CW SSTV & Data Modes => CW - The most robust Radio Communication mode => Topic started by: Basu (VU2NSB) on March 07, 2021, 13:55:28 UTC
Title: Check your Morse Code decoding skills for CW Radiotelgraphy
Post by: Basu (VU2NSB) on March 07, 2021, 13:55:28 UTC
Are you a skilled CW operator who can comfortably decode Morse code radiotelegraphy transmissions on HF radio bands? Go on, test your skills to find out if you need more practice.
HF radiotelegraphy environment can often be far from ideal. HF radio DX circuits are subjected to a variety of propagation phenomena that might lead to some or all of the following to make life difficult... Are you geared up to negotiate these conditions? Of course, there are many other effects beyond what I have listed below...
Deep fading (QSB) - It may either be slow or fast in nature that could at times sink the RX signal below the noise floor.
Background Static Noise (QRN) - At different time, band, and operator's QTH, the magnitude would vary. Lightning and thunder would further add to the noise and crackle on the channel.
Man-made Noise (QRM) - Not only could the channel be affected by local electrical noise sources but adjacent channel or co-channel interference from other transmissions could produce adverse effects to compound difficulties.
Multi-path Propagation phenomena - Signal arriving at the receiver could be via multiple ionospheric skip paths that produce amplitude as well as phase distortion on the received signal
Selective fading and non-uniform Group Delay - This could drastically alter the tonal quality and the pitch of the signal at the receiver. The effect could be time-dependent and result in pitch alteration and flutter.
Polar Cap Distortion - Many of the intercontinental DX paths have to pass through or adjacent to the polar region. At times when we experience CME and similar solar activities, there is a tendency for increase in Aurora Borealis and Aurora Australis. These result in producing a very hollow sound at the CW radiotelegraphy receiver.
The question is, are you ready to comfortably handle these situations and continue to copy a CW radio transmission with ease? ... Forget the CW decoder software. They will do no good. You have got to be skilled to copy by the ear.
Test your skills below by trying to copy the following recorded transmission.
It is nearly a 35 minutes plain English passage comprising of alphabets, numerals and a few basic punctuation marks. I have not included pro-signs for the sake of simplicity...
The transmission speed is approximately 25 WPM... Now don't say that it is too fast... :) If you can't copy at this speed then it means that there is a fundamental flaw in the way you were originally taught how to copy Morse code. You need to address this flaw. I will help you do it with a comprehensive set of CW lessons on this website.
The recorded transmission below, simulates a moderately weak-signal HF DX path that follows a 14000 Km Great-Circle path over the polar region with a moderately disturbed ionospheric condition... There is deep QSB, tonal distortion due to pitch dithering, manual keying using a straight key resulting in a slightly variable weighted character stream, etc... This is as real as it gets. TRY to copy it ALL...
25 WPM using Straight Key manual keying Deep, slow QSB, Great Circle Polar path with Auroral pitch dither distortion
Could you copy all of it? Probably not in entirety... That's OK...
Some might have tried to use software decoders. In all probability they failed miserably... All other genuine CW operators who attempted to copy by the ear, here is how you could realistically assess yourself...
More than 90% copy in one go - You are truly a MASTER of CW Radiotelegraphy... My Respects.
More than 50-70% copy in one go - You are pretty good but maybe a bit rusty. Practice to sharpen your skills
Could copy a few sentences at a stretch - You can copy CW, no doubt. However, You are very rusty and mental fatigue sets in quickly. You need to seriously practice.
Could copy only a couple of words in succession - You have the basic underlying skills. But you tend to lag behind the transmission rate and hence loose it after a few words... Practice at 25 WPM, preferably using Farnsworth method.
Could only copy occasional alphabets but not complete words - You learned CW the wrong way. You tend to mentally break the characters into dits-n-dahs and do not register them in your mind as a single and homogeneous character sounds. You have hit the speed barrier which can only be overcome be following a proper code learning process... Follow my Morse code lessons that will come up very soon on this website... Stay tuned.
Could not copy anything. It all sounded so alien - That's very good. It means you have clean slate. You are therefore in a position to learn CW in the proper way from the scratch, if you try... Comprehensive CW lessons are coming up on this website... Stay tuned.
Hope you enjoyed the exercise... 73, de Basu VU2NSB
Title: Re: Check your Morse Code decoding skills for CW Radiotelgraphy
Post by: KS1K on March 08, 2021, 14:41:40 UTC
TKS OM GUD EXERCISE. 73 DE KS1K TU EE
Title: Re: Check your Morse Code decoding skills for CW Radiotelgraphy
Post by: G4ELD on March 08, 2021, 16:16:49 UTC
Well after tuning my ears around 80 percent copy. Rusty as I know DE G4ELD. Damned good straight key QSK operation