MS / HSMS ( High Speed Meteor Scatter )

Meteors travel at @ 223 times the speed of sound !!!

Meteors typically create ionized trails for use for radio reflection at @ 60 miles up 

  What is MS / HSMS ??? :  Meteor Scatter and High Speed Meteor Scatter are forms of communication that radio operators use to reflect their signals off of the ionized trials left by meteors to try to make a contact. 24 hours a day, the earth is bombarded by small particles the size of grains of sand from space. This debris, in many cases, are remniscents of comet tails, asteroid particles, and possibly other elements floating around in space. As this debris enters the earths amphosphere at high rates of speed, they burn up and generate heat and light which vaporizes before it hits the ground. As it streaks across the sky, it enters the " E " layer of the ionosphere and causes a small area of the " E " layer to ionize in the area of its trail for a short period of time. When this happens, it is possible to reflect radio waves off these ionized trails and make use of it to use as a form of radio communication. The U.S. Military has been using this technique for decades to conduct secure two way telecommunications.

    What is the difference between MS and HSMS ??? :  MS stands for Meteor Scatter. This is a general term which can apply to all forms of Meteor Scatter including SSB and CW, ( FM and AM modes are nearly never used in Meteor Scatter Work however many stations report decoding distant packet stations during high meteor activity !!! ) .

  HSMS stands for High Speed Meteor Scatter. This is a type of Meteor Scatter that is more of a specialized form that uses High Speed CW.

    Why High Speed Meteor Scatter  / CW ???  :  During periods of time when meteor activity is low, the use of SSB Meteor Scatter becomes relatively useless. This is because the ionization time becomes very short ( usually less than 1 second and in most cases, less than .5 seconds ). If SSB was used during these low periods, at most, only bits and pieces of a word would be copied at best. This is where High Speed CW can become useful. This is because the CW words are sped up to a much faster rate  ( 200 to 1500 W.P.M. !!! ) . In HSMS, these faster speeds are referred to as LPM ( Letters Per Minute ) . Common speeds used today are 1000 to 6000 LPM . When this CW is sped up to these higher speeds, it is possible to utilize the short ionization times to carry more data or info to make a QSO. This is why HSMS is more commonly used when meteor activity is low which happens to be most of the time during the year .

  MS / HSMS  Frequencies :  Meteor Scatter Operation can be utilized as low as the 10 meter band as as high as the 1296 MHz band ( the 1296 MHz band hasn't really been tested that much but technically can be used ) . The most useful bands seem to be the 6 and 2 meter bands.These are also the two most populated bands of Meteor Scatter Operators. This is because these two bands give the best conditions for Meteor Scatter Operation.  The Meteor Scatter calling frequencies are 50.125 on the 6 meter band ( which i think is still be negotiated ) and 144.100 on the 2 meter band. 50.125 - 50.200 is the MS segment used on 6 meters and 144.100 - 144.150 is used on 2 meters. Users are to avoid the SSB segment above 144.190 and EME segment below 144.100 on 2 meters. Likewise, below 50.125 on the 6 meter band. The calling frequency should be avoided during scheduled contacts and should only be used for random CQ's. Once a response has been yielded on a CQ on the calling frequency, it is best to move off the frequency using a frequency offset method . This " frequency offset " method is described in the Meteor Scatter Procedures described at the link site below  .

 Get a copy of the High Speed Meteor Scatter Procedure >>>  Procedure

    When are the best times for meteors ??? :  ( For Random Meteors ) Typically the morning hours, ( 2 AM - 9 AM local time ) , yield the best results for meteor contacts. This is because the particles that create meteors are accelerated faster in the earths amphosphere during the morning side of the earths rotational  position. Likewise, the least amount of acceleration occurs on the evening side of the earth . The difference between the two sides are noticeable but not enough to prevent Meteor Scatter Operation. As a matter of fact, successful contacts are common on the evening side of the earths rotation but more successful on the morning side.

    Major and Minor Meteor Showers  give the BEST results on both SSB and HSMS. The number of meteors per hours expressed as " ZHR ( Zenithal Hourly Rate ) " is at its highest during a Major Meteor Shower and at its lowest during non- shower times. Actually, meteors occur at any given time during any time of a 24 hour day period anywhere on the earth. I personally have ran skeds in the afternoon, early evening, early morning and late mornings with success in making partial to complete QSO's.

    Meteor Scatter Range :   The typical range for working Meteor Scatter is @ 1600 miles maximum. Each station draws a circle of 800 miles radius around their location, if the one stations 800 mile circle falls within the other stations circle, the two stations can work each other.On the other hand, it is possible to be too close to work Meteor Scatter without having to resort in pointing the antennas at some oblique elevation and azimuth angle. Anything within @ 400 miles or so seems to be too close to work Meteor Scatter efficiently. The optimum distance between two stations varies but seems to be @ 1000 miles plus or minus 400 miles or so.

    Antenna Pointing :  Normally and most the time , the antenna is pointed directly at the station. However, if the other station's distance is too close, then the antenna should be pointed to a " offset " position. This offset position is to allow maximum signal from the meteor signal to be directed toward the other station by bouncing the signal off the meteor at the correct angle. If this isn't done under these conditions, the stations signals will overshot each other. Some of the Meteor Scatter Software will show what offset angle should be used.

    Pings and Bursts :  These are two commonly used terms used in Meteor Scatter Operation. They refer to the length of the signal received. A " Ping  " is referred to as a signal that is usually less than acouple of seconds long and is a signal that is reflected off a " underdensed " Meteor. A underdensed meteor is a meteor that has insufficient capability to ionize the " E " layer of the ionosphere. What really happens is that the signal is bounced off the meteor itself rather than the trail it produces. This becomes sometimes evident when a " doppler shift " of the  signal appears, especially on the super short pings. Only High Speed CW can utilize  these kind of signals.

Here is an example of a " Underdensed Ping " on 2 meters :   kd7tsu.wav

    A " Burst " or " Burn " is referred to as a signal that is reflected off of a  " Overdensed " Meteor. A Overdensed Meteor is a meteor that HAS sufficient capability to ionize the " E " layer of the ionosphere. The length of the signal can go from acouple of seconds to a minute or longer.

Here is an example of a " Overdensed Burst " on 2 meters :  n0kqyo.wav

Equipment required for Meteor Scatter :  

  Antennas:  To make reliable contacts on Meteor Scatter, there is a requirement for an antenna with gain over a dipole. On 6 meters, a antenna as little as a 3 ele beam can give good results. On 2 meters, the typical antenna is a beam with @ 12 dBd or a 13 ele. These antennas give very good to excellent results. The antenna gain requirements become higher as the frequency becomes higher. This is because the signal attenuation becomes larger as the frequency becomes higher. The best results come from EME style arrays. On 432 MHz  and 1296 MHz , an antenna gain of 18dBd or higher should be used.

    Transmit Power : On 6 and 2 meters, 100 watts is a very good starting point. 30 watts on 2 meters has been easily accomplished into a pair of 12 ele. with contacts greater than 1000 miles away !!! On 432 MHz and 1296 MHz,  100 watts may be somewhat marginal but can yield some contacts usually only during large meteor showers. 400 to over 1000 watts give the best results on any band.

   Note:  Listening to a station with the higher power will result mostly in receiving more ,( in quantity ), pings and bursts,  not necessarily higher signal strength.

    Receive Requirements :   Having a good receive capability is almost mandatory in meteor scatter work. A preamp with a low noise figure should be used at 2 meters and above. A preamp is not required on 6 meters since the sky noise is already at a high level anyway. It is also very important to have a very accurate frequency readout on the radio ( or at least have an idea where the exact frequency is located on the dial ). This is because the station on the other end will not be able to copy  a station that is off anymore than a few hundred cycles away, especially on HSMS. In general,  a station should use a amplifier with a built-in receive preamp.

    Computers and Software Requirements: This is only for HSMS. SSB Meteor Scatter doesnt require any computers or software. In order to decode and transmit the High Speed CW, there must be away to slow the CW down so that it can be read. One way to do this is to use a conventional mechanical tape recorder with the capability to slow the CW down. Some HSMS Operators still use this method but these type of recorders are really not readily available in the U.S. The most common way to transmit and decode the HSCW is the use of computer software. There are acouple of good programs that have become popular amongst most HSMS Operators lately. One software program is called " MSDSP ". It is a DOS based program that must be used in conjunction with a Soundblaster 16 stereo compatible soundcard. This program will also function very well within the Windows 95 shell. The MSDSP Software and info can be downloaded here >>> msdsp70b.zip

The new MSDSP 2000 Windows Version can be found here >>>  MSDSP 2000

     Another very popular program is a Windows 95 based program. It is called " Cool Edit ". This program has the ability to display the pings and bursts on a spectrum analyzer screen within the program so that the CW can be " read " as dots and dashes across the screen. The only disadvantage using this program is that the TX files must be prepared ahead of time before a sked ( usually takes about 10 minutes to do ) but it tends to be much easier to decode the receive CW. Cool Edit and info can be found here ( K0SM has a excellent tutorial at this location as well ) >>> cool edit

The Importance of Sequencing during a QSO :

     Join the HSMS E-Mail Reflector : You can receive regular messages from HSMS'ers and be apart of the HSMS group. To join the HSMS Reflector, do the following : go to majordomo@qth.net and in the body of the text, type "subscribe hsms". 

Checking Meteor Scatter Conditions in Realtime using 6/2 Meter Beacons :  Checking on Meteor Conditions before a sked or  a random contact can be very helpful. The 6 Meter band is loaded with 24 hour a day beacons scattered in many locations. For example, to check on a particular path, find a CW Beacon on the 6 meter band located in the direction and close to the location for the QSO. Locate a beacon in or around the grid of interest on this Beacon List >>> 6 Meter Beacons.  The W0MTK Beacon out of DM59 Colorado works very well out here in the west coast. It is on 50.065 MHz. Also, Robert, N7STU in DM07 reports hearing the N0CE Beacon out of Colorado on 2 meters Meteor Scatter on 144.275 MHz .This beacon runs 200 watts into a horizontal omni directional antenna.

   Point the antenna in that direction and park on the Beacon Frequency. Listen for several minutes for the beacon. If Meteor Conditions are good, the CW beacon will show up as pings and bursts. This will indicate the Meteor Conditions for that path. To check on another path, repeat the actions above and reposition the antenna.

Here is the very first HSMS signal I received   >>>AA6HA
It was a signal from AA6HA in DM43 on 2 meters during one of my first skeds on Feb 7th 1998. It is a 0.5 second "ping". A typical HSMS signal will sound something like this.

Here is a sample of my first completion on HSMS with N0KQY in DM98. He is sending " RRRR" confirming we have completed. Again, this is on 2 meters @ 1100 miles away !!!    >>>N0KQY

Click here to make a High Speed Meteor Schedule or check on HSMS activity in realtime    >>> MS Rocks Live

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