Such constantly high temperatures can cause long term issues of the chips and other parts on board.
The CPU alone runs up to 80° (the fan gets on, so it never gets beyond 82), I’ve just removed the case temp/humidity/pressure sensor, however the temperature inside the never exceeded 45°C, and maximum recorded humidity never exceeded 50%, so to me it is a bit warm, but not that much.
I think for many people there will be much more noise/RF/interference risk inside the home than outside and away from the house. Just depends on local conditions and what gadgets are operating inside the house. Until I see a clear A/B test on a real-world ADS-B station, I find it hard to believe the site performance would be noticeably worse in low temps vs high temps and standard cooling.
I can see my Airspy gain dip by around 1db or so on the hottest days. That’s expected with any receiver and it does not impact performance since it just heat, not interference.
What does this even mean?
Your Pi’s no more protected if it’s in your house should lightning strike near your antenna. Long vs. short coax makes no difference to lightning.
What are you doing to make your Pi run so hot?
(sounds like it has no heatsinks and lives in a small box)
Rule of thumb is every 10°C temp rise halves the life of electronic components.
To understand the EMF noise @SoNic67 is referring too, you need to understand the difference between a super heterodyne receiver and an SDR.
What the SDR sends to the Pi is un-demodulated noise. If you add a load of additional noise, you are distorting the “noise” you want to demodulate which will degrade your ability to pull signals out of it.
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I understand this, but how is putting the Pi near the antenna increasing the noise floor?
Pi’s run multiple bus’s and clocks at a dozen different clocks. If any of this gets into the receiver chain (input, ref, LO, IF), it will degrade performance.
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I have never heard of anyone picking up RFI in their ADS-B antenna that’s being generated by a Pi that’s mounted near the antenna in an enclosure, while I have heard of many people who do locate their Pis near their antennas then power them over PoE in order to reduce attenuation from long coax runs, which is a much bigger issue than any possible RF noise made by the Pi. Anyone concerned about Pi-generated RFI could simply put it in a metal case to shield it, though I’ve also heard of people using plastic waterproof electrical junction boxes as outdoor Pi enclosures and they’ve never mentioned noise or interference issues from doing so. And 1090MHz filters do exist, you know. Pis are extremely low-power devices which is why people use them as ADS-B feeders as running them 24x7x365 doesn’t affect their power bills. They’re not going to generate enough RFI at a high enough power level to matter compared to PCs, TVs and household appliances.
Not only antenna can pick up RF. The filter that you add will be before that point where RF noise gets inside the receiver itself. Those plastic cases don’t offer any shielding. Except Airspy. You put the noise generator right next to them (that’s the Pi). Does it work? Yeah. Would be better with more spacing between them? I think yes.
Also when the lightning strikes near the antenna, and the Pi is there, there will be damage, because of induced voltages.
If the receiver and Pi are in house, you can add a surge suppressor at the entrance in the house, with a ground connection.
That’s just me, thinking as a stupid EE…
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As long as you don’t know what the full lifecycle is, i am good with it 
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That’s an OrangePi Zero, Raspi-compatbile SBC, but they are known to run hotter than equivalent Pis, and to report falsely high temp readings.
The heatsink is suboptimal.
Today, with 28-30° out, the CPU temperature has not gone over 75°.
So update on my set up since the aerial upgrade, I installed the newly bought RTL-SDR LNA and my positions have increased by 2-3000 per hr on average and aircraft around 15-20 extra per hour. I’m amazed how small it is compared to the uputronics one it replaced.
I still have an illusive dead spot in the 250nm plus band, from NW through to ESE, I have been trying to figure it out but come to the conclusion it must be something to do with Winter Hill 8miles away, the hills north of Bury/Oldham and top section of the Pennines around Glossop area that’s killing the reception.
I took a video of the view from the height of my antenna where it is now at 32ft above ground level to get an idea if anything local was blocking it, their are trees about 70-100m away from NE to ESE so it might be them affecting it, so that area might open up once the leaves fall in autumn.
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Both my cheap Chinese SAW filter and my RTL-SDR filtered LNA have aluminum enclosures not plastic. All of the other filters I’ve seen except the extremely cheap PCB-only ones have metal cases too. If the FlightAware ones have plastic cases, then bad on FlightAware. Either way, anything that’s off-frequency but still gets received by the antenna will be filtered out regardless of the filter’s case material.
Look at the block diagram of an SDR dongle if you can find one. Those are usually plugged directly into the Pis and they’re extremely broadband radio receivers. The FlightAware ones also have plastic cases. If the Pi was emitting enough RF energy to interfere with the ability to receive ADS-B messages don’t you think the plastic-enclosed radio being directly connected to the computer would be swamped by this RF? Especially since for the antenna to pick up this noise it (the noise) would have to either be extremely powerful or be on a harmonic of 1090MHz or both, and as I replied earlier the Pi is such a low-powered device to begin with that it’s incapable of emitting RF energy at a high enough power level to matter, particularly when it’s enclosed by a metal case that acts as a Faraday shield.
Which is worse, a chance of a very slightly higher noise floor or a 50% or higher loss of the strength of the desired signal due to feedline attenuation at UHF frequencies?
But that’s just me, thinking like an experienced electronics, radio and computer technician.
(If you ground your lightning protector to its own ground rod don’t forget to bond it to your electrical service’s ground rod to prevent ground loop noise.)
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HDMI noise
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I live where there is lightning almost every day. This happened yesterday near me.
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That is what Jetvision is using for their Radarcape/Airsquitter device. But due to a hardware decoder, the CPU usage is pretty low and the devices are running therefore never hot.
My outside Airsquitter achieves never > 55°C even with +30°C environmental temperature. Passive device in a solid metal case
(current outside temp is 21C)
My receiver dongle is attached with an USB cord, not directly.
Mechanical forces acting on boards and RF noise reasons.
My gain budget is sufficient to attach a coax line. The LNB at the antenna takes care of that and maintains the low noise performance.
That is my solution using the Airspy. It keeps both devices independent and heat is not flowing back and forth
The Airspy is directly connected to the Uputronics
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My CPU settings are 480-960MHz (I bar the 1.01GHz clock to avoid too much heat dissipation), “Conservative” governor. It lets way enough processing power for ADS-B, and a lot of MLAT.
Yesterday, with 25°, it did not go far beyond 70°. Unless it is a very hot day, I virtually never reach 80.
Still too hot. But if you’re fine with it…