Wednesday, December 11, 2024

6474km TEP contact on 144 MHz from Argentina to a ship off the coast of Florida - 9th Dec 2024


Over the last few years, I've reported on many Trans-Equatorial Propagation (TEP) contacts from South America to the Caribbean on the 144 MHz band... links on my 144 MHz page.

For this mode of propagation at 144 MHz, signals must generally cross the Geomagnetic Equator at right angles. This usually means that stations in the south of Brazil work places like Guadeloupe, St Martin & Puerto Rico. Stations near Buenos Aires in Argentina work stations in Curacao & the Dominican Republic.

There has been a distinct lack of 144 MHz TEP openings further west in South America mainly due to a lack of stations at one or both ends of the paths.

So it was a really big surprise to hear that Carlos, LU7MC in the west of Argentina managed to complete a contact with Yuri, UT1FG/MM on a ship to the north of Cuba!

The contact was made using the Q65B mode on the 9th of December 2024 at 01:34 UTC. This is just after 20:00 local time for both stations which is about the peak time for evening type TEP.

The distance was in the region of 6474 kms which is exceptionally long for a 144 MHz TEP contact for South America.


The map above shows just how close UT1FG/MM  was to the Florida. His ship was just 80kms south of the road going to Key West and about 170kms south of Miami.

It's hard to know for certain but I suspect that the TEP signal from LU7MC almost certainly reached Florida. It was most likely that there was nobody active there and looking.


Mode of Propagation... As indicated already, the mode of propagation was TEP - Trans-Equatorial Propagation. There may have been an extension at the northern end of the circuit with some marine tropo / ducting north of Cuba.

Mode of contact... The Q65B mode was used for this 144 MHz contact. The screen shot from LU7MC is shown below...


As you can see below, the signal level was about 0dB to -8dB which is probably too weak for SSB but should be strong enough to be heard by ear and a CW contact would be possible.

The screen shot from UT1FG/MM is shown below...


The signal levels were about the same at -4dB to -8dB.

Equipment... Carlos, LU7MC is located in the city of Mendoza in grid locator square FF57OB. He was running 100-watts into an array of 4 x 10-element Yagi antennas.


Yuri, UT1FG works on a commercial ship and was Maritime Mobile between Cuba and Florida in grid locator EL94PC. He was running 200-watts into a single 7-element Yagi antenna.


In conclusion... This really was an important contact on the 144 MHz band because it shows that there is a very good possibility of a TEP path from the west of Argentina to Florida. Could it extend even further north to some of the other southern US states by tropo? Could the stations in Chile get in on the action?

The really big question is if anyone in the United States is paying attention and is going to try and make a contact?

Link...
a) For more information on long distance 2m contacts, see my 144 MHz page.

Monday, December 9, 2024

3770 km contact on 144 MHz between Brazil and St Helena - 7th Dec 2024


On the 7th of December 2024, PY1MHZ in Brazil and ZD7GWM on St Helena Island managed to complete a contact on the 144 MHz (2m) band. The distance was in the region of 3,770kms.

This was an amazing contact for tropo on 144 MHz and it raises the question if a contact from the east coast of Brazil to the west coast of Africa might be possible?

Marcos, PY1MHZ sent on the following information... "After many years of trying over the sea, a contact was finally made last night on 144MHz 2m with the Garry Mercury ZD7GWM on Santa Helena Island at a distance of 3,768km.

Contact completed with the Q65D mode

Garry was using a Diamond X700 vertical antenna and approximately 50w. On my side, I was using 8 vertical elements with 200w. I could work up to 500w but there was no need.

Very happy with this Christmas present. 73 de Marcos PY1MHZ in grid GG98LC."


Comment & Analysis... Yet again, this is another fine example of some of the undiscovered paths that exist once there are stations active in the right location. Some of the VHF contacts that Garry, ZD7GWM has been able to complete with a vertical omni-directional antenna are nothing short of remarkable.

In the last few years, he has managed to work South Africa at 3000kms on 144 MHz and 432 MHz via tropo, he has worked Spain and Portugal at about 6000kms on 144 MHz via TEP and now, he has worked across the South Atlantic on 144 MHz to Brazil.


As for the contact to Brazil, it seems likely that it was a marine duct across the South Atlantic. The tropo prediction map from Pascal, F5LEN certainly seems to support this theory.

How many other undiscovered long distance paths are out there?

I have a previous post about Garry's set up HERE

For more information about other long distance openings on the 2m band, see my 144 MHz page.