Hi @dsj David,
On my first day of distance tests I managed the Sky 700m away to the hub inside the window.
The next day using the Sky on the roof I extended the hub location Northwards from one headland to the next as far as practical to over 7km without requiring any extra antenna.
Today I ventured Southwards and was unable to pick up a signal to the bare hub at over 12km.
Great so now I had the opportunity to try adding a parabolic reflector to see if I could extend the distance without changing anything in the hub.
Bingo I had it working about 12.4km away. Over 40,000ft or over 7 miles.
RSSI was -93.
So after I watched it working and doing its 3 sec updates for a few minutes I then removed the reflector to check its effect, and it lost reception.
The Hub was held at the focal point of the reflector by rubber bands.
The reflector aimed at the Sky on the headland:
The Sky is on a pole at the North East or top right of this picture and the hub is at the headland in the South West or lower left of this map
This is the Australian frequency hub to a Sky running at 3.33 volts.
cheers Ian 