We’ve recently begun experimenting with a WSJT-X derivative for FT8 and other JT Modes. Its called JTDX. The stated purpose of the JTDX software is (from the JTDX website):
The latest release candidate of of the JTDX software supports some interesting additional features beyond WSJT-X including:
Additional FT8 and JT65 decoder options which can provide improved sensitivity
Advanced automatic sequencing and QSO selection features
Decoded messaging filtering features
We’ve been testing JTDX V2.0 release candidates here for about a month now. The feature additions definitely provide some useful enhancements. The software is derived from WSJT-X and we’ve been using it here for DX’ing and for weak signal FT8 work on 6 meters. It appears to have most of the features of the current version of WSJT-X with the notable exception of support for specific contest exchanges.
JTDX Main Window and Waterfall
The JTDX software adds a number of FT8 decoding options that are useful on crowded bands and in situations when signals are very weak. These features can be selectively enabled to match band and signal conditions as well as the user’s available CPU horsepower. With all features enabled, JTDX seems to decode more signals on a crowded band than WSJT-X.
You can read more about the features of JTDX and how to get started with it via the link that follows.
We have received several requests to share the image and construction details for the Raspberry Pi Satellite Tracker Interface. We use the Sat Tracker interface with MacDoppler as part our Portable Satellite Stations. The Sat Tracker described in the article uses a Raspberry Pi Computer with a touch screen interface to interface MacDoppler to Green Heron Engineering RT-21 Rotator Controller(s). You can read about how to build your own Sat Tracker Interface via the link above.
Small software defined radios have never been more affordable. Free and Open Source Software (FOSS) makes integrating one of these radios into your shack easy. This article is a follow-on to the SMALL SOFTWARE DEFINED RADIOS ~ PART 1 article on hardware published last month.
Basic Tuner and Pan Adaptor
Most of us will use one of these SDRs with our computer (instead of creating a Raspberry Pi or other small computer for a dedicated solution). This section will give you some ideas for your Macintosh, LINUX, or Windows PC. There are many offerings for each of these application areas. I can only cover a few here.
CubicSDR is a cross-platform and open-source software-defined radio application. This runs on Macs, LINUX, and Windows (both 32 and 64-bit versions). A screenshot for this application appears at the top of this article. The software supports about a dozen types of radios including the little RTL-SDR radio mentioned in the other article.
With CubicSDR you can see a spectrum view of a frequency range and listen in on the signals tuning with frequency, bandwidth, and modulation type (FM, AM, etc.). This is a great program to try if you are new to SDRs.
GQRX
Gqrx SDR is an open software application for SDRs that is available for LINUX and MacOS X. If you want to run on a Raspberry Pi this is a good place to start.
Watching Airplanes
One of the really fun things that can be done with these inexpensive SDRs is tracking aircraft data. FlightAware has a package that can be installed on a simple Raspberry Pi computer that will not only monitor transmitted data on 1090 MHz, but will also upload that data to the FlightAware servers. This crowdsourced data is then used to drive their Apps. Piaware produces a display like the above (this is a screenshot from my setup). This is a standalone project that can be completed for less than $100.
There is a version of this called dump1090 that is open source and the original program that FlightAware enhanced. The RTL-SDR website has a write-up for this using Windows. Macintosh users can visit Black Cat Systems for Cocoa1090.
Just the tip of the iceberg
These programs are a great place to start, but there are many more offerings available. My advice is to get things working with something simple, then try one of the more elaborate programs.
I hope to see everybody at the December 11, 2018 Tech Night where we’ll apply all this to radios you bring. See you there!
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Radio Amateurs Developing Skills Worldwide
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