I have almost completed the setup of a new ADS-B Station for Sydney, located in the Northern Beaches.
Thanks first up to AirNav Systems for supplying me with a free RadarBox receiver, as one of 50 people in
the world they selected to expand their global reception network.
ADS-B operates at 1090MHz, so the antenna, location and coax is critical for good reception. After searching
a number of suppliers and forums, I decided to go for a special antenna from
DPD Productions in California. Their
57 inch 9db gain model looked to be perfect, however it was too long to ship at a reasonable price, so Dave
made me a special slightly shorter version that just fits the max shipping dimensions for the US Postal Service
(performance will be only slightly less that the 57 inch model). Being a special, it took about 10 days to build
and another 10 days for delivery using the US Postal Service. Dave from DPD productions was extremely helpful
all the way through the process, so very happy to recommend DPD.
I received the antenna last Tuesday and mounted it on the roof ridge on Anzac Day. Immediately the reception
was very good, but mainly on the eastern quadrant. The best reception with the antenna mounted in this location
has been 280nm (518km) which is about as good as it gets.
DPD Productions Antenna mounted on the new 3 metre mast.
The screen shot below shows the Polar diagram of the reception, which has been excellent from north around to
the south east. There are regular plots out as far as Coffs Harbour, and 100nm plus out to sea.
This afternoon I mounted the antenna on a three metre mast on the ridge of the roof, instead of being just at
roof height, and the polar diagram is now starting to build quite well out in a westerly direction. The 3 metre mast
gives me a better outlook to the west, and being a line of sight transmission, any obstacles will affect the signal
received. It will take a day or two to build the new Polar diagram for this antenna setup.
Only thing left to do now, is to replace the RG58 coax with RG213 to maximuze the signal from the antenna.
