<div dir="ltr"><div>Highly recommended: </div><div><br></div><a href="http://www.rtl-sdr.com/rtl-sdr-tutorial-measuring-filter-characteristics-and-antenna-vswr-with-an-rtl-sdr-and-noise-source/">http://www.rtl-sdr.com/rtl-sdr-tutorial-measuring-filter-characteristics-and-antenna-vswr-with-an-rtl-sdr-and-noise-source/</a><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Oct 1, 2015 at 9:23 PM, Martin <span dir="ltr"><<a href="mailto:dcmk1mr2@gmail.com" target="_blank">dcmk1mr2@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Wrapping the dongle in aluminum or copper tape for shielding is popular. There are newer RTL-SDRs that are packaged in a metal box with a TXCO for another $20-30.<div><br></div><div>For the noisy urban environment: <a href="http://www.ebay.com/itm/B1602-SAW-filters-Epcos-1090MHz-ADS-B-AirNav-SBS-/110619017914?hash=item19c16842ba" target="_blank">http://www.ebay.com/itm/B1602-SAW-filters-Epcos-1090MHz-ADS-B-AirNav-SBS-/110619017914?hash=item19c16842ba</a></div><div><br></div><div><a href="http://ava.upuaut.net/store/index.php?route=product/product&product_id=85" target="_blank">http://ava.upuaut.net/store/index.php?route=product/product&product_id=85</a></div><div><br></div><div>My rig was a collinear antenna in the attic with the preamp and saw filter at the antenna and really long usb extender to the shack. </div><div><br></div><div><a href="http://www.amrad.org/wp-content/uploads/2014/12/wideareamap.png" target="_blank">http://www.amrad.org/wp-content/uploads/2014/12/wideareamap.png</a><br></div></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Oct 1, 2015 at 8:42 PM, Robert Seastrom <span dir="ltr"><<a href="mailto:rs@seastrom.com" target="_blank">rs@seastrom.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
Readers of this list are almost certainly well-acquainted with the "$20 USB SDR" (RTL2832U and R820T[2]) sticks that were originally intended for DVB-T reception. Plenty of bad things to say about them (wide open front end, low resolution ADC, uncertain build quality when acquired via eBay etc), but hey for $20 what do you want? Complaining would be like griping about your Baofeng or Wouxun HT not being up to the quality you've come to expect from Icom.<br>
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GNU Radio supports these on Linux and there's a cast of various other programs for Windows and Mac that work too.<br>
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These little radios-on-a-stick have attracted the attention of the Flightaware folks and their community of ADS-B receiver-and-feeder folks (same thing as AIS for ships and APRS for hams, but on 1090 MHz rather than VHF high band). For a while now they've had a setup known as PiAware which turns a Raspberry Pi (use a B+ or a 2; the original B was weak in the USB power department) into an ADS-B receiver that can feed to FlightAware (you get an "Enterprise" level account for free as a thank-you for feeding them data). There are two ways to put it together: download and write a ready-to-go canned distribution (easy) and download NOOBS or Raspbian and do package installs and driver blacklisting by hand (hard). Naturally I chose the hard way, which explains why it took me 20 minutes to get it up and running instead of 5.<br>
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Of course it's a good idea to put a better antenna on it than the crummy telescoping mag-mount that comes with it. The popular antenna for this application seems to be a coax stacked collinear of 8 or 10 elements - more is way into the land of diminishing returns. There are youtube videos out there on how to make these.<br>
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Some people use amplifiers, often the inline amplifiers intended for use with satellite tv receivers (available for a few bucks on Amazon), powered with a bias tee. I'll confess I don't know where to get the latter on the cheap, which Mini-Circuits sure isn't. Not sure it's necessary anyway if you have a short cable run and a good antenna.<br>
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I don't have a good antenna yet. My setup is sitting on a window sill at my office on the 7th floor overlooking Dulles Airport.<br>
<a href="http://flightaware.com/adsb/stats/user/res3066" rel="noreferrer" target="_blank">http://flightaware.com/adsb/stats/user/res3066</a><br>
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To see what can be done when you throw a few bucks at it and don't have the facilities guys getting in your way, check out my friend's setup:<br>
<a href="http://flightaware.com/adsb/stats/user/jaredmauch" rel="noreferrer" target="_blank">http://flightaware.com/adsb/stats/user/jaredmauch</a><br>
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Anyway, pretty spiffy and pain-free to put together and get on the air. More at <a href="http://flightaware.com/adsb/piaware/" rel="noreferrer" target="_blank">http://flightaware.com/adsb/piaware/</a><br>
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(the RTL stick I got was <a href="http://www.amazon.com/dp/B00P2UOU72/" rel="noreferrer" target="_blank">http://www.amazon.com/dp/B00P2UOU72/</a> )<br>
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-r<br>
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