Category Archives: SDR

Rocket Smartphone APRS Payload

Greg, N4KGL and I worked on a joint project to build and launch an APRS rocket payload. We finally got to launch it yesterday after a small delay due to field availability. It included the Mobilinkd bluetooth adapter, Baofeng Uv-5r HT and a eBay special android smartphone (appropriately from “Boost”).

Our goals were to:

  1. Have a successful launch and recover (of course!)
  2. Use APRS for tracking using stock Ham radio equipment and smartphone
  3. Use the on-board smartphone sensors to record audio and accelerometer data
  4. Map ground track using My Tracks for further analysis

Ground Station:

Note: You can view the Google Doc prepared for this flight with more detail.

The ground station was connected via 802.11g while the rocket was sitting on the launcher. I was able to control the phone screen through VNC and start the audio recording, Sensor logger, APRS and My tracks while it was sitting on the pad waiting for launch. That capability was instrumental in starting and checking all the services prior to launch.

Field conditions were excellent, although it was a little windy at times and very hot. Greg prepared the rocket while I prepared the ground station and prepped the payload. Greg decided to try out a new rocket motor that he had never used before. It was a disposable J425R-14A high powered rocket motor.  It performed flawlessly from start to finish and sounded awesome!

I was quite surprised in how the phone GPS performed. It lost GPS fix during the accent phase but quickly reacquired lock after chute deployment. I chose My Tracks to do the GPS logging because of the logging rate and it integrates well with other GPS software. I am sure there is something better/faster but this seemed to work well for this launch.

Data Sets:

Please visit Greg’s post for more pictures and info.


Video of Launch:  The second half of the video is of smartphone audio synchronized with video, very cool!


RTL-SDR + SDR Radio + Funcube Sat = Fun!

With the recent record number of cubesat launches this month most  Amateur Radio enthusiasts been busy, myself included. There hasn’t been a better time to get into receiving these satellites. With the inexpensive hardware,  free software,  a ton of information and an active community it is “easy” and quite a thrill to get into this hobby.

I will focus on one satellite and one method of receiving and decoding in this post. There are so many ways to do this but I think this method is the least expensive and provides really good results.

You will need:

  1. RTL-SDR Dongle – E4000 or R820T model (I prefer the R820T model and they are the easiest to find now)
  2. SO-239 Pigtail adapter for the Dongle – This is great if you don’t want to cut and solder on a connector like I did!
  3. Zadig Drivers – For the RTL-SDR USB
  4. RTL-SDR Libraries for V2 software – Choose
  5. V2 Software – I used the November 15th, 2013. Version 2.1 build 1571
  6. Good receiving antenna – 2m Yagi, Quadrifilar Helicoidal (QFH), Ground Plane,etc
  7. VB-Cable Driver – Virtual Audio cable (Center Column)- NOTE: Please Donate if you use it. As a bonus once you donate you get to download A and B Channels.  I am glad I did, the extra channels are nice to have!
  8. Funcube Dashboard Software
  9. Time to put it all together!

The total cost depending on what antenna you have or choose to build can be between $11 to whatever. Very minimum investment is required to receive and decode the funcube telemetry. This is fantastic for everyone, especially those on a budget that would like to experience this hobby first hand. If there are any educators reading this please take the time to show your students how much fun this can be. After all, it is part of the funcube mission!

I must say this as well: if you can afford to buy a Funcube Dongle, please do! It has better performance than the RTL-SDR and the money goes back to funding the funcube initiatives, like the Funcube satellites.

On to the setup:

I won’t go into detail on each and every install. Please read the pages I linked above for further instructions.

  1. Install V2 Beta
  2. Plug RTL-SDR USB Dongle into computer
  3. Install ZaDig Drivers – NOTE: You may need to click Options and then List All devices. Select Bulk-in, (Interface 0) then click the replace Driver button.
  4. Extract and Copy the three  RTL-SDR DLL’s for V2. NOTE: Overwrite existing files in the’s directory and use the correct architecture!
  5. Install VB-Cable Virtual Audio Interface
  6. Install the Funcube Dashboard

Configuration: V2:

  1. Launch SDRConsole (V2)
  2. On the Home Tab click the Select button from the Radio Group
  3. Click Definitions
  4. Click Search and Select the RTL SDR (USB) Option. If that option does not exist please check to make sure you copied the correct DLL’s into the Program Folder
  5. Click Yes on the 1 Entry Found alert and Click OK
  6. Highlight the new entry (ezcap USB2.0 DVB-T/DAB/FM Dongle)
  7. Click Start
  8. Tune into a known frequency like the National Weather Service, this is required to adjust the PPM
  9. On the Home tab again, click the Radio Configuration button
  10. Click the + or – buttons to adjust the PPM. For example one of my dongles is +82 and the other is -133 so they vary widely.
  11. Click the more options selection and click the Internal AGC box. (You can experiment with this, mine worked better with it on)
  12. Select the frequency to 145.927 Mhz and set the Mode to SSB Data-U OR Wide-U, it doesn’t seem to matter
  13. Drag the bandwidth bar out to 24000 Hz to get full coverage. Note: This is required so you don’t have to “chase” the satellite because of the doppler effect, Funcube will always be in the bandwidth coverage. The Funcube Dashboard will Autotune on the transmission. (See screenshots)
  14. On the VFO-A box Click the Audio dropdown (next to the little audio speaker)
  15. Click the Playback device and Select VB-Cable for the output – Took me a while to find this one!!!
  16. For satellite data you can use whatever you are used to but the SDR-Radio’s works great. The current satellite number is 2013-066B and is likely to change to AO-73 in future TLE’s

Funcube Dashboard

NOTE: Be sure to register at the Funcube Data Warehouse to be able to submit your decoded packets automatically. If you ONLY want to decode and not send you can still use the software but not contribute. The more contributors the better though!

  1. Click File; then Settings
  2. Select the Audio Tab and select the Input Device as the Cable Output VB-Audio
  3. Click the Warehouse Tab and fill in your Site ID, Auth Code and click the Stream data to warehouse and Click Save
  4. Click Capture from the Menu and select Capture from Soundcard
  5. On the tuning panel change the High Value to 24000 and make sure the Auto Tune check box is checked
  6. You should see a sudden drop off in the tuning window around 24000 hz (See screenshots)

Final Thoughts:

This should get you started on receiving and sending the telemetry back to the funcube data warehouse. There are other great options out there like Analog receive to Souncard, Funcube Dongle but this seems to be the most inexpensive to get started. Now that you have your station setup for the Funcube you can go chase other sat’s as well!  There are other folks doing much more that I am and have great resources available. Please visit the links sections for more information.

I hope this helps you get started and most importantly have FUN!

 Other Links:

I/Q Data and Audio files:

  • Audio from 21 Nov 2013 0352 UTC Pass – Telemetry Only:

Download: 21-Nov-2013-3052UTC-Pass-Telemetry

  • Audio From the 24 Nov 2013 0436 UTC Pass during Active Transponder:

Download: 23-Nov-2013-232647 145.958300 MHz

Screen Shots:

PhoneSats and SDR Fun – Build your own Sat Station Cheap!

UPDATE: On 27 Apr 2013 the phonesats are officially silent. Use can still use this guide for many other current and future satellites.

Sidebar update 23 Nov 2013: Please visit my post on how to use RTL-SDR and (V2) to listen to and decode the recently launched Funcube


The recent launch of the PhoneSats got my SDR and satellite juices flowing again. This time I decided to automate things because work seems to get in the way of my satellite listening fun. I found a combination that works great and incorporates FREE software and inexpensive hardware.

What you will need:

Software List

Hardware List

  • Computer – A fairly decent powered computer or laptop is needed to run HDSDR, DDE and Orbitron
  • Cheap Realtek RTL2832U USB DVB Dongle with the E4000 or R820T tuner chipsets
    • Sources:
    • NooElec – Best Price Fast shipping guaranteed compatible chipset R820T
    • – It’s Amazon!
    • Aliexpress – Slow from China shipping but great prices
  • Antenna

Putting it all together:

Please visit the page for the latest information on the cubesats. NOTE: They are not solar powered and are expected to fail about a week after deployment which occurred on April 21st 2013.

Antares Launch Video – As you can see all systems were nominal and deployed nominally. 🙂


  1. Install the Driver with Zadig  – DO NOT install the OEM driver that comes shipped with the device. Use Zadig only. Instructions HERE
  2. Install HDSDR using the defaults
  3. Download the ExtIO_RTL.dll file and place the file in the HDSDR program location (C:Program FilesHDSDR or C:Program Files (x86)HDSDR)
  4. Download and Install Orbitron
  5. Download the MyDDE driver for Orbitron
  6. Unzip the MyDDE driver and place the mydde folder in the Orbitron program directory (C:Program FilesOrbitron or C:Program Files (x86)Orbitron)
  7. Download the PhoneSAT TLE’s and place them in a directory of your choice
  8. Download and unzip UZ7HO’s Sound Modem


  1. Setup Orbitron first by setting your Home location. It will use your Grid square to translate to the lat/long coordinates.
    • Click the Load TLE button and browse to the PhoneSat.txt file. Select the PHONESAT satellite in the Satellites list.
    • Select the Rotor/Radio tab. Input the Downlink frequency, for Phonesats it is 437.425 Mhz.
    • Click the Driver drop down box and select MyDDE
    • Click the Activate button. This will prompt you to browse for the driver. Go to the folder you copied it to under the program directory (C:Program FilesOrbitronmydde or C:Program Files (x86)Orbitronmydde)
    • The MyDDE status window should now be displayed with Satellite data
  2. Launch HDSDR and confirm the  USB Dongle is functioning.
    • Left-click the EXTIO button and turn on the Tuner AGC and RTL AGC.
    •  NOTE: I ran into an issue that required me to launch HDSDR with “Run as Administrator” or I would end up with a ExtIO DLL not active error. Right-click on the HDSDR icon and select “Run as Administrator”. If you want the settings to be persistent you check the run as administrator box located under the compatibility tab while in the shortcut properties.
    • Click on the Options button then Select DDE Client. Set the format to Orbitron and the Sync Type to Tune. If you would like to record the Satellite passes automatically check the “Record all satellite passes” box.
    • Click the Manual connect button and it should give you a green connection successful message.
    • The TUNE indicator on HDSDR should be synced with the Doppler readout in Orbitron. If the Record all satellites option was checked when a satellite comes into view at AOS it will automatically record based on the options set in HDSDR.
  3. Launch UZ7HO’s Sound Modem program
    • In the Modem settings change the modem type to VHF AX.25 1200 baud.
    • Select your input sound device to either Stereo Mix if you have one or you can download VAC (Virtual Audio Cable)
    • Another option would be to use a separate computer or use a Stereo cable loopback. (Actual audio cable looped back to input)

Recording options:

To access the record options, right-click on the red record button. There are a three ways to record on HDSDR: Full RF, IF RF and AF. Full RF will give you the largest file size but capture the entire RF session to go back and replay and analyze. If you are only interested in the audio portion pick the AF recording option for the smallest file size. I like to record the Full RF to see what I missed or see how far the Doppler settings were off. In the case of the Phonesats you can see all three satellites clearly at different frequencies although they are all transmitting on 437.425 Mhz due to Doppler shift. Very cool to see it visually!


  • If you are running Windows 7/8 Pro you may need to add User modify rights to the Program directories (C:Program FilesHDSDR and C:Program FilesOrbitron). You can install the software in a Non-Program Files location (e.g. User Documents) to avoid this step.
  • Use “Run as administrator” when launching HDSDR
  • Be sure no other programs are running in the background causing your system to slow down. The SDR decoding can be CPU intensive.
  • Make sure EXTIO_RTL.dll is located in the program directory C:Program FilesHDSDR or C:Program Files (x86)HDSDR

I hope you enjoy some satellite listening!

DVB Dongle makes a great VHF UHF SDR Radio

Updated on: July 16, 2012

SDR Radios are  the latest and greatest things to come along in Ham Radio since solid state was invented.  Ok, well that may be a stretch, but it certainly has made some incredible advances in SWL and Ham radio.  Thanks to the ingenuity of some super smart people we can all enjoy an inexpensive alternative to some of the VHF and UHF dongles out on the market. Interesting enough a product that was meant to be a DVB-T, DAB and DAB+ tuner actually makes a great SDR Radio!

There is a specific model chipset that is required to utilize the SDR tuner. It requires the e4000 tuner and the Realtek RTL2832 chipset. Unfortunately on my first try I received an upgraded DVB dongle that had a newer chipset that is not compatible with any SDR software.  I was a little disappointed at first but I am using it for local ATSC channels for my PC so no big loss. I later found that Reddit maintains a list of compatible tuners. I ended up ordering a Newsky TV28T  from which had the correct tuner/chipset and worked perfectly. I was surprised at how well it actually worked, I was receiving the NOAA weather radio broadcast, our local airport tower communications, APRS,  neighborhood weather stations, and some FRS chatter.  I originally wanted to use it for the reception of Amateur radio satellites/Cubesats which I am sure it will work well for but I haven’t had a chance to try it. Pretty amazing stuff considering it was less than $30 shipped.

Using the Windows software was the easiest way to get this SDR to tick. I enjoy using Linux but I was already used to using HDSDR and wanted a “quick fix” for my SDR listening enjoyment. Fortunately there is a fairly straight forward way to use Windows and the DVB dongle. I followed instructions such as those on the Ham Radio Science Blog and was up and running in no time. I won’t list all the steps here for the Windows setup as this webpage does a good job at outlining all the steps.

After using the Windows setup for a while I decided to give the Linux offerings a try. It wasn’t that all that difficult after putting all the pieces together.

If you would like to give Linux a try here a few links to hopefully make it easier for you:

Components you will need for LINUX:

  1. GNURadio Package – I highly recommend the build script  to help install the dependencies and compile all the necessary components.
  2. The Linux RTL-SDR driver (not needed if using the script from step 1)
  3. gr-osmosdr Package (also not needed if using the script from step 1)
  4. GQRX (optional but recommended, nice GUI interface) – Be sure to read the compile instructions

Also see an excellent post on how to use BackTrack and a offline package.

Windows Software

Some very helpful pages:

  • AB9IL Blog – More information about the RTL DVB-T tuner
  • SuperKuh – Many links and info on the  Realtek RTL2832U/Elonics E4000

Important Notes: My DVB dongle was off-frequency by 21khz but the ExtIO plugin for HDSDR makes it easy to correct for the frequency error. You can right-click the ExtIO button on the HDSDR interface to bring up the Tuned frequency adjustment.  Left-clicking the same button brings up the normal ExtIO options. On the Linux side of things GQRX has an option to adjust the ppm value for frequency adjustment. To access the option click View, then Input Controls on the menu bar. A Tab will appear under the Squelch control labeled Input Controls. From there you can correct for frequency errors. I used my APRS signal and the built-in 1200 AFSK Decoder dial it in.

Screenshot-Gqrx v2.1-git-76-g781b4441 - ezcap USB 2.0 DVB-T-DAB-FM dongle-2 Screenshot-Gqrx v2.1-git-76-g781b4441 - ezcap USB 2.0 DVB-T-DAB-FM dongle Screenshot-AFSK1200 Decoder

Adventures in SoftRock SDR Land

SDR? What does that mean? I know I asked myself the same question when first looking into how to get on the air on with the HF bands.  After a visit to a local Hamfast and talking to some very helpful Hams,  I was turned onto the SoftRock SDR. My mind was filled with SoftRocks and SDR’s and more questions… I still wasn’t very clear on how it actually worked. I knew three things: You needed a computer, SDR stood for Software Defined Radio and I really wanted one.

Whenever I “Googled” SoftRock  the top links were pointing to Tony Parks, KB9YIG site: and  WB5RVZ,   Ok, I thought I will check out these kits and see if I can afford one. What was shocking to see was how inexpensive the kits are. Only one problem, every kit said to “Come Back Soon”. Just on a whim I decided to email the admin, which of course turned out to be Tony himself. I wanted to see when some kits would come available.  He just happened to have some SoftRock Lite II Combined Receiver Kits available.  I just couldn’t wait to get my first SDR!

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