On ”sporadic” po novom
Sporadic E layer, which allows you to make DX connections in bands 6 a 2 meters. It occurs in two seasons. The main time is roughly from May to August, however, new research also points to secondary ones – from mid-December to January. Even with relatively small equipment it is possible to make a connection around 2000 km, while the signal strength ranges from minimum to extreme S9. However, the occurrence of the Es layer cannot be predicted, which places increased demands on continuous monitoring of the band. Its height above the earth's surface ranges from approx 90 po 120 km.
While on 6 in the meter band, Es is not so rare, 2 the meter band can sporadically count on the fingers. The first symptom of Es is usually the presence of distant FM radio stations in the band 88 – 108 MHz. Little, what are they working on 28 MHz (or CB) they can register it anyway, that they will have stations from a distance on the band 200 to 400 km, which are otherwise unattainable. He is a perfect helper DX cluster. Most of the spots, however, come from stations from Western and Southern Europe, from OM only a minimum. Thanks to James K9SE's SE-Prop program, it doesn't have to hurt. So what does SE-Prop do??
The spot of the Italian station from JN65 will appear in the cluster, which worked with the English station from square JO01 in the band, that interests us. From this data, SE-Prop calculates the location of the reflection point. From its position and its own square, it is possible to calculate the position of the counter station, with which it is possible to work with this Es.
We will need: connection to the DX cluster (packet or I-net), a computer with W95+ and of course the SE-Prop program. It is freely redistributable as public domain without the support of the author. After installation, the disk will lose a few hundred kilobytes.
The program is controlled by mouse or keyboard. However, it is not exactly the same, because when the mouse button is pressed, the QTHs are entered with the mouse, after pressing the key, the program expects text input. The frequency is preset 50,1 MHz, virtual height Es 105 km a map USA. Changing the map is possible via the top menu “OPTIONS”, change the height by clicking the button “SET VIRTUAL HEIGHT” and frequency by clicking the button “SET FREQUENCY OF OBS. “.
Next, we enter own QTH “SET USER LOCATION“. A red dot will be added to the map. Now enter data from the cluster “PATH EVALUATION“. After entering both squares, the location of the reflex point will be displayed automatically.
The green oval indicates the MUF. If we are inside, is lower than the chosen one and this reflection point has no meaning for us. The dotted oval bounds the largest distance between stations for this reflection point. It can happen on long connections, that the program will mark a connection probably not reached by a bounce from Es. In that case, try changing the virtual height.
Now let's do the math, whether this point is also suitable for us. We click on “PATH PREDICTION” and mark the reflex point and own QTH. SE-Prop immediately calculates a place where we could call.
In the JN65 connection example – JO01 after entering the reflex point and your own QTH, the location of the prostitute in the Atlantic comes out and it is not worth calling. However, if it comes out on land, we do not hesitate to call!
The sporadic layer often moves, that's why we enter the data, the more accurate the results will be. However, it is not possible to calculate multi-hop Es (multiple reflection from Es).
It all probably sounds complicated. Those who have a non-stop Internet connection can only smile, because there is a page, where these calculations can be performed effortlessly. But for the average VHF DX-man, the SE-Prop can be a boon. UI-View displays the contents of packets below the map with a text report!
You can download the SE-Prop program at CQ.sk.
