Last year I had a flood in my basement, and my PiAware was caught up in it. A Raspberry Pi 2B+ running PiAware and the 978Mhz radio dongle were destroyed, but my 1090Mhz Pro Stick was above the water. With the ridiculous cost of SBCs at the time, I didn’t replace it.
SBCs have since come back down to reasonable prices. The other day I installed a new Raspberry Pi 3B+ running Raspberry Pi OS with Flight Aware added on. I had expected that the new receiver would pick up right where the old one left off, but instead I’m finding that the performance is awful.
I have a similar result as this thread. My range has reduced from roughly 160nm to about 50nm and I’m only picking up aircraft coming into KMKC or KMCI, or aircraft at very high altitude (32,000+). I used to see 60+ aircraft at a time with lows in the 10s at night, and now I see maybe 10 at peak hours if I’m lucky.
There are no new obstructions, no new radio sources that I’m aware of, and my neighbor and I have each even had some major tree branches cleared. I have the 1090Mhz bandpass filter on it (removing it seems to kill off any reception at all). I’ve adjusted gain down to 0 and even set it at 60 just to see. It does seem that I lose any reception with gain below 40.
My antenna is the FlightAware 61cm unit that’s available on Amazon. It’s on a pole mounted 16ft above ground. I’m essentially at the top of the hill my neighborhood was built on, and while there is a low ridge above me to the north and east, it’s far enough off that I should still be able to see aircraft at 40,000 almost to St Louis and Des Moines. The antenna isn’t above the roofline of two of my neighbors, but its above everything else except the local trees. It’s connected by a 10-meter LMR400 cable with the proper connectors.
Unlike the user in the linked thread above, my cable and antenna were functioning normally right up until the flood. I had considered the radio dongle might be the problem, but it was not caught in the flood and I’d expect it just wouldn’t work at all if it had been affected. Is it possible there is a problem with my antenna or the cable but yet I’m still picking up some signals?
True enough. It allows you to make custom length cables and check each and everyone for proper impedance before connecting them to your expensive radio gear. Impedance mismatches and short circuits from stray strands of ground braid will destroy your transmit power transistors in a heartbeat. Great for avoiding problems along with trouble shooting ones not of your own doing. If you have the tools to do diagnosis, you don’t spend money on shotguning issues with new parts and pieces.
I have plenty of RG-6 cable leftover from when I wired my house up for cable/satellite TV. Would it make sense to replace the LMR400 cable with RG-6 and F-to-SMA and F-to-N connectors? Or would RG-6 cause me more problems?
I realize that more connections = more potential future problems and more potential signal loss, but it’s what I have.
Every connection is a reflection point along the signal path. Additional connections in any design are not a good thing. Adapters and 90’s are not preferred.
Well, I plugged the original wire antenna into the dongle and immediately saw a huge difference. In seconds, even in the basement window facing west-southwest, it’s picking up 33 aircraft at up to 110nm. So, clearly I have a problem in either the 10-meter LMR400 cable or the 1090Mhz FlightAware antenna.
I’ll probably replace the cable first (since I can get a longer one and extend the height a few feet). Then I’ll replace the antenna if that turns out to not be the solution.
Good for you! You are on the scent now and the culprit won’t get away! Those little wire antennas are valuable test tools. Coax and antenna all in one!
Old ham radio person, sounds like water got into either the antenna, the cable, or the connectors. Can you connect any kind of antenna at the end of the cable to test if the cable is working or not? Perhaps lower the antenna and connect it via a short RG-6 cable to see if the antenna is the problem. As the above posts mention, changing one item at a time is generally the best way to isolate problems. Good luck, best wishes, and have fun, you got this.
I don’t currently have anything with the right connectors other than the 10-meter LMR400 cable that’s attached. I’ll start with the cable and work my way up the pole.
I’m in the process of getting my antenna outside, though with the weather turning it may have to wait until spring My biggest concern by far is avoiding water ingress to either the antenna or cable. After some research I purchased rolls of Temflex and Super 33+ tape to make watertight seals.
My initial test to see how the tapes handled (as I had no previous experience with them) was to add additional protection to the top/bottom seals on my FA antenna. Despite the antenna being well-made those are just potential ingress points to my paranoid mind! I was impressed at how well they made a tight seal. Well worth the investment for peace of mind and confidence that once outdoors things will stay dry.
Not sure if you had any protection already on your setup, but something to consider if you did not. Good luck.
Have a look at a product called “Rescue” tape. Bought my first rolls of it at a Hamfest and have used nothing else since for coax connector sealing. I find it to be a superior product. You stretch it as you apply it and it seals and holds amazingly well.
I’ve also discovered that I cheaped-out back when I originally built this setup. Instead of LMR-400, I had bought LMR-240 cable (6cm vs 10cm outer diameter). So while that’s not the cause of my poor reception, it means I probably could’ve done better back when it was in full operation.
Replaced the 10-meter LMR240 cable with 50-foot LMR400. Boom. On a snowy Sunday afternoon, I immediately jumped from 22 aircraft positions out to 120nm to picking up 50+ aircraft out to 150nm (280km). Position reporting had already gone up to about 4,000 positions per hour. Now up at nearly 9,000. And that’s on a Sunday afternoon/evening.
I didn’t want to miss the Chiefs game (boy, I wish I had!), so I still have some work to do securing the cable, but now I can extend the antenna height another 6-8 feet (it’s co-located with the TV antenna, the cable for which is now the limiting factor).
Someday I’ll get another UAT dongle and set that up in the window as before. Eventually I’ll put it on the antenna mast.
Well done. Be sure to keep your new antennas at least 20 inches or more away from other metal things. Lots of interaction between antennas and things nearby. Stay safe out there with the tower and snow.
My biggest concern by far is avoiding water ingress to either the antenna or cable. After some research I purchased rolls of Temflex and Super 33+ tape to make watertight seals.