I am about to harden my existing and working set up.
First thing, I power my Pi via Power Over Ethernet. So I can mount it as close to the antenna as I want. Per my current weather proofing infrastructure, (which sucks), I need to use a 6ft cable between the Airspy I use and the Pi. I am tearing it all down this weekend and rebuilding it right.
Here is what I am thinking. Remove the cable. I then attach my Uptronics LNA that I just bought from Airspy. I then attach the Airspy to the LNA. No pigtails involved. Direct connections only. Finally, I would attach the Pi to the Airspy, then run my ethernet back inside the house and power it all up. The whole shebang fist inside of 4 inch PVC tube with top cap. Cap is drilled and treaded for the FA antenna. Seal up the threads with some sort of goop. Slather on some Boeshield T-9 and Dielectric protective grease on the exposed meatal and electronics.
Problems I foresee but not sure is exist:
Interference. Will the location of the Pi, less than six inches from the LNA cause some sort of interference?
Heat. Will stacking all of those parts so close together cause any heat issues? I live in a cool coastal climate and will use white pvc. When it rains, it rains hard. I prefer not to ventilate but can figure that out if needed.
One thought would be to run a long and USB cable between the Airspy and the Pi. If I did that, I could move the Pi inside and keep it out of the heat and interference equation. though I would still use POE to power the Pi, I wouldn’t feel compelled to use POE. I could use a power plug. But, does the long USB cable introduce other issues? I know there are long USB cables that are configured to work over long distances. Not sure what the impact on reception would be. I figure the signal is digital once it hits the USB cable no there would be none.
The cool part of this set up is that I eliminate the need for an expensive piece of Coax. The 6ft section I paid a professional to make was really spend. No way would I have paid for the thirty-five feet I would have needed.
There are more experts than i, but i have seen that the Airspy is getting pretty hot especially during summer months. An extra cooling with some passive heatsink might be required if you can’t keep it inside.
If you have enabled Bias-T and/or 20 MHz it might get even hotter and heatsinks are highly recommended.
Mine was outside for a while with the Raspberry and i used a short USB cable instead of connecting it directly to the Raspberry.
There was no failure at all, but touching the device was not possible for a longer period. I have no clue if i am right or wrong, it was just my investigation.
For all the other questions, i am sure you will get answers soon
35ft won’t be that much more expensive than 6ft … for 6ft good part of the price is the connectors and the labor to attach them.
This will save you buying a new pi / LNA / airspy when they corrode
It will also save you from going up the tower when you need to reflash the sd-card or something something …
35 ft without an LNA is very acceptable with LMR400 or something similar, having only the antenna exposed eases maintenance considerably.
Anyhow as to your actual question, that’s indeed gonna get pretty hot even if you run airspy_adsb on a lower setting.
I’d connect the LNA via USB in this case instead of using the builtin biastee.
Also i’d recommend a fan blowing over the airspy an the RPi from the side, that should make this work.
And before anyone starts arguing that a fan is useless if it’s in an enclosed space, some thermodynamic hints:
Heat moves due to temperature difference
to move heat outside the enclosure, the walls of the enclosure need to be hotter than the outside
with a fan, the differential between the pi / airspy and the air / walls of the enclosure will be reduced to around 10 to 20 C, without a fan the differential would probably be around 50 C or higher
the enclosure has a relatively big surface compared to the pi / airspy, thus even 5 to 15 C differential will be sufficient to move the heat outside
Nope, it shouldn’t do. I have a Pi, bias-T, Airspy and LNA in the same box, all right next to each other.
How cool? I’m on the east coast of the UK and I’m sure you know what our reputation here is like for cold and rain. Mine is all in a box, mounted 35ft up in the air. I’ve got a PoE hat with an additional fan mounted just passing air over the kit and it’s been fine. I’ve got one small hole drilled in the bottom of the box just so it’s not air tight.
Not sure if the device would work in this environment without additional heating:
I have mine outdoor on my balcony, shaded and covered by the overlapping roof. I put it in a box pretty much isolated inside. The SoC Temperature is going to around 20°C in case the outdoor temperatures are somewhat below -5°C
It’s not a Raspberry but a passive OrancePI device (Jetvision AirSquitter). It’s the second winter and no issues at all.
Guys. I grew up in Minnesota. I used to sit on a bucket, staring down a hole in the ice, slamming shots of Peppermint Schnapps, while fishing for Walleyes. I have ridden snowmobiles in air so cold , -27 before windchill, it snaps the nose hairs if you breath too hard*. I know what to do with a credit card when there is an inch of ice on my windshield. I have shoveled driveways at 6:00 AM so that I could get my car out of the garage and go to work.
For the Canadian Commentator. I know how it feels to take off a pair of hockey skates after practicing in 10 below. As you might know, it hurts. Hurts like hell. Hurts so bad I’ve seen the toughest cement head kids cry like babies. It really hurts. I’ll let you do the metric conversion.
I know what cold is. And I am here to tell you. It is cold in Sin City by the Bay.
