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   The collinear elements are assembled by inserting the exposed center conductor from one piece between the outer jacket and aluminum foil of the next piece, in an offset chain as shown in Figure 4. Pinch the outer jacket with your fingers to create a small gap, and then insert the longer wire between the jacket and foil using a gentle pushing and twisting motion. Do the same with the shorter conductor (see Figure 5) and continue to gently twist and push the two pieces together until a gap of about 1⁄8 inch remains (see Figure 6).

   Continue to connect all eight coax sections together in the same way with the 412 inch wire on top (see Figure 7)

. Use an ohmmeter to verify that there are no shorts between the foil and inner conductor. A schematic of the completed antenna is shown in Figure 8.

   Cut 3 inch pieces of electrical tape and wrap each joint to hold the elements in position and provide protection against the elements. Heat shrink tubing of the right size would work nicely as well. [A dab of silicone sealant at each joint before taping or heat shrinking might be a good idea. ó Ed.]

   Attach a Type F male connector to the bottom of the antenna. The electrical assembly of the antenna is done!

   The collinear elements are mounted inside a length of PVC pipe for additional weather protection and to provide for mounting. Feel free to incorporate your own ideas, but the simplest method Iíve found is use a right-angle Type F adapter (available at most home improvement stores) and a few PVC pipe fittings as shown in Figure 9.

   Cut a piece of 34 inch PVC 42 inches and slide the antenna inside with the right-angle adapter attached to the Type F connector at the base. Drill a hole large enough to pass the feed line coax in a 34 inch plug and feed the coax through the plug and middle of the T as shown. Add a Type F connector to the end of the feed line, and fit the pieces together as shown. Finish weatherproofing the housing by placing a 34 inch PVC cap on top. The PVC pipe can be pressed together very tightly, so gluing should not be necessary. This makes it easy to disassemble the antenna if needed in the future. Add a dab of silicone to seal the hole where the feed line goes through the plug.

Just Add Software

   All thatís left is to install two free software programs: ADSB# and Virtual Radar Server. ADSB# is a server that manages the dongle, extracts raw data frames and then transfers them via Ethernet protocol to Virtual Radar Server for further processing, and the visual tracking map and user interface.
 

ADSB#

 
 
Download ADSB# by running the automated script from: http://sdrsharp.com/ downloads/adsb-install.zip.

   Run the script and open the ADSB folder that it creates. A program called Zadig must be run one time to install the WinUSB driver before the dongle can be used.7 Launch Zadig, then click OPTIONS and LIST ALL DEVICES. The DVB-T dongle will show up as BULK IN 0 ó select it, make sure WINUSB is the selected choice, and click INSTALL DRIVER. Thatís all there is to it!

Note: Zadig must be run with administrator privileges, and some anti-malware programs may try to prevent it from installing the needed driver. For more help with Zadig issues see https://github.com/ pbatard/libwdi/wiki/zadig.

   To launch ADSB#, leave all settings at their default values and click the START button. The FRAMES/SEC indicator will give an indication of how many ADS-B signals are being received (see Figure 10).

Virtual Radar Server

   Virtual Radar Server is an open source .NET application that runs a local web server. You can connect to the web server with any modern browser and see the positions of aircraft via Google Maps, generate reports, and integrate other useful information. Your PC must be running Windows XP SP2 (or newer), either 32-bit or 64-bit, along with Microsoft .NET Framework 3.5.5, which can be obtained from the Microsoft Download Center if necessary.

   Download VRS from the following URL and follow the installation guidelines: www.virtualradarserver.com/download. aspx.

The first time Virtual Radar Server runs it will prompt you for some user configuration information (see Figure 11). The configuration can also be changed at will by using TOOLS-OPTIONS. Configure the following fields as shown:

1. DATA FEED

1.1 DATA SOURCE: AVR OR BEAST RAW FEED

1.2 CONNECTION TYPE: NETWORK

2. NETWORK

2.1 ADDRESS 127.0.0.1

2.2 PORT 47806

   VRS communicates by way of a built-in web server and the above settings tell it to look to port 47806 of your computer (127.0.0.1 is the "local host" or the local Ethernet interface) for the raw ADS-B data stream that is being generated by ADSB#. Click TEST CONNECTION and confirm that a connection can be made.

   Return to the main screen and note the URL adjacent to SHOW LOCAL ADDRESS ó click this link and your browser will

   display a map generated by Google Maps and information about ADS-B-equipped aircraft that are within range. Most aircraft are not transmitting position information at this time, so donít be surprised to see real-time tracking of only a fraction of the total ICAO identifiers that are displayed. Congratulations, you are now viewing your own virtual radar!

   Virtual Radar Server offers many features and options that are too detailed to attempt to describe here. With a bit more configuration you can put your map page live on the internet for others to view, and better yet, send your raw data to ADS-B "hub" sites that aggregate data from many locations to provide up to a global view. One such hub is operated by the developer of ADSB#, and can be enabled by simply clicking the box on the ADSB# control panel. Change the NETWORK ADDRESS in VRS to SDRSHARP. COM and you will see your data along with that from other ADSB# users around the world. Clearly, with this low-cost solution, it wonít be long until a global network of ADS-B monitoring stations will emerge

   The author of VRS, Andrew Whewell, has created an online forum for help and assistance. Most common questions can be found by via the forum http://forum. virtualradarserver.co.uk/.

 

The author.

   ARRL member and Amateur Extra class licensee Robert Nickels, W9RAN, was first licensed as WNōOHO in 1965 at age 14 while living in Nebraska. He has a BS degree from Fort Hays State University in Kansas and credits Amateur Radio as a major influence during his 35 year career in electronics manufacturing. He holds three US patents and recently retired from Honeywell where he held positions as a principal engineer, engineering manager, and strategic marketing director. Bob now heads up RAN Technology Inc, a business and technology consulting firm. An avid cyclist and cross-country skier, he enjoys Amateur Radio history and homebrewing, in addition to his main interest ó collecting, restoring, and operating a growing collection of vintage electronics and boatanchor radios from the last five decades. You can contact Bob a 2645 East Dr, Freeport, IL 61032 or at wran@arrl.net.

This article was reprinted with the kind permission of the WIA and ARRL This artical was first published in the January 2014 QST.
 

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Westlakes Amateur Radio Club Inc. York Street, Teralba NSW