricky to us, was that thin flakes of the specific MXene used degrade in the air due to oxidation. That means production needs argon gas and the final product has to be laminated with something to protect it from the air, so that’s going to add thickness in a practical device.
Of course, PCB antennas are nothing new. But if you read the paper, you’ll see these antennas can readily outperform conventional thin antennas.
https://hackaday.com/2018/10/09/using-ai-to-pull-call-signs-from-sdr-processed-signals/AI is currently popular, so [Chirs Lam] figured he’d stimulate some interest in amateur radio by using it to pull call signs from radio signals processed using SDR. As you’ll see, the AI did just okay so [Chris] augmented it with an algorithm invented for gene sequencing.
His experiment was simple enough. He picked up a Baofeng handheld radio transceiver to transmit messages containing a call sign and some speech. He then used a 0.5 meter antenna to receive it and a little connecting hardware and a NooElec SDR dongle to get it into his laptop. There he used SDRSharp to process the messages and output a WAV file. He then passed that on to the AI, Google’s Cloud Speech-to-Text service, to convert it to text.
Despite speaking his words one at a time and making an effort to pronounce them clearly, the result wasn’t great. In his example, only the first two words of the call sign and actual message were correct. Perhaps if the AI had been trained on actual off-air conversations with background noise, it would have been done better. It’s not quite the same issue, but we’re reminded of those MIT researchers who fooled Google’s Inception image recognizer into thinking that a turtle was a gun.
Rather than train his own AI, [Chris’s] clever solution was to turn to the Smith-Waterman algorithm. This is the same algorithm used for finding similar nucleic acid sequences when analyzing genes. It allowed him to use a list of correct call signs to find the best match for what the AI did come up with. As you can see in the video below, it got the call signs right.
https://destevez.net/2018/08/aircraft-reflections-of-a-2-3ghz-beacon/A couple months ago, Andrés Calleja EB4FJV installed a 2.3GHz beacon in his home in Colmenar Viejo, Madrid. The beacon has 2W of power, radiates with an omnidirectional antenna in the vertical polarization, and transmits a tone and CW identification at the frequency 2320.865MHz.
Since Colmenar Viejo is only 10km away from Tres Cantos, where I live, I can receive the beacon with a very strong signal from home. The Madrid-Barajas airport is also quite near (15km to the threshold of runway 18R) and several departure and approach aircraft routes pass nearby, particularly those flying over the Colmenar VOR. Therefore, it is quite easy to see reflections off aircraft when listening to the beacon.
On July 8 I did a recording of the beacon from 10:04 to 11:03 UTC from the countryside just outside Tres Cantos. In this post I will examine the aircraft reflections seen in the recording and match them with ADS-B aircraft position and velocity data obtained from adsbexchange.com. This will show the locations and trajectories which produce reflections strong enough to be detected.
Upeaa, kertakaikkiaan upeaa!S-K turvaviestintäverkon on rakentanut Suomen Radioturva Ry (SRT) radioharrastajien, vapepa-aktiivien ja reserviläisten omakustanteisena talkootyönä, ja se on osa kansalaisaloitteena liikkeelle laitettua kansalaisten välttämättömimpien viestiyhteyksien varmistamiseen pyrkivää turvaviestintähanketta.
Mikä kanava metsästys VHF:ssä on varattu tuohon? Näissähän ei taajuus näy, vain kanavan numero.Savo-Karjalan turvaviestintäverkkoa testataan
Mm. pelastuspalvelu- ja kyläturvayhteyksiin, sekä myrskytuhojen ja sähkökatkosten aikaisiin viestikatkoksiin varautumiseen sopiva Savo-Karjalan turvaviestintäverkko (TUVI S-K) on kesän aikana asennettu ja otettu käyttöön. Se käsittää kolme vapaaehtoisen pelastuspalvelun (Vapepa) ja metsästäjäradioiden tuki/toistinasemaa, jotka välittävät langattomasti puheyhteyden keskenään. Verkko on suoraan yhteensopiva myös pataljoonaradioiden kanssa. Mallina on käytetty jo aikaisemmin rakennettua ja varmatoimiseksi havaittua radioamatööritaajuuksilla toimivaa turvaviestintäverkkoa.
Tämän jatkuvassa valmiudessa olevan 'tuviverkon' tukiasemat muodostavat tavallisista lyhyen kantaman radiopuhelimista riippumattoman maakuntakantaman langattoman verkon samaan tapaan, kuin matkapuhelinten tukiasemat muodostavat verkon kännyköistä. S-K tuviverkon mobiilikantama kattaa nyt valtaosan Pohjois-Karjalaa sekä Keski-Savon ja osan Pohjois-Savoa. Parhaillaan ovat meneillään tuviverkon esittelyt vapepassa mukana oleville valmiusyhdistyksille, sekä verkon testaukset ja kantamamittaukset radioharrastajien avulla.
S-K tuviverkko välittää maakuntakantaman yhteyksiä paitsi yleisimpien radiopuhelinten kesken, niin myös tavallisten älypuhelinten ja radiopuhelinten kesken ilmaissovelluksen avulla. Keski-Savon tukiasema sijaitsee Leppävirralla, ja Pohjois-Karjalan tukiasemat Kolilla ja Outokummussa. Tukiasemat ovat akkuvarmistettuja usean vuorokauden toiminta-aikaa varten. Tukiasemien taajuusinfosivut ovat:
S-K turvaviestintäverkon on rakentanut Suomen Radioturva Ry (SRT) radioharrastajien, vapepa-aktiivien ja reserviläisten omakustanteisena talkootyönä, ja se on osa kansalaisaloitteena liikkeelle laitettua kansalaisten välttämättömimpien viestiyhteyksien varmistamiseen pyrkivää turvaviestintähanketta.
T: - Juha
https://spectrum.ieee.org/geek-life/profiles/building-a-time-machine-for-radioThomas Witherspoon is building a time machine, of sorts. With it, you’ll be able to pick a date and tune through an entire broadcast band as if you had a radio that could pick up transmissions from the past. Sure, well-established shows already make past episodes available, but with Witherspoon’s time machine you’ll be able to hear not just that programming but everything else that was on the air as well: the local news, the commercials, the pirate stations, even the mysterious number stations that lurk on shortwave.
Witherspoon’s time machine is The Radio Spectrum Archive. The technological advance that makes it possible is the proliferation in recent years of cheap software-defined radios (SDRs), which can digitize enormous swaths of radio spectrum. The SDR’s software can be used to select individual transmissions and listen to them live. Or the swath of spectrum can be recorded and played back through the software later, letting listeners tune into broadcasts just as if they were live.
Shortwave listeners and amateur radio enthusiasts have been using SDRs mainly to find interesting signals, “but not a lot of people thought about saving the spectrum and archiving it. But there were those who had,” says Witherspoon. Part of their motivation was to capture how radio has been evolving in the Internet era: “The AM broadcast band here in the States, the FM broadcast band, and...the shortwave broadcast band, are going through a lot of changes, especially the shortwave bands. A lot of stations are going off the air.”
Jahtiradioiden kanavat 15 ja 17.Mikä kanava metsästys VHF:ssä on varattu tuohon? Näissähän ei taajuus näy, vain kanavan numero.
Myös Zello on eräjuttuja varten puhelimessa, kyseessähän on eräänlainen netissä toimiva VHF. Jos netti on pystyssä, kuso kulkee vaikka 5000 km.
Mitä yhteysasetuksia tuohon tarvitaan siinä sovelluksessa?
https://hackaday.com/2019/02/13/a-network-attached-radiation-monitor/It started as a joke, as sometimes these things do. [Marek Więcek] thought building a personal radiation detector would not only give him something to work on, but it would be like having a gadget out of the Fallout games. He would check the data from time to time and have a bit of a laugh. But then things got real. When he started seeing rumors on social media that a nearby nuclear reactor had suffered some kind of radiation leak, his “joke” radiation detector suddenly became serious business.
With the realization that having his own source of detailed environmental data might not be such a bad idea after all, [Marek] has developed a more refined version of his original detector (Google Translate). This small device includes a Geiger counter as well as sensors for more mundane data points such as temperature and barometric pressure. Since it’s intended to be a stationary monitoring device, he even designed it to be directly plugged into an Ethernet network so that it can be polled over TCP/IP.