KNBR (AM 680) Antennas, Redwood City, CA, 2024
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KNBR (AM 680) Antennas, Redwood City, CA, 2024.
All the pixels, none of the sports, news, or weather, at https://www.flickr.com/photos/mattblaze/54131419266
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KNBR (AM 680) Antennas, Redwood City, CA, 2024.
All the pixels, none of the sports, news, or weather, at https://www.flickr.com/photos/mattblaze/54131419266
Rodenstock 50mm/4.0 HR Digaron-W lens (@ f/6.3), Phase One IQ4-150 digital back, Cambo 1250 camera (vertically shifted -23mm).
This simple photo pushed the 50mm lens to the limits of its image circle with the large shift required to keep the tall antenna mast fully in the frame while maintaining its geometry. Hard vignetting of the upper corners was visible in the full sensor image, but fortunately the composition benefited from a narrower aspect ratio that cropped out the dark corners.
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Rodenstock 50mm/4.0 HR Digaron-W lens (@ f/6.3), Phase One IQ4-150 digital back, Cambo 1250 camera (vertically shifted -23mm).
This simple photo pushed the 50mm lens to the limits of its image circle with the large shift required to keep the tall antenna mast fully in the frame while maintaining its geometry. Hard vignetting of the upper corners was visible in the full sensor image, but fortunately the composition benefited from a narrower aspect ratio that cropped out the dark corners.
KNBR is a 50KW "Class A" (formerly "clear channel") mediumwave (AM) rado station broadcasting on 680 KHz, serving the San Francisco Bay area (and, at night, most of the west coast of the US). Opened in 1922, It was originally known as KPO, (later KNBC, and still later KNBR), and soon became the flagship station for the National Broadcasting Company (NBC)'s new western radio network. It is currently owned by Cumulus Media and now broadcasts a sports format. It sits next to the former KGEI site.
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KNBR is a 50KW "Class A" (formerly "clear channel") mediumwave (AM) rado station broadcasting on 680 KHz, serving the San Francisco Bay area (and, at night, most of the west coast of the US). Opened in 1922, It was originally known as KPO, (later KNBC, and still later KNBR), and soon became the flagship station for the National Broadcasting Company (NBC)'s new western radio network. It is currently owned by Cumulus Media and now broadcasts a sports format. It sits next to the former KGEI site.
Mediumwave (AM) broadcast radio uses lower frequencies than other modern broadcasting and so requires much larger antennas (generally getting larger and larger as the frequency gets lower on the dial). This often entails highly customized antenna designs engineered for the particular site and station frequencies. For most radio stations (FM, TV, etc), the towers are there simply to get the relatively small antennas up high, but for AM stations like KNBR, the towers generally ARE the antennas.
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Mediumwave (AM) broadcast radio uses lower frequencies than other modern broadcasting and so requires much larger antennas (generally getting larger and larger as the frequency gets lower on the dial). This often entails highly customized antenna designs engineered for the particular site and station frequencies. For most radio stations (FM, TV, etc), the towers are there simply to get the relatively small antennas up high, but for AM stations like KNBR, the towers generally ARE the antennas.
The taller tower (550 feet) at right is the main KNBR antenna, built in 1949. It employs an unusual "pseudo-Franklin" design; it's actually an array of two antennas stacked atop one another. The 400 foot lower section is insulated from the ground. The upper 150 foot section is insulated from the lower section. The large (50 foot) diameter "capacitance hat" at the top (reminiscent of the Parachute Jump at Coney Island) electrically lengthens the top section, saving 250 feet of additional height.
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The taller tower (550 feet) at right is the main KNBR antenna, built in 1949. It employs an unusual "pseudo-Franklin" design; it's actually an array of two antennas stacked atop one another. The 400 foot lower section is insulated from the ground. The upper 150 foot section is insulated from the lower section. The large (50 foot) diameter "capacitance hat" at the top (reminiscent of the Parachute Jump at Coney Island) electrically lengthens the top section, saving 250 feet of additional height.
This distinctive stacked dual antenna arrangement is used to lower the radiation angle of the antenna, concentrating transmitted power to the "ground wave" and reducing energy that would otherwise be sent upward into the sky.
The smaller (300 foot) freestanding mast in the background left is not in current use. It can be used as an emergency spare antenna for KNBR during maintenance of the taller main antenna.
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This distinctive stacked dual antenna arrangement is used to lower the radiation angle of the antenna, concentrating transmitted power to the "ground wave" and reducing energy that would otherwise be sent upward into the sky.
The smaller (300 foot) freestanding mast in the background left is not in current use. It can be used as an emergency spare antenna for KNBR during maintenance of the taller main antenna.
The antenna field is in the final approach and takeoff flightpath for SFO airport's runways 28L/R (and 10L/R), and so the site has special markings to warn pilots of a collision hazard. In addition to the usual tower lights and red/white paint, 3-dimensional "HAZ" warnings were installed around the field. These are easily visible in areal photos; see, e.g., https://earth.google.com/web/@37.5471204,-122.23429544,0.73120256a,577.14725587d,35y,0.01179999h,0t,0r/data=CgRCAggBQgIIAEoNCP___________wEQAA
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The antenna field is in the final approach and takeoff flightpath for SFO airport's runways 28L/R (and 10L/R), and so the site has special markings to warn pilots of a collision hazard. In addition to the usual tower lights and red/white paint, 3-dimensional "HAZ" warnings were installed around the field. These are easily visible in areal photos; see, e.g., https://earth.google.com/web/@37.5471204,-122.23429544,0.73120256a,577.14725587d,35y,0.01179999h,0t,0r/data=CgRCAggBQgIIAEoNCP___________wEQAA
Note, important safety tip: you can get closer to this tower without clearly trespassing or jumping fences than most other 50KW broadcast antennas I've encountered. I measured a field strength of over 80V/m a bit outside the tower fence, which is an incredibly strong signal (though still within OSHA limits at the frequency involved).
Resist any temptation to jump the fence and climb the (energized) tower. You'd be electrocuted as soon as you touched it.
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Note, important safety tip: you can get closer to this tower without clearly trespassing or jumping fences than most other 50KW broadcast antennas I've encountered. I measured a field strength of over 80V/m a bit outside the tower fence, which is an incredibly strong signal (though still within OSHA limits at the frequency involved).
Resist any temptation to jump the fence and climb the (energized) tower. You'd be electrocuted as soon as you touched it.
AM broadcast is a technically interesting and somewhat endangered medium. The low frequencies mean that signals routinely travel well beyond their local coverage areas, especially overnight in winter. So there's a bit of mystery in tuning around the dial late at night; you never know what you might pick up.
Sadly, industry consolidation and the growth of higher bandwidth media (FM, satellite, podcasts) has greatly reduced the variety and local focus of programming. But it somehow hangs on.
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AM broadcast is a technically interesting and somewhat endangered medium. The low frequencies mean that signals routinely travel well beyond their local coverage areas, especially overnight in winter. So there's a bit of mystery in tuning around the dial late at night; you never know what you might pick up.
Sadly, industry consolidation and the growth of higher bandwidth media (FM, satellite, podcasts) has greatly reduced the variety and local focus of programming. But it somehow hangs on.
The rapid decline in recent years of local content on the mediumwave bands has considerably reduced the romantic mystery of tuning around and seeing what you find. It's mostly now a sterile mix of mass-produced, syndicated right wing talk, sports, and so on. But there are still a handful of stubbornly local stations producing their own programming.
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undefined Oblomov ha condiviso questa discussione
Gli ultimi otto messaggi ricevuti dalla Federazione
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https://www.nssmag.com/it/lifestyle/42692/konbini-cosa-sono?utm_source=firefox-newtab-it-it
Hanno reinventato i negozi di quartiere. A volte ritornano.
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@140caratteracci invece lei sì che manda poliziotti a infiltrarsi nell'opposizione
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@gordoooo_z dear baby jesus, do not plug that PSU into an electrical source, unless you really want to smell burning PCB and melting wires.
which model MB is this?
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@neil indeed, and a good morning now from across the pond 🌞
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Arriva YiBackdoor: cosa c’è da sapere e come difendere la rete
In un nuovo report, Zscaler ThreatLabz ha rivelato i dettagli di una nuova famiglia di malware chiamata YiBackdoor, osservata per la prima volta nel giugno 2025.
Fin dall’inizio, l’analisi ha evidenziato corrispondenze significative del codice sorgente con i downloader IcedID e Latrodectus, ed è proprio questa connessione che Zscaler indica come fondamentale per comprendere la possibile origine e il ruolo del nuovo campione negli attacchi.
Il malware è una libreria DLL modulare con un set base di funzioni di controllo remoto dell’host e un meccanismo di estensione basato su plugin. Di default, le funzionalità sono limitate, ma gli aggressori possono caricare moduli aggiuntivi per espanderne le capacità.
Il programma si copia in una cartella appena creata con un nome casuale, ottiene la persistenza tramite il tasto Esegui di Windows e avvia regsvr32.exe con un percorso dannoso.
Il nome della voce di registro viene generato utilizzando un algoritmo pseudo-casuale. Il modulo primario si autodistrugge, complicando le misure di risposta e l’analisi forense. La logica dannosa viene eseguita tramite una configurazione crittografata incorporata, da cui viene estratto l’indirizzo del server di comando e controllo, e la comunicazione con il C2 avviene tramite risposte HTTP contenenti comandi.
Le funzionalità di YiBackdoor includono la raccolta di metadati di sistema, l’acquisizione di screenshot e l’esecuzione di comandi shell tramite cmd.exe e PowerShell, nonché il caricamento e l’inizializzazione di plugin crittografati in Base64. I comandi chiave identificati nel meccanismo di controllo sono elencati di seguito: Systeminfo, screen, CMD, PWS, plugin e task. La tecnica di iniezione di codice prevede l’iniezione nel processo svchost.exe e le tecniche di anti-analisi integrate sono focalizzate sul rilevamento di macchine virtuali e sandbox, riducendo la probabilità di rilevamento durante l’analisi in un ambiente protetto.
Gli analisti di Zscaler notano diverse somiglianze con IcedID e Latrodectus: un metodo di iniezione simile, formato e lunghezza identici della chiave di decrittazione della configurazione e algoritmi simili per la decrittazione dei blocchi di configurazione e dei plugin. Date queste somiglianze e l’architettura osservata, i dipendenti dell’azienda valutano con un livello di sicurezza da moderato ad alto che YiBackdoor possa essere opera degli stessi sviluppatori responsabili dei precedenti downloader. Tuttavia, le implementazioni attuali sono limitate, il che indica una fase di sviluppo o test e il potenziale ruolo del campione come precursore di successive fasi di sfruttamento, inclusa la preparazione dell’accesso iniziale per il ransomware.
L’organizzazione sottolinea l’importanza di monitorare le richieste HTTP in uscita e le modifiche al registro, nonché di implementare regole di rilevamento incentrate su indicatori comportamentali di iniezioni di svchost.exe e anomalie associate all’avvio di regsvr32.exe da percorsi casuali. Questi indicatori consentono il rilevamento tempestivo dei tentativi di iniezione di YiBackdoor e la prevenzione di ulteriori attività da parte degli aggressori.
L'articolo Arriva YiBackdoor: cosa c’è da sapere e come difendere la rete proviene da il blog della sicurezza informatica.
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Ieri è stata una serata fantastica.
Al teatro Kismet di Bari ho avuto l'onore di precedere lo spettacolo della Compagnia del Sole, uno splendido monologo di Flavio Albanese su Einstein, con una conferenza dove ho anticipato in chiave divulgativa molti concetti che Flavio avrebbe ripreso in chiave scenica, come solo lui sa fare.
Prima di me, un giovane attore in un significato monologo sulla intelligenza artificiale ha degnamente aperto la lunga serata.
Dopo la mia relazione un fuoco di domande, pubblico attentissimo. Si sentivano onde di energia positiva nel teatro. E dopo ci siamo fermati nel foyer per dialogare ancora con il pubblico. A mezzanotte circa ci hanno dovuto cacciare perché il teatro chiudeva!
Bello quando la fisica, l'astrofisica, si mischia e si impasta con l'arte, va in scena con chi va in scena abitualmente e propriamente. Bella l'intesa che si è creata con il gruppo della Compagnia, tutte persone splendide.
A breve un articolo su EduINAF!
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Marco Cavallo arriva al CPR di Ponte Galeria. Intervista con lə attivistə della rete Stop CPR
@anarchia
Marco Cavallo, il grande cavallo azzurro di cartapesta realizzato da Vittorio Basaglia e Giuliano Scabia insieme a internatə e operatorə del manicomio di Trieste, arriverà il 27 settembre davanti al CPR di Ponte Galeria. È il simbolo
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