Radio (general)

The Radio Tirana antennas at Fllakë near Durres, Albania. (DSCN0450)

Two yellow Gonset Communicator portable AM tranceivers, by Dave Emerson. Original on Flickr: www.flickr.com/photos/daveemerson/26921195400 under a Creative Commons BY-NC-ND license. The radio at the left is a Gonset Communicator II "Civil Defence" model, covering 144-148 MHz. Gonset built a number of these during the Cold War for Civil Defense use and they were intended to be used by fallout shelters to communicate with one another. RACES operators did use them a great deal for regular activities and exercises. The radio at the right is the 6m (49-54 MHz) model. (DSC08641.jpg) This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 2.0 International License .

Vintage Hallicrafters model S-108 receiver, broadcast band plus three shortwave bands and bandspread on 5 amateur radio bands, 8 tubes, metal cabinet. Made In USA, circa 1959 - 1965 (Auction Item 247). Photograph by Joe Haupt uploaded on Flickr under a CC-BY-SA-2.0 free license. Flickr file: www.flickr.com/photos/51764518@N02/26372620010 Short URL: flic.kr/p/Gbsz81 This work is licensed under a Creative Commons Attribution-ShareAlike 2.0 International License .

An IR camera and Wi-Fi link powered by a solar array, installed near Keratea by the General Secretariat for Civil Protection. (DSC_9360) This work is licensed under a Creative Commons Attribution 4.0 International License .

An IR camera and Wi-Fi link powered by a solar array, installed near Keratea by the General Secretariat for Civil Protection (detail). (DSC_9357) This work is licensed under a Creative Commons Attribution 4.0 International License .

SV1BJY lecturing about propagation in the 2m band. This work is licensed under a Creative Commons Attribution 4.0 International License .

SV1BJY lecturing about contesting in the 2m band. This work is licensed under a Creative Commons Attribution 4.0 International License .

Transmitting loop antenna of MF directional marine beacon TNTS on 308 kHz. For more info see: Longwave Directional Beacons in Thessaloniki, Greece (DSCN0363) This work is licensed under a Creative Commons Attribution 4.0 International License .

Released 15/01/2016 11:10 am Copyright ESA–G. Porter, CC BY-SA 3.0 IGO Description What might look like an abstract artwork is actually a novel antenna, small enough for a minisatellite, to track global ship traffic from orbit. Commercial vessels are mandated to transmit Automatic Identification System (AIS) signals, which are used to track maritime traffic – the oceangoing equivalent of air traffic control. The system relies on VHF radio signals with a horizontal range of just 40 nautical miles (74 km), useful within coastal zones and on a ship-to-ship basis, but leaving open ocean traffic largely uncovered. However, in 2010 ESA fitted an experimental antenna to Europe’s Columbus module of the International Space Station, demonstrating for the first time that AIS signals could also be detected from up in orbit, opening up the prospect of global ship tracking from space. “Based on our testing, this new prototype designs offers a four-fold increase in ship detection performance,” explains ESA antenna specialist Nelson Fonseca, overseeing the project. “The AIS detection system on Columbus employs a low-gain ‘whip’ antenna, receiving signals within a very broad beam, with corresponding potential for signal overlap and interference. “This antenna design combines higher-gain with a more reduced footprint, allowing more of a focus on regions of highest interest, and can also discriminate between polarisations, increasing the likelihood of detection for any individual AIS signal within the antenna field of view.” In addition, clever engineering has shrunk the overall antenna size to a size where up to five could be hosted on a single cubic-metre minisatellite. “Despite its name, VHF is quite a low wavelength in space terms, implying a bulky antenna of about 1 m across and half-a-metre thick to operate ideally at that frequency,” Nelson adds. “But the patterned square-shaped structure on the underlying face of our antenna changes the signal behaviour, enabling us to shrink the design to 50 cm width and 3 cm thickness – making it suitable for hosting on a smaller platform.” The antenna was developed through ESA’s ARTES Advanced Research in Telecommunications Systems – Advanced Technology programme with Italian companies CGS as prime contractor and MVG as subcontractor in charge of the electrical design. “CGS and MVG are highly interested in moving forward with the optimisation and environmental qualification of this outstanding antenna element,” explains Andrea Di Cintio, managing the project at CGS. “The next step will be to identify a specific mission and then optimise the design and qualification accordingly.” “Significant reduction of antenna dimensions and weight without compromising electrical performance was challenging,” adds Andrea Giacomini, lead antenna designer at MVG. “It required a radical change in the design and validation approach. We are proud to have been involved.” (Id 353083)

A S-band UHF Yagi antenna at "Panepistimio" metro station. (DSCN0316) This work is licensed under a Creative Commons Attribution 4.0 International License .

SV1GE, the new president of RAAG, at the annual General Assembly of 2016. This work is licensed under a Creative Commons Attribution 4.0 International License .

Amateur Radio Science, by Eric P. Nichols, KL7AJ.

Vintage low VHF band TV Yagi antenna, surviving on a roof in Athens, Greece. (DSC_9238)

Broadband sensor antenna of the National Observatory of Electromagnetic Fields (Εθνικό Παρατηρητήριο Ηλεκτρομαγνητικών Πεδίων) on the roof of Heraklion Town Hall. This broadband station is a NARDA AMB-8057-03/G and measures the intensity of the field in the band 100 kHz – 7 GHz and in three special bands related to GSM mobile networks (EGSM 900 925 MHz – 960 MHz, EGSM 1800 1805 MHz – 1880 MHz and UMTS 2110 MHz – 2170 MHz). (DSC 9235) This work is licensed under a Creative Commons Attribution 4.0 International License .

Two UHF Yagi antennas and a vertical sleeve dipole on a latice tower at Attiki metro station, Athens, Greece. (DSC 9202)

Dimensions for a 5.3 MHz (60 m) wire dipole antenna by Din SV1DB, publshed in 5-9 Report, volume 168.

Οι ραδιοερασιτέχνες επικοινωνούν με άλλους ραδιοερασιτέχνες, κάνοντας χρήση των δικών τους εγκαταστάσων ραδιοεκπομπής. Οι ραδιοερασιτέχνες εημερώνονται ώστε να αποκτήσουν περισσότερες δεξιότητες, π.χ. για την υλοποίηση ραδιοτεχνικών πειραμάτων, και επηρεάζουν σημαντικά την ανάπτυξη της ραδιομηχανικής, γεγονός που δικαιολογεί ότι συγκεκριμένα φάσματα συχνοτήτων τους έχουν διατεθεί προς χρήση.

Six meters (50 MHz) beacon SV1SIX (50040 kHz, F1A) in the club station shack of the Radio Amateur Associaton of Greece (RAAG). (DSCN0297) This work is licensed under a Creative Commons Attribution 4.0 International License .