Hello Brian and all, I don't think there is to compare RTTY with ALE400. The objectives are really different and there is nothing common. ALE and ALE400 permits a rich system of communications with different possibilities (see my paper "ALE and ALE400 easy"). Without speaking of PC ALE and Mars ALE which offer really a lot of interesting possibilities.
Neither ALE nor ALE400 have for objectives to replace RTTY. The huge advantage of RTTY is to be simple and universal, but that's all. RTTY technology is old. His performance is very poor. The bandwidth is not optimized (for optimized RTTY, choose RTTY with 23 Hz of shift). However, it matches very well quick QSO in contest. Necessarily, modern modes will need more bandwidth because: * you need to code your data (to finally gain in the minimum S/N), * more bandwidth permits a diversity in frequency which helps to make the transmission robust (in general all modern modes as MFSK16, Olivia, ALE have a diversity in time and in frequency). About the bands crowded. For this side of the ocean, the digital bands don't seem very crowded except during contests. It seems there are widely enough room for 400 Hz bandwidth transmissions. 73 Patrick ----- Original Message ----- From: Brian A To: digitalradio@yahoogroups.com Sent: Friday, November 02, 2007 1:29 PM Subject: [digitalradio] Re: ALE400 - Narrow band ALE mode now available I'm not trying to be a pain in the butt, honest. If one put ALE400 and RTTY side by side for the average ham ALE-400 would be a hard sell. Same speed in twice the bandwidth. I guess one may conclude all the bells and whistles of ALE, ARQ etc are doubling the bandwidth requirements. One can copy RTTY with a 200 HZ filter. I doubt one can do the same with ALE-400. Are the benefits really worth doubling the bandwidth? Put another way, halving the number of stations possible for a given band. Perhaps so, but certainly only for a narrow slice of the ham hobbiest needs. We need narrower bandwidths not wider bandwidths for real progress with the real life crowded bands. I think that is why PSK has worked so well. Anybody pushing for wider bandwidths seems to be swimming against the current. I want to point out the old fashioned analog mode of SSB this weekend had at least one station making 10,000 DX QSO's in a 48 hour period. This was the bottom of the sunspot cycle with incredible QRM. It just seems to me that to replace existing technology, the newer stuff has to be able to do all the old technology could do and much more in the same or less bandwidth. I'm not seeing this in these digital modes. Yep, laws of physics do tend to get in the way. Those interested in what can be done if the bandwidth were available should read the proceedings of the AMSAT meeting held this month in Pittburgh. They are talking about a geosyncronous satellite with 6MHz of bandwidth available. Supposedly being able to be reached with 5 watts and a 60cm dish. They think this is the future of emergency communications. 73 de Brian/K3KO --- In digitalradio@yahoogroups.com, Steinar Aanesland <[EMAIL PROTECTED]> wrote: > > What is your point? > LA5VNA Setinar > > > > Brian A skrev: > > > > So one gets the 60wpm of 170Hz shift RTTY for a 400 Hz bandwidth? > > > > 73 de Brian/K3KO > > > > --- In digitalradio@yahoogroups.com > > <mailto:digitalradio%40yahoogroups.com>, Mark Thompson <wb9qzb@> wrote: > > > > > > ALE400 - Narrow band ALE mode now available > > > > > > Patrick F6CTE has announced that a narrow band version of the > > popular Automatic Link Establishment (ALE) software is now available. > > > > > > On the HFLink Yahoo group he writes: > > > > > > For those interested in doing ALE and ARQ FAE using a narrow > > bandwidth (400 Hz), I have derived from the standard ALE a new ALE > > with a bandwidth of 400 Hz (instead of 2000 Hz) and which is called > > 'ALE400'. > > > > > > This ALE system has exactly the same functions as the standard ALE > > (in Multipsk) except that the: > > > . bandwidth is 400 Hz (so ALE400 can be used where 500 Hz modes are > > permitted) > > > . the speed (and consequently the text throughput) is 2.5 slower, > > > . no fix frequency (it is as MFSK16, Olivia or DominoEX modes) > > > . the S/N is 5 dB better: > > > - 9 dB for AMD messages and Unproto > > > - 11.5 dB (- 13.5 dB with many repetitions) for ARQ FAE > > > > > > For ARQ FAE, it has been added a compression system using a modified > > IZ8BLY (Nino) MFSK Varicode. So the text throughput (in ALE400) is > > typically 60 wpm (up to 107 mpm in bilateral and 63 characters frames). > > > > > > This test version in a ZIP test package is available in my site > > > http://f6cte.free.fr/MULTIPSK_TEST_28_10_2007.ZIP > > <http://f6cte.free.fr/MULTIPSK_TEST_28_10_2007.ZIP> > > > (copy and paste this address in Internet Explorer (or equivalent) > > Net address field). It contains the Multipsk test version, the help > > files (in English and French) and the specifications (in English) of > > the ARQ FAE mode (version 1.4). > > > > > > Create a temporary folder (C:\TEST, for example), unzip the files in > > it and start C:\TEST\TEST\Multipsk.exe (the auxiliary files will be > > created automatically). > > > > > > For the contextual help, click on the right button of the mouse, > > with the focus over the mode button "ALE400". Use also the button > > hints (wait a fraction of second over a button). > > > > > > Hints: > > > . if you are the "Master" (initiator of the CQ): confirm the RS ID > > transmission in "Options" (to permit an automatic tuning for other > > Hams), check "Master" on the Mode panel and, afterwards, push the > > button "CQ" > > > . if you are the "Slave" (the Ham who answers): push the button "RS > > ID detection" (to permit your automatic tuning on CQ), check "Slave" > > on the Mode panel and, afterwards, push the button "Answer". > > > Both will push on the "AFC" button. > > > > > > Note: it rings on successful connexion (on both sides). > > > > > > 73 > > > Patrick > > > > > > Related URL's > > > > > > HFLink Yahoo Group > > > http://groups.yahoo.com/group/HFLink > > <http://groups.yahoo.com/group/HFLink> > > > > > > HFLink > > > http://www.hflink.org/ <http://www.hflink.org/> > > > > > > MultiPSK Website > > > http://f6cte.free.fr/ <http://f6cte.free.fr/> > > > > > > ALE400 Software - A Test version has been available at > > > http://f6cte.free.fr/MULTIPSK_TEST_28_10_2007.ZIP > > <http://f6cte.free.fr/MULTIPSK_TEST_28_10_2007.ZIP> > > > but like all test software it could be frequently updated. > > > > > > __________________________________________________ > > > Do You Yahoo!? > > > Tired of spam? Yahoo! Mail has the best spam protection around > > > http://mail.yahoo.com <http://mail.yahoo.com> > > > > > > > >
