Sentinel 4 VLF/LF/HF SDR receiver...first batch under construction

Chris Moulding

We are building the first batch of a new SDR receiver.

The Sentinel 4 VLF/LF/HF receiver covers from 5 kHz to 55 MHz using CAT control so that the frequency can be controlled by many SDR and data mode programs.

A new web page with provisional details in now available:

The photographs show the Sentinel 2 but will be updated when the new batch is completed.

This receiver will replace the SDR-4+ Special Edition and Sentinel 2 receivers.

We will be releasing a new active antenna based on the reference design in ITU-R P.845-3 to work with the full frequency range of the new receiver. This is an antenna design we have built before to special order.

While I write this I'm using the prototype receiver and antenna with HDSDR listening and watching lightning strikes between 5 and 15 kHz from thunderstorms in the Mediterranean Sea off Italy and Israel and comparing what I see and hear with  VLF is fun!



Patrick kelly

Hi Chris, I'm keen to know when the new Sentinal 4 is available for sale and the price range.


Patrick Kelly


Hello Chris. I would really like to give the new SDR a spin! Please let me know when it is ready for purchase. 73
Charles Rolph