WebSDR Support Forum

General Category => PhantomSDR Software => Topic started by: Emmanuel SV1BTL on Mar 01, 2026, 01:40 PM

Title: CW decoder
Post by: Emmanuel SV1BTL on Mar 01, 2026, 01:40 PM
CW decoder has been added to the version 1.7.0 and CW bandwidth filters have been fixed. Now CW mode is in DSB. It uses the same window for text as FT8 window does.
CW decoder is as much accurate as could it to be (not perfect). It measures audio frequency and WPM.
Try to tune near to 650-750 Hz audio for better results. If there are too many mistakes during decoding, try to refresh it by clicking CW button again, so decoder to restart. Easy to understand that when two or more CW signals being together, it would be hard to decode!...

Only these files is needed to be replaced and recompile frontend, without to restart server:

frontend
├── src
│  ├── App__analog_smeter_.svelte
│  ├── App__digital_smeter_.svelte
│  ├── App.svelte
│  ├── App__v2_analog_smeter_.svelte
│  ├── App__v2_digital_smeter_.svelte
│  ├── audio.js

73, SV1BTL Emmanuel
Title: Re: CW decoder
Post by: F1NSK on Mar 03, 2026, 10:09 AM
Hello Emmanuel

Compiled on my Phantom
Works fine when at the other side the CW is computed...
Don"t worry, all CW decoders give the same result.
Only MRP40 is a little better.
You can try on my Phantom , my SNR is better than your's.

One more time , congratulations for this fine business

73's
Title: Re: CW decoder
Post by: F1NSK on Mar 03, 2026, 03:07 PM
Works very fine on high bands with low noise.
80% decoded.
Perhaps a narrow IF filter at 250 HZ will be a must....

73's
Title: Re: CW decoder
Post by: Emmanuel SV1BTL on Mar 04, 2026, 04:36 AM
Thank you Eric. In lower bands try also to use NR or any gate filter. This makes the decoding much more efficient.
Title: Re: CW decoder
Post by: Emmanuel SV1BTL on Mar 04, 2026, 05:01 AM
Something else for your server. It would be better to add PhantomSDR+ in your .toml description, because in the map your v.1.7.0 is indicated as "legacy" (!!!). With this PhantomSDR+ added, the description will be as ours and not indicated as "legacy". This happens after the newer update of the map https://sdr-list.xyz/ (https://sdr-list.xyz/)

For example, you can do it this way:

[websdr]
register_online=true # If the SDR should be registered on https://sdr-list.xyz then put it to true
name="ORSAT BY F1NSK PhantomSDR+" # Name that is shown on https://sdr-list.xyz
Title: Re: CW decoder
Post by: F1NSK on Mar 04, 2026, 10:03 AM
hello Emmanuel

It's done. I'm now a real Phantom !  :D but with no national flag...

For the filters, I've made a mod. Gate is always on at start.

On low bands the decoder works better with a physical 15 dB attenuator at the antenna....
The décoder works about 95% when the SNR is high.

CW seems simple but in fact very hard to decode with a computer.

Really happy as a bêta tester !  ;D

73's
Title: Re: CW decoder
Post by: Emmanuel SV1BTL on Mar 04, 2026, 11:55 AM
Quote from: F1NSK on Mar 04, 2026, 10:03 AMCW seems simple but in fact very hard to decode with a computer.

Well in practice it's not easy to decode, because the operators are different, there is not the stability of the digi signals, some OM operate too fast, other too slow, some others use a pc for sending CW signal, other operate by hand etc. etc. And of course, is impossible for a pc decoder to distinguish two or more signals in the same frequency. But it is a try to make CW readable from an End User that has not the experience to decode using his brain (like me)...  :)
Title: Re: CW decoder
Post by: Emmanuel SV1BTL on Mar 04, 2026, 11:59 AM
Quote from: F1NSK on Mar 04, 2026, 10:03 AMbut with no national flag...
This might be produced by your QTH Locator, not anything else. Maybe a bug in the map, I don't know.