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ANTENTOP- 03- 2003, # 004

Half-Loop Antennas




II.7. Qualification

A 2-12 MHz demonstrator was built with acceptable dimensions for land mobile applications (height=90cm, length=2.4m, width=30cm). All adjacent bandwidths were covered within the 2.5:1 VSWR specification.

Its efficiency was measured every 0.5 MHz on a test station by substitution of a refence whip. These values were not more different than ñ1dB from the values deducted from the Q-factor measurements.

A second version with a 2-30MHz frequency range was developped. It was qualified for military environment with mechanical tests (chocks, vibrations) and climatic tests (-40C +70C, rainfall, salted fog, windspeed, ice, dusts, etc...) according to MIL SPEC standards. It is now in service in quantities in the French Army.


Extract from the field trial made by Thomson-CSF in octobre 1994 for the French Army:

"From 0 to 600 km, all Q/S and S+N/N measurements have confirmed a behaviour without fault of the half-loop. It always gave results much higher than that of the guyed 5m whip whatever the climatic conditions were (rain, intensive fog...). We tried to use the station in the most extreme environment conditions noting the link results, while driving under the rain, under the high voltage cables either parallel or perpendicular to the road, measuring signal/noise in highly industrialized towns (like Clermont Ferrand) , on the country roads through humid forests, etc...


"The results were independant of these environmental conditions, the reception signal/noise beeing only slightly affected under the very high voltage cables.

"...The half-loop antenna bring the best results in terms of link budget and listening comfort".

Thomson-CSF also confirmed that the half-loop antenna on a moving car allows fast data transmissions without fault in the silent zone of the whip antenna, and that it improves the probability of successfull synchronisation of the new procedures in bad ionospheric conditions.

Other field trials were successfully conducted in France and several foreign countries in the Middle East and America.


Mobile and naval half-loop antennas and fixed/semi-fixed loop antennas using the same electronic components and softwares are working today with various radiosets for military and civilian applications as well, in frequency hopping, ALE or fixed frequency modes A modular and universal interfacing unit makes it possible to fit the antenna at the radioset RF output using the control interfacing designed for its antenna coupler.

The control exchanges can be done in RS232 or multiwire cable according to the speed. The frequencies can be provided in clear, as a channel number or not provided at all. A frequency counter is necessary in this last configuration.

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STAREC has been involved for a long time in the design of specialized antennas, a wide range.of which has been proved in operation with French and foreign Armed Forces.

This equipment is mainly used in fixed or mobile weapons or telecommunication systems, such as shelters, trucks, battle tanks, forward armoured vehicles, etc. STAREC is involved in the RITA, ROLAND, PR4 G, HF Carthage programs.

Agile half loop on vehicle




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