TEP (Transequatorial propagation) on 144 MHz.

QSO reported >> America Europe-Africa JA-VK
Maps of QSO >>  America   Europe-Africa   JA-VK 

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This page is a compilation of  information I have got about TEP on 144 MHz. These openings seem to be relatively common between The Caribbean and south America and between Japan and Australia, but very rare between Europe and southern Africa. According to the reported QSO we can get to some statistical conclusions.

  1. A high level level of ionization in the F2 layer over the geomagnetic equator is required, but SFI is not completely determinant. QSO have been reported with a Solar Flux lower than 70. 
  2. A moderate geomagnetic activity seems to improve the possibilities of openings, but some QSO have been reported even with an A index over 30 (Minor storm)
  3. No big antennas or power are strictly required. Some QSO have been made in FM using a ground-plane antenna and 10 w. only, although this is not the rule.
  4. Although signal strengths are usually high, the signal is subject to deep and rapid fading and very strong distortion (from multi-pathing and large Doppler motions). Doppler spread up to 2kHz has been observed on a CW signal.
  5. QSOs are possible on higher frequencies. A few QSO have been reported even on 432 MHz !!
  6. Best dates are definitively near the equinoxes (February to April and September to November), but QSO in other months are also possible.
  7. Best times are always from one to three hours after the sunset. (17 to 19 UTC for Europe-Africa / 00 to 02 UTC in America / 11 to 13 UTC for JA-VK).
  8. The circuit should be symmetric with respect to the geomagnetic equator. That is, the receiver and transmitter should be located at approximate equal distances from the magnetic (dip) equator.
  9. The path must be within about 15 degrees of geomagnetic north-south.
  10. Path lengths may vary from 3000 to 8000 kilometres

It's important to notice that there are two types of TEP, the so called afternoon-TEP which only supports communications up to 70 MHz and the evening-TEP that is the type supporting the contacts on 144 MHz (and even 432 MHz). The afternoon-TEP seems to be a result of the equatorial anomaly while the evening-TEP is field-guided mode which relies on the existence of ionospheric bubbles, tubes or plumes that have an electron concentration lower than the surrounding area. Rays are reflected from the surfaces of the bubble walls, at all times staying within the ionosphere until they finally emerge on a path down to the ground.

If you have ANY additional information about TEP on 144 MHz or QSO achieved please send it to my E-Mail so that I can complete these pages. Your comments will also be welcome.

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For stations in Southern Africa area, remember that the call frequency in Europe is 144.300 MHz, and that there is where everyone is listening most of the time. Please use 144.300 when calling for TEP to Europe !. And remember that best times in our longitude are between 17:00 and 19:00 UTC

Join the TEP on 144 MHz mailing list for more info !!

QSO reported >> America Europe-Africa JA-VK
Maps of QSO >>  America   Europe-Africa   JA-VK 
 
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