Thanks. I was thinking the attic might be the problem also. I don’t know if there is some kind of shielding up there or not. My ADS-B antenna is near a homemade TV antenna that is also mounted in the attic. Could the TV antenna cause problems?
Is there a cost-effective way to measure if I’m getting radio interference? I live in a rural area, but I can see a cell phone tower from my house.
This weekend, perhaps I’ll move the antenna outside, to my front lawn as a test.
My plan was to get things optimize while the setup is in the attic, then move the antenna to a ground-mounted mast. Last weekend, I got on my roof to take a closer look at potential antenna mounting points. I decided that I don’t want to go up on the roof anymore, so I’ve been researching telescoping ground-mount masts.
I made a number of changes to my setup. I took out the splitter and the 978 Mhz receiver so that now, I’m only getting 1090 Mhz. I moved my antenna out of the attic. It is outside at ground level temporarily until the parts come to mount the antenna on my roof.
My current setup:
• PiAware image
• ADSBexchange 1090/978 N-Type antenna
• 3ft KMR240 Coax cable
• Uputronics 1090 Mhz filtered preamp
• RTL-SDR Blog V3 dongle for 1090 Mhz
Here are the graphs for the last 48 hours. I made the changes to my setup about 24 hours ago.
The most significant change that I’ve noticed is that my weakest signal is down to -33. I still don’t understand why that is a good thing.
For an hour or so, I temporarily had the antenna mounted about 8 feet off of the ground. During that time, my message rate and number of aircraft tracked seemed to increase. I had to bring my antenna back to the ground because it was getting too windy and the temporary mounting solution was unstable. The hardware for a permanent roof mount will arrive next week.
I need help in getting the software controlled bias t in the dongle to work. I tried the steps listed in the RTL-SDR.comarticle. I also tried the script from @wiedehopf. Neither seemed to work. The only way I was able to get the red light on the preamp to light was was by supplying power through it’s USB port. Can anyone help me to get the bias t in the dongle to work?
Getting your weakest signal lower indicates that you are able to receive signals over a greater distance and that increases your receiver range.
So that’s why a lower weakest signal level is better
The red light on the preamp did not come on when I tried to use the bias t in the dongle. I assume the red light indicates that the preamp is getting voltage. The only way I could get the red light to come on is when I supplied power through the USB cable. That is not a long-term solution for me as I plan to mount the antenna on my roof (with the preamp a few feet from the antenna) and won’t be able to supply power to the preamp through a USB cable.
I went with PiAware because that seemed to be the easiest for a beginner like me. Would switching the readsb, tar1090 and/or other @wiedehopf projects resolve the bias t issue or provide other benefits? If so, how do I switch without losing my FlightAware streak?
I’m embarrassed.to report that the problem was caused by me using the wrong adapter to connect the preamp to the dongle. I was using a female adapter instead of a male adapter.
I finally got around to mounting my antenna outside on the roof. I wasn’t able to reach the apex of my taller roof. I may buy a ground mounted mast to run up the side of the house of the shorter roof. Without having to use guy wires, I think I will be able to extend the mast about 10 feet above the shorter roofline, which would put the antenna above the apex of the taller roof.
This is my current setup:
• PiAware image (the Raspberry Pi is inside the house)
• ADSBexchange 1090/978 N-Type antenna
• 6ft LMR-400 Ultra Flex cable
• Uputronics 1090 Mhz filtered preamp
• 30ft LMR-240Ultra Flex cable
• RTL-SDR Blog V3 dongle for 1090 Mhz
Compared to my last setup, with this setup my range seems to be about 50 nm farther and my message rate has increased. Does the graph below indicate that my noise level is too high? If so, perhaps I will get a barrel filter from FlightAware.
EDIT: I think my gain was too high. I tried a number of times to lower the gain using the steps in this post (For Beginners - How to Set/Change Gain) but the gain seemed to stay the same. It wasn’t until I saw this post (Disabling Adaptive Gain?) that I figured out that I needed to disable adaptive gain to set the gain manually. I currently have my gain set at 32.8 dB.
Do the graphs indicate other opportunities to optimize my setup?
You may want to keep knocking back the gain and see how that impacts your stats. Gain seems still too high to me. There is no perfect level, it is more what you want to achieve between close by and distant traffic.
As one reference point for you, I have a FA antenna + Uputronics and enabling auto dynamic range sets the gain at 38.6. In reality I run at 19.7. A mere 19 dB difference! I’ve found the aphorism popularized by the German-American architect Mies van der Rohe is applicable here too - less is more.
