[digitalradio] Re: A new concept in digital mode band plans- reducing the number of tongues in the tower of Babylon
I think it's fair to discuss, which is to say question, whether military standard ALE is the best thing to use on amateur frequencies. It's good to make use of existing standards when they fit the situation, but military radio is not amateur radio. With our crowded bands, and with amateur radios that are stingy on the bandwidth, maybe we would be better off using something like Patrick's ALE-400. Jim W6JVE
[digitalradio] Re: New subject: FSK clicks
--- In digitalradio@yahoogroups.com, Wes Linscott wrote: > > The EPC PSK125 contest was in operation. Is that possibly what you were > seeing/hearing? > > Wes W1LIC Well if PSK125 signals are clicky then that's just as bad as if it's FSK. However I was able to copy one or two of the clicky signals as FSK RTTY. Didn't try on all of them.
[digitalradio] New subject: FSK clicks
I was just listening on 80M - some kind of RTTY contest is on - and I hear a bunch of normal-sounding FSK RTTY signals, and some that are awfully clicky, like key clicks except it's FSK. I wonder what those guys are doing wrong. Having the speech processor turned on, perhaps? Or too-rapid switching between mark and space? Please listen when you get a chance and see if you hear what I'm hearing and if you can guess what is causing it. On the waterfall it shows up kinda like an overdriven PSK signal, but that shouldn't matter so much for FSK. Jim W6JVE
[digitalradio] Gtor
I guess I'm hearing a Gtor QSO right now, because every now and then I get a screen message DATA: comp=Huffman, block=1 and that sort of thing. but I also get CONNECT (greek) TO (greek) and DISCONNECT (greek) FROM (greek) never have seen any intelligible text. This is on 3585.5 KHz and has been going on since about 0230Z here in NW Arkansas.
[digitalradio] Re: GTOR- has anyone tried this?
I think I have it working, but haven't heard any signals or tried to contact anyone yet. What works is that if I punch CONNECT the transmitter gets keyed and I can hear signal bursts going out on the sidetone. And I guess I am receiving audio because I'm getting a bunch of garbage on the screen with noise input. Is there a procedure for calling CQ? Or do you have to have a definite call sign you want to connect to? I assume that's what goes in the box that by default contains GTORTOCALL
[digitalradio] Re: ROS Advantage- mode ranking
--- In digitalradio@yahoogroups.com, "John Becker, WØJAB" wrote: > > Not really Jim > I for one never stopped using the old machines. > Therefore never had to bring em back out. > It's the only way I do RTTY here. > > John, W0JAB > Cool! I have a lot of TTY machinery out in my "baudy house" but none of it is on the air right now. I switched to sound card RTTY back when K6STI's RITTY software first came out. At my request he did make available a cleaned-up Baudot output on one of the connector pins so I could drive a Real Teletype printer from it.
[digitalradio] Re: Curious sound card modes question -
--- In digitalradio@yahoogroups.com, "John" wrote: > > Thanks Skip, > > Unfortunately, this really does not get to the crux of my question(s). I > understand how an SSB transmitter works, but that is not really what I am > after. > > What I am driving at is if like this. If I use DM780 to run some version of > digital mode via an SSB transceiver, it uses a tone or series of tone > modulation/shifting to create the output of the transmitter, and not one > single mode is called "spread spectrum" output, but is called FSK or PSK, > etc. Now, we get into the aforementioned discussion regarding ROS, and > suddenly, still via the microphone input of the same transmitter, those > shifted frequencies are now called "spread spectrum" instead. I am having a > great deal of difficulty understanding, other than the author happened to > call his scheme "spread spectrum" in his technical documentation. > That's a good question. If we run RTTY with 850 Hz shift like we did in the old days, has that turned into spread spectrum?
[digitalradio] Re: GTOR- has anyone tried this?
--- In digitalradio@yahoogroups.com, "sholtofish" wrote: > > > I tried some connects with Andy and Skip and can confirm the sound card > version of G-TOR works with a real G-TOR modem (my KAM-XL). Throughput got up > to 200 baud and of course no errors due to the ARQ. > > The GUI is basic on the sound card program and not particularly intuitive but > it seems that sound card G-TOR is possible on Windows. > > 73 > > Sholto > K7TMG > That's really interesting. I had no idea there was a sound card modem for G-TOR, and of course G-TOR has seen very little use since you always had to have a Kantronics TNC to use it. Maybe somebody can write up how to operate the sound card version.
[digitalradio] Re: Something to consider about external automatic antenna tuners
--- In digitalradio@yahoogroups.com, "Dave 'Doc' Corio" wrote: > However, there is one thing the tuner will NOT do. It will not remember > any band or frequency, until the transmitter is keyed. > Well, sure. The only thing going from the radio to the tuner is the antenna cable, so the tuner has no way to know that you have changed frequency on the transceiver. Whereas a tuner built into the radio, or one made for the radio you have and connecting to the radio with a control cable, can get frequency information from the radio. But the third-party tuner only knows you have changed frequency when you tickle it with some RF.
[digitalradio] Re: ROS Advantage- mode ranking
--- In digitalradio@yahoogroups.com, Alan Barrow wrote: > I've also observed a significant power mindset with many RTTY ops. > Bigger is better. > This pretty much comes with the territory. I've been in RTTY since the late 1950s, and I just remembered recently that back then we all ran lots of power - had to, to get good copy. I used a home-built 500 watt transmitter for a number of years, then switched to a TMC rig with a KW linear amplifier. Used that until the AMTOR mode came along, and then I got a TS-940 and used that barefoot and other radios in the 50-100 watt class ever since. And I don't do much RTTY anymore, but then nobody else does either except the DX guys and contesters.
[digitalradio] Re: ROS Advantage- mode ranking
--- In digitalradio@yahoogroups.com, Dave Ackrill wrote: > > Otherwise why so much RTTY on the bands? Even AX:25 is getting a bit > long in the tooth now, but people still struggle on with it... My belief is that all the RTTY is largely from contesting and DX chasing. Those two operations have two things in common: they benefit from very fast turnaround, and the operators don't care much about the high error rate. Other modes like PSK31 have a longer turnaround time because they transmit for a second or so before and after the keyboard text, while RTTY is immediate and that translates into more contacts. The operators don't care much about all the errors because they already know what they want to see. They already know the call sign of the other station, and they already know the signal report will be 599, so if the mess on the screen looks like their call sign and QSL that is enough to consider it a contact. Then I guess there are a few people bringing old mechanical Teletype gear back to life and using it for rag-chewing for old times' sake. Jim W6JVE
[digitalradio] Re: ROS, legal in USA?
--- In digitalradio@yahoogroups.com, "n9dsj" wrote: > > Hi Jim, > > Actually CHIP worked ok, especially on the low bands. The Virginia NTS net > used this and still may. Worked OK, but I didn't think it worked as well as or better than other modes that were more popular. Jim W6JVE
[digitalradio] Re: ROS, legal in USA?
--- In digitalradio@yahoogroups.com, KH6TY wrote: > > I agree Dave, and Chip64 was abandoned over here on the same basis! > I remember trying Chip64 without worrying about whether it was legal. I got the impression it was abandoned just because it didn't work very well compared to some of the other modes that came out about the same time. Jim W6JVE
[digitalradio] Something to test
It would be interesting to try to find out how much ROS interferes with other modes when it operates on top of them. That is, if you had a RTTY or PSK or Olivia or some other kind of QSO going, and a ROS signal started up in overlapping bandwidth, does the ROS signal tear up the other-mode QSO, or is its dwell time on any one frequency too small to have much effect? Jim W6JVE
[digitalradio] Re: Digital modes band plans.
--- In digitalradio@yahoogroups.com, bruce mallon wrote: > > I remember several spredsprectum people commenting that they didn't care if > they obliterated legacy modes. > Â They didn't happen to be in the BPL networking business, did they?
[digitalradio] Buglet in ROS
A minor but annoying problem I'm having is that in Windows XP it keeps maximizing the window without being told to. I haven't found for sure what triggers it, but just now I am monitoring and a ROS signal came on and a second or two after the initial tone the window maximized itself. Yup, just happened again, started receiving and about 1 second into the transmission it maximized the window. Jim W6JVE
[digitalradio] Re: RTTY and mode selection on radios
--- In digitalradio@yahoogroups.com, "John Becker, WØJAB" wrote: > > RTTY "should" be used in the LSB mode regardless of the band. Well thats when you aren't using the FSK mode for RTTY; the FSK mode does put it into LSB. > > I don't use software for RTTY so I cant tell you a thing about that. > Users of software for RTTY have come around to using USB regardless of band, just for the sake of uniformity. In that case they use a reverse shift switch in the software to make the signals come out right side up.
[digitalradio] Re: RTTY and mode selection on radios
If the radio has RTTY as a mode, as does the TS-940 for example, it means (1) there is an input on the back where you put in a baseband signal and FSK comes out the antenna, and (2) for receiving it will use a narrow filter and center the filter up around 2.2 KHz. (By "baseband" I mean the actualy RTTY signal at 45.45 baud, as would come out of a Teletype keyboard.) In the case of the TS-940 and other radios there is a misfeature that in SSB mode you can't get the narrow filter switched in; you have to use RTTY or CW mode to get the narrow filter. The main reason you want the narrow filter is to suppress strong signals that are in the IF passband of the radio but not in the middle of the signal you are trying to receive. Such signals will affect the gain of the receiver through AGC action, so that the level of the desired signal goes up and down as those off-channel signals come and go. So you want the narrow filter to have the AGC focus on the signal you are trying to receive. The reason the receiver puts the filter up at 2.2 KHz in the FSK mode is that in olden days FSK signals were translated to audio, originally at 2125 and 2975 Hz, later changed to 2125 and 2295 when 170 Hz shift came into use. So if you were using a typical RTTY terminal unit for receiving its input frequency range would be up there. Jim W6JVE
[digitalradio] Re: RTTY decoding
--- In digitalradio@yahoogroups.com, Sven wrote: > > Hi, > I' ve searched the Internet for RTTY decoding methods and found the following: ... > Are there other known methods and who knows something about or can explain > the above decoders ? How do they perform in a noisy environment ? > I'm far from expert and up to date, but let me reveal how little I know. The original concept for FSK was to use a separate filter and detector for mark and space and combine the outputs of the two detectors by taking the difference or by running them into oppositely-poled windings of a polar relay. This was worked on by Schmitt of Teletype and by Armstrong about the same time. Presumably they were unaware of each other's work. Both of them hoped that noise would affect both detectors equally and cancel out. Carson of AT&T showed that this hoped-for effect would not work, although he may have missed that the two-frequency scheme has an advantage over make-and-break keying because the transmitter is transmitting all the time; hence the transmitted power is higher with FSK than with make-and-break. Armstrong went on to develop FM as we know it, with a limiter followed by a discriminator. The next incarnation of FSK reception used the same principle. FM systems have a threshold property: with SNR above threshold they improve the SNR in the output signal, and with SNR below the threshold it gets even worse in the output. A professor at MIT proposed using positive feedback aound the input filter and limiter. This has the effect of sharpening the threshold. In the 1960s some hams got interested in returning to the limiterless two-tone schemes. Some of this was probably a revival of Armstrong's hope, unaware of Carson's rebuttal. I only became aware of the Armstrong and Carson material in the last year or two. In two-tone systems there is a definite advantage if the transmitting station is using "diddle" as this gives both detectors some signal to chew on all the time; there are no long pauses when only the mark signal is present and the space detector forgets how strong its signal was. Work continued on terminal unit designs as new ICs came along, such as the phase locked loops. There was also a scheme that I don't know if anybody ever tried, called frequency feedback. This uses a VCO heterodyned with the input signal and controlled by the discriminator output. It does not phase lock, but reduces the apparent shift of the signal so that a narrower filter can be used ahead of the discriminator. L-C filters gave way to active filters and then to switched-capacitor filters, the latter making it easy to vary the center frequency of the filter to accomodate odd shifts and arbitrary audio frequencies. There may have been some work done with DSP using some of the DSP-engine development kits that I am unaware of. Then about 1996 K6STI announced his RITTY program, using the ordinary 486 or Pentium PC with a sound card to do DSP. One of his innovations he called the "digital flywheel". This took advantage of the constant character rate, if the sender was using diddle or was sending from a file, to lock to the character rate and use matched-filter detection. He continued developing and improving this software for the next four years or so. I believe he achieved about the best that can be done for FSK reception. He pulled the product off the market when some people cracked his copy-protection scheme and also when the original sound-card PSK31 software came out and was offered free. Today you find the vast majority of rag-chewers have switched from RTTY to PSK-31 because the latter usually performs better for a given SNR. RTTY continues to be popular for contests and DX because of its more rapid turn-around and because you don't care that much about errors when you already know pretty much what the other station is going to say to you. I'll confess I don't have any idea what algorithms the various RTTY demodulators are using today. Jim W6JVE
[digitalradio] Re: Comparison of RTTY software sensitivity
Now I don't know about TrueTTY, but MMTTY has a number of things you can play with in terms of the filtering and detection, so I wonder if we could get some comparisons of those - or at least tell us what the setup was when it was tested. Jim W6JVE
[digitalradio] Re: Comparison of RTTY software sensitivity
--- In digitalradio@yahoogroups.com, "Vojtech" wrote: > > Both yours and Alex's graphs show superiority of TrueRTTY and MixW. I wonder > whether TrueRTTY is doing synchronous detection. This is what I plan to try > when I retire, hi. > There used to be the K6STI RITTY program which does synchronous detection. I wish we had a comparison of it with some of the modern RTTY software. Trouble is, RITTY requires a DOS environment and a SoundBlaster ISA sound card, and you don't find those much anymore. And it's no longer on the market. I was really excited when it came out, because I had wanted to do synchronous detection for a long time. However it didn't appear to be all that helpful, maybe a db or two. Then PSK31 for the sound card modem came out and most of the rag chewers switched to that from RTTY. Jim W6JVE
[digitalradio] Mystery signal on 75M
I was listening on the top end of 75M this afternoon about 4PM CST and heard a strange wideband signal, sounded a little bit like rushing wind. Brought up a digital waterfall and found that it extended from 3990.15 to 3997.85. The waterfall display was rather blotchy, suggesting some internal structure, tho I'm not clear on how many carriers might be present or what their spacing is. I was beginning to suspect the neighbor's cable TV box which has put noise on some other frequencies, but then the signal went away about 5PM CST. I've heard the signal before, but didn't note the times and spectrum. This is in NW Arkansas.
[digitalradio] Re: CSS to release The PK-232 25th Anniversary Software CD
--- In digitalradio@yahoogroups.com, Mark Thompson wrote: > > CSS to release The PK-232 25th Anniversary Software CD > A pre-order price of $139.95 is available at the CSS online store at > http://www.cssincorp.com. What a deal! Just the thing to run on your 8088 PC.
[digitalradio] Re: Dxing and long winded digital ops
I would love to have rag chews with DX stations, but in fact I just about never answer CQs from DX stations because they seem to automatically assume that I'm only interested in bagging a DX QSO for DXCC or something and they terminate the contact right away. Jim W6JVE
[digitalradio] Re: what's the latest on WINMOR
--- In digitalradio@yahoogroups.com, "aa777888athotmaildotcom" wrote: > Just send to your Winlink account. That would be your calls...@... However > note carefully the spam control features that are in effect at > http://www.winlink.org/help. You may need to add "//WL2K" to your subject > line. > > Waiting mail is automatically transferred when you connect to a Winmor RMS > server station. > Thanks to Yahoo that callsign@ address got obscured, but I would guess it is callsign at winlink dot org. Do I have to register with winlink to have that work, or does it just happen? Jim W6JVE
[digitalradio] Re: what's the latest on WINMOR
--- In digitalradio@yahoogroups.com, "aa777888athotmaildotcom" wrote: > > There are now 4 beta RMS server stations on the air. I've transferred mail > to/from the real world through one of them. I've sent mail from radio to Internet through a couple of them. What do you have to do to send mail in the other direction?
[digitalradio] Which is a better rig for digital work?
FT-1000MP or TS-850S with DSP-100? Jim W6JVE
[digitalradio] Re: 7036kHz Digital ops
But it's not ARRL vs. IARU in this case; it's FCC versus the rest of the world. 7070 is not in a phone band in the U.S., but is in some other countries. If it were in a phone band in the U.S. then U.S. hams would not be able to operate digital modes there.
[digitalradio] Is there a convention for stereo phone plugs?
I've never known if there is a standard for whether tip or ring is left or right channel. And is left or right normally used for the computer DSP radio software?
[digitalradio] Re: Mail/File Tranfers on HF: Some Reflections on Winmor, PSKMAIL, FIdigi, and ALE.
Thanks for the fine review. It seems like the main thing WINMOR wants to add is the ability to switch the data rate on its own, going faster when conditions are good and slowing down when they are bad. This is something Clover tried to do, but apparently was imperfectly implemented and hasn't been worked on in years. So maybe we need to ask the fldigi developers for some hooks into the program that would allow changing modes on the fly, perhaps using RSID to let the receiving station know what is going on. That makes me wonder about PSKmail, which I haven't tried yet. I see a message just after yours that someone's server is going to be running THOR. I wonder if I could be trying all day to connect to a PSKmail server and failing because I don't know which mode it is expecting. Is there some provision for using RSID and beaconing to announce its presence and the mode it expects?
[digitalradio] How does one get started with pskmail?
Is there a document?
[digitalradio] Why so much interest in WINMOR?
Seems like people are falling all over one another to participate in WINMOR testing, yet we have other ARQ schemes that aren't getting exercised at all. I don't understand it. Jim W6JVE
[digitalradio] Re: An open letter: W1AW and 80m psk31 interference
--- In digitalradio@yahoogroups.com, Rik van Riel wrote: > In my opinion, the why isn't nearly as important as the fact that > we have a problem on the band nowadays. The fixed frequency psk > kits have been built and cannot easily be changed to another > frequency. Easily changed by changing the crystal I guess, but then people have to decide which frequency to use for the crystal. Or substitute a VFO. So it seems we have color TV to blame for the fact that there is only one usable frequency on the 80M band. It's just a happenstance that the color TV frequency is in the CW portion of the 80 meter ham band. The amateur way has always been to QSY to get away from interference, rather than assigning exact channels to various users. I just don't have much sympathy for hams who marry themselves to a particular frequency because the crystal for it happens to be lying around everywhere. As for whether W1AW should listen before transmitting - I don't expect many of the QRP rigs that are stuck on that frequency are audible in Newington.
[digitalradio] Re: An open letter: W1AW and 80m psk31 interference(A dissent)
Maybe I haven't been paying attention, but what is it that makes 3580 a sacred gathering place for PSK? Why isn't it 070 like it is on some other bands? Why can't we just QSY to get away from W1AW?
[digitalradio] Re: Best Software
--- In digitalradio@yahoogroups.com, "vrygood10" wrote: > > Hello All, > Is there any software out there that will identify and display > all hf digital signals.. > I can identify some of the signals but there are many I can not.. > > Norman > If you're talking about amateur signals, then the advice given in response to your question is good. If you're talking about digital signals in general, well, there is some expensive SWL stuff like Hoka and Skysweeper. There used to be some modems such as the Universal Radio M-7000; and you can find those on ebay sometimes.
[digitalradio] Re: More RSID - PLEASE!
--- In digitalradio@yahoogroups.com, "Ed Hekman" wrote: > > I was monitoring PSK on 20 meters today with DM780 V5.0 Beta when a window > pops up in the lower right corner of the screen that says, "MFSK32 > transmission on 2632 Hz. Click here to select." I guess I could go read the manual, but, Simon, what is the criterion for the software to make such an announcement? I mean, the band might be full of various kinds of transmissions, so how does it decide which one(s) to announce? Jim W6JVE
[digitalradio] Re: Zapped PCs, data recovery, and Windows !
Even though you cannot in general boot a computer with a C: drive from a different computer, the BIOS should tell you if it sees the drive. After a lightning strike a month or so ago I had two computers dead. Each of them had two hard drives. I was able to learn from the BIOS that the C: drives were both dead, but the other drives were still usable - and they had all my important stuff on them. However this shows the hazard of having your backups on one computer and the live stuff on the other - I could easily have lost both the live stuff and the backups at the same time if the two slave drives had not survived. I'll have to figure out a better way to keep my backups safe. Jim W6JVE
[digitalradio] Re: QRV ALE-400 ARQ chat mode -- 14074.0
--- In digitalradio@yahoogroups.com, Rick W wrote: > > It seems that there are only a handful of hams who have any interest in > ARQ modes for chatting. I guess I'm one of that handful, but right now I'm working my way back from some lightning damage that killed two computers, among other things. Jim W6JVE
[digitalradio] Re: WTD a baudot to ASCII / ASCII to Baudot terminal program for PC not sound card
Google for rtty12git's in BASIC and comes with the source.
[digitalradio] Re: Manual for Hal ST-8000A
--- In digitalradio@yahoogroups.com, "Ken LoCasale" wrote: > > Does anyone know where I can get a manual or copy for an, st-8000a? > > Thanks, > > ken - wa4mnt > You can order a copy from HAL, and if anybody else publicly offers you a copy then HAL is likely to jump on him about the copyright.
[digitalradio] Re: Spotted on Usenet: running HRD under Linux with Wine
--- In digitalradio@yahoogroups.com, David wrote: > > Hi Mike. > Trouble is, I'm not Mike - I just cut and pasted Mike's message from the other group. So we need other resources to learn how he did it.
[digitalradio] Spotted on Usenet: running HRD under Linux with Wine
From: m II Newsgroups: rec.radio.shortwave Subject: Ham Radio Deluxe on Linux It took a while to get it working right. there was a lot of fiddling with the 'Wine' setup. http://encyclopaedia-galactica.org/screenshot.png This thing has enough bells and whistles to last a lon, long time. mike
[digitalradio] Re: New version of Mixw
--- In digitalradio@yahoogroups.com, chas wrote: > > Rick W wrote: > > What is the attraction of MixW now that we have so many other multimode > > digital programs that are freely available with one program even open > > source and cross platform? > > > > 73, > > > > Rick, KV9U > > Rick, nearly all members of Texas Army MARS and Region 6, are using > MixW. idly curious, what else is out there that can even almost > compete with Nick's software?? > > look and feel is not a consideration but what else has all the > features of or even is better than, MixW? > No, let's get back to Rick's question and ask what it is about MixW that you find to be superior to everything else out there. I downloaded a trial version of MixW long ago and wasn't impressed enough to want to go further with it. What am I missing? Jim W6JVE
[digitalradio] Re: backup
--- In digitalradio@yahoogroups.com, "Simon \(HB9DRV\)" wrote: > > FWIW with the exception of laptops I always run RAID 1 (mirror). I've had > disks die but never lost data as a result in far too many years of coding. Note that RAID is protection against a disk failure, but not against some other kinds of mishaps. If you, or your computer, should accidentally delete or scribble on some files it will corrupt the RAID copies equally. So it's good to have backup copies that are safe from that kind of destruction.
[digitalradio] Re: Olivia
--- In digitalradio@yahoogroups.com, "Siegfried Jackstien" wrote: > > i like the ida of automatic changing of the modes . would act as pactor > 123 . But the reason Pactor can do that is that the sending station is constantly getting acknowledgment packets that tell it how the last sent packet got through, or did not. We would need a wrapper around Olivia or PSK that would send signal-quality responses so the sender could adjust its speed.
[digitalradio] Re: Olivia
--- In digitalradio@yahoogroups.com, "Simon \(HB9DRV\)" wrote: > > Would not WINMOR be an option here? > Well, except that WINMOR seems to be single-mindedly a message passing mode. I wish there was some layering so that the modulation means and the error correcting means and the message passing were separable. Of course adapting to varying conditions means some communication down through the layers, changing the modulation scheme when error control indicates that is needed. CLOVER had that kind of operation - trouble is that it (amateur version) seems to lack the ability to go downhill when conditions worsen - it's aggressive enough about going uphill when conditions permit. Times I have used it, it would invariably get stuck trying to send long blocks that never made it through, when shorter blocks probably would have been successful. Jim W6JVE
[digitalradio] Re: popular software
--- In digitalradio@yahoogroups.com, "ww6aa" wrote: > > i am new to dig.radio and apologize for asking a question that i am sure has > been answered many times, but search came up with >1000 replies. What > software seems to be most popular @ this time > You mean today? Or last week? Seriously, a lot of people get started in digital radio with Digipan and PSK31 on Windows. Or do RTTY with MMTTY and Windows. Then many move on to multimode programs. I've been talking to lots of hams lately who use HRD Ham Radio Deluxe with DM780. Haven't tried it yet myself. I've been using MultiPSK, which has a pretty intimidating user interface but does an awful lot of modes if you want to try them all. I still occasionally talk to people using MixW. Then there is fldigi, which is one of my personal favorites, mainly because it does a lot of modes and works under Linux and Windows both. I prefer Linux but keep Windows around so I can run the software that doesn't work under Linux. Jim W6JVE
[digitalradio] Re: Another "what is this mode" question
--- In digitalradio@yahoogroups.com, Andy obrien wrote: > > What frequency was this mode? > Oh, about 7073. There was an Olivia signal nearby, which made it easy to see that the displays were different. Olivia looks more random, like snowfall, whereas this signal seemed to have a pattern to it.
[digitalradio] Re: Another "what is this mode" question
--- In digitalradio@yahoogroups.com, Mike Blazek wrote: > > Hi, Jim: > > Might have been MFSK16? > > Mike N5UKZ > Nope, MFSK16 is much narrower than 500 Hz. And I tried MFSK32 with no results.
[digitalradio] Another "what is this mode" question
I was listening to some stuff last night on 40M, and it was clearly 500 Hz wide and about 16 discrete tones, but it was not Olivia and I couldn't find anything else that would decode it either. Tried Contestia and RTTYM and various settings of Thor and DominoEX. The signals looked and sounded a bit different from Olivia - with Olivia the spots on the waterfall seem to be more or less random, whereas with the mystery signal they seemed to be more clustered around a frequency a little below the center of the group. And seemed to have more of a pattern to them. Jim W6JVE
[digitalradio] No FCC data bandwidth limit on HF Re: USA ham rules
--- In digitalradio@yahoogroups.com, "Dave AA6YQ" wrote: > > Thanks. > > To repeat my first question, "What's the bandwidth of an FSK signal whose > shift is 1 kHz and whose symbol rate is limited to a maximum of 300 baud? > Feel free to parametize as necessary." > Using the approximation I just posted, treat it as a pair of on-off keyed carriers 1 KHz apart. For 300 baud the dot-cycle frequency is 150 Hz, the frequency of a square wave made up of 1010101010... So you're going to have the first pair of sidebands at 150 Hz each side of the carrier, or a total width of 1300 Hz, with a big hole in the middle. Then depending on signal shaping you'll have the higher-order sidebands in there, the third harmonic at 450 Hz each side of the carrier for a total width of 1900 Hz. With random signals rather than the square wave the general shape of the spectrum will be filled in under the shape of the square wave signal. Or you can answer the question experimentally by generating such a signal with your radio and looking at the waterfall or spectrum display. Jim W6JVE
[digitalradio] Re: Bandwidth v Shift in RTTY ?
--- In digitalradio@yahoogroups.com, "expeditionradio" wrote: > > Hi Andy, > > There is no simple universal relationship between > the "shift" and the transmitted "signal bandwidth", However, for the particular case of binary FSK where the shift is wide compared to the bit rate, you get a reasonable approximation by treating the signal as a pair of carriers being switched on and off alternately. For each carrier you get pairs of sidebands. For the worst case of a square wave digital signal you'll get sidebands at the dot-cycle frequency and odd multiples thereof. So, depending on signal shaping, the signal at 850 Hz shift will have a bandwidth extending over about 950 Hz with a big hole in the middle.
[digitalradio] Re: ALE musings
Rats! I just hit the wrong key and sent an unintended message. Wish I could delete it. And before that I had written a lengthy comment which Yahoo seems to have lost. So I'll try again. Seems like there are several aspects to ALE One is the notion of going through a list of frequencies in hopes of finding one that works for the station(s) you are trying to contact. Another is the set of MIL STD modems, codecs, and protocols that implement the system as we know it. Now the frequency jumping part is something we could call "HF Radio for Dummies" and I don't mean Dummies as a pejorative but rather in the sense that has sold all those yellow books. It means you can get right to the point of communicating without first having to learn a lot of arcane stuff about propagation modes and times and seasons. And even the experts are sometimes fooled by propagation, so ALE may succeed at times when the experts tell you it could not. As for the MIL STD part, it's good that these things are being standardized, and we know the military spares no expense in search of the best communication technology. Still, I wonder if these modems and codecs and protocols are necessarily the best for the amateur service, considering the legal restrictions we operate under, the kinds of equipment we have to use, and the operating conditions we encounter. (Rhetorical question: Separate the frequency scanning from the modem/codec. What if we had a system that could scan through a list of frequencies but used PSK instead of the MIL STD modem/codec?) Another aspect is the use of ALE as a communication medium in its own right versus the use of ALE to find a usable channel for further communication in some other mode. Speaking only for myself, I'm a keyboard mode operator so I don't get excited about using ALE to initiate a contact that will be continued in SSB voice. And I can't see myself using ALE to establish a contact and then saying, "let's QSY to such-and-such a frequency and continue in PSK63." Finally, it seems ALE is best suited to establishing communication with a particular station, or with a group of stations having a common interest. This probably affects the number of hams who are interested in trying it. I used to keep a weekly sked with a friend; ALE might have been helpful to us in finding the best frequency to use on any given evening. Back in the late 1950s I was in a RTTY roundtable of friends practically every night. ALE would probably not have been helpful then. Some hams chase DX, some contest, some are interested in emergency services, some do it all. ALE serves some of these operating styles and not others.
[digitalradio] Re: ALE musings
--- In digitalradio@yahoogroups.com, "expeditionradio" wrote: > > > Andy K3UK wrote: > > Bonnie, I have no doubts about automatic > > link establishment. It seems like a most > > logical method of establishing communications. > > I added the rather provocative end to my > > earlier post because I am not sure WHY ALE, > > in its present amateur radio configuration, > > is needed . > > Perhaps the best answer to your question may > be in the form of questions for you: > Why is "CQ Contest" needed? > Why is "You are 5-9" needed? > Why is a repeater needed? > Why is a weekly net needed? > > The purpose is similar. > > Bonnie KQ6XA >
[digitalradio] Re: Some More Thoughts On WINMOR and Winlink
I have a friend who years ago twisted my arm to get me into Clover. Back then the original Clover modem, the PCI-4000 was arguably more costly than the SCS modems in constant dollars. We used to keep skeds and use it conversationally - he seemed to really enjoy the quasi-full-duplex operation where we could both be typing at the same time and our two-way communications were going along with the ACK and NACK signals. Eventually we gave up on Clover, partly because we both got busy with other things, but also because Clover seemed to have a particular shortcoming: when the channel quality deteriorated it would keep trying unsuccessfully to send a long block, instead of dropping back to a shorter block that might have a chance of getting through. But when it worked we did enjoy the error- free conversations under band conditions that were too bad for the only other keyboard mode we had at the time, which was RTTY. Jim W6JVE
[digitalradio] Possibly an important article
The new (March 2009) issue of Communications of the ACM has an article by Guruswami and Rudra, "Error Correction up to the Informaton-Theoretic Limit" that may be important. I'm not enough of a theoretician to say whether it is or isn't. Jim W6JVE
[digitalradio] Re: Some More Thoughts On WINMOR and Winlink
--- In digitalradio@yahoogroups.com, "Andrew O'Brien" wrote: > I assume that many people know already, but just in case there are > some that do not, WINMOR will not be a digital mode that your can use > for keyboard "chats" or QSOs, it is intended to allow you to connect > to a HF Radio Message Server and unload your email formatted messages > . The part of this I know, but don't completely understand, is - there is going to be some kind of modem, and some kind of codec, and some kind of ARQ protocol on top of that, and then the application that sends and receives messages as part of Winlink or Paclink or whatever. Is there something unique about the modem that makes it better than some of the others we are now using for keyboard chats as well as for the Winlink application? Same for the codec?
[digitalradio] Re: on another note
--- In digitalradio@yahoogroups.com, "W5XR" wrote: > > I'm asking. :) > > Bob, W5XR. O.K. For START-STOP synchronization to work the receiving shaft (selector or distributor) has to stop between characters. The Morkrum Co. (ancestor of Teletype Corp.) had the sending and receiving distributor shafts running at different speeds, so the receiving distributor completed its rotation part way through the STOP pulse and was held there until the next START pulse. the STOP pulse was the same length as all the others, so it was 7.0 unit code. Western Electric had built some teleprinters of their own, and in theirs the transmitting and receiving distributors were on the same shaft. So to give the receiver a chance to stop they had to stop the transmitter between characters. They did this by adding a relay to operate the transmitting distributor clutch. At the speed they were running at the time, something like 45 wpm, the relay added a delay in milliseconds that was equal to 0.42 of a pulse duration. When Western Electric discontinued making their own teleprinters and started buying from Morkrum they insisted on interoperability with the W.E. machines. Morkrum didn't want to use a relay in the transmitter clutch, so they simply elongated the STOP segment on the transmitting distributor to 1.42 times the length of the other segments and changed the shaft speed to keep the pulse duration the same. So we got 7.42 code; and this continued as speeds were increased and after the Western Electric equipment had all been phased out. Western Union didn't have the problem of interoperability with old Western Electric designs, so they insisted on 7.0 unit code because of the slightly higher speed that gives, roughly 65 wpm instead of 60. For many years Teletype had to make equipment that could transmit either way, by supplying the appropriate transmitter cam and gear. The printers all had no trouble copying 7.0 unit code. At 100 wpm, 7.42 unit code gives a speed of 74.2 baud. At some point the U.S. military decided to round that up to 75 baud, and then to standardize on speeds that are 75 multiplied by a power of two, so we got 75,150, 300, 600, 1200, etc. for our terminals and modems. For some reason Europe standardized on 50 baud and 7.50 unit code; I can only assume that some equipment manufacturer had trouble with a unit-length STOP pulse and needed extra time to get the receiver stopped.
[digitalradio] Re: on another note
--- In digitalradio@yahoogroups.com, "Patrick Lindecker" wrote: > A synchronous RTTY under Windows is possible with a standard symbol > synchronization (with or without a PLL which can be seen as the "digital > flywheel"). However, the stop bit (1.5 symbols) complicates all as it is not > an integer multiple of the symbol length. > > Now, RTTY must be supposed to be asynchronous to be compatible with all RTTY > apparatus and programs. Let's work on more modern modes... I did some work earlier with "compatible synchronous RTTY" using 7.00 unit start-stop code, to make it easier to synchronize. Even mechanical TTY machines can easily receive 7.00 unit code. I built a transmitting converter that would send the 7.00 unit code, and insert fill characters (LTRS or FIGS) if there was no input character available when one was called for. Another ham was working on the receiver - I don't know if he ever got it working. Then years later K6STI did his "digital flywheel" and he said it didn't matter that the character length was not an integral multiple of the bit length so long as the character length was constant. Which required transmitting "diddle". But I fully agree about more modern modes. Last night I was copying a couple of RTTY stations, pretty good copy except for QSB, and one of them was using 1KW and the other using 500W. And back in the glory days of RTTY we were all trying to run that kind of power. I have a big TMC kilowatt transmitter gathering dust out with all the TTY machines. There is an amusing explanation for why TTY uses a 7.42 unit code (in the U.S.) but I'll forbear to tell it unless someone asks. Jim W6JVE
[digitalradio] Re: on another note
--- In digitalradio@yahoogroups.com, "Vojtech Bubnik" wrote: > Patrick, I have a proposal for one low hanging fruit project. How > about to receive RTTY in a synchronous way? I believe most SW really > generate precise synchronous RTTY, where the only variable is the > unknown stop bit length (mostly 1.5?). If the stop bit length is being > estimated or selected from menu, one could receive RTTY synchronously > and greatly increase sensitivity of this legacy but often used mode. It's been done, in the K6STI RITTY software some years ago. Not that it couldn't be done again. K6STI was selling his software and pulled it off the market when users began stealing it. Also it was basically DOS software, and that may have been a necessity considering the timing vagaries of multitasking operating systems. There was for a time an implementation of Pactor-I in RTTY, later taken out. What K6STI did was something I had been dreaming about ever since the vacuum tube and heavy metal days of RTTY, so I was tickled pink that he did it. I had a few arguments with him about the dynamics of the "digital flywheel" as he called it; but he's the expert and I'm not. As things turned out it did not greatly increase the sensitivity - it was good for a db or two and that was about all. One neat thing he did, that I wish other RTTY software writers would do, was to output cleaned-up Baudot while receiving, so that one could drive a TTY machine from it, using his software as sort of the ultimate T.U. Jim W6JVE
[digitalradio] Re: Harmonic of some Sort on 20mtrs, includes a Computer Power Supply Interference Issue.
It can be awfully helpful at times to have a portable battery powered shortwave receiver so you can listen to the interference while you are walking around, and with all your AC power shut off.
[digitalradio] Re: on another note
Something I forgot to mention earlier in suggesting a Pentium with sound card might be usable as a dedicated DSP engine - the K6STI software absolutely required an ISA SoundBlaster. If we want to define a new DSP engine we need some higher level of abstraction to be able to cope with hardware that becomes unobtainable. This is also a problem with other kinds of DSP engines out there - sooner or later you can't get the DSP chip and the A/D and D/A chips that you can today.
[digitalradio] Re: on another note
--- In digitalradio@yahoogroups.com, "Rud Merriam" wrote: > > First, I would not dismiss sound card modes. I think there is much more > that can be done with them. One of the main issues IMO is that they > don't (1) adapt to changing band conditions, and (2) don't utilize FEC > as much as is possible. (We also might need much better sound cards. > I would say that adapting to changing band conditions and utilizing FEC as much as possible are not inherent limitations of sound card modems, but are simply artifacts of the higher-level protocols. There's the modulation scheme layer, and the encoding layer where the FEC is applied, and then an adaptive layer that comes in where the sender gets feedback from the receiver that things are not going very well and something else should be tried. Now this layer may call for a change down in the modulation scheme layer, to use something more robust and slower when things are not going well, and to hop up to something faster and less robust when conditions permit. I think you're right too about the quality of sound cards. What we get with onboard sound or with the low-priced add-in boards is the lowest grade the consumer will accept. You can't blame the manufacturer for providing that when the consumer will accept such junk - I mean if all you are going to use it for is to listen to loud, intentionally-distorted rock music then you aren't going to care much about signal to noise ratio or linearity. You can find some sound card evaluations on the web; and some have been discussed on this group. There are really good ones, but then the prices are up there with the dedicated DSP engines like the SCS modems. The challenge is to find one that is good enough - and considering all the noise and crud of the HF channel maybe it doesn't have to be very good to be good enough. The big win for sound card modems is that everybody has one already, and that lots of people are writing software that can use them, so lots of experimentation is going on. We've already got dozens of digital soundcard modes that nobody uses because they have not attracted enough attention or shown enough superiority over others to make people want to use them. > Second, further gains could be made using external DSP boards. > These are not that expensive today. What we are talking about here are products that have their own DSP processor and memory and A/D/A conversion, and you can download the firmware that runs the DSP from a PC. The advantage seems to be that the DSP processor is not getting interrupted by all the other activity that is going on in the PC; and the receiver can maintain synchronism with the transmitter over a long period of time. This is presumably important for some modulation and coding schemes - they can spend as much time as they want getting synchronized initially, and then they don't need to spend much effort to stay synchronized afterward. The problem we all realize is that there is no single DSP engine out there that we have all agreed to use and therefore people have an incentive to write software for; so it remains a niche activity. I recall this is where PSK was before the sound card software was developed - it ran on a dedicated DSP engine and so few people had them that there was little incentive for others to get them. If the SCS products were (are?) open to third-party development, so that others might write PSK or MFSK or Olivia modems to run on them, perhaps we would all buy them and quit using the sound cards. I don't think it's realistic to expect SCS or any other vendor to spend their own money to add popular modes to their products, esp. when the sound card versions are out there for free. There once was the HAL PCI-4K DSP modem developed for Clover but later adapted to run RTTY and Pactor-I. Clover was once used for message-passing systems as well as for conversational operation. I don't know how relatively good or bad it was as a modulation scheme compared to some of the others. It seemed to me that a main drawback could have been remedied - it seemed to get stuck trying to send a long block when conditions were too poor and for some reason it could not fall back to sending short blocks which might get through. There also once was the K6STI RITTY software that was designed to run under DOS and for a while could run Pactor-I as well as RTTY. This leads me to wonder if a suitable DSP engine could be made from a PC and a sound card but not running a general purpose operating system. Maybe FreeDOS is a candidate for the operating system, or maybe we just need a single-minded loader that can load and run a single PC program and communicate with another PC over Ethernet or USB or even RS-232. The other PC running a conventional OS would handle the higher-levels of protocol and the user interface. Jim W6JVE
[digitalradio] Re: Comparison of Performance of Digital Modulation in the Presence of adjacent QRM
--- In digitalradio@yahoogroups.com, "Andrew O'Brien" wrote: > > FYI, anyone have the full articel ? > > Andy > Comparison of Performance of Digital Modulation Techniques in the > Presence of Adjacent Channel Interference > Milstein, L. Pickholtz, R. Schilling, D. > Univ. of California San Diego, La Jolla, CA, USA; > > > This paper appears in: Communications, IEEE Transactions on > Publication Date: Aug 1982 > Volume: 30, Issue: 8 > On page(s): 1984- 1993 > ISSN: 0090-6778 > Current Version Published: 2003-01-06 I'm trying to understand what that means - Publication Date Aug 1982, Current Version Published 2003-01-06 That seems to say that if I go to the library and look up IEEE Transactions on Communications I will find it in the Aug 1982 issue; and that there is a version published almost 10 years later that is somewhere else. Jim W6JVE
[digitalradio] Re: Recent MFSK16 DX
--- In digitalradio@yahoogroups.com, "Graham" wrote: > but with the stability of modern rigs I dont see why the > original mfsk should not make a come back ? The only time I had trouble with MFSK16 and frequency drift was when I was using the Elecraft K-2 radio with its 100W amplifier, and before installing a frequency stability mod they developed. Never had any trouble after that.
[digitalradio] Re: HF packet
--- In digitalradio@yahoogroups.com, Mark Milburn wrote: > Yes, there are a LOT of repeats when the bands are poor. Signal strength is not the only criteria. I don't have a technical background to explain it or even understand it, but there are plenty of days when a signal of S7 will be solid copy..and other days when it will not. Part of the problem is that at 300 baud the bit length is only 3.3 milliseconds. You can have multipath echoes that smear the short bits even when signals are strong. (That's one reason why 110 baud ASCII never caught on with hams, and even 75 baud Baudot can be dicey.)
[digitalradio] Re: Digitalradio on Facebook
--- In digitalradio@yahoogroups.com, "Briggs Longbothum" wrote: > > Andy, I'm not convinced at all that this is a good idea. I hate to > sound naggish and I do applaud you efforts with the good of the group > in mind, but I've had a raft of bad experiences I agree - one of my old friends from green-key RTTY days nagged me to join Facebook, so I did, and immediately turned off all the things that would cause it to send me email, and I never remember to log into Facebook when I have so many other things to read on the net, so it has been of zero value to me.
[digitalradio] Re: FlDigi version 3.10 need some help
--- In digitalradio@yahoogroups.com, Russell Blair wrote: > > I down loaded and installed ver.3.10 and for the life me I cant get to work the (Compute 2.5Ghz,1.5gig of ram windows XP Pro SP3) SB soundcard. I cant get the program to show any audio, even thou the program shows my soundcards, but I see no waterfall audio. Sometimes you have to open the Windows volume control and fiddle with it - some things may be turned off or turned down low. I've also had funny things happen when I turned on the check box in fldigi that lets fldigi control the volume. That's in one of the tabs for the sound card. Then sometimes you have to fiddle with the two numbers near the lower left corner of the screen that set the signal level range and the minimum signal level. Jim W6JVE
[digitalradio] Re: Information Please re Reading the Radio for Digital Modes
--- In digitalradio@yahoogroups.com, "Gmail - Kevin, Natalia, Stacey & Rochelle" wrote: > > DM780 through the sound card to Kenwood TS-480S/AT, in the data socket. > When I start DM780 and look at the screen, waterfall I see the data mode, in this case PSK31 on 14.081.5, but the radio is showing 14.080. > I remember when I first was using PSK31 I could see other stations within the window of the waterfall, they could of been on 14.082.5 or 14.080.6 and that I was able to leave the radio freq alone and just click on the other station and then make a contact. > What I was interested in, is, should I have moved the radio freq. to pull the station onto the 1.5Khz above the. (Don't know if I explained that correctly) Unfamiliar as I am with the TS-480, when you are using the data mode I guess it is choosing a particular bandpass filter, and probably setting the transceiver to lower sideband as well. That bandpass filter might be narrow, like 500 Hz. So what you see on the waterfall is 500 Hz of spectrum that is centered maybe 1.5 KHz below the dial frequency. Or maybe not. It is more usual in the digital modes to always use USB, and to use SSB mode so you get the filter that is about 2.8 Khz wide. Then if the transceiver dial is set to 14.080 you will see on the waterfall frequencies above that by the amount indicated on the waterfall frequency scale: maybe 500 to 2500 Hz, meaning actual frequencies of 14.080500 to 14.08300 And you point and click with the mouse to choose a PSK signal in that range. One problem then is that if you are trying to copy a weaker signal and a very strong signal comes on nearby the strong signal will cause the receiver AGC to cut down the gain of the receiver, so that the weaker signal is cut down also to where you can barely see it. Hence you would rather have a narrower filter, such as the one you use for data mode, to separate the signal you are trying to copy from the nearby strong signal. And you could tune the main tuning so as to push the strong signal off the edge of the filter, one side or the other, while keeping the desired signal in the passband. > > Also there is heaps mentioned about NO ALC, I have set my TS-480S/AT to the requirements for digital mode, and even dropped the input down further. > I was still getting some ALC when in TX. No-body said I was producing a bad signal so I don't know if I was TXing right. > Should I set the radio up as stated and then drop back the audio out from the soundcard? There are two potential problems with transmit audio level. One is that there might be an amplifier ahead of the gain control in the radio - this is very typical if you are going in through the mike connector rather than through the back panel connector. If you overdrive this amplifier it creates distortion products, and since it is ahead of the gain control knob there is nothing you can do with that knob to eliminated the distortion. The remedy is to cut down the sound card output from the computer, either with the computer volume control or with an attenuator between the computer output and the radio input. The other problem is that PSK requires no ALC. Many other digital modes such as RTTY and MFSK do not have this problem as they transmit only one tone at a time; but PSK is effectively a two-tone signal. This one you can control using the gain control on the radio, just turn it down until the ALC goes to zero. Also you want to be sure that any speech processor is turned off, as this distorts the waveform too. Jim W6JVE
[digitalradio] New fldigi 3.10
The latest fldigi 3.10 is now available on the w1hkj.com web site.
[digitalradio] Re: No audio from soundcard
This may seem too obvious, but get a pair of earphones and some clip leads if necessary and see if you are getting audio out of the cable that plugs into the radio. That tells you whether the trouble is in the computer, like something to do with the volume controls, or in the radio like the D-mode that has been mentioned.
[digitalradio] Re: Sunair RT 9000A Help
--- In digitalradio@yahoogroups.com, Ed wrote: >I wasn't trying to "flame" you, but I do think you might get a > better response on manual_excha...@yahoogroups.com . Or armyradios group, or perhaps hflink, which is for ALE-capable radios, if it is that kind of radio.
[digitalradio] Re: ASCII ?
Related to the earlier question about amateur radio ASCII, there was also the occasion when the 60wpm limit was lifted and 100 wpm Baudot was allowed. This too never became popular because only the guys who had Model 28 machines could use it, and because the shorter bit length (13 ms. versus 22 ms.) was more sensitive to errors, both from increased bandwidth and from multipath propagation. I believe Navy MARS made some use of 100 wpm RTTY.
[digitalradio] Re: QRV MT63 14106
I think it would be more useful if you would announce your plans to be operating well in advance of the time you start up. I tend to read the group once a day, usually in the morning, so what I learn from your message is what I could have been doing last night, if I had not been busy with other things. Jim W6JVE
[digitalradio] Re: ASCII ?
--- In digitalradio@yahoogroups.com, "Jose A. Amador" <[EMAIL PROTECTED]> wrote: > but there was a GM - Microsoft > controversy that ended with a caustic reply from the GM's President > that explained it too well. That's interesting, because I think it was GM that is generally credited with inventing "planned obsolescence" and the annual model change.
[digitalradio] Re: ASCII ?
I guess some people thought it was a Big Deal, but there were lots of reasons why it didn't go anywhere. I'd say the overriding one is that with 60 wpm Baudot RTTY the bit length is 22 milliseconds. With 100 wpm ASCII 110 baud the bit length is 9 milliseconds. That means 2.4 times the bandwidth, and correspondingly more noise sensitivity. Maybe for VHF local work it wouldn't matter; but for HF that's a big penalty. And we were already running 500 watts or so to get good copy on RTTY. Other reasons include the plentiful supply of old Baudot Teletype machines, versus having to buy a new one for ASCII, until CRT terminals came along. And so many guys can't even type 60 wpm that the ability to operate at 100 wpm wasn't interesting. And for rag chewing, contests, and DX, the upper case only Baudot character set is entirely sufficient. Of course the earlier ASCII Teletypes were also upper case only. And the lower cost ASCII Teletype, Model 33, had terrible keyboard touch compared with the older Baudot machines. ASCII was advantageous only for applications involving connection to computers, or for applications requiring upper and lower case characters. Teletype's original up/low machines, Model 37 and Model 38, were failures; so it was the CRT terminal business that really made ASCII practical. Jim W6JVE
[digitalradio] Re: RTTY Dilemma
--- In digitalradio@yahoogroups.com, "Rick Ellison" <[EMAIL PROTECTED]> wrote: > It is a long standing standard that The standard for BOTH amateur and > commercial FSK has ALWAYS been "specify MARK" with MARK being the higher RF > frequency and SPACE being the lower RF frequency (e.g., shift low). I'm aware that is the de-facto standard for amateur use, was not aware that it is also standard for commercial use. The U.S. military has long used the center frequency rather than mark or space - this was pretty annoying in setting up a MARS station since the center frequency is one that you never transmit. I suppose it is the result of using military FSK exciters such as the O-5/FR where if you set the shift control to zero you get the center frequency, and as you turn it away from zero the mark and space move away from the center by equal amounts. Amateurs most often used diode shifters on the VFO in the days before SSB, and thus setting the shift to zero resulted in transmitting either the mark or space frequency (depending on how it was wired) rather than the center frequency.
[digitalradio] Re: RTTY newcomer looking for some information
--- In digitalradio@yahoogroups.com, John Becker <[EMAIL PROTECTED]> wrote: > I have a couple of books on RTTY dating back to the 1960's. They talk > about using TU's that can decode with only the mark or only the space > signal. This seems pretty straightforward, since the mark and space > together provide 100% redundancy. I haven't figured out how to do that > with what I'm running, and on weaker signals I'm finding a tuning error > of only 10Hz can make the difference between copy and no copy. > Decoding with mark only or space only was something that seemed like a good idea at the time to get improvement over the true-FM limiter-discriminator design. It didn't turn out to be all that useful, because when signals are so bad that they fall below the threshold for FM then they are so bad that you don't copy much anyway. I honestly don't know much about the modern sound card DSP decoders, but I imagine they detect the mark and space separately and then combine the results. > What do I need to do better? Are there any good recent books on RTTY? I don't expect to see any new books on RTTY, because it is a technology that is pretty much as good as it is going to get. Better performance these days comes from the newer sound card modes. RTTY is mostly used now for contests and DX, and the reason I think is that it has very fast turnaround, so you can make contacts as quickly as possible. You don't care that much about accuracy so long as what you see looks like what you want to see, hi. Also back when RTTY was the only keyboard mode we had most hams were running quite a bit more power than is the norm today. 500 watts was pretty standard for RTTY back then. For general rag chewing today most everybody has gone to PSK-31. There is some tweaking you can do with RTTY things like the MMTTY engine, which has several different filtering and detecting options. Maybe somebody will speak up about how to use them to best advantage. You might benefit by putting on the whole MMTTY program and using it to learn how to take best advantage of the displays and features. As a 50+ year user of RTTY I hate to sound so negative about it; but the fact is that technology has moved on. Jim W6JVE
[digitalradio] Re: Emcomms : NBEMS v.ALE: Score one for ALE.
--- In digitalradio@yahoogroups.com, "Andrew O'Brien" <[EMAIL PROTECTED]> wrote: > > I gave up on NBEMS after several hours of 20/40M beaconing. It is a > great application but heard NO one today. ALE on the other hand > proved quite active and the http://hflink.net/qso link made it easy to > see how I was getting out. > > > -- > Andy K3UK > Well I meant to listen for your beacons, but got busy with other things and never got around to it. And then, since it only sends files, I didn't have any files I need to send to you. Jim W6JVE
[digitalradio] Fedora 9
I noticed last night that just added to or updated in Fedora 9 Linux are xdemorse, xpsk31, and xlog.
[digitalradio] AMTOR
I was just thinking as a purely whimsical thing, wonder if it would be hard to use AMTOR as the communication link and use Real Teletype machines for the keyboard and printer, 5-unit code and all. What got me to thinking of this was that RCA used to have a service based on their ARQ system, which used a code similar to AMTOR but a full-duplex HF circuit, and they connected to plain Teletype customers at both ends.
[digitalradio] Re: MFSK31 QSO's wanted
--- In digitalradio@yahoogroups.com, Howard Brown <[EMAIL PROTECTED]> wrote: > > I worked Tony K2MO last night on 20 meters using MFSK31 and MMVARI. This mode seems very robust. It worked through deep fading and some horrible noise very well. Also, it is quite a bit faster than I worked him too, using MFSK31 under the alpha test version of fldigi. But copy was pretty rough and we soon gave up. Jim W6JVE
[digitalradio] Re: Open wire feed line length
100 feet of ladder line is sort of a magic number for being easily tunable on all the bands. One of my friends bought a ready-made 80M dipole with 100 feet of ladder line and a tuner; and the instructions were not to cut much if any off the ladder line. I learned the reason for that later when I ran across a web page (which I can't find right now) where the guy has a similar antenna that he tunes by inserting various lengths of feedline. He has a graph showing that 100 feet comes pretty close to being a good match on all the ham bands. Here it is http://www.w5dxp.com/notuner.htm
[digitalradio] Re: K2 Elecraft
--- In digitalradio@yahoogroups.com, Yves Dussault <[EMAIL PROTECTED]> wrote: > > I want to use my K2 on digital modes. > Any suggestions? > Nothing very specific...I've used a K2 on digital modes. Depending on how old yours is, there is a modification that makes the VFO more temperature stable, which is very helpful and almost essential if you run MFSK as it is very intolerant of drift. Mine has the 100W amplifier built into the main case, and the antenna tuner in a separate box. Perhaps there is need for cooling improvement when using the amplifier and digital modes. Seems like somebody had a hack for bringing out the audio at a constant level for putting into the sound card. I don't have that, but did make a modification where plugging into the speaker jack does not cut off the speaker, so I can get sound into the sound card and still hear what I am receiving. Jim W6JVE
[digitalradio] Re: Multiple Digital Modes: Time to get rid of most ?
--- In digitalradio@yahoogroups.com, "Dave AA6YQ" <[EMAIL PROTECTED]> wrote: > In seeking to displace PSK31 with a better alternative, a good place to > start is to consider PSK31's weaknesses: > > A. no error detection/correction > > B. simplex > > C. can't convey files (messages, pictures, documents, etc.) > I don't know if that would lead to a displacement of PSK31 so much as it would an accomodation of other activities that PSK31 doesn't do well. I mean, the lack of error detection/correction and inability to convey files doesn't seem to bother the kind of people who make up the majority of PSK31 users now. Nor does simplex. BTW I enjoy MFSK-16 when I can find it on the air, but the ability to send pictures is not a selling point to me. I don't have any pictures I want to send, and I'm almost never interested in the pictures people want to send me.
[digitalradio] Re: Multiple Digital Modes: Time to get rid of most ?
--- In digitalradio@yahoogroups.com, "Dave Bernstein" <[EMAIL PROTECTED]> wrote: > > I don't believe that PSK31, PSK63, or RTTY are the best that can be > done on HF-- but no protocol attractive enough to displace them has > yet been developed. > I think, too, that each has its place. RTTY was once our only keyboard mode. Now it is still in use mostly for DX and contests, where the very rapid turnaround is important and you don't care if you get a lot of errors so long as what you get looks like what you want to get. PSK-31 is the "new RTTY" as a general conversational mode. PSK-63 for those who can type faster, but that doesn't seem to be very many of us. Olivia is really impressive under poor conditions. If only it were not so slow - I forget how slow it is and type up a big buffer full and then get bored waiting for it to go out. Feld-Hell is fun because it is quaint. I'm still waiting to make a contact using flarq or ALE-400.
[digitalradio] Re: RFI-Free PCs?
You mentioned Class B for industrial applications. Is the intent of Class B to hold down the amount of RFI coming out of the computer and bothering other things? Or is it more to prevent strong RFI in the environment from screwing up the computer? I guess for ham radio we are concerned with both - I get noise in the receiver generated by the computer (and all the other assorted electronics lying around) and also have had RF get into the computer and mess up the keyboard.
[digitalradio] Re: Vista
We conspiracy theorists can always believe that Microsoft deliberately made Vista so bad so that there will be lots of buyers for the next version of Windows. Gotta keep the revenue stream flowing.
[digitalradio] Re: RFI-Free PCs?
I agree on building your own PC. I built one using a cheapie case and power supply and it was pretty quiet. So I ordered another case and power supply, same catalog number from the same supplier, and what came was a bit different. The power supply was the worst broad-band noise generator I have ever met, even when the computer was turned off. I've been told that Antec makes good power supplies and boxes. On the other problem, high noise on CB and 10 meters, I've found that a battery-operated portable shortwave receiver is a great tool. I had a lot of trouble at first with power line noise. The power company was cooperative but not very skilled in finding it. I could walk around with the battery receiver and find the noise hot spots and then they could find the faulty line hardware. I read somewhere that your house is a high noise zone, and if you get about 15 feet away things get much quieter. I haven't yet got around to trying that with the portable SW receiver. I'm told that even wall-wart power supplies these days generate RF noise. Touch lamps are known to be a bad source of noise. One of my friends says to turn off Everything in the house, unplug all the wall warts, and see what kind of noise you have, and then put things back on one-by-one.
[digitalradio] Re: FDMDV below 10MHz: LSB or USB?
--- In digitalradio@yahoogroups.com, Ian Wade <[EMAIL PROTECTED]> wrote: > > We all know that we should use LSB for analog voice below 10MHz, but > what is the consensus for FDMDV and other digital voice modes below > 10MHz: LSB or USB? I don't use FDMDV, but for the keyboard digital modes, after a lot of questioning like this, the consensus seems to have settled on USB everywhere. And then for FSK RTTY most of the software has a reverse check box so you can use USB and still have the tones come out right side up (mark high, space low) in the RF signal.
[digitalradio] Re: Operating FSK RTTY in a contest ?
--- In digitalradio@yahoogroups.com, "Robert Chudek - K0RC" <[EMAIL PROTECTED]> wrote: > > I started my RTTY career using 2125 and 2975 tones... Same here, and with a pre-WW-II Super Pro receiver that would have drifted right out the window if it had not been screwed down. And a transmitter of the same vintage with a VFO down in the broadcast band and multiplying all the way up. Operation on 20M was practically unthinkable, even if we had not been in an extreme fringe area for TV and even if the transmitter had not had about 18" of excess lead length in the PA tank circuit. until those young brats started pushing the envelope (or should I say, squeezing the envelope) with those 170 Hz tones... things were much simpler in those good ole days... your betcha... the smell of a well oiled machine, a whiff of ozone from the commutator, polar relays! (hey remember them?), and the quiet roar of all that machinery pounding out your CQ's... It was great... well, except for two things... having your platen pounded to death at the right margin, and coming home to find a half roll of paper behind the machine because some smart-a** thought it was cute to auto start your machine and feed it 15 minutes of line feeds. Yep, the good ole days... ! ! ! Seems like the late Irv Hoff was especially plagued with that problem, as he had a large fan club and a small but vocal anti-fan club. He worked out a scheme for the Model 28 stunt box - I have one of the machines fitted out that way, but I no longer remember exactly what it all was. It involved putting in the automatic carriage return and line feed kit, to take care of the occasional missing carriage return. Then it was something like having the carriage return character also do the line feed, and suppressing line feeds on repeated carriage returns. Jim W6JVE
[digitalradio] Re: New ARRL HF Digital Handbook - Fourth Edition (Available October 2007)
--- In digitalradio@yahoogroups.com, "tremont245" <[EMAIL PROTECTED]> wrote: > > --- In digitalradio@yahoogroups.com, "AE9K" wrote: > Hi Dan > > Go for the Digital Modes For Occassions by ZL1BPU, I have just > received this book and can't put it down. I have the other book as > well, which I feel is more of a primer,where as the ZL1BPU book digs > deeper without loosing your interest and without getting too > technical and loosing you. > > Good reading > > Trevor G8IIN > > It must be a great book indeed. I looked for it on amazon.com and all they had was a used copy priced at $92.70.! However you can get a new one from CQ for a lot less.
[digitalradio] Re: Robust Packet-Radio (RPR)
--- In digitalradio@yahoogroups.com, Rick <[EMAIL PROTECTED]> wrote: > > Andy, > > What I don't understand is if you already have a suite of modes, Pactor, > Pactor 2, and Pactor 3, then why create another mode like they did? > > This is not compatible with existing packet, right? So you would have to > have SCS products on both ends? Then why not use Pactor modes, > especially the Pactor 2 mode which is of a similar bandwidth and throughput? Maybe not. Seems like that say it doesn't involve tight timing the way Pactor does, so potentially it is a mode that can be implemented on sound cards, either by reverse engineering or by their publishing complete specs.
[digitalradio] Re: Help files in vbdigi
--- In digitalradio@yahoogroups.com, "kh6ty" <[EMAIL PROTECTED]> wrote: > > What do you have on C: drive that makes Windows default to D: drive? Maybe > that is a clue. > What I have on the C: drive is Win95. WinXP is installed on the D: drive. Anyway, that fixed it - I removed it using the add-remove thing, and then used search to track down and remove everything about NBEMS, and then reinstalled and the help files work. Thanks.
[digitalradio] Re: Help files in vbdigi
--- In digitalradio@yahoogroups.com, "kh6ty" <[EMAIL PROTECTED]> wrote: > > > Please try creating a folder, C:\Program Files\NBEMS, copying the files > there, and see if VBdigi finds those. > No, it did not find them there either.
[digitalradio] Re: Help files in vbdigi
--- In digitalradio@yahoogroups.com, "kh6ty" <[EMAIL PROTECTED]> wrote: > > VBdigi is looking for the following files in D:\Program Files\NBEMS > directory: > > > emailsetup.rtf > flarq.rtf > logbook.rtf > messaging.rtf > vbdigi.rtf > vbdigisetup.rtf > > Do a search for flarq.rtf and tell me where it is located on your system. > That's where it is: D:\Program Files\NBEMS\flarq.rtf
[digitalradio] Help files in vbdigi
I have vbdigi installed in D:\Program Files\NBEMS The help files are in there but when I click on help in vbdigi it doesn't find them. Where is it looking for them?
[digitalradio] Re: Mode identification
--- In digitalradio@yahoogroups.com, "Bill McLaughlin" <[EMAIL PROTECTED]> wrote: > One I had trouble with the other day, was > Clover, but had not heard it in so long I had forgotten what it > sounded like. > You heard a Clover signal?! What kind of time machine do you have there? Heard any spark lately?
[digitalradio] NBEMS setup
I'm trying to follow the instructions in VBdigi under Help->Radio email setup. I navigate to C:\NBEMS\Mail I put the mouse pointer on the ARQout folder and hold down the right mouse button and try to drag it to the menu bar at the bottom of the screen, and I get the slashed-circle "not" symbol. (and all my open windows get minimized).
[digitalradio] Re: 30 Meter digital
--- In digitalradio@yahoogroups.com, "kh6ty" <[EMAIL PROTECTED]> wrote: > > It is my belief that if "voice" of the same bandwidth were allowed everwhere > "data" is allowed, the data segments of the bands would be overrun with > phone stations using DV. We could, for the sake of argument, use that software that translates voice to keystrokes, transmit the resulting data as a text file, and then at the other end play the text file into software that turns it into speech. Of course it wouldn't sound anything like the actual speaker's voice...
