Britain's HF Radio Heritage: Military HF Radio Stations

Penhale Sands Radio Station

Penhale Sands is located on the clifftops 6km North West of Perranporth on the North Cornwall Coast, near to the village of Holywell.

It is a receiver station paired with St Eval, and appears to have much direction findng equipment installed. The picture below shows a Plessey Pusher (AN/FRD-13 in NATO speak) array; however it is not clear if there are actually antennas on it. The pusher was a smaller version of the AN/FLR-9 direction finder such as that at Chicksands, which used a full-size Wullenweber array.

DF Arrays at Penhale Sands: Image: Google

The image also shows, bottom right, a much smaller array looking from above like a child's playground roundabout.

Loop DF Array at Penhale Sands

There are two of these on the site, one right beside the coast path. This picture was taken by a walking enthusiast who kindly granted me permission to use the picture.

It is known that a loop antenna has a figure-of-eight pattern with two nulls 180 degrees apart in the plane of the loop. For direction finding this is of limited value as the station being received could lie either in front or behind the antenna. However it is also known that in an array where two loop antennas are set at 90 degrees to one another, their outputs may be combined in such a way as to produce a cardioid (heart-shaped) pattern with a simgle null. Thus determination of bearing is possible.

Further more, when a number of loops are arranged in a line, and their outputs combined via a phasing system, the response lobes can be electrically steered up to about +/-30 degrees. I would fully expect that these two principles are used in this array to give a single null that may be electrically steered to any bearing. The bearing may even be spinning around constantly, the receiver output being displayed on a synchronised circular timebase to show in real time the antenna response pattern relative to the bearing of the received station. Several receivers and displays could use the output of the array simulateously. I'm speculating now though!

Google access
There are no roads covered by Street View near enough to be able to see anything. Google Maps however provides an interesting view.

Last Modified 03/04/2010