Charly25 SDR project

Charly 25 RADIOlab

Our Charly 25 RADIOlab is meant to be built by the experienced Home Brewer using our C25 modules and mechanical kits. However, completely pre-configured versions are available as well.

The following pptions are available:

Technical Specs




Overview of Modules, Preconfigured RADIOlab & Pricing:

STEMlab 16

STEMlab 16 from Red Pitaya is at the core of our Trx: https://www.redpitaya.com/Catalog/p52/sdrlab-122-16-standard-kit?cat=c99

It has been renamed by Red Pitaya to SDRlab.

Technical data from an amateurs point of view:

C25 Mainboard

To get as much out of the STEMlab as possible we developed a board which we call C25 mainboard:

C25 Codec

There are cheap Chinese codecs available on the internet, however we were not satisfied with their performance and we did have additional requirements like:

Power Distribution Board

C25 Rx Preselector

We have developed a very powerful preselector with 11 Amateur Bands (+ passthrough for broadcast listening)

Chassis / Mechanical Kit

You can find some pictures here: https://smartradioconcepts.com/p/charly-25-radiolab-mechanik-satz-komplett

Price is 442,00€ excluding VAT


We use RG316/SMA cabling for all cables inside our Trx – cables are available in the shop in length of 10cm, 20cm, 30cm, 40cm and 50cm.

Currently power cables, audio cables and I2C cables are to be built by the builder—a complete cable kit offer might be available in future.

Multi media cabling will also be available (2x USB + 2x HDMI specially built to our specs).

PC Board

People who want a PC built in, can use our 100mm x 100mm PC Board. Currently we are using an Intel core i3 CPU with Windows 10.

You can find some details here including a handbook for download:


Price is 300,-€ excluding VAT and excluding Memory & SSD (we will charge day prices for memories and SSD as these are fluctuating very much)

In future we will move to Intel core i5 because of higher CPU demands from Thetis. Price not fixed yet but will probably in the range of 380,-€ excluding VAT..

Complete Devices (Preconfigured Trx Kits)

We call it RADIOlab because STEMlab is still accessible from outside so that you can still use all apps like signal generator, VNA etc.

Minimum Version includes

Price 2113,-€ excluding VAT

Standard Version

Includes all of above plus Preselector

Price: 2628,50€ excluding VAT

Standalone Trx with built in PC

Includes all of above plus

Price 3096,82€ excluding VAT

You can find a lot of pictures here—done by the guy who has written the article (at the end of the article): https://saure.org/cq-nrw/2020/08/23/18989/

Standalone Trx with PC and Screen

And finally our latest device includes all of above plus:

Price is not fixed yet; we are working on some final aspects of it but I guess it will be in the range of 3450,-€ to 3550,-€ when finished

Picture of RADIOlab with screen and PC

We will also sell the front panel with display as a complete module – so anyone who has purchase a RADIOlab before can upgrade later on to make it a complete Trx.

Software is Free and Open Source