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Jump directly to notes on : WSJT HSMS and EME  -  Needed Accessory programs  -  Sporadic E alerting service


Welcome to the VHF DX opportunities of
High Speed Meteor Scatter Operation
(Also, JT65 weak-signal communication, allowing EME operation by stations that are 10 dB too small for CW EME, with links for Sporadic E and other modes, plus the "Hot News" page!)

Why use HSMS? It is much more efficient than slow CW or SSB meteor scatter! Also, HSMS is usable every day of the year, not just during the peaks of major showers. This is because HSMS needs only the fractional-second underdense pings of sporadic meteors. These are available just about all the time. Grids can be worked that aren't available by other propagation types.

Screen shot of WSJT, click for enlargement.
FSK441 Digital Meteor Scatter
and JT65 EME
WSJT ("Weak Signal communicatons, by K1JT") is the DIGITAL FSK meteor scatter and EME program written by Joe Taylor, K1JT. It is now the primary meteor scatter program and mode over nearly all the world. It works!

FSK441 uses 4-tone FSK keying, running at approximatly 9000 lpm (1800 wpm) for FSK441A. It contains a number of features to increase its sensitivity and reliability over any other method now available.

There are now three submodes of FSK441. FSK441A is the "classical version". FSK441B and FSK441C use the same 4-tone frequency shift keying at 441 baud. However, they use forward error correction (FEC) on a character-by-character basis to inprove message reliability. FEC information in FSK441B and FSK441C is conveyed by sending additional channel symbols (tones) for each character, using special codes designed to optimize the error rate and sensitivity with very short pings. The additional symbols are redundant when the S/N is high, but they allow recovery from transmission errors when the S/N is low. Note that the three submodes are not compatible with each other. That is, a tranmission in FSK441B must be received in FSK441B, etc. For further technical information, see the information with WSJT.

FSK441 A Pings. Several have requested FSK441 meteor scatter pings. Here are several. (Even zipped, they are large). Also, the four from K1JT on 144 MHz and the 50 MHz file from K7BV are much better than the usual pings.
010607.zip K1JT, 144 MHz, big pings.
010609.zip K1JT, 144 MHz, big single tone (ST) pings.
010614.zip K1JT, 144 MHz, big pings.
010616.zip K1JT, 144 MHz, burst with text.
W1LP/MM W1LP/MM, typical small 144 MHz ping.
K7BV, 50 MHz K7BV, 50 MHz, big signal.

The JT65 weak-signal modes have been very successful in establishing EME contacts when the signals could not be heard aurally. Many stations who otherwise would have had great difficulty making an EME contact have done so rather easily, even near apogee and when the sky noise was very high!

The latest versions of WSJT include three JT65 submodes. JT65A is the "classical" JT65. JT65B and JT65C include Forward Error Correction (FEC) to improve reception. The latest version also includes an entirely new decoding algorithm that uses "soft decisions" to recover the transmitted message. The new decoder is more sensitive by slightly more than 1 dB and is based on software licensed from CodeVector Technologies, LLC, and protected under US Patent 6,634,007. For further technical information, see the information with WSJT.

For the latest information on FSK 441 MS and JT65, see the Hot News page.
To download the latest free version of WSJT, go to http://pulsar.princeton.edu/~joe/K1JT or the mirror site, http://www.vhfdx.de/wsjt/.
And watch the Hot News page or K1JT's Web site for information on updated versions.
(Joe is currently working on yet another addition to the program. Stay tuned....)

NEW OPERATORS - if you're new to HSMS, MS in general, or weak-signal VHF work, please - immediately check some of the papers and references linked from the Hot News Page, especially the Procedures paper. They will help you get started and understand what is happening.

JT65 EME - One of the best sources on EME operation is W5UN. While his EME primer is for CW EME, the requirements for a successful EME contact are similar when using JT65 mode. (W5UN is also active on and JT65 mode EME).
This EME primer should be read by everyone new to EME operation. It can be found at http://web.wt.net/~w5un/primer.htm

A page listing a number of accessory programs. Some may be necessary, some simply interesting, some worthless to you. All are available on other Web sites, but we've brought several together here.
Click here to check on these programs.

Windows XP users - Trouble running Dimension 4? Trouble with the com port? See WB5APD's Web site for a fix, and other good stuff, both for Win XP and other versions of Windows.
Check the latest news concerning MS, Es, and other VHF DX news of interst.
Screen shot of Windows version, winmsdsp V. 0.009.
HSCW Meteor Scatter
Go to the MS_DSP page for data on the Windows version of MSDSP , as well as papers and helps for both the DOS and Windows versions. (If you're using the Windows version, be sure to also download the "Problems" paper).

If you are not familiar with HSCW, we suggest that you bring up the FAQ, Semi-Technical FAQ, and especially the Procedures (necessary). Then continue on from there.

If you are already familiar with HSCW but are looking for something specific, check out the various topics. If you don't find it under the many different sections here, we suggest that you try the W6/PAØZN Web sitea. And hyperlinked from both that site and this one are a lot more VHF DX/MS/HSCW Web sites. What you need is probably there.

Thanks to PE1NWL, North America now has a Sporadic E Alerting Service similar to the one that has been in use in Europe for several years.
To learn how to sign up for this free service, go to the
E Skip Alerting Service paper.

This Web page is simply to alert you to the possibilities of working DX on 144 MHz (and some of the other bands). Use the links above and to the left to find lots more information!

73, Shelby, W8WN, EM77 - E-mail,



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This work is licensed under a Creative Commons License.