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--- guides:sdr_tracker [2013/03/14 21:04] – Updated with new images upu
+++ guides:sdr_tracker [2018/08/21 12:57] (current) – [Decoding the Payload] kevwal
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 The RTL2832U outputs 8-bit I/Q-samples, and the highest theoretically possible sample-rate is 3.2 MS/s, however, the highest sample-rate without lost samples that has been tested so far is 2.8 MS/s. The frequency range is highly dependent of the used tuner, dongles that use the Elonics E4000 offer the widest possible range (64 - 1700 MHz with a gap from approx. 1100 - 1250 MHz).
+WARNING : It is unlikely you will be able to use these devices for tracking a real flight unless you have a very good antenna. However for bench testing payloads they are more than adequate.
+===== Note on Antennas =====
+For testing all that is really needed is a piece of wire 164mm (1/4 the wave length of a 434Mhz signal) pushed in the end of the dongle. A small 433/434Mhz stub antenna screwed in the end will also suffice. Neither of these will allow you to track real flights unless they are extremely close.
 ===== Compatible Devices =====
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 Data sourced from http://sdr.osmocom.org/trac/wiki/rtl-sdr. The E4000 is hard to get hold of these days to the one you should be going for are R820T based boards. Some of the earlier boards lacked the anti static protection to allow the use of these with larger antennas.
+**Warning. I don't know if mine is broken but its totally useless at receiving actual in the air HABs. Ok for testing but it drifts badly too. I would appreciate anyone else who has uses these giving some feed back thanks - Upu**
 The [[https://www.cosycave.co.uk/product.php?id_product=288|NEWSKY TV28T RTL 2832U / R820T]] is a extremely cost effective unit that comes with an SMA adaptor.
+Older versions of TV Dongles do drift however more recent (2015) versions are much better and are used by many people for tracking.  Dedicated dongles such as Airspy are now much more common and form the basis of very good receivers.
 ===== Mac Software  =====
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 The guys at SDRSharp have done a very easy script for installing the dongle. Go to :
-http://sdrsharp.com/downloads/sdr-install.zip
+http://airspy.com/download/
 Extract this zip and double click Install. This will create a sub directory called sdrsharp. Within this sub directory double click zadig.exe and you will see the following with an empty list :
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 For the next step you will need to download and install Virtual Audio Cable or some other such software.
+Some sound cards under Windows support "Stereo mix" which is a built in feature to perform this function for you. Enable it following these instructions: http://www.howtogeek.com/howto/39532/how-to-enable-stereo-mix-in-windows-7-to-record-audio/
+If not, chose one of the below pieces of software.
 Virtual Audio Cable is available here : http://software.muzychenko.net/eng/vac.htm
+Virtual Audio Cable demo send some voice over the channel saying "TRIAL" so it's pretty useless now for this use.
+VB-CABLE Driver: http://vb-audio.pagesperso-orange.fr/Cable/index.htm, (21/08/18 Now moved to here: https://www.vb-audio.com/Cable/index.htm). VB-Cable driver is a donationware. The configuration steps are the same than VAC. You should try this one.
 Jack Audio is availble here : http://www.jackaudio.org/