Key
LNA = RTL-SDR Triple Filtered LNA powered with bias-t from dongle
RTL-SDR = RTL-SDR V3
Sp = two way inductive aerial splitter
dvbt = generic DVB-T dongle
Cloud = LAN (not a direct connection to the internet but I couldn’t find a symbol for that in the software I used).
ADS-B Antennae are home made 8 legged spiders located in the loft as high as possible under the ridge tiles - one each side of the house.
VDL2 and ACARS Antenna is an FM dipole in the loft.
RPi 3B+ run Dump1090-fa, timelapse, heatmap and graphs
RPI 3B runs ACARSdeco2 and DumpVDL2
no photos because everything is just things everyone has seen before
Received my Jetvision A3 antenna today.
Looks promising from the manufacturing, size and technical data (below the picture)
It came with a steel fixing bracket, connector is a N-female, i’ve ordered a 5m low-loss cable together
This is not the final position, it’s just mounted internally for testing. Forget about the mess in the background
I have to rearrange my system and was wondering if this case would help to lower my RPi4B temperatura, since my system in inside a plastic box I’m also planing to replace parte of the plastic cover by aluminium to help heat exchange with the outside.
I bought a couple of these for my kid’s RPI4’s. I like that they are quiet(no fan) and also provide a case for not a lot of money. They are similar to the Odroid N2 with its huge passive heatsink/case.
I do like a heatsink and fan for anything that is under a moderate amount of load. Even in a hot attic they remain cool enough, all of the time.
Today I reconfigured the physical layout of my site that was in my attic. The RPi temperatures were passing 70°C and it isn’t even summer. I connected 25’ of LMR200 to the attic antennas and moved the electronics to my comm closet. Temps are now running around 45°C with the case fans set to high.
Nice setup, but if your antennas are in the attic, why don’t you have your LNA / Filters close to the antennas?
RTL-SDR recommend at lease 3dB attenuation between the Amp and receiver as the gain is so high.
(I found with RTL_SDR V3 + matching amp, I needed 8dB attenuation when the receiver and amp are directly coupled)
The issue is heat. The LNA runs very hot in a room temperature environment. It would probably fail in a 140°F environment. The gain is optimized for my cabling setup.
Following up on my own post from March and reporting on how this went for a month. Altering the gain at different times ended up making no noticeable difference compared to just keeping it at a particular gain all the time. There was a slight advantage during rare instances when all these conditions were met:
Quiet periods such as early morning, AND
No aircraft within 50 NM or so, AND
Aircraft visible on edge of horizon
In those instances the setup could see well at the horizon. As soon as aircraft appeared closer, and especially within a few NM the setup reverted to a normal state with results suggesting a gain too high.
During the coronavirus dropoff it’s kind of like this quiet period all the time, but there are still plenty of aircraft nearby to render the effect moot. As an aside, traffic has started picking up a bit and I’m told by a microlight friend that aviation restrictions were eased in the UK a week ago, which probably accounts for a slight pick up in traffic again.
There may be people with no nearby aircraft who have traffic on their horizon and this timed gain approach may still have value there.
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