I feed ADSB data to ADSBexchange and Flightradar24, it is done with a RTL stick and a Raspberry PI, download the latest image from ADSB exchange and you have it up and running within no time. The RPI is reasonably stable, but you should expect to replace it every year or so, either the software crashes or the SD card dies. The antenna is your problem, I’m testing currently a cross-dipole and attach a 8 hour flight track. It probably shows the antenna pattern and this is the fun of it, test 1090 MHz resonant antenna’s that you design with a VNA.
Raspberry PI3 and RTL stick, I use a 10mm coax cable to minimize the lossProvisional ADSB antenna setup, this is a cross dipole with a 1/2 lambda delay cable. All is made out of 7mm ecoflex cable which is low loss at 1090 MHz. The better you make it resonant, the better the performance. As soon as I’ve found the best antenna it does in the mast.This shows the 8 hour track plot in the ADSBexchange web interdface running on the RPI, the distance rings at 100, 150 and 200km. this is a test where both dipoles are oriented NS EW.
Elon Musk is not happy and banned the mastodon migration account on Twitter. This is how you do it, don’t post it on Twitter or face the risk of suspension.
Since Elon Musk took over twitter I’m not too certain what to expect from it. Created several escape routes, @pa1ejo@mastodon.social is one, another one is on Telegram where I’m PA1EJO, also I run a channel for hams and friends there, DM me to join the channel. On Mastodon simply type PA1EJO in the search field and it will show you all instances I created. I stopped using twitter, I do not like the situation around Elon Musk and wrote an opinion article about it.
It was already longer known to me that rain deteriorates the quality of the 10 GHz downlink signal from the Oscar-100 satellite. This is the reason why there is a canopy over the feed and the downconverter that turns the 10 GHz signal in a 433 MHz signal. The canopy is the white 150 mm tube and I glued a polycarbonate window on the side that faces the satellite. Figure 1 is the image after installation, it worked fine with some minor rain attenuation since May 2021. Light to moderate rain was never a problem, but the occasional downpours with a lot of rain in an hour give you some 3 to 5 dB loss on the CW beacons, after the rain has gone the signal comes directly back to its original strength.
Until Friday night the 9th of September 2022, the set-up worked well for nearly 1.5 years until one rainstorm caused persisting wide banded noise on the NB transponder range which I could not detect on a WebSDR of the satellite. This type of noise did not directly go away after the rain, it took a bit of heat from the sun next morning to make it disappear. There are several possibilities, like is there local RF interference at the 433 MHz signal, is the T-bias providing the feed with power and 10 MHz still working, or is it a moisture problem inside the feed, either affecting the 10 GHz antenna or the downconverter or the semi rigid between the 10 GHz and the downconverter. The transmit part at 2.4 GHz was not the problem, the transmission was there at the WebSDR, the SWR did not change and other possibilities were also excluded. A moisture problem under the canopy remained as the last possibility.
The QO-100 antenna, it is a 100cm offset dish. The white tube over the arm is the rain canopyInside the canopy facing the feed
What probably happened on the 9th of September is that rain water entered the feed through the rear opening of the canopy near the offset dish as you can see on figure 1, on figure 2 you see what is inside the feed, the cables and connectors are labeled. All cables and connectors are in acid-free Vaseline but this is not enough to keep the water away. I made a second detachable cap from PVC and polycarbonate that also closes the rear end, installed it on Sunday the 11th and since then all wide banded moisture noise has disappeared, reception even appears quieter than before. If this is not the solution then the last two possibilities are that the downconverter or the piece of semi-rigid from the downconverter to the feed are affected. This is more work and you need better weather for it. So far there is no need for opening the canopy, a second cap seems to have solved the moisture problem I hope.
This example once again demonstrated moisture and 10 GHz are not a good combination, a critical part in this installation is the 10 GHz semi-rigid cable.
Between 2 and 4 September I participated in the organisation of this fieldday, HF conditions were difficult but it was a very nice weekend. 160m QSOs at 2AM showed evidence of aurora like propagation, but I had a pileup. Here is a video impression,
The owner of the camping did not mind me flying around, demonstrated to his grandchildren the capabilities of this drone:
A day trip in the summer: Some images of the location, purpose was also to test a new designed dish adapter for an existing unused tripod, the area is the Meuse river valley running between Sedan and Verdun in France.
Looking towards the East, Meuse valley in the backgroundThe other side to the WestThis is where we are on google Earth: it is one of the rural roads in JO29MO The adapter is a piece of aluminum pipe with a threaded rod and three pieces of Teflon, made out of thick sheet material. Teflon is polytetrafluoroethylene thankfully shortened and called PTFE (copycat from https://www.thekitchn.com/what-is-teflon-260009) The adapter at the base has two pieces of PTFE, one on the inside held in place with three Parker screws to align the threaded rod, one bigger piece at the end to balance out the torsion of the tube relative to the base plate of the tripod. PTFE is very strong plastic that is heat resistant, you can make bearings out of PTFE.Top end of the adapter, the piece of PTFE in the tube is machined such that it is snug tied inside the tube.
On 18-Jul-2022 I went to the club PI4DEC to demonstrate what the ground station looks like, how you set it up and how to handle it, etc. A couple of photos:
Made with the theodolite app on an iPhone, the satellite is visible between two treesThanks to Wim PA3L for making this photoAfterparty under the HF antennas of the DEC
Hardware: IC705, Malahit, SGlab upconverter and PA, 80cm offset dish, DXpatrol downconverter, GPS DO R.E.F. and 12Ah 12.8V LifePO4 battery.
Four 10m radials within the ribbon taped box, random wire vertical (about 12m), travel tuner between radials and vertical, and everyone within Europe receives you with 100W from a FT991.
In a public park I always use safety tape to warn people, it is generally appreciated.
PA1EJO 