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6 days of non stop tropo-ducting - 5R8 FM radio on 103 Mhz and 104.8 Mhz

The general situation :


Each picture represents abt 24h data.

2010-10-10-19z 2010-10-11-04z

2010-10-11-16z 2010-10-12-04z

2010-10-12-16z 2010-10-13-12z

2010-10-14-18z 2010-10-15-18z


2010-10-09to11 2010-10-10to12-16z

2010-10-11to13-16z 2010-10-13to15-18z


2-The Hepburn predictions

3- Real data soundings :


2010-10-10-12z-FDauphin 2010-10-11-00z-FDauphin 2010-10-11-12z-FDauphin

2010-10-12-00z-FDauphin 2010-10-12-09z-FDauphin 2010-10-12-00z-antananarivo 2010-10-12-12z-antananarivo
2010-10-13-00z-FDauphin 2010-10-13-12z-FDauphin 2010-10-13-00z-antananarivo 2010-10-13-12z-antananarivo
2010-10-14-00z-FDauphin 2010-10-14-12z-FDauphin 2010-10-14-00z-antananarivo 2010-10-14-12z-antananarivo
2010-10-15-00z-FDauphin 2010-10-15-12z-FDauphin 2010-10-15-00z-antananarivo 2010-10-15-12z-antananarivo
2010-10-16-00z-FDauphin 2010-10-16-12z-FDauphin 2010-10-16-00z-antananarivo 2010-10-16-12z-antananarivo

4-The surface pressure charts


5-The visible maps

6-The airmass maps (Copyright 2010 Eumetsat)

Very interesting maps showing the warm-cold areas.

For analysis of airmass maps see :

On some meteo website, i have read this :
This airmass image can be used for day and night.
Warm air (high tropo) are green when  they have a high humidity
in altitude.
Warm air (high tropo) are  brown-orange when they have a low humidity in altitude.
Cold air (low tropo) are blue to blue-purple.
But due to the roundness of the earth, , warm air may appear as blue.
Tropo anomaly shows reddish color.
Intense red shows jet, and jet advection area.
















7- Some meteorological data recorded at 130m altitude by Manu at Saint-Pierre (Thanks Manu!)

FR  is UTC+4, on the charts you can see some T° increase in the night time.

8-The QSO's

Nil, a wall towards South Africa, but some observations on 2010-10-12 and later:

For more than 36h now i have very strong tropo at 1600km average.
It seems that it did not reach zs that time.
I am on some holidays so i played a bit on ais rx side.
This morning i went up at 700m of altitude with my portable ais setup,
and whouaa, what a difference compared to home at 300m.
Was getting 283 ais decodes/mn, while at home with same setup was 107.

Also i could hear 164Mhz FM phone from 5r8. Also 5r8 103Mhz radio was
booming (got it at home too this morning when i came back; good
So bad no 5R8 station is getting qrv. Looked for them on HF but no luck!

This afternoon i decided to go up again and monitoring 103Mhz from the
I had no positive rx at home at that time on 103Mhz.
Started to get rx while driving at abt 550m of altitude.
I was starting to get into the inversion layer.

Still climbing... I can notice that while driving i could get perfect rx
in some altitude layer. Strong, low, strong, low etc...

Up again driving at 1000m just before the forest. Signal strong, low,
strong, low. Some fog up the mountains.

Decided to go into the forest, still climbing on the road.
Signals are getting stronger...
Up again, and getting inside the fog layer at some 1100m. Signal strong
on some places. Getting some more 5R8 FM stations on the FM radio.

Up again, getting above fog layer at 1400-1500m. Signal still strong.

going down a bit again, inside the fog. Stop the car. Call 5R8 on
145Mhz. No signals. 5R8 FM 103Mhz loud. Amazing...

As dark comes, i can see the upper part of the fog layer going down.
103Mhz down a bit. Still no 5R8.

Almost night now. i move down slowly. Again 103Mhz up, to really very
strong on some places.

Down again, still in the fog, stop at 1050m, 103Mhz 5R8 really STRONG.

Down again to back home. Some very nice rx at lower altitude, sometimes
no signal at all. While down to 500m there was good signal at some small
layers (i mean altitude difference).

Well, very nice experience of moving inside the layer, above, and just
under the layer. I can see that at some few meters difference in
altitude, there was LARGE rx difference, from places just some 10ths
meters away. For sure some different angles, but sometimes very
localized enhanced signals....

First time i experience climbing inside the layer with good indicator as
FM broadcast, really exciting!....

I really need a good portable station!

Really, what impressed me was how the signal was strong at some layers
while climbing!....

I could not identify 103 and 104.8Mhz from 5r8 land, i'm not very familiar with 5r8 language, so bad, hi...

Today, 16/10/2010 at 0830z (1230 local time) while driving home from St-Denis at sea level on the North part of the island i could get 103Mhz nice rx .
Altitude was around 10m and directly on the ocean side.

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