# Link to SARL VHF, UHF & MICROWAVES DX TABLE Click here
THE TERAHERTZ SPECTRUM – Most radio amateurs are only active on the bottom 30 MHz of the entire radio spectrum, which covers in total 300 000 MHz (300 GHz). Fortunately a number of amateurs also experimented on the VHF and UHF bands, while only a few ventured to explore the SHF and EHF bands up to 241 GHz. Radio astronomy, military, commercial stations either terrestrial or satellite, as well as radio scientists have investigated and/or occupied frequencies in the microwave spectrum. The top end of Microwave radiation overlaps the bottom end of the Deep infrared radiation, and for years nobody paid much attention to this Terahertz gap that covers 0,1 THz to 10 THz until they stumbled on to the unique properties of this submillimetre radiation.
It was with great difficulty that they first produced a few milli watts of power on Terahertz. Water vapour in the air limits communications normally to about 10 metres, but it is not a problem in space or from the high altitude sites, such as the infrared telescope at Alma, Atacama, Peru. Terahertz can see through walls and is a substitute for X-rays without its radiation hazard, including many other uses. Radio amateurs have already pioneered two-way contacts in Germany and the USA above 400 GHz up to a maximum distance of 1,4 km. During the World Radiocommunication Conference scheduled for 2019 new frequency bands will be allocated from 275 – 450 GHz to the different radio services including amateur radio.
THE SARL HALL OF FAME AND THE FORGOTTEN SK PIONEER – There are many Halls of Fame in the world including amateur radio, covering the various fields of achievements, where homage is paid to their early pioneers, some who are now Silent Keys. A total of eight Silent Key members were inducted in the SARL Hall of Fame during 2016 and 2017, but the first licenced radio amateur and pioneer in South Africa, also a Silent Key, was overlooked. His name is William Edward Dixon Bennett (A3V, ZS4F, ZS4W, ZS5EG) and he wrote the first South African history of amateur radio spark transmissions before World War I under the title “Amateur Radio in Retrospect”, which was repeated in RADIO ZS starting August 1949. He is also featured in the prelude of Part 1 of the new series entitled “History of Amateur Radio from World War I to World War II” in the August 2017 issue of RADIO ZS. Dixon Bennett was also a founder member of the SARRL in 1925. Let us honour this old-timer during the next round of the SARL Hall of Fame and show him the respect that he deserved.
VHF NEWS – Scientists have predicted that global warming would affect weather conditions worldwide, and the weather in South Africa this year has confirmed it. The severe drought in the Western Cape, the wild fires along the southern coast and the more recent heavy floods in Durban, including the massive hailstorm in Johannesburg, have proven that our weather pattern has changed. We have even noticed it on VHF propagation where tropospheric propagation such as Tropo Enhancement and Ducting have been affected. Fortunately Tropo Scatter propagation is not affected by the weather, but one has to put up with deep QSB cycles and weaker signals. Hopefully things will change by the time the warmer months appear.
BACAR-5 REPORT – According to Gavin ZS6BWW the first attempt to launch Bacar on Saturday morning 21st October failed caused by a hole in the balloon. During the next attempt the second balloon did not want to rise until more gas was added. Apparently the launch took place before 10:30 CAT and its cruising speed was later recorded over 100 km.
Carl ZS6CBQ reported that he managed to work ZR6AMC, ZS6TW and ZS6QL on the Parrot repeater on 433,550 MHz. Signal was 5/9+40 in Krugersdorp ZS4A could hear me in Bethlehem but he could not get into the Parrot. Also heard the Telemetry on 144,100 MHz 5/9+ 40. Nothing heard from Kletskous transponder.
ASTEROID GRAZES PAST THE EARTH IN A NEAR MISS – A house-sized asteroid grazed past Earth Thursday 12 October, passing harmlessly inside the Moon's orbit, as predicted, to give experts a rare opportunity to rehearse for a real strike threat in future. Dubbed 2012 TC4, the object's passing allowed scientists to practice spotting incoming objects, predicting their size and trajectory, and tracking their passage with a global network of telescopes and radars. The asteroid flitted past around 05:41 GMT at less than 44,000 kilometres from Earth's surface – just above the 36,000 km plane at which hundreds of geosynchronous satellites orbit our planet. A spokesman of the European Space Agency’s Near Eart Object stated that this is exactly why they do this exercise, to not be surprised by these things, so they pretended that it was a critical object and the trial run was a big success. A radar system in Puerto Rico, for example, that keeps an eye on asteroids was out of service due to damage from the recent hurricane there. TC4 is on a 609-day loop around the Sun, it will return to Earth in 2050 and 2079.
LATE FLASH! ZS4A Rickus and ZS2BK Andre were the first SA Sat Operators to work the new CAS-4A and CAS-4B satellites (SSB) , and they are performing quite well with strong VHF down links.