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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

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Old 18th Jan 2019, 12:58 am   #1
Skywave
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Question Morse code decoder boards

PCB modules for decoding CW / morse code with an LCD display: there are several such items for sale on e-bay. Has anyone here have any experience of these?

Al.
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Old 18th Jan 2019, 7:27 am   #2
G4YVM David
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Default Re: Morse code decoder boards

All I will say is that I've never yet met a cw decoder tjat handles real.life band conditions.

They are notoriously unreliable and the decoder between your ears is far, far more reliable if all you are after Is reading morse. I have played with several but could not recommend any particular one.
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Old 18th Jan 2019, 8:04 am   #3
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Default Re: Morse code decoder boards

They work moderately well provided the incoming signal has a good signal to noise ratio, other CW signals are dramatically more damaging than random noise. AND provided the incoming Morse is machine-sent.

Morse decoders are becoming common in aircraft navigation radios. Pilots are required to listen to the Morse ident which is included in navigation signals so they can be sure that they are actually using the beacon they think they are using. Frequencies are reused at hopefully distant sites, but high flying aircraft and anomalous propagation conditions introduces risks beyond those of someone forgetting to change channel. The beacons are all automatic and the Morse speed is accurately standardised, as is the modulated tone. In other words, the most favourable circumstances possible. It's still normal to watch the decodes for a while so you don't catch it just while an error is going through.

I found it rather illuminating to send hand Morse into one of these things. It's very very difficult to send precisely enough to get what you want to appear on the display.

For amateur use, audio tones can be all over the place, speed wanders even within the same character and the signal will be a palimpsest with others under it and to the sides.

The old joke has it that a motorist stopped to ask directions from a pedestrian "How do I get to Carnegie Hall?" "Practice, practice, practice" came the reply. What your brain can do makes a mockery of automatic readers. No one ever appreciates the difference until they've tried one, though.

Following wandering speed is the hardest thing for the machiine.

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Old 18th Jan 2019, 8:46 am   #4
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Default Re: Morse code decoder boards

Quote:
Originally Posted by Skywave View Post
PCB modules for decoding CW / morse code with an LCD display: there are several such items for sale on e-bay. Has anyone here have any experience of these?

Al.
I haven't tried the modules you saw on ebay but I can say the same as other responders in that the CW you are decoding needs to be well-sent and of a readable strength.

Due to health problems (hand and arm tremor) I bought a K42 keyboard sender a couple of years ago which incorporates a CW reader. I hadn't used a reader for many years, the last time was using an AEA PK232 multi-mode terminal back in the late 90s but I don't feel the K42 is significantly better than the PK232, although of course that's not a technical comparison, just the impression I get.

Has CW reader technology moved on in recent years? It would be interesting to hear from someone who has tried the ebay types.

You can find the specs on the K24 here:-

https://www.hamcrafters2.com/K42_C.html

73

Roger
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Old 18th Jan 2019, 9:04 am   #5
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Default Re: Morse code decoder boards

To try the idea there are many programmes for PC/soundcard available.
 
Old 18th Jan 2019, 11:01 am   #6
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Default Re: Morse code decoder boards

I built this Cumbria Designs kit in 2011 with the intention of standing it in a smart case and having a very impressive stream of letters and numbers whizzing across the screen when connected to a receiver. No Chance!

It worked, and looked very good, it should do as it cost me £50 inc vat but wouldn't accurately read any more than 3 hand sent letters in any group of 5. A G0 friend and I spent an hour one day each sending the simplest letters like an O or an E to minimise operator errors with very disappointing results. Each of us listened to the other's Morse and were confident that it was well sent.

I tried feeding it with a clean off air CW signal that sounded as if it was sent by a keyer or keyboard in the hope that the characters were accurate but the results were poor.

Whether the Chinese ones are any better would be anyone's guess but at the cheap price that they seem to be there's not much to lose. They could be worth a try.

Jim
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Old 18th Jan 2019, 12:49 pm   #7
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Default Re: Morse code decoder boards

I thought of the aircraft systems when I typed my response. My airbus has a very good cw decoder...provided we recall that it is always line of sight vhf on private channels!
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Old 18th Jan 2019, 1:13 pm   #8
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Default Re: Morse code decoder boards

You can download free morse code reader "apps" for you mobile telephone.
If the Chinese kit is cheap give it a try.
I have used CW Get and CW Decoder on the PC and those two seemed to work best.
But if the human morse sending speed is not steady they do get confused. The human ear/ brain is best.
The CW decoding progams are useful for your own sending practice as if they read what you send then you have a reasonably steady sending speed.

John
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Old 18th Jan 2019, 1:27 pm   #9
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Default Re: Morse code decoder boards

Another vote for the Windows desktop program 'CWGet' - free to try, donate if it works for you. It works well on my old XP netbook, and it is sophisticated enough to let you 'tune' to a single audio frequency by picking it out on an audio spectrum display, even if there are several other QSOs going on at +/- a few hundred Hertz.

As with the hardware decoders though, the stronger the wanted signal relative to the noise, the better. Unfortunately I have all sorts of QRM here in my location so HF signals of any sort have to be quite strong to burn through it in the first place.
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Old 18th Jan 2019, 1:29 pm   #10
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Default Re: Morse code decoder boards

I've not tried the little decoder-boards, but as others have mentioned there are free programs available for CW decoding on PCs. Some of the modern ones are deeply impressive - with things like adjustable speed/capture-range AFC to handle drifty/chirpy signals, and really good adaptive digital filtering that varies the effective 'bandwidth' in response to varying SNR.

Best ones of these take the I- and Q- signals from a software-defined radio fed straight into the PC's soundcard before demodulation. You get a nice 'Waterfall" display and a spectrum-scope that shows activity across a few tens of KHz of the band as free extras.

I also used to have an app on my old phone that decoded CW surprisingly well - I used it to monitor 28MHz beacon-IDs when there was Sp.E about!

CW is the original "Digital mode" so I have no qualms about using digital technology to decode it!

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Old 18th Jan 2019, 1:43 pm   #11
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Question Re: Morse code decoder boards

Thank you everyone for your informative replies.
The type of item I referred to has an LCD display. One further Q., please. Does the decoded Morse appear on that display or does this item require a connection to a PC running a suitable programme, with the decoded Morse appearing on the monitor attached to that PC? (The product descriptions do not provide the answer to that Q.)

Al.
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