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!

122GHz challenge

When Harry WA0CNS and Herbert AF4JF made their first 122GHz QSO on September 20, 2020 during second leg of the ARRL microwave contest, everybody was surprised how easy it was. Our second 122GHz QSO during the SPRINT Contest on October 12 made it look even easier. We were planning on extending the distance spanned by our QSOs over 10 miles. First step was supposed to be a QSO from EM48rq (Chesterfield, MO) to EM48rr (Harvester, MO) across the Missouri river over a distance of 3.65 km with direct line of sight. We have found suitable locations, checked them ahead of time ... everything seemed to be "granted":

This picture shows Herbert's location and open view towards Harry (on a hill on the horizon):

However, neither of us heard a beep, just a noise. We have tried to turn our antennas, tune the radios up- and down, move around the parking lot ... nothing. Herbert even went across the river to Harry's location to make sure that Harry really points his antenna in correct direction. Everything was OK, just no signal. 

Weather situation (recorded on Herbert's side of the river) was:

• temperature 4.1 deg. C
• dew point 1.3 deg. C
• pressure 1011.9 mBar
• humidity 43.2 %

The day was actually very windy, we were both "frozen to the bone", so we gave up for the day and decided to continue on the next day, make sure our stations still work and decide how to continue.

Next day was a little warmer. It was also the day of a SLAMS meeting. The SLAMS just started having meetings in the local park instead of eating breakfast together at Denny's. Harry WA0CNS and Herbert AF4JF got together in the Creve Coeur park. (EM48sr). Armand KD0PXF joined us for a short talk later. Harry started a small fire to keep our fingers movable:

Weather situation was:

• temperature 16.3 deg. C
• dew point 3.9 deg. C
• pressure 1000.5 mBar
• humidity 40.2 %

We have set up our stations approximately 100 ft. apart first, then about 1000 ft. In both cases, we have heard each other immediately. Signals were very strong and stable, exactly on the frequency (IF on 144.4 MHz CW) where expected:

WA0CNS

AF4JF

View from AF4JF towards WA0CNS

Well, our stations appear to be in good shape. Signals were very strong and aiming was not too critical (at least not for Herbert who uses a conical horn). We are not sure why our contact across the distance of 3.65 km didn't work. Looks like QSOs on the 122GHz band will be a challenge and come with surprises...

Herbert and Harry already decided on next try, two weeks ahead from now. We hope to have more good news to report after that next test.

73 Herbert

AF4JF

ARRL 10GHz And Up Contest from another hilltop

Ron KO0Z nicely described his contest activities in his postings below. Congrats! Well done!

Group of SLAMS members attended this contest from our usual location at YMCA in EM48sq. We were able to make some long-range microwave contacts on 10GHz and we have almost made 260 miles contact with Bob WA5YWC in EN52sa early in the monring on Sunday. However, he was running 30+ Watts and our stations output barely 3 Watts which, multiplied by the dish gain, makes huge difference. Although we have copied Bob S8 in St. Louis, he didn't even see us on the "waterfall" of his Flex-1500 SDR radio.

We have worked Zack W9SZ on 10GHz in EN50rl on Saturday. That's a 160 miles QSO - one that you need a little support of propagation for. Speaking about propagation, we have worked Ron KO0Z in EM59ji across a distance of 81 miles on Saturday. His signal was quite strong, some of us worked him on SSB too. Quite different situation on Sunday - not a beep from him in St. Louis, not even after we moved Jim's (N5MU) station across the YMCA parking lot to a place with more open view towards Ron's location. We have also tried with Ron W9ZIH, heard his weak signal on Saturday but it was not enough for a QSO. Repeated the test on Sunday, but didn't hear a beep from Ron.

We have also used this opportunity for testing 24GHz between Herbert AF4JF and Harry WA0CNS on Saturday. Technical workshop continued on Sunday with Rich N0PQU adjusting LO injection for his 10GHz transverter and Mike N0OBI tuning his "plumbing system". Mike designed nice circular waveguide feed for his offset dish, all made from copper water piping elements.

Some pictures from the event follow:

Harry WA0CNS at his station

Harry calling on 24GHz

Rich N0PQU and Armand KD0PXF setting up

Mike N0OBI used a surplus box for his 10GHz

(very stable oscillator, works better than looks)

Mike N0OBI checking

focal point of his dish

(note the plumbing)

Jim N5MU checking his dish

N5MU (left) and AF4JF set up 10GHz stations

in a position with open view towards WA5YWC in EN52

Mike N0OBI (left), Jim N5MU and Herbert AF4JF

Waiting for 10GHz signals ...

Following two pictures are actually from different location - Harry WA0CNS and Herbert AF4JF moved to Chesterfield area to test their 24GHz equipment. Distance between stations was ~ 2 miles and AF4JF copied WA0CNS about S7 on 24192.1 MHz CW, but Harry didn't copy AF4JF. Herbert tested a bare mixer (DB6NT design) without any amplification. It received fine, but radiated power was too low even for 2 miles between us. There will be more power next time.

 AF4JF pointing 1ft. dish for 24GHz in EM48rq

towards WA0CNS located at Chesterfield Mall

AF4JF station for 24GHz located in EM48rq

Overall, very successful contest - some QSOs were made, some equipment tested and everybody has had a lot of fun! A local police officer stopped by and chatted with us for a while - he was a former radar operator and recognized dish antennas as something "less-than-usual" for ham radio operators.

73 Herbert

AF4JF

More DX on 10GHz

Jim N5MU and Herbert AF4JF worked Garth W0GR across 185 miles long path between EM48rq and EM38ax on 10GHz at 12:24 and 12:27 UTC today.

Garth has a 2ft. dish in 1017ft. a.s.l. and 8W into long waveguide, he thinks that only 4W make it to the antenna.

Jim has approx. 2ft. offset dish with DEMI transverter, 2W at the feed:

Herbert has the same 2ft. offset dish with 10mW DEMI transverter and external PA, only approx. 1.4W at the feed:

We have operated from EM48rq, using a parking lot of St. Luke's Rehabilitation Medical Facility just above the "Butterfly House" near Chesterfield. This place is in 700ft. a.s.l. and has nice open view towards West:

I believe that these QSOs were made through "wapor duct" that gets created by evaporation around sunrise. First, we didn't copy Garth until sunrise and second, we were aiming our dishes 5.5 deg. up (I have a digital gauge for that). There were no signals audible when aiming at the horizon, but I have copied Garth S8 after raising the antenna! 

Tropo conditions were promising today, so it might also have been tropospheric propagation:

Garth did NOT copy the WB9PNU/B beacon today.

73 Herbert

AF4JF