ELTRES Radio Coverage Trial in South-East England

Road tested coverage achieved by a single ELTRES base-station

Figure 1: Leith Hill Tower, Surrey, site of the ELTRES base-station

Leith Hill, along with its tower is situated in the North Downs range of hills in Surrey. At the top of the tower, it is over 1000 feet above sea level, making it one of the highest points in the whole of the south-east of England. As such, it was expected to offer good radio reception coverage across a wide range, including London.

The tower itself is owned by a charity, the National Trust, and is normally open to the public. However, during March 2023, public access to the tower was closed and Sony was able to secure the tower for 3 days of work for performing radio coverage tests.

Receiver Setup

The ELTRES base-station receiver was carried up from the car park and installed along with its receiving antenna at the top of the tower, see Figure 2.

Figure 2: ELTRES receiving antenna secured to the tower battlements

Transmitter

Handheld ELTRES transmitters were positioned in two vehicles for the drive tests, see Figure 3.

Figure 3: ELTRES transmitters installed in cars

Drive Test

Reception was confirmed by drive tests covering a variety of road routes:

Down to the South Coast at Shoreham by Sea
East from Slough, through central London, North London to Potters Bar
East from Guildford in Surrey to Sutton Valence near Maidstone in Kent
South from Slough via Ascot, to join the M25 anti-clockwise to Leatherhead
North-east from Hindhead through the Surrey hills towards Leith Hill

After performing the drive tests around South-East England, the corresponding locations where ELTRES transmissions were received are shown in Figure 4.

Figure 4: Locations from where transmissions were received at the Leith Hill receiver.

The coverage obtained was impressive, considering most of the ELTRES transmitter units were located inside the vehicles and were transmitting through the vehicle windows. The maximum transmission power was only 25 mW, and all transmitters were operating from batteries.

Taking a zoom into the central London route, this covered an area with some high buildings at the edges of the road. Even in this difficult radio environment the ELTRES signal was correctly received, see Figure 5.

Figure 5: Central London ELTRES transmissions received

Capacity

However, with such a large potential service coverage area, there may be concerns that the ELTRES system could run out of capacity for the number of transmitting nodes present. Fortunately, as explained in this article, the high efficiency of the ELTRES system means it has a huge capacity, about 7-50 times that of a LoRa based system, enabling a huge number of end device nodes to send information to their destinations.

Summary

With the installation of a single ELTRES base-station, it has been demonstrated that very wide coverage of South-East England is possible, including within central London.

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