vhf propagation

Transatlantic Contact Completed on 2 Meters!

You can’t DX on VHF, right?

Amateurs in South America and Africa successfully completed a transatlantic contact on 2 meters on October 4 and 5. Setting the new record were Marcos da Silva, PY1MHZ, in Rio de Janeiro (GG87jc), who copied the 2 meter WSJT signal of Pieter Jacobs, V51PJ, in Rosh Pinah, Namibia (JG82IE) via tropospheric ducting. The distance between the two stations is 5987 kilometers (approximately 3712 miles).

The contact will not qualify for one of the Irish Radio Transmitters Society (IRTS) Brendan Awards, which require that one of the transatlantic endpoints be in Europe.

The contact took place on 144.250MHz, with PY1MHZ heard at a signal-to-noise ratio (SNR) of –36 dB, and V51PJ copied at an SNR of –37 dB. The contact took place from 2038 UTC on October 4 until 0028 on October 5.

PY1MHZ was running 400 W into a 2 × 12 element horizontal array, using a 16 dB preamp on receive. V51PJ was running 1 kW into a 2 × 13 element array.

“Look at those SNRs of –37 and –36 dB!” enthused Ward Silver, N0AX. “That’s a signal 4000 times weaker than the noise, and it did not take massive dishes or arrays.” He said the continued progress of digital-mode development demonstrated by the WSJT suite of protocols “represents true innovation by amateurs.”

Silver noted that the Brazil-to-Namibia path is 50 percent longer than the Southern California-to-Hawaii path. He speculates that even longer transpacific paths may exist, for which no amateur stations are currently available.

Hans Blondeel Timmerman, PB2T, commented, “Only thanks to the persistence and determination of these OMs was this historic achievement possible.” He expressed appreciation to WSJT developer Joe Taylor, K1JT, for continuing to provide state-of-the-art Amateur Radio digital software.

(Original story source:  arrl.org)

UPDATE:  Closer Look Reveals that Reported Transatlantic 2 Meter Contact Did Not Happen

The reported transatlantic 2 meter contact between PY1MHZ in Brazil and V51PJ in Namibia turned out to be a false alarm, based on an incorrect interpretation of screen captures from the event — possibly the result of using an unreleased “development” version of the WSJT-X protocol’s QRA64 mode. As initially reported, extremely weak signals using QRA64 were received and decoded on both the African and European ends of the path across the southern Atlantic. Screen captures of the protocol software were supplied to document the contact, but the software’s lead developer, Joe Taylor, K1JT, noticed debugging information, indicating that a prototype version of the protocol was being used. On closer inspection, the indicator values showed that the decodes were probably based on call sign information being known in advance, as is common with scheduled contacts.

“There was no intention to deceive,” Taylor told ARRL. “It was a perfectly honest mistake. It’s unfortunate. Many of us wish the report of such a QSO could be true — but it’s not.”

Read more about the ‘non-contact’ here:  https://goo.gl/GZqYTF

/Begin op-ed

Frankly, I believe them — there was no intention to deceive whatsoever. Since 1960 each and every QSO I’ve ever had is from contacts I have heard with my own ears. Nowadays things are different. You can have QSOs only readable via technology. Ears not required. It’s a brave new world.

/End op-ed