Description

"Hertzian Radiation" is the oldest, yet the least common way to refer to radio-waves.
The present invention relates to an hertzian radiation passive detector which exploits a secondary ionization fluorescence phenomenon. Untill now, it was thought that the radio-fluorescence phenomenon was only property of very short wavelength emission such as x-ray or those caused by radioactive materials. The detector and its method of employ, as described hereafter, allow to convert an hertzian radiation directly into a visible light radiation so to permit the naked eye appreciation of the hertzian radiation's energy distribution over the body of a radio antenna and its immediate surroundings, during transmit mode. This is, most importantly, done in a non-intrusive manner as the detector is it-self radio-transparent(*) and does not interfere with the resonance and radiation of the radiator. Moreover the energy absorbed by the detector is neglectable.
As an hertzian radiation invests the low pressure gasses inside the detector, a first ionization takes place with the result that a scattering of higher energy particles will end-up against the luminophore layer covering the inner side of the walls of the detector tube, giving origin to a visible light emission which increases correspondingly to the increase of the flux of the hertzian radiation untill the detector is fully lit.

In practice, a secondary ionization fluorescence hertzian radiation passive detector in his most elementary and economic form, comprises of a 100 Watt straight fluorescence tube(1) for general purpose indoor lighting, having a physical length of about 2.4 meter and a trolley(2) which is made of dielectric material and standing on 4 swivel castor wheels.

The trolley(2) allows the detector(1) tube to stand up and be free to be moved up and down along the body of the antenna(3) under examination, which is placed horizontally and at a suitable height so to encounter the detector at about its middle.

Generally, a power of little more than 40 Watt RF is enough to fully lit a resonant radiator for the short waves as an ½ wavelength open dipole antenna. Once the tube is excited, by progressively reducing the RF power supplied to the aerial or by progressively moving the detector away from the radiator, it is possible to visually appreciate the relative strength of the field generated on each and every point along the antenna or its immediate proximity.

An excited tube will maintain its fluorescence untill the hertzian radiation ceases or drastically diminishes or ceases all together. By reducing the RF power supplied to the exciting antenna, the region of the tube previously lit will decrease correspondingly and its visible light emission will be extinguished as soon as the excitation RF power will drop below 0,1 Watt.

By means of a number of detector tubes, it is possible to generate a field strength dynamic luminous diagram, both bi-dimensional or tri-dimensional. However, it is advisable to build a diagram by putting together several photograms of the same tube in different point along the radiator. This is easily done by first exciting the tube and then moving it alongside the radiator or the space around the antenna under examination.
Untill the tube is fully lit, to a certain strength of visible radiation correspond a certain strength of the hertzian radiation. It is, therefore, possible to estimate the attenuation introduced by the space in the proximity of the antenna.