There have been objections from local residents with particular reference to the current planning application for 4 new satellite dishes , 2 of 9.3m, 1 of 6.3m and 1 of 3.8m diameter. These objections are, I believe, based on fears of perceived unproven health risks and fears of increased interference to domestic electronic equipment and telephones. This explanation seeks to show that the satellite dish installations should not be adding to these fears.


The Brookmans Park site has been used for medium frequency broadcasting since the late 1920's. The nature of this type of radio transmission is that the power emitted from the antennas is in all directions and the powers used quite high. For example, Radio 5 has a transmitter power of 1 50 kilowatts and this is but one of several services transmitted from the site. For a mile or so around the site, therefore, the signal is very strong and any length of wire or pipe will act as a receiving antenna and pick up a strong signal. e.g. telephone lines, loudspeaker wires etc. Unless precautions are taken, which could include careful routing of cables and the fitting of filters, then the equipment connected to the cable can turn this energy into audible sounds.

The nature of the transmissions from satellite dishes is that the frequencies used are very much higher, and thus well removed from the medium wave band. On that score they would be unlikely to interfere with domestic equipment. However, the satellite dish emits and receives on a very narrow beam, rather like a very narrow searchlight beam, to pin-point the satellite many thousands of miles away. The transmitter power is a fraction of the broadcast transmitters. Also the dishes are elevated upwards and thus the beam is way above people and houses.

There will be no increase in interference to domestic equipment due to the installation of satellite dishes.


The guidelines of the National Radiological Protection Board are followed at all times. i.e. levels of radio frequency energy are well below NRPB recommended levels in areas to which people have access.

What is worth emphasising is as stated above under "Interference", i.e. the very narrow beam used by the satellite dish ensures that any radio energy is directed well away from people and buildings.

How Many Dishes on the Site?

The "commercial" answer is as many as possible but only within the area defined below (see 'Master Strategy'). A submitted planning application is the result of an enquiry from a potential operator and does not necessarily mean more dishes. Before any agreement can be catered into that operator needs to know if planning permission would be granted. If it is, then the operator has a 5 year option to build those dishes. This may or may not happen. Additionally, there are physical limitations in that a dish must not obstruct the beam of another dish.

Master Strategy

In 1993 a "Master Strategy for future development of the site was drawn up and agreed with the Planning Authority (Welwyn Hatfield Council). Briefly, this will restrict the installation of satellite (or any other aerials) to a north - south strip some 110 metres wide, at the rear (east) of the site. This leaves the whole of the front of the site, from the A1000 road and inwards to a depth of about 200 metres, clear of any future development.

The area of the site for future satellite dish installation is restricted to a strip of land at the rear of the site.


A landscaping scheme has also been agreed with the Local Authority. This involves the planting of several strips of trees and bushes right across the site between the "dish area" and the public roads, together with re-enforcing existing and the planting of new hedgerows. Extensive planting scheme is ongoing in consultation with the Planning Authority.

Preservation of Wildlife and Grazing.

The woodland area in the north field by the public footpath is preserved under the agreed Master Strategy. Thus the wildlife therein is flourishing. All other unused areas of grassland are fenced and used for grazing animals.

Existing Woodland retained and grazing continues.

Written by George Bath, Castle Communications International.