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.
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.
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)
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.
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.
QSOs are possible on higher frequencies. A few QSO have been reported
even on 432 MHz !!
Best dates are definitively near the equinoxes (February to April and September to
November), but QSO in other months are also possible.
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).
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.
The path must be within about 15 degrees of geomagnetic north-south.
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.
Latest news
(20-Oct-2008) Matej, OK1TEH, has kindly provided a copy of the
article "TE Propagation - VHF Discovery extraordinary", published in QST in
April 1963.
You will find it in the bibliography section.
Have a look also to Matej's page on
The
first Amateur Lunar tests & contacts
Many thanks Matej !!
(5-Aug-2008) Matej, OK1TEH, has kindly provided a copy of the
article "A newly
discovered mode of propagation", by Joseph H.Reisert, W1JR, ex-W6FZJ,
W1JAA and Gene Pfeffer, K0JHH, published in QST in October 1978.
You will find it in the bibliography section.
Many thanks Matej !!
(1-Aug-2008) PY2REK reports the following TEP contact in 2006:
11/17/2006 00:30 utc PY2REK GG64BX FM5CS FK94KP USB 144200
(1-Nov-2007) This is just a reminder that DX-Sherlock is keeping a
database of all VHF&up contacts and SWL reported through the DX-Cluster. You
can query the database at any time looking for TEP
contacts reported in the past days, months or between two given dates.
You can also look at several maps showing in
real time the spots being submitted.
(1-Nov-2007) Máximo, EA1DDO/HK1DX send us the following
interesting information:
DH5HG has developed a program that shows rotatable 3-D-images of the
duct model for the Trans Equatorial Propagation (TEP) in the years 1950 ...
2010. You can download it
from his home page (2.8 MB), but bear in mind that in order to run it
you need to have installed the
Matlab Component Runtime (102 MB)
(8-Oct-2007) First PJ4-LU TEP QSO. Tonight(08.10) I had a very nice
QSO on 144.200.
At around 00:40 UTC I gave CQ and Delmer LU1FDQ came back for me. We
exchanged 5/5 reports and the distance between FF97OW and FK52UD is 4979 km. This was my first ever TEP contact and I used my EME setup with the
4x 9el Wimo yagi's and 1kW.
I tried elevating while receiving and I lost the signal at 15 degrees of
elevation. Except YV4DYJ in tropo I did not copy any other signals on
the band.
Peter, PJ4/PA3CNX. (QSO is now in the
QSO listing)
(4-Oct-2007) André PY5EW reports he had 144 MHz QSOs via Ducted
(evening-type) TEP with stations in Trinidad & Tobago on Monday 1 October
from 0059 UTC. He worked 9Z4FZ, 9Z4GU and 9Z4DMA with signals 5x5. André is
in Londrina, South Brazil, and runs an FT-857D (170W) to a 15-element
horizontal Yagi. Solar activity - Low. 10.7 cm Flux - 65. They have been
included in the QSO listing.
(Thanks Steve, VK2KFJ, for forwarding the info)
(25-March-2007) Todd Emslie has compiled a web page, including all
photo attachments, or Roger Harrison's "Evening
Transequatorial VHF propagation" article.
(24-March-2007) VK2ZRH (ex-VK2ZTB) has
provided some interesting additional bibliography from
the proceedings of the 1979 Symposium on Future Amateur Communications Techniques. Many thanks Roger!
(24-March-2007) VK4ZSH has submitted some further updates to the VK-JA
QSO list. They have been included in the QSO
listing. Many thanks again
Steve!
(18-March-2007) VK4BFO contributes with the following information:
"Steve,VK4ZSH,recently spoke to me and asked if I would send details of my
2m contacts from Mount Isa in northwest Queensland. I have attached a
copy of an article that was
printed in the Japanese CQ magazine in 1983. The contacts were made in
1983 and the dates as indicated. Steve's contacts and mine are shown on the
page. I cannot remember the times or names of the operators although the
time would have been between 09.30 and 10.30 hrs GMT. Sorry about my poor
record keeping but it was a long time ago".
"There was a good opening in 1991 and on 15/04/1991 I worked JI7DMB from
Mount Isa for an Australian record that still stands. The distance was
6763km and it was on CW mode and as above I cannot remember the operators
name or the time. I did work other J stations around that time but they are
also lost."
Many thanks Mike !
(18-March-2007) OK1TEH contributes with the following
information:
"I have some interesting info from John, IV3GBO from Udine, JN66OA. He said,
that he worked on 2m 20years ago some Namibian station ZS3 and heard ZE2JV beacon. I asked him about elevation and answer was no elevation at
all.The signals were strong with auroral characteristics. He has record on
tape and he'll look for more info soon."
(18-March-2007) PY5ZD and PY5AQ have send their recent QSO
listings. They have now been included in the American sector QSO listing.
Many thanks Marcelo and Arnaldo!
(18-March-2007) VK4ZSH has kindly sent some updates to the VK-JA
QSO list. They have been included in the QSO
listing and some also in the map. He has also
provided some additional bibliography. Many thanks
Steve!
(1-January-2007) The Japy DX Group will be active again from GG64BX
between 2-Jan and 7-Jan looking for TEP. (More details)
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
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