Underfloor services

Himatangi Radio after some rain
Himatangi Radio after some rain. Courtesy Rex Johnson. Click to enlarge.

By Rex Johnson

Rex JohnsonHimatangi Radio Station was located on the flat, sandy plains of coastal Manawatu near Foxton. Being only a few meters above sea level it sat above a relatively shallow underground water table, which meant that drainage after heavy rain was a slow affair. It also meant that rain water seeped into any low-lying area, one of which was the services ducting beneath the main transmitting hall.

There were access points to the transmitting hall underfloor services via hatches in the floor. Lifting the hatch lid near the Drive Room revealed the state of any ‘seepage’ and made it easy to drain the space as required. After a decent rain it was anticipated that water would have got into the ducts so a system had been devised to ’empty the station bilges’.

First, a deeper hole had been cast in the concrete floor of the duct below the Drive Room hatch entry, making this the low point of the underfloor ducts and ensuring good collection of any duct water that was present. Next, an electric motor had been installed to drive a water pump and a cunning arrangement had been devised to prime the pump to allow it to get into ‘sucking mode’.

Access to the underfloor ducting and sump pump
Access to the underfloor ducting and sump pump. Courtesy Rex Johnson

An old paint tin had been mounted on the water siphon pipe to hold the priming water, a tap beneath this tin kept the water from draining away until action was required. A baked-bean can on a string had been supplied, the tin having a lead weight mounted on one side of the rim so it would sink into the well and fill with water.

The operator scooped a few cans of water into the paint tin, opened the tin’s drain tap and turned the motor on. The water primed the system and the pump expelled duct water out the side of the building.

Rex Johnson checks underfloor services cabling at Himatangi Radio c1970
Rex Johnson checks underfloor services cabling at Himatangi Radio c1970. Courtesy Rex Johnson

It was quite important to keep a watch on water conditions under the transmitting hall as this area was where all power and communications wiring was run. The only services run above floor level were high-power RF feeds.

Published: November 2016