homebrew ssb receiver part 3 – receiver

For labor day weekend, I had some extra time, so I put together the direct conversion receiver from the first chapter of EMRFD. I made some small changes to the circuit and used the si5351/arduino combo as the vfo. The receiver uses a NE602 as the mixer and an LM386 as the audio amp. I connected it to my 40 meter dipole, but I wasn’t hearing anything. After playing around with it for a while, I put together a simple rf amp and added it to the input and that seemed to help.

sharing pulseaudio devices over the network for sdr

I finally put together the SoftRock Lite II kit that I picked up a while back. The kit itself was a pretty fun build, but when I was done, I couldn’t get it working with either of the laptops that I had at the time. They both had those combo headphone/mic jacks and I tried in linux and windows and I couldn’t get either to work. The only other computer in the house with an audio line in port (that was in an operable state) was my media server.

rover project – part 3

Since the last post, I have set up a raspberry pi and connected it to the arduino over usb. I configured wifi on the raspberry pi and I’ve written a simple python script to control the rover. Now, I can ssh into the raspberry pi, launch the python script and I can remotely control the rover using the same keys from the arduino sketch (‘l’ for left, ‘r’ for right, etc.

rover project – part 2

In the last post, I replaced the steering servo with a standard hobby servo. Now I should be able to control the drive and steering with an arduino. For the drive motor controller, I am using a Pololu MC33926 motor shield with a 7.2v NiMH RC battery pack hooked straight to the shield. I plugged everything in, tweaked the example code from the DualMC33926MotorShield library and it worked like a charm.

rover project – part 1

I am currently waiting on parts from China to continue working on my radio receiver, so I thought I’d start working on a robotic rover. I’ve picked up several remote controlled cars from the thrift store and I have been meaning to turn one into some kind of autonomous vehicle that can roam around the yard. Here is what I am starting with. I think I paid $1 for this truck without the controller.

ads-b coaxial collinear antenna

After I killed my homebrew upconverter, I went back to messing around with ads-b and dump1090. The little antenna that came with the rtl-sdr dongle worked okay, but I wanted to build a better antenna to see if I could get more range. I looked online and found quite a few pages on coaxial collinear antennas and I had everything I needed to build one, so I figured I’d give it a shot.