Microwave Activity in Malta by 9H1LO
The Malta Amateur Radio League, established in 1922, has never stopped evolving. Since the very early days of Radio, when a handful of dedicated radio amateurs, through their hard work and dedication, and under great duress from the very fact that Malta was a colony and these amateurs operated under strict guidelines from the authorities concerned and in some cases, one can say, were only tolerated rather than permitted, managed to advance this wonderful hobby ‘amateur radio’. The early days of AM radio, was the forerunner, and here great advances were made - it is enough to mention Professor TONNA BARTHET,whose contribution to Radio and radio amateurs could be described as a "GOLDMINE".
In radio technology, Robbie Galea established the first radio contacts on the Island, hence laying down the road to progress, it is well worth mentioning, that in those days, radio amateurs were not allowed to experiment as much as they would have liked to do, everything they did, had to be authorized, suffice to say that the use of the 2 metre band was acquired by sheer co-incidence, and by the intervention of a radio amateur, whose occupation was a dentist - the same goes for construction work, this was a taboo for the authorities, shortage of spare parts and components did not help either, however, in spite of all these difficulties, MARL and it’s members continued to grow in numbers and experiments . As time moved on, advances in radio techniques and the launching of more satellites, the availability of satellite dishes and the hard work and dedication by some radio amateurs, the use of high frequency transmissions appeared on the horizon.
MARL once again is in the forefront of these experiments as one can deduce from the following article, the idea is to encourage and inform other radio amateurs in the use of 10 GHz SSB and A.T.V. transmissions.
Around 1983, three very dedicated radio amateurs namely 9H1ES, 9H1GB AND 9H1FX carried out the first test transmissions, using Home Brew equipment, void of many test instruments and limited output power .e.g. 20 mill watts, wideband I.F. of 250khz and only using a mixer diode (IN23) and a Parabolic Antenna with a diameter of 45 cms and using a penny feed system.
Around 1987, 9H1ES constructed a 10GHz transverter with an output power of 200 mwatts. For I.F. AN FT290 MK1 WAS USED - and contacts were made with I8 stations - SARDENIA AND SPAIN using 1metre parabolic dish using front fed horn system with a waveguide feed.
Two years later in 1989 due to personal situations and family bereavements, 9H1ES interest declined and all activity stopped completely.
Malta Amateur Radio League showed a lot of interest in these tests and activities, and permission for the ATV mode was applied for and eventually obtained.
As 9H1LO had limited experience, he asked for assistance from 9H1ES, WHO HAD vast experience in Microwave Techniques.
This created and regenerated a lot of interest on the part of 9H1ES, and 9H1ES restarted building the required A.T.V. EQUIPMENT from scratch, although 9H1ES had 10GHZ transverter and Gunn plexers and associated materials i.e. WAVE GUIDES, WAVE GUIDE BANDS, DISHES.
For someone who was only equipped with SSB 10GHZ equipment, 9h1es had to build again from scratch a modified TVRO LNB WITH IF OF TVRO RCVR FROM 950 to 1700 MHZ with a local oscillator of 9.410 GHz.
After completing and building this equipment 9H1ES, TESTED FOR RECEPTION WITH RAGUSA REPEATER SIGNALS.
10 GHz SSB TESTS
Another radio amateur involved in the 10 GHZ operation is 9H1BN, but had to relinquish his interest due to lack of operators and lack of activity in this mode. 9H1BN AND 9H1VW DISCUSSED the possibility of setting up equipment for this operation, 9H1VW ordered assembled and in some cases manufactured wave guides with the assistance of 9H1BN, together they tuned the equipment and more and more operators were encouraged and interested in the 10GHz SSB mode, 9H1LO modified a commercial data transceiver tuned to 10.368.200MHz.
9H1LO's setup consisted of:
9H1ES installed a beacon at his residence using modulated frequency shift keying fed into a wave guide from shack to roof area approx 15metres up and carried out tests on 10.368.900 to revive and regenerate his equipment, carried out tests between his home qth and selmun area approx a distance of 9 kms and another test from his qth to mellieha approx 11kms distance -it was here that 9h1es established the following based on his observations;-
Although there was no line of sight, contacts was established, this was remarkable, as every theory indicated that line of sight conditions must be present.
As the results obtained did not include line of sight conditions- 9h1es asked Marco 9h1bn to carry out further tests, because it was evident
That the case for line of sight conditions held no solid ground.
Test equipment was once again set up by 9H1ES and 9H1BN to prove that line of sight conditions was not mandatory
Mentioned earlier, 9H1LO completed building his equipment for 10 GHz and tested with 9h1es to establish, exact frequency off-set, a requirement, and had to be accurate.
9H1LO set up his test equipment at xemxija inside a hotel situated at sea level and was 6 stories high, 9H1ES set up similar test equipment at his QTH between these two operators, there was one large obstacle, Wardija Hill.
Once again, results from these tests showed poor results, signal levels were 3 by 3.
MARL members organized a field day coordinated and set up by 9h1es, using maps and coordinates were as follows:
The test to end all tests :
On the 31 st January 2004, a test to end all tests took place between 9h1es , 9h1lo and 9h1vw located at two different points and coordinates.
The article has been written with one thing in mind, to encourage radio amateurs to get interested in this mode of communication, it is a unique form of contact, gives enormous satisfaction to all those that want to get involved in constructing or building or installing their home brew equipment, should they try to get involved, they will find assistance and experience of operators who have personally tried, tested, built, modified and improved equipment,and marl is looking forward with pride and satisfaction, to the day, not in the far distant future, when 10GHz SSB operation becomes what the 2 metre operation was a few years ago.