Tuesday, March 15, 2011

Proliferation of digital modes?

Too many digital modes? That’s the question. There are approximate 13 digital modes. Contestia, DominoEX, Hell, MFSK, MT63, Olivia, PSK, QPSK, RTTY, ROS, WSJT modes, Thor and Throb. It must be crowded on HF, or isn’t? Well, the most used digital mode is PSK31.

Number 1 of the digital modes is PSK31, the most used. The speed of PSK31 is average, about 52 wpm. The bandwidth is small 31 Hz. That’s pretty nice. And there is enough good software to run PSK31.

PSK10 is almost not in use but is very small in bandwidth but too slow, about 18 wpm. Only MultiPSK supported PSK10. But as you know MultiPSK is user unfriendly. If you want to combine 'small' bandwidth and higher speed than PSK63 is a good option.

PSK63 is perfect on the higher bands as 12 and 10 meter for Es propagation. But there is always a but, when you tell a story. Sensitivity. The sensitivity of PSK modes is not that great. The maximum sensitivity for PSK31 is about -10 db.

PSK63 about -7 db. When compared with JT65A, the sensitivity of JT65 have reached -30 db. (I think the best there is at the moment) ROS claimed that they could have -30 db, but I have never seen a report that goes beyond -24 db. Not bad at all, but too wide.

PSK10 can reach -18 but only a few users worldwide. A good second place for most used digital mode is for RTTY. But why? Maybe it has to do with nostalgia. It is a less sensitive mode, only about -5 db. Not suitable for QRP because you have to put a lot of power in your finals to be heard. And the bandwidth is 450 Hz.

Because of lack of space on HF it is necessary to use small bandwidth modes. Modes like ROS, Olivia 500/16, Contestia 500/16, Olivia 500/4, and RTTYM 500/16 are too wide, and will not be recommended for daily use. RTTY is average in bandwidth and speed comparison.

JT65A become more popular in use. It is extremely sensitive (-30 db) the bandwidth is comparable with RTTY, but in daily use the band is crowded sometimes because they only gather around the pre-arranged dial frequencies -/+ 1 KHz. It’s perfect in use with QRP and very low power. A lot of hams don’t understand the principle when they use more than 50 watts with JT65A.

MFSK16 is comparable with PSK31. Only it’s slower and have more bandwidth then PSK31. When we look to performance of digital modes and the percentage of errors / signal to noise ratio, than MFSK has a high percentage of errors, though it’s sensitive.

For weak signals than DominoEX8 is one of the best (a good second place!) a low percentage (10%) of errors is found and rather sensitive (-16 db). The third place goes to PSK31 12% errors / -10 db.

For me is JT65A the best digital mode. And all the other digital modes, except PSK31-63, RTTY, and ROS? Do you ever hear them? I don’t. (I do not search, really)

All we need is a good behaviour on the amateur bands and respect for each other. We just want to be involved with our great hobby and share the fun and knowledge with each other.

9 comments:

  1. Very nice round up on all the digi modes I never did realize just how many were out there.

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  2. Hello Mike, most of them are not in general use. I did not mention WSPR because it´s not a QSO mode. How was WSPR on 30 meter, last night? 73 Paul

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  3. Hallo Paul, inderdaad "ongeveer" 13 digitale modes, ik denk dat als je schreef dat het er 26 waren je nog niet eens op de helft zat. Het zou wel eens leuk zijn om uit te zoeken hoeveel digi modes er zijn. Je vergat bijvoorbeeld V4, heb jij daar wel eens weer wat meer over gehoord. Zo zijn er wel meer goede ideeën geweest maar uiteindelijk weer vergeten door tijdgebrek of gebrek aan doorzettingsvermogen van de makers. SSTV is ook een digitale mode in feite, dan heb je ook nog digitale SSTV. Schijnt veel op 80m gebruikt te worden, ik ben er nog nooit aan toe gekomen maar wil dat altijd nog eens proberen. Waarom er nog zoiets is al een RTTY DXCC en RTTY contesten? Iets uit de (pre)historie, RTTY of TELEX machines had je natuurlijk al voor computers net zoals de HELL mode machines die er al in de 2e wereldoorlog waren. Vergeet ook niet de professionele digitale modes die daarnaast ook nog met frequentie hopping werken. Op dit deel van de radiohobby kan je nooit uitgekeken raken. 73, Bas

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  4. Hallo Bas, ik heb de 'meest' voorkomende opgesomd. Digi modes die vrijwel niet meer gebruikt worden hebt ik niet genoemd. Binnen elke digi mode zijn alweer diverse verschillen. Inderdaad heb ik V4 vergeten. Die heb ik trouwens ook al geïnstalleerd. Ik heb er nooit 1 verbinding mee kunnen maken. SSTV, tja is in feite ook een digi mode die nog wel steeds gebruikt wordt. Professionele digi modes laat ik buiten mijn beschouwing. 73 Paul

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  5. Hi Paul:
    Not been doing much here (Playing with various software on Linux) missed the High SF last week.
    Well I only ever use PSK31, and Jt65 - they are really the only ones I fancy, I have used Hellschreiber, but like many of the other modes there are'nt too many operators - I always end up back on CW - Microphones are strictly prohibited in my shack - I think I could count on my fingers the number of Phone contacts I have had since I was licensed in 1982 (Not Many)

    73 Peter

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  6. Hallo Bas, V4 gedeïnstalleerd, moet het zijn. 73 Paul

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  7. Hello Peter, me either, but sometimes I like SSB too, but only QRP. Not too much. 73 Paul

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  8. Hi Paul,

    You've made ​​a nice overview, with good comparisons. In the club I heard that JT65 is amazing, just great with low power.

    I once worked with PSK31 for less than one month with 4W and 500 mW.
    During a QSO, a G3 station with 4 W, he wondered if it could done with less power. I knew I could. :-))) So I went from 4 W to 10 mW in a few steps, in a few overs. With 10 mW 80% could still be copied. When I mentioned that I was using just 10 mW, I could almost hear him "fall from of his chair". hi

    I enjoy the regular up date in the photo at the top and the background of the Blog.
    I really enjoy the current picure of the windmill at the poldervaart and it color. FB

    73, PA1B Bert

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  9. Hallo Bert, het is altijd leuk om te zien die verbazing als je met heel weinig vermogen nog hoorbaar bent. Ik vind het leuk om af en toe met de header te veranderen. Met Photoshop kun je leuke dingen doen. 73 Paul

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