Saturday, November 7, 2020

Success on 122 GHz

Harry WA0CNS and Herbert AF4JF met together for another round of testing our new 122GHz units from VK. Ron KO0Z has been in some activity with his grand children and supported us on the phone.

We have decided to repeat the test from October 25 (2020) when Harry went to SSM facility in EM48rq and Herbert found a nice parking lot on Katy Trail in EM48rr. We didn't make that QSO on October 20. There is a direct line of sight between both locations, so we tried again using rifle scopes to aim our antennas today. Following pictures show Herbert's side of the path on Greens Bottom Road in EM48rr:

Thanks to using powerful binoculars, Harry spotted Herbert's car arriving at the parking lot and knew exactly where to aim the antenna. We have made our CW QSO at 08:43 am with signal strength S5-9 on both sides. The distance, according to Google Earth, was 3.26 mile (5.25 km):

Weather info taken in EM48rr at 08:30 am CST:

  • temperature 22.8 deg. C
  • dew point 9.3 deg. C
  • pressure 1010.2 mBar
  • humidity 43.1 %
  • no wind

This was first part of our plans for the day. The second part was moving to the town of Defiance, MO to our "backup location" along the Katy Trail. Harry stopped close to Defiance in EM48op and Herbert went a little further to Matson in EM48oo. The distance between these points is, according to Google Earth, 1.74 mile (2.80 km):

Weather info taken in EM48oo at 10:39 am CST:

  • temperature 26.8 deg. C
  • dew point 12.2 deg. C
  • pressure 1008.7 mBar
  • humidity 38.9 %
  • wind 2.2 km/h ( 2 feet / sec)

This location, despite the shorter distance, turned out to be more difficult due to a problem with direct line of sight - rifle scope on Herbert's side revealed that he was pointing at wrong location and had to move a little to see the correct one. After moving the station, QSO was made at 10:49 am CST wit the same strength as the first QSO (S5-9 QSB). However, thanks to the blowing wind, the frequency was a little unstable. We definitely need to pay more attention to thermal insulation of the 122GHz board to prevent wind from changing frequency through making temperature changes. Both stations were using GPS reference 1 pps, which seems to be too slow. We need to modify our stations for 10MHz reference signal disciplined by GPS.

Picture shows the "Judgement Tree" memorial park in Matson, EM48oo where Herbert was located:

Herbert is only using a 19dBi conical horn for antenna. Harry's station has a 13 inch dish antenna:

This was our last attempt for QSO for the day. Next topic on our plan was the SLAMS/BARS planning meeting at the Chandler Hill winery. We usually do not eat inside any facility these days, but this winery is offering outdoor seating and online ordering of food and drinks. Here is how the seating looked like (and Yes, this facility allows dogs even inside):

Everything considered, a very successful day! We have pushed our 122GHz record up to 5.25 km. Our next attempt, hopefully this year, will be to get it over 10 km. Watch for new posting soon!


  1. Herb and Harry,

    Good going. Thought you would have a nice day early this AM but then the clouds rolled in quickly here. But you still made it. GOOD JOB.

    Bob, N0IS

  2. Congratulations Herbert and Harry, nicely done!