current state of the rtl-sdr (plug and chug) art...

Fri Oct 2 15:36:18 CDT 2015

The preamp made a huge difference for me.  IIRC the number of packet
decodes increased by an order of magnitude.  The filter didn't seem to have
so much impact on decodes.  Even without the preamp the RTL-SDR gains
settings make a big difference.

The etch-a-sketch software is Plane Plotter - they offer a free trial but
it expires.

The elevation was about 400'  (Tenleytown) and the attic was about 40'.  I
had big hill to the east so I was surprised that I received so many tracks
in that direction.

Also worth a look is RTL-1090 and RTL-1030.  These include a signal
visualizer that might help with amplifier tweaking.

On Fri, Oct 2, 2015 at 5:25 AM, Rob Seastrom <rs at seastrom.com> wrote:

>
> Did you do any a/b testing with and without the filter and the amplifier?
>
> I was looking at the metal boxes that go with my particular rtl-sdr -
> i'd imagine it's reasonable to add one on spec if you're putting an
> amplifier in too.  http://www.amazon.com/B00NZ2I6QA/ It'll also
> complete the job of blocking *all* the other USB ports on the Pi.
>
> A footnote here - Using these with a non-plus pi-b is Right Out; the
> USB power is super weak on those.  Using it with a Pi2 was painful -
> couldn't use an Apple keyboard/mouse at the same time due to power
> issues.  I moved it temporarily to an external powered hub; the
> permanent solution was to not run a keyboard/mouse at all, since it's
> under the desk of a colleague who has a window office.
>
> That amplifier looks nice if a little expensive in context.  A little
> disappointing that while it's compatible with a power injector they
> don't have a version sealed for outdoor use.  The satellite amps of
> course are OK outdoors, but they don't have the bandpass filter.  Then
> again, they tend to be specced as 950 MHz to 2100 MHz or so, and the
> skirt on the bottom end may offer enough rolloff that as a practical
> matter the 928-932 MHz band is attenuated "well enough".
>
> For the link you uploaded last fall, what's the software you were
> using that leaves the persistent tracks?  Not bad at all for an attic
> antenna - what's your elevation there and HAAT?
>
> -r
>
>
> Martin <dcmk1mr2 at gmail.com> writes:
>
> > 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.
> >
> >
> >
> > For the noisy urban
> > environment: [[
> http://www.ebay.com/itm/B1602-SAW-filters-Epcos-1090MHz-ADS-B-AirNav-SBS-/110619017914?hash=item19c16842ba
> ]]
> >
> >
> >
> > [[
> http://ava.upuaut.net/store/index.php?route=product/product&product_id=85
> ]]
> >
> >
> >
> > 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.
> >
> >
> >
> > [[http://www.amrad.org/wp-content/uploads/2014/12/wideareamap.png]]
> >
> >
> >
> >
> > On Thu, Oct 1, 2015 at 8:42 PM, Robert Seastrom <[[rs at seastrom.com]]>
> wrote:
> >
> >                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.
> >
> >      GNU Radio supports these on Linux and there's a cast of various
> >      other programs for Windows and Mac that work too.
> >
> >      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.
> >
> >      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.
> >
> >      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.
> >
> >      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.
> >      [[http://flightaware.com/adsb/stats/user/res3066]]
> >
> >      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:
> >      [[http://flightaware.com/adsb/stats/user/jaredmauch]]
> >
> >      Anyway, pretty spiffy and pain-free to put together and get on the
> >      air.  More at [[http://flightaware.com/adsb/piaware/]]
> >
> >      (the RTL stick I got was [[http://www.amazon.com/dp/B00P2UOU72/]] )
> >
> >      -r
> >
> >
> >      _______________________________________________
> >      Tacos mailing list
> >      [[Tacos at amrad.org]]
> >      [[https://lists.amrad.org/mailman/listinfo/tacos]]
> >
>
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