From: "Shelby Ennis, W8WN"
Subject: HS CW MS To: MOON-NET@VM.STLAWU.EDU
North American EME ops - this is a copy of a msg we posted on two MS and
weak- signal VHF reflectors. I realize that many EME ops are not interested
in meteor scatter. But many, probably most, are. Since most may not be
subscribers to the other reflector(s), we are repeating it here. But since
this reflector is primarily for EME operation, future notes on this subject
will likely NOT be repeated here. But just the technical aspect of this
project has been fascinating, and thus the one posting. For more, please
contact me directly at firstname.lastname@example.org.
Tnx & 73, Shelby, W8WN.
North American Meteor Scatter Operators:
Wouldn't it be nice if we could get more info across during a single ping? Well, it can be done. And now it may even be relatively easy, thanks to some new developments.
In a 15-second period, using phone, I can transmit approximately 10 sets of 2x2 calls; fewer sets with longer calls, of course. To get this many call sets into a 15-second period using CW would require running at about 70-75 wpm, faster than nearly any of us can copy.
We usually run at 25-40 wpm for MS on CW. This would give about 3 to 5 sets of calls in a 15-second transmission. Even though many VHF operators can copy 25 wpm or more OK for a schedule, SSB appears to be quite a bit more efficient for using those short pings.
However, there are the problems of signal strength and receiver tuning. It is possible to copy a weaker signal on CW than on SSB. Also, if the receiver is not right on the transmitter's frequency, the signal may not be readable. So wouldn't it be nice if we could combine the advantages of both methods, while adding some other enhancements to push yet more information through?
Well, the Europeans have been doing it for many years. They use high-speed CW, at speeds much faster than can be achieved even with SSB. "Forget it," you say. "I never could handle anything like that!" Neither could I. But my computer can!
Speeds of 100 wpm to 1000 wpm are used, with 200-400 wpm seeming to be common. Operators would modify an audio tape recorder, which would then record at normal speed but play back at a much slower speed, thus slowing the high-speed CW down to something readable. But the tape recorders were hard to handle, and some simply could not be modified successfully. Now the computer has changed all that!
Two DOS-based programs have recently been written that do all of the work
of the modified tape recorder. One is SBMS ("Sound Blaster Meteor
Scatter"), written by DL3JIN. It can be found at:
A second one is MS_DSP ("Meteor Scatter-Digital Signal Processing") by 9A4GL.
This program can be found at:
Both programs use the Sound Blaster compatible audio board to do the work. While the programs are quite different in many ways, they do the same thing for you, and they do it very well.
Note that both of these programs are early versions, and both lack some features and refinements that Americans might prefer for our style of operating. But both work very nicely. One note concerning SBMS - you must edit the first line of the SBMS.INI file to show your directory path to the program (making sure you keep the same format). If you use a RAM disk, you must edit the 2nd line showing where it is located. If you do not use a RAM disk, you don't need to edit the 2nd line. But you DO need to go to your root directory (usually c:\) and make a new directory, RMDSK. You will also later need to edit a couple of more lines after you establish your usual operating conditions. (Also, several features are not yet available, but are to be included in later versions as time permits the authors to work on their programs).
For transmitting, most keyers can run up to 100 wpm. For something faster,
try OH5IY's multi-featured MS program, found at:
W5UN's CWKEY and other programs can also do this. And while you are at these Web sites, go back to the home pages and take a look at some of the other VHF DX goodies there.
To learn more about the European standards, see "Operating Procedures for
Meteor Scatter QSO's" found at:
Note, though, that some of their procedures are the reverse of ours (over here, the western station normally transmits first - over there it is the eastern station). Things such as this have no real bearing on the actual method employed, of course. Also, these procedures were originated some years ago. No doubt the computer will cause continued development of them.
If you get as much kick out of trying one of the new technologies as in getting a new grid, download these programs and play with them! They don't do everything for you. You still have to copy the final code in your head (but if you're a serious VHFer, you can handle this at a reasonable speed). Remember that this type of operation has been done very little in North America for over a generation; but much MS operation over here did start out just this way, using the technology of the times. I know. I listened to it; and if the tapes haven't disintergrated, I still have some of the signals on reel-to-reel audio tape.
I have been running daily higher-speed skeds for awhile, and have been amazed at how much information can be pushed into a "long ping" at the "relatively slow" speed of 100 wpm. Pings that would have given a letter or two on SSB often give most of a set of calls on CW under sporadic, non-shower conditions. As we approach the July-August shower period and wonder what the Leonids will do this year, this might be a good time for you to become familiar with this style of operating. If you could line up a sked with a similarly-equipped station, at a distance, etc, where you can expect some pings, you really should give this a try.