Monthly Archives: April 2019

ALE [MIL-STD-188-141A]: Which one is the best Decoder?

This is an update from my post two days ago. I have expanded the number of test signals and added some hints.

Does your decoder read this track? Buried in noise and plagued by multipath fading, the recordings below will separate the wheat from the whaff.

Often I am asked – and sometimes even asking myself! – “Which one is the best decoder for ALE?” This means: Which one delivers the best decoding under demanding conditions?

To test this, I made a recording of twelve stations “on the air” plus one weak signal, buried in Additive White Gaussian Noise, AWGN. All signals are correctly tuned, no one invers. All were read by at leastby one of my decoders “in a row”.

To test your decoders, you should download this WAV file of 131 seconds length and play it. It can be either directly opened by some decoder, or feed it via virtual audio cable (VAC) into a decoder. I used Audacity for this.

I am as interested in the results as you are – so please drop me a line to dk8ok [at] gmx.net. I like to encourage you to try all ALE decoders you have at hand – the more, the better.

Already the first results were surprising. This concerned both, the decoding ability of the decoders and the repeatability of the test. So far, the following decoders had participated: go2monitor, Krypto500, MARS-ALE, MultiPSK, Sorcerer, and W-Code. Steve, N2CKH, had written some valuable hints to optimize his MARS-ALE software for SIGINT purposes – please see his comment.


This WAV file contains the calls of thirteen ALE stations. Download and save this file (point to the icon, press right mouse button …). Then feed it to your decoders. Copy the results and send them to me. Have fun!