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The SDR SOLO Kit - A Portable Antenna Toolkit

The SDR SOLO Kit - A Portable Antenna Toolkit

I'll be the first to admit some of my projects are a little weird- but they usually find their way to a use for some- or close enough that they can be modified for a different task. This is a slightly whimsical project that started off from a random Hackaday comment (no, I won't link the comment) that seemed to worry a RTL-SDR radio would get hot enough to melt PETG plastic. I'm doubtful they could, but as a though experiment I wondered, what about four radios?

From there I started to sketch out a modular system where you can print a single "cage" that maintains minimal contact with the radio, while also creating space for passive cooling. The photo of the individual unit is towards the end, but you can see the other end of the build spectrum - a portable system for 4 RTL-SDR's and different antennas. This breaks down with just an electric screwdriver and can easily fit in the trunk of a car for your favorite superconference, or just stow away for storage.

The idea is simple- print the radio enclosures as you need them- this cage was printed in carbon fiber PETG, but that's what I had available- really any PETG should do fine. All my STL files are available for paid subscribers.

The premise here is simple, the cage ensures airflow around the RTL-SDR, with some slots near the USB connector for a USB cable. The smaller slots are for zip ties in case you want to keep the USB cable attached, and the longer center slot is raised a bit to reduce tension on the USB connector. There's room on the antenna end for adapters, and as you can see I have a BNC adapter on here as an example.

The cage is printed in two parts with flush mount hex M3 screws at the corners. The print files don't need any supports.

One last shot at an angle to see some of the detail here.

Now that's not too different from many other enclosures for SDR's, but where this gets a little cooler is the ability to stack them in an array like the photo below:

This offers a few advantages- want to skip the use of the fans? No big deal, they are an optional add-on and the files assemble fine without them.

Want to only use 1, 2, or 3 SDR's instead of the full 4? Just don't add them- the system works fine with the number you want, assuming you don't need the active cooling.

There's also plenty of room in the base model cage in case you want to redesign that part for a different brand SDR- but even if you needed to make a much wider one, the base is probably the only file beside the cage that would need to get updated. The goal here is to provide as much flexibility as possible for the SDR's.

I designed much of the rest of this kit with either M3 or M4 screws- I really suggest having those on hand for this build.

The fans are 80mm Noctuas which proved to be pretty quiet, although I'd prefer to have a 5V model like these but in black or grey. The 5V models make this so they can run off the powered USB hub, reducing the number of wire runs just a little.

On the back you can see how the SDR assembly wires directly into the powered hub- this helps keep the cable runs short too- so that aside from antennas, you only need the USB cable from the hub to your PC.

The USB hub here is a real help, given the power and connectivity is sufficient for all four SDR's. The 3D parts are available below, with the USB mount for the tripod mast being 3 parts- a top and bottom to hold the hub in place, then a retaining bracket to hold the hub to the tripod mast. This build uses heat set inserts for all the mast mounts- pressure fit simply would not stand up to repeated use here.

The other item here that is designed to be modular is a bracket allowing you to attach a 20mmx40mm aluminum extrusion for antennas. This can be unstable if you add a long section or burden with heavy antennas- so be careful and check the capacity of your tripod before using.

The idea is simple though, this chunk of PETG allows you to clamp to your tripod mast and then slide in some 2040 extrusion, then use the channel screws to lock it in place.

In summary, this was a quick build done over the last few weeks as a proof of concept. The parts list is pretty short and the STL files are available on my site as a separate post for my paid subscribers. There's also a plan that gets you access to my Fusion 360 files as well. Both STL and CAD plans come in monthly and annual prices, with steep discounts for annual plans- they really help me out!

There are a ton of variants in the STL files that I didn't cover here, with 3 different sizes for the SDR cage, plus a thin and thick frame for the SDR cages. If you make this, please send me a pic or an email if you share it somewhere- thank you!

Parts List

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