Techie Stuff - Transmission Gear

Written on 20/05/2016
Toby Mills

Now that we have our broadcast encoder working, we have to actually get the signal up to Popoiti Hill where Freeview is broadcast from in the Wairarapa.

These are our high capacity microwave links in their boxes all the way from Christchurch.

The signal goes over what is basically a long range wireless internet link and uses basically the same technology as your home WiFi router, except the signal is concentrated into a very narrow beam that travels a very long distance.

These microwave links will transmit up to 40km but we only need to get 23k but the real challenge is lining up both ends. At 23km distance, the beam is only going to be a few meters wide and it has to hit the tower spot on from our transmission location in Masterton. The slightest bit of movement and the beams will be out of alignment and the signal will drop.

Popoiti is a windy place with gusts of over 150km common so we have to use super strong industrial strength mounting clamps to attach it to the antenna tower.

If you ever wondered what was inside one of these things that you often see mounted on Cellphone towers, you can see inside ours above. Its actually very similar to a sky dish. The protective front cover keeps the wind and rain out and the hoop around the outside stops interference from all of the high powered transmission gear on the tower getting in and interfering with the signal.

The actual television signal that transmits to your house doesn't actually come out of these dishes, these are only used to get the signal to the actual tower.

On the tower are much more powerful transmitters that send the signal out in all directions. When we install the equipment on Popoiti Hill we will be posting images and video so you can see how it all works.