University of Michigan Amateur Radio Club net on 145.23- in Ann Arbor, coming in strong. Monitored with Youloop antenna, Airspy HF+ Discovery SDR, SDRSharp.

I am still learning SDRSharp - it has quite a few features that the other tools I had been using (GQRX, CubicSDR) do not, so there's a bit of a learning curve.

The new antenna + SDR combo covers HF as it says on the box so I'm also enjoying some shortwave listening.

OpenWebRX is able to decode APRS packets. Listening here in Ann Arbor, MI. (Frequency of the receiver is a little bit off.)

pirate radio, first SSTV decode 

The decode is from a transmission of "Wolverine Radio", a pirate station on 4055 KHz monitored from the N4TVC KiwiSDR in Burke, VA.

I used the "RX-SSTV" software to do the actual decoding. The sound of the signal is very much like what a fax machine sounds like, with a rhythmic beat as the scan lines go across.

remote tuning with rtl_tcp 

Proof of work below, showing WCBN-FM 88.3 tuned in, with WEMU-FM 89.1 adjacent, via a Tailscale VPN connection to an rtl-sdr running on a Pi 4 under Ubuntu 20.04 LTS arm64.

The antenna I'm using is my 2 meter antenna, which should usually mean that FM signals are unwanted noise - for now they are ok.

On the Pi 4 one process is pinned at about 70% CPU, so it's working hard to keep up the VPN stream. The actual rtl_tcp process that's decoding the radio is not so busy.

Ubuntu 20.04 LTS on Raspberry Pi 4 + SDR 

Proof of work is a screen capture of dump1090, picking up signals from nearby aircraft (a few of them) through the ladder line antenna that I usually use for 2 meters.

Which is to say this is something that needs a better antenna etc, but at least I got all the libraries working right even if it was a bit of a bodge.

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adsb, antenna, Flightaware, height above average terrain 

I moved my ADS-B antenna, can you tell when?

Flightaware has this handy graph of airplanes seen. It's hard to tune the receiver in real time, but over a few hours it becomes evident.

ADS-B is 1090 MHz line of sight. Alas, I have a building to the east, but I think I can get the antenna even a bit higher with the correct tweak. Fortunately a Raspberry Pi is light weight enough that you can easily suspend it by its Ethernet cable.


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