New Indoor Antenna with a Tiny Receiver

1090mhz Bi-Quad 

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Built this over the holidays to see how it might perform.  The back panel is about 11 by 9 inches of scrap copper-sheet mounted on a short aluminum angle with four small bolts. The angle is in turn held onto an indoor second-floor railing with a couple of zip ties.

The center stub is a short length of LDF2-50 Heliax and the feedline is 1.5 meters of RG402 semi-rigid coax. The receiver is a FlightAware ProStick Plus connected to a Nexx WT3020 mini-router running OpenWRT with Dump1090-mutability, which then feeds an instance of Virtual Radar Server.

WT3020 mini-router and FlightAware ProStick Plus

These two devices together are less than 6 inches wide and draw less than 0.5 amp between them, and seem to perform quite well with the bi-quad antenna. (The front connectors on the router are WAN, LAN and power, with the USB connector on the side)

 

Here is a 24 hour plot from this combination. The antenna is indoors, facing S-SW, and has not yet been adjusted or fine-tuned. Although bi-quad antennas typically have a back lobe, I'm surprised by how much is received from behind the antenna. Perhaps after adjustments, that will improve.

24 hour range plot 

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 Red rings are 100km apart.

 Currently aimed S-SW, and reaching about 375km.

 

 

December 2016 Rangeplot

from Planeplotter

 

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and from Virtual Radar Server

 

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Range rings are back to being in kilometers, with the outermost red ring being 400kms.

 

The aircraft up near Cold Lake at 4225 feet is not real. It is an artifact from a garbled signal received a few days ago, that didn't clear out properly.