6 May 2018 :: May UHF Contest
First G <-> DL Tropo QSO on 24GHz

On Sunday morning, 6th May we tried on 24GHz with a number of PAs and DLs but all failed - the only exception to this was the test with DK0PU (JO31JN) at 381km.

At 0543z we called DK0PU on 24GHz after QSY from 'KST. The most surprising thing was the ease with which we completed the contact. CW signals were not very strong at 519 each way, but the S-meter was moving!

Some of the other operators in the contest tent were able to hear DK0PU as well on the second set of 'phones.

This was definitely not aircraft or any other kind of scatter, since DK0PU's frequency was constant. There was some QSB, but not to the extent that it made the contact difficult at any time.

Working conditions at M1CRO/P on 24GHz were a GPS locked PLL, sub harmonic mixer/transverter and RX preamp all from DB6NT, plus an SSPA delivering 3W output. The path from the RX and TX is via a Spinner four port relay into a Flann 30cm lens horn. The masthead unit was 13m above ground (33m above sea level on the Walton sand cliffs) - and the IF 144MHz.

2018 M1CRO/P <> DK0PU 24G QSL
2018 M1CRO/P <> DK0PU 24G QSL

DK0PU transmitter output was 430mW into a 35cm Andrew dish with a waveguide switch from I3OPW. The antenna height was 5m AGL and 80m ASL. and the view is entirely clear in the direction of the UK.

In an email received from Ralf DF6VW (one of the operators at DK0PU), he commented

"even today I can't believe our 24GHz contact. Not very often I can reach PA3AWJ at 160 km, but 381 km seemed impossible. Thanks for very nice QSO - QSL will follow."

2018 DK0PU <> M1CRO/P 24G QSL
2018 DK0PU <> M1CRO/P 24G QSL

While this is not a 24GHz tropo distance record (we believe this is currently held by DL7QY and F6DKW for a 581Km contact); this is the first terrestrial G<->DL QSO on 24GHz.

73 de CCG

Updated: 7 May 2020