SM6FHZ 432 MHz Meteor Scatter

Patience and persistence is the mother of 70cm meteor scatter!

I have just recently started working 432 MHz meteor scatter from JO67AQ.  My first QSO was made during Quadrantides 2018. From Perseids 2019 I work 432 MHz meteor scatter from my EME QTH in JO57XJ as well.

Rig

Today (from summer of 2016) I am using a 4x9 el yagi array fully steerable in azimuth and elevation. The rig is an IC-706Mk2G driving a SSPA with an BLF184XR. The yagi array is depicted below as well as an description of the yagi and array design in an pdf-document. The IC-706Mk2G is injection locked to a 10 MHz oven reference for good frequency accuracy and stability. I can use either FSK441 or JTMS from a ASUS GL552VW computer via a home made interface circuit. For the moment I prefer FSK441 as I have not had too much luck using JTMS.

432 MHz 4x9el yagi array description

My present QTH in JO67AQ is unfortunately on the south side of a hill and only 100 m from the steep southern slope of that hill. This means that I am shielded from signals from about 270 degrees azimuth over north and to about 80 degrees azimuth. I need to elevate the array at least 20 degrees to clear the peak of the hill. I will be limited in working meteor scatter in those directions as I need to use the elevation to beam above the obstructions. 

   My present take off in direction south. Antennas are slightly elevated. 

The RF-environment is quite harsh with a lot of noise and spurious signal sources all around me. This is very annoying.
A well loaded tower of a cellular site just 150 m from my antenna in SSW direction. Good filtering is needed in front of the LNA. Fortunately, I do not think there is any 450 MHz system in this tower.

It is however fun to see what can be done in 70cm meteor scatter with these limitations and a moderate station in an suburban location.

Meteor scatter features I have experienced on 432 MHz

The meteor scatter signals on 432 MHz show some features compared to lower bands. There are still a lot of exciting things to learn about meteor scatter on 432 MHz. I would appreciate to get your feedback and you to share your experience on the 432 MHz meteor scatter features.

Direction

You can chose between direct path, Hot A or Hot B. I have not yet seen any favorites here. I do not use Hot A or Hot B on greater distances (>1100-1200 km). Choosing a time when the radiant is in a good position seems to help a lot. Perpendicular to the path and not too high or too low in the sky. Too high radiant seems to be worse than a very low radiant, as long as the radiant is above the horizon.

Doppler

I have not yet seen too much of Doppler shift on meteor scatter signals on 432 MHz, as I am aware of. Maybe some of the frequency off-sets I have seen on sked partners could be attributed to Doppler shift. It does not seem to be happening on every burst nor ping. During Perseids 2019 I got some bursts with a clear Doppler distortion. These bursts did not decode.

  Burst from F6DRO received during a sked i Perseids 2019. You can see the clear Doppler distortion on the burst. The sound when receiving this burst had a clear Doppler sound to it.

Meteor showers

So far I have only experience from Quadrantides, Lyrids, eta-Aquariids, Perseides, Leonids, Ursids and Geminids of 2018 in meteor scatter signals on 432 MHz. What I have noticed, is that you need to be close to the peak of the shower to have a decent chance to complete a QSO. Persistence and perseverance is what is needed. Dedication does help as well. Do not settle for less than a 2 hour sked, you may need more than that. Only Quadrantids, Persides and Geminids have produced any completed QSO's. Lyrids, eta-Aquariids, Ursids and Leonids produced some reflections but no QSO's. It looks like a good rule to use the major showers with good meteor count and avoid the smaller showers to have as good as possible success rate. However, some of the minor showers are known to have outbursts (meteor storms) now and then, e.g. Orionids, Leonids and Ursids. Keep track of any predictions for such at the IMO web site.

Planning

There are a few parameters that are good to grasp when planning for meteor scatter skeds on 432 MHz. 

1. Predict the time for the peak of the shower for the year in question by using RadiantCalc. Solar Longitude information can be found at the IMO web page (see link below) as well.
2. Radiant position versus local time can be calculated with RadiantCalc. Detailed information on how to use RadiantCalc and how to download and install it is to be found here.
3. Make sure you know that your rig is correct in frequency within <100Hz and that it does not drift in frequency with time or temperature. Locking the master oscillator to a known good source may be a good idea.
4. You need plenty of meteors to succeed, make sure you are close to the predicted peak of the shower and that the radiant is above the horizon at the time for your sked.
5. Try to be within +/-30 deg of the Best directions line with the direction to your sked partner.
6. Avoid, if possible, extensively high radiant positions (i.e. >60-70 deg) for best success rate.
   

You can follow this procedure and use these tools for planning your 432 MHz Meteor Scatter skeds and work. There may be different opinions on some of my statements above. Please tell me if you have other experience and recommendations!

Examples of radiant graphs produced by RadiantCalc below.

I am using RadiantCalc for prediction of the radiant position for the meteor shower in question for the year in question. RadiantCalc is written in Matlab, but is compiled to an standalone application where you need have the Matlab Run-time Environment installed on your computer. The Matlab Run-time Environment is free and is included in the installation file of RadiantCalc. RadiantCalc is still being evolved and I have a few more ideas to be implemented into it.

Handy assets

I use the following web sites to get information about radiant calculations and the probability for meteor scatter propagation on 432 MHz. 

International Meteor Organization (IMO) web site with shower lists and data: https://www.imo.net/

Sidereal time calculation on line: http://www.jgiesen.de/astro/astroJS/siderealClock/

Calculations of radiant position from IMO data: http://www.stargazing.net/kepler/altaz.html

Calculation of the time for maximum from Solar longitude (found in the meteor shower table from IMO): http://wise-obs.tau.ac.il/~eran/Wise/Util/SolLon.html

OK1TEH has a lot of information about 432 MHz meteor scatter at his web page: http://ok1teh.nagano.cz/ms_70cmlog_text.htm

All five contain relevant information.
  

Results

  I received from G4RGK a 3 seconds burst via meteor scatter on 432 MHz i Perseids 2018. 

  My final rogers as received by OK1TEH on 2018-08-12 via 432 MHz MS in a 6 seconds burst i Perseids 2018.

The longest burst received so far is 23 seconds in the QSO with GM0ICF on August 12, 2024. Se below screenshots.

  The second half (11.5 seconds) of the same burst as GM0ICF received me for a total burst lenght of 23 seconds.

QSOs

Below is a summary of all 432 MHz meteor scatter QSO's / stations worked by me over time.

Updated December 2, 2024.              http://www.2ingandlin.se/SM6FHZ.htm