# Link to SARL VHF, UHF & MICROWAVES DX TABLE Click here
Tutorial 4 – Sporadic-E Propagation.
Today we are going to have a look at Sporadic-E propagation that can produce the strongest signals on 50 MHz, or even weaker signals as high as 144 MHz or as far down as 27 MHz. It produces a skip distance around 600 km on 50 MHz and about 900 km on 144 MHz, and could cover about 2500 km on a single hop. Under certain conditions double-hop Sporadic-E becomes possible and extend the range considerably.
It is unpredictable and its cause has puzzled scientists for a long time. Small Es clouds can appear in the E-layer at a height of 90 to 120 kilometres in circular or irregular form, and when tilted can extend the range of a single hop. Even low power on 50 MHz can cover some long distances. It usually starts off with a fluttery weak signal that could increase to a strength of S9 within minutes. The midlattitude Sporadic-E season usually occurs during a number of days in December and January, and could last from a few minutes up to several hours.
Sporadic-E clouds my form quickly and slowly move westward. Scientists have focused on the ion content caused by burnt-out meteors in the E-layer. They have also paid attention to the high velocity winds that could cause windshear in the E-layer. These two factors could be responsible for the dense patchy regions of the E-layer ionization.
Then there are also the almost daily Sporadic-E openings that occured around noon for an hour or two during the Es season, The FM sound channels around 53,750 MHz have been copied at full limiting in Port Elizabeth emanating from the old Band III TV stations in Gwero, Kabwe and as far north as the Congo.
Next week we will concentrate on Meteor Scatter propagation.
VHF, UHF & MICROWAVE NEWS
RESULTS OF THE PEARS NATIONAL VHF & UHF CONTEST 2018
THE DIGITAL CONTEST
The Grand Overall Digital Winner
Pieter Jacobs, V51PJ, scored 212 904 points as a base station on 50, 70 and 144 MHz
Christo Greyling, ZR6AUI, scored 71 940 points as a base station,
Andre Botes, ZS2ACP, scored 44 345 points in a four hour per session Limited Category.
Longest distance achieved on Digital.
Willem Badenhorst, ZS6WAB, and Pieter Jacobs, V51PJ, established a new distance record of 1348 km on 50, 70 and 144 MHz Digital.
We would like to welcome new participants in our digital contest. They are: Alan Saul. ZS1LS of Cape Town, Michael Steenkamp, ZS2MIC from Despatch, and Andrew Prideauw, ZS2PA at Uitenhage.
THE ANALOGUE CONTEST
Grand Overall Analogue Winner
Carl Minne, ZS6CBQ, scored 171 220 points from a base station in Krugersdorp.
Pierre Lindeque, ZS4PF, scored 45 240 points from a base station in Welkom.
Rickus de Lange, ZS4A, scored 22 170 points as a base station in Bethlehem.
Longest distance worked on Analogue
Carl Minne, ZS6CBQ, in Krugersdorp and Servaas Wahl, ZS6SER, at Louis Trichardt recorded a distance of 402 km on 144 MHz.
Winner of Limited Category
ZS1CRG as a muli-operater station scored 4176 points during a four period per session, and was run by ZS1DUP and ZS1DWH.
Al Akers, ZS2U, scored 700 points as a base station from Port Elizabeth during the Limited Category
Winner of the FM category
Max Bouckley, ZS6MAX, scored 300 points on 145,500 MHz FM from his base station in Lyndhurst, JHB.
Divisional Analogue Winners
Division 1: ZS1CRG, mukti-operator station – 4178 points.
Division 2: Al Akers, ZS2U – 700 points.
Division 3: Poor propagation conditions.
Division 4: Pierre Lindeque, ZS4PF – 45 240 points.
Division 5: Dave Jones, ZS5DJ – 650 points.
Division 6: Carl Minne, ZS6CBQ – 171 220 points.
It appeared that there were many amateurs active during the analogue contest, but only a few bothered to send in log sheets.
WIRELESS INSTITUTE OF AUSTRALIA SEEKS AMATEUR RADIO POWR INCREASE – The Wireless Institute of Australia (WIA) is seeking a power increase for radio amateurs. WIA is pushing telecommunications regulator the Australian Communications and Media Authority (ACMA) to bump up maximum power levels for all three licenses classes to 50 W for Foundation licensees, 200 W for Standard licensees, and 1,500 W for Advanced licensees. For some time the WIA has pushed for higher power limits for Advanced licensees, who feel the current 400 W HF power limit (120 W on constant-carrier modes) puts them at a disadvantage, especially in contests, while other countries permit 1 kW or more. In 2013, ACMA ended an 18-month trial that allowed participating Advanced licensees to run up to 1 kW on HF. Currently, Foundation licensees on HF may run up to 10 W PEP on SSB (or 3 W on CW, AM, or FM), while Standard licensees have a 100-W PEP HF power limit (SSB) or 30 W for constant-carrier modes. It could also be a boon for VHF experiments.
NEW BLACK BOX TO SEARCH FOR LIFE BEYOND EARTH – In the world's driest desert, an unassuming black box called Espresso is about to begin a very big mission: scouring the Universe for planets like ours to find signs of life beyond Earth. Espresso, an instrument known as a spectrograph, has a humble appearance that belies its cutting-edge technology: it is the most precise instrument of its kind ever built, 10 times stronger than its most powerful predecessor.
In the Atacama Desert, in northern Chile, Espresso will be hooked up to four telescopes so big that scientists simply named them the Very Large Telescope, or VLT. Together, they will search the skies for exoplanets—those outside our own solar system—looking for ones that are similar to Earth. The Atacama is a particularly good place for this kind of exploration. Its skies are completely cloudless most of the year, which is why the highly respected European Southern Observatory, which runs the VLT program, set up shop there in the first place. In fact, many of the world's major telescopes are located in the area. By 2020, the Atacama is expected to be home to about 70% of the world's astronomy infrastructure.
It will analyse the light of the stars observed by the VLT, enabling it to determine whether planets orbit around them, and important information about those planets themselves: what their atmosphere is like, whether they have oxygen, nitrogen and carbon dioxide, and whether there is water—all essential for supporting life. Espresso will be available on all four telescopes at once, which is something that had never been done before. That means the likelihood of finding planets similar to Earth in mass and size, or the conditions for life, are greater.
Espresso will help us answer one of the greatest questions we have in astronomy, which is analysing and understanding planets outside our solar system. The new spectrograph is housed inside a giant metal cylinder chilled to an average temperature of -150 C (-238 F)—essential for its delicate optical instruments to do their work. It was installed early last year beneath the base of the VLT, which is perched atop the 2,600-metre altitude Paranal mountain. Espresso is currently in testing phase, but in 10 months' time it will officially begin its big mission—which is also a solitary one.