RTL-2832 and Raspberry Pi for ARPT and FUNcube

RTL-2832 and Raspberry Pi for ARPT and FUNcube

Last year I was playing with a cheap USB dongle for weather satellite reception. Eventually though I gave up on it, as although I could receive reasonable pictures with it, the device kept causing my machine to freeze.

Anyway, I recently dropped a raspberry Pi in the shack to act as a router between my shack and my wireless network. It got me wondering as to the possibilities of running the dongle via it. Turns out, it was as easy as… pi! (Sorry… 🙂 )

It really only takes a few simple steps:

  1. Download the rtl tools source code via git from OsmoSDR
  2. Build up the tools (make sure you’ve installed the build-tools package on your pi)
  3. Make sure you unload an DVB kernel modules with rmmod (after checking with lsmod)
  4. Run rtl-tcp on the raspberry pi
  5. And then connect via TCP from something like SDRSharp

Doing this I’ve had no problems with anything freezing, and have captured images with as much ease as I did before – although I have a dodgy coax cable I need to fix.

Further, I’ve gone on to receive beacons (6m, 2m and 70cm) as well as the FUNcube telemetry. Actually, to my surprise I’m the only VK7 to have recorded reception of any telemetry (according to the FUNcube Upload Ranking page).

To finish, here’s a couple of images received via this setup (one from NOAA-15 and one from NOAA-19). And the title picture of New Zealand is from NOAA-19.

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Improved NOAA-19 Reception

Improved NOAA-19 Reception

This week, my ebay ordered RTL2832U based USB digital TV receiver dongle arrived! I’ve been working through a bit of a cold, but that wasn’t going to stop me going down to the garage and having a play. I was too excited at the possibilities!

With no time at all I had my RTL-SDR solution up and running with SDR#. All that was needed was a custom driver install and then a couple of very minor mods to SDR# and all was working. Other than that, I connected the antenna socket out via my access panel to the Diamond X-50 on the roof. Before I knew I had local WFM radio stations playing on my computer.

The main purpose though for even trying all this, was the hope that it’d improve on my weather satellite reception as per my previous attempt. My thinking was that the main limiting factor was the narrow bandwidth of my receiver.

With using an SDR setup, I should be able to have as wide a bandwidth as needed (and more if wanted). However it required one extra bit of software, and that was a virtual audio cable to route the audio out of the SDR software into the audio in of WxtoImg. For this I chose VB-Audio Virtual Cable. It’s free and couldn’t be easier to use.

NOAA-19 @ 0446 UTC - Both Channels

NOAA-19 @ 0446 UTC – Both Channels

After getting past some recurring computer freezes (think I need to rebuild my PC) I was able to play with an initial pass to play with some settings. But before even changing anything things were looking drastically different. Then on turning the gain in SDR# up full and increasing the AF Level slightly things were looking (to my eye) perfect!

So with all trimmed and ready to go, I  keenly awaited 0446UTC for the next NOAA-19 pass. The results were amazing – the best by a long shot that I’ve every received. These can be seen in the first NOAA-19 image with both channels,  and you’ll notice only a few spots of noise which I believe was mainly due to physical obstruction.

To consider this was achieved with essentially a $25 receiver and some free software is amazing. Considering further I’m still just using the Diamond X-50 and haven’t even bothered to consider the circular polarisation. And further, this was from the West were I do have far less of a view – South/East is the preferred approach.

With that success, what now? Well, I’ll keep trying some more receives (hopefully my PC will stop freezing) and I might try some of the other SDR# features/plugins so that I can attempt to switch frequency for each of the three active NOAA satellites. That way I can aim for a full set of images!

Further, I’m also interested to see how some of the other SDR software offerings go and then I can also start to look at all the other possible items to receive out there – considering this dongle (with the FC0013 chip) covers from just below 30MHz to just up over 1Ghz. So many options! Oh, and then there’s the idea of an upconverter for all the offerings below 30MHz!