KO0Z's 2nd 24 GHz QSO between Missouri and Illinois !

 Saturday morning, July 16th, TV weather forecasters promising a hot, humid day.  A high pressure cell is retreating from an advancing northwesterly, cold front.  A good day to attempt my second ever 24 GHz QSO.  A week before, Harry WA0CNS lent me his second 24 GHz rig to experiment with.  I made my first 24 GHz Q with Harry and Herbert AF4JF across Creve Coeur Park (approximately 110 yards).  

TV weather forecasters were right (this time) it was hot, getting hotter and the relative humidity increasing from the low 60s.  Outside temp at 10 am CDT, 15:00 Z was 90 F.  Earlier in the morning Herbert AF4JF took the Golden Eagle Ferry across the mighty Mississippi River to the Calhoun County, IL peninsula to gather some peaches before crossing the Illinois River near Grafton and on to Pere Marquette State Park in EM48rx.  His destination is Eagle Roost, a scenic, 800 foot overlook with a uninterrupted view of the southeast to almost west direction.  It is shaded and relatively cool.  A great spot, and one of our favorite microwave locations.  Ron KO0Z, using Harry's loaner 24 GHz rig set up in (EM48qt) MidRiver's Mall, western parking lot (468 ft) looking 17 degrees and 13.22 miles (21.3 km) towards the distant Illinois river bluffs and AF4JF's location.

Herbert aimed his dish southwest (197 degrees) and transmitted USB.  Ron immediately heard his 3 x 9 signal. Herbert's signal strength was solid, but his transmitted audio was distorted.  AF4JF is using SDR/Pluto.  It sounds like his SSB is a bit over driven, but it is copy able.  Herbert's audio sounded cleaner today as compared to last week's test.  Apparently my audio and signal were fine at Eagle Roost!  Herbert is running 100 milliwatts output and Ron has 25 microwatts and we made the 21 km path today!

 We made the 24 GHz QSO around 10:35 am, 15:35 Z and not a minute too soon.  Although Eagle Roost has shade, the parking lot does not. Ron pointed his truck so it would offer a little, precious shade on this hot day.  Remarkably, the Q was made on the first try.  Harry cautioned me that the dish beam width is very narrow and he is so right.  After we made the Q, I experimented and moving the dish. Moving the dish more than a degree made the difference between hearing AF4JF and not hearing him.  

I'd like to thank Harry WA0CNS for lending me his second 24 GHz rig and Herbert AF4JF for making the trek to EM48rx.  I only had to travel less than a mile to get to my uW spot, but Herbert took two ferry boats and crossed the Calhoun county peninsula to reach the park.  Of course there was the added benefit of procuring delicious Illinois peaches and a road trip for his loving canine,companion Darcy.

                               Elevation profile between EM48rx and EM48qt.  The peaks in the middle are the Illinois bluffs just north east of the Mississippi River.

                           The white line is the path between Eagle Roost, IL and MidRiver's Mall, MO.

              Ron KO0Z's truck temporarily offered welcome shade from the 90 F plus temps. The dish is looking 17 degrees towards Eagle Roost 21 km to the northeast.

                               Just to the left on the light pole near Famous Shoes was the 17 degree marker. Eagle Roost and Pere Marquette park are off in them yonder hills.

                       KO0Z's setup and shade on the otherwise, hot, asphalt parking lot at 16:00 Z

                            Harry WA0CNS rig is using a W2PED 24 GHz transverter.

                               Herbert AF4JF forged across the mighty Mississippi via the Golden Eagle Ferry from St. Charles county, MO to Calhoun county, IL and the Calhoun peninsula.  Later, he took the Brussels Ferry across the Illinois River to IL Hwy 100.

                 Herbert AF4JF's Eagle Roost, EM48rx, Illinois 24 GHz location.

                   AF4JF is using SDR as his IF rig for 24 GHz.  He is making a lot of progress working out any bugs.

                                                   Darcy, is always up for microwaving!

                               AF4JF (EM48rx) aiming southwest, 197 degrees towards Ron KO0Z in St. Peters, MO EM48 qt,  13.22 miles (21.3 km) away,.

             NOAA's weather forecast map for Saturday, July 16.  Note the approaching cold front.  Although the map shows rain potential for Missouri, it did not rain on our parade today.  Sunday's forecast calls for much needed rain, so we picked a good day to try out 24 GHz.

24GHz activity in St. Louis EM48

The SLAMS group usually meets at Denny's for breakfast, then goes to the Creve Coeur park in Saint Louis for technical activities. One such activity took place on Sunday 7/10 and the main topic for the outdoor activity was 24GHz.

Harry WA0NCS, Herbert AF4JF, Ron KO0Z and Armand KD0PXF met in the park to test Harry's second 24GHz station (low power transverter of the W2PED concept) and Herbert's idea of using SDR Pluto as the IF radio for his 24GHz. Following pictures document the setups:

Harry WA0CNS setting up the small station
(this was later operated by Ron KO0Z)

Harry WA0CNS with his regular 24GHz station

The AF4JF station for 24GHz
(the SDR IF plus laptop are located inside the car)

We were able to make 3-way contacts across the park easily. Herbert was dealing with a power issue on his 110V power inverter (voltage dropping, will use bigger inverter next time). Nice outdoor activity, getting ready for the contests!

Activity from EM38xw

The EM38xw location is conveniently accessible from the interstate highway I-70, exit 144 (easy to remember). We usually set up on the intersection of a service road that goes parallel with I-70 on its southern side and the gravel country road. There is little to no traffic on either road, but we always make sure there is enough space left for farm vehicles.

We have been there several times in the past, see for example the postings here, here or here.

I went there twice this year so far. My first trip there was on Saturday June 4, 2022 for a MAD Day (Microwave Activity Day). I took 1296MHz and 10GHz with me and tried to work several stations on both bands. It was a hot day without any clouds, no Rain Scatter on 10GHz possible. I have only made 2 QSOs on 23cm - with Zack W9SZ who was 350km away (I used 2W of RF power) and with Pete N0OY who was 498km away (but I needed 40W of power to my 16el. COMET antenna).

AF4JF set up in EM38xw

My second trip to that location took place on Saturday July 2nd, 2022 for another MAD Day. I only took 10GHz with me. It was a rainy day and I was hoping for some Rain Scatter (RS) QSOs on that band. The weather map looked very promising in the morning - I expected the storms to pass just South of my location. Unfortunately, the storm cells decided otherwise and included me in their path.

I have tried to work Greg WQ0P in EM19, but there was too much water in the air between us. We tried several times, but no luck. However, several attempts that we made with Gedas W8BYA finally lead to success. We have made a nice RS QSO on 10GHz across 620km (387miles)!

AF4JF aiming for WQ0P (dish pointing West)

View towards West

Aiming East (South of W8BYA) at a storm cell

Rain Scatter map that day

Zoom in on the pictures from July 2nd, you will see lots of water drops on the equipment. I was hiding under the open back gate of my SUV but the station was exposed to the water, so I have packed everything up after spending 2 hours at that location and went to nearby gas station for hot coffee. My dog refused to leave the car the entire time.

This is one good location for future activities, the SLAMS team will return here in the future.