Nice range from 95 meter Haarlem radio tower

Arjan van B.

Software engineer

Posted on 12-05-2016

Gerard Duineveld invited us to the well-known Cellnex (formerly Alticom, formerly KPN/PTT) radio tower and data center in the Waarderpolder today, to discuss options to get a gateway installed at 95 meters.

As shown earlier by others, near line-of-sight situations with high altitude gateways/nodes can yield very nice ranges. From Haarlem, showed that an ESP8266/RFM95W node with a half wavelength dipole antenna, sending at SF7, SF9 and SF12, got its packets received at SF12 in Dronten, which is 73 km away. Utrecht even received at SF7 at 48 km, and so did Almere at 34 km, and Noordwijk at 23 km. (Details.)

Note that at 95 meters altitude, if the gateways are at, say, 20 meters, line-of-sight propagation would limit the theoretical distance to 3.57 × (√95 + √20) ≈ 50 km. So, some funny tropospheric propagation may have helped.

Gerard also reached a non-TTN Rotterdam gateway at 50+ km, SF12, using a simple quarter wavelength wire as an antenna.