[HCDX]: New type of antenna used in MW broadcasts
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[HCDX]: New type of antenna used in MW broadcasts
First of all, I wish a very happy new year to you all. Then, I must say that
I have no interest, whatsoever, in the antenna business.
A couple of years ago, the excelent British magazine "Electronics World"
published an article, by Maurice Hateley, about a new type of antenna, to be
used in MW broadcasts, that he invented and named "crossed field antenna"
(CFA). The explanation he gave about the functionning of the antenna was
that it generated an electric field and a magnetic field independently from
each other, thus "synthesising" a Poynting vector, being both modulated by
the signal to be transmitted. This article raised a discussion in the pages
of the magazine, where some readers argued that the antenna could not
function in that way and "proving" that it could not work at all. Mr.
Hateley replied that maybe he was wrong about the explanation he gave about
the functionning of the antenna, but that it really did work. He added that
an experimental setup was already working in Egypt with very good results.
In the issue no. 1750, vol. 104, October 1998, of "Electronics World", I
found an advertisement of a firm called Hateley Antenna Technology, which
said the following:
***
CROSSED FIELD ANTENNA AUDIBLE IN UK ON MW
Following a recent technical survey in Egypt it is now evident that the
signals provided by the 22kW Tanta CFA are the strongest and clearest
programme audible in the Cairo area on Medium Wave. In fact the Ground Plane
CFA in the centre of the Nile Delta is audible both day and night in Cyprus
(480km to the north) and at Khartoum (600km overland to the south). The
quality is remarkable, many listeners reporting "sounds like an FM station".
Why this is so is not yet understood but may be due to the source being so
small.
As technical comparisons between CFA and conventional mast antennas six or
ten times taller are still on-going, on some days the 22kW from Tanta is put
to another antenna as a check, thus the signal heard at every distance may
be weaker. At night time one can easily hear it on 864kHz in the UK, if on
the CFA. It is distinguishable as a male Arabic speaker reciting. The other
two stations on the channel are on masts and said to be 200kW at Sofia
Bulgaria, and 500kW at Moscow and are completely overwhelmed on the nights
when the CFA is in use. We at this address will welcome reports and
endeavour to confirm with a colour photograph of the Tanta GP Crossed Field
Antenna. Please comment on fading and sound quality.
[snip]
***
(the ad goes on saying that they market new variants of this antenna for
transmitting and reception, and so on).
The address of the firm is the following:
HATELEY ANTENNA TECHNOLOGY
1 Kenfield Place, ABERDEEN AB15 7UW Scotland, U.K.
Tel/Fax: +44 (0) 1224 316 004
On January 3rd, at 2350-2355 UTC, here in Lisbon, Portugal, I tuned my Sony
ICF 2001D, with its built-in ferrite antenna only, to the frequency of
864kHz and, after some orientation of the receiver, there it was, the
Coranic reciting by a male speaker in Arabic, as the ad referred. Besides
this station, the frequency was occupied by RNE (probably a weak transmitter
elsewhere in the north of Spain) and another Arabic speaking station that I
could not identify (probably from North Africa); no signs from Sofia or
Moscow. According to the orientation of the receiver, the Coranic reciting
could well come from Egypt. Again on the night of 5 to 6 of January, I tuned
again to the same frequency, first at 2355-0005 UTC and then at 0055-0105
UTC, looking for an identification of the station, but I only heard the
reciting again. Was it Tanta with its CFA?
73
Fernando de Sousa Ribeiro
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