The timing of the failure as related to the roofer’s work is far too strong to be easily dismissed as mere coincidence. Yes, it’s possible, but I wouldn’t be putting any money on that horse.
1 Like
I feel I should mention that in my experience, as well as those aired in other posts on this forum, the Uputronics LNA doesn’t perform as well as a good RTL-SDR Triple Filtered LNA.
So, if the problem is related to the changes made to the roof you may see even fewer aircraft with the Uputronics than the RTL-SDR and if the RTL-SDR LNA has gone bad, then you may not see as much improvement with the Uputronics as you would have hoped.
I was aware that the Uptronics LNA had reduced performance compared to the RTL-SDR blog LNA. However, the RTL-SDR LNA is no longer available and as I understand, they are currently working on an LNA + Antenna Combo, but nothing is listed yet on their website. They did mention however, they anticipate being ready to accept orders around late 2024 or early 2025. Latest update on this was four months ago
Further, I figured I can confirm the RTL-SDR LNA went bad if I connect the Uptronics and see improved performance. Look at my stats below, specifically the dark blue and navy blue lines compared to the light blue line of the last 7 days. There was a dramatic reduction in performance that I can suspect attributes to a component failure of some sort. If I continue to see reduced performance with the new LNA, then more testing will need to be done.
The Uptronics LNA arrived today and it is installed. Despite the fact that it does not perform as well as the RTL-SDR Blog LNA, I do like the fact it has a green power light on to let me know it is receiving power. This dismisses my suspicion of whether or not the SmarTee is working.
However, aircraft targets are still significantly reduced making me suspect it may be in fact the new roof causing the attenuation. Tomorrow, I plan to remove the antenna from the attic and try some temporary stuff outside to see if that changes anything. Will also test both LNAs since it very well likely may be that both are functioning normally.
More to come…
With the Uputronics installed, be sure to adjust the gain so as to get the most from the SDR. This usually means dropping the gain a bit to use the full spread of the SDR and not bombard it with too loud signals.
By this I am assuming adjusting the gain settings in the Piaware Config text, using the command:
sudo nano piaware-config.txt
However, when I do this usitn PuTTy, all I get is a blank page.
I guess I need to locate the file first, but am not to skilled in using the terminal that well. Any pointers? Also, recommended setting? I understand -10 would be max, so perhaps setting at -5 and tweaking from there?
Almost, it’s in /boot
sudo nano /boot/piaware-config.txt
For a RTL-based stick you want to use one of the values below. I include the line below as a comment next to the setting to remind me, eg:
# For a receiver type of 'rtlsdr', this setting controls the dongle gain.
# Use "max" for maximum gain. Other values are interpreted as a gain in dB.
# max 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6
rtlsdr-gain 20.7
This article is very useful, it gives a good way to home in on the optimum setting. Without the Uputronics I had to have a gain of 42.1. With the Uputronics it’s reduced to 20.7 and I get way more positions, aircraft and range. My RSSI range is from around -2.5 to -35 (you can switch to column view and then click the RSSI column to sort by that).
-10 is a special gain setting, it doesn’t actually mean -10. Similarly, -5 has no meaning. Stick to the values in that list.
When you’ve made a change you can quickly restart the decoder with the new setting with the command:
sudo systemctl restart dump1090-fa.service
and confirm it’s in use with the command:
ps -ef | grep -E "gain[[:space:]][\.0-9]+"
Edit - just noticed your great decade+ streak, nice work!
1 Like
This is SO helpful!!! Looks like my sweet spot is around 40.2, with RSSI values between -2.7 to -24.3 currently. Still not seeing range of traffic increase, but I suspect that is due to the attenuation from the new roof. Tomorrow’s tests outside should confirm.
I’m trying my best! Airplanes really make me nerd out and I love the support I’m getting from this community. 
It’s worth trying a few – pick one that’s too large, see the large numbers (eg -1.8 down to just -15). Then switch to one too low and see the numbers change (eg -13 down to -39). Then pick a gain value between those and slowly home in on the right amount, halving each time. It’s a quick way to get close to where it should be.
The Uputronics has a built in filter and presents a stronger signal to the SDR, so its gain can almost certainly be reduced to somewhere in the mid-20s. The gain you mention, 40.2, seems a little strong and those RSSI numbers, -2.7 on the strong side and down to just -24.3 on the weak side, seem a bit too amplified. See if you can spread them out more and get a spread from, say -4 to -32, just to use a couple of example numbers.
When I had no Uputronics my gain was around 40.2 with RSSI from -2 to -35. With the Uputronics I had to reduce the gain to 20.7, giving me a RSSI spread from around -2.5 to -35. You can see what a big difference the Uputronics made and how it meant I had to drop the gain right down so as to not overload the SDR.
Yes it will be interesting to see how you get on outside the roof.
Don’t forget to the power the Uputronics – it needs powering, probably with a USB-C cable if it’s near the Pi.
I am using a Nooelec SmarTee with a built in bias tee feeding power to the LNA.
I’ll definitely give that process a try. I also still have my RTL-SDR Blog LNA, so I’m guessing values will be the same? I suspect that my new roof may be attenuating a large amount of the signal, but just to give you some backstory, BEFORE the new roof went on, I was getting targets 200+ miles out (but faint.) I could also pick up targets <500 feet at the airport 10 miles from my house. This was using the Nooelec SmarTee, RTL-SDR Blog LNA and a Vinnant ADS-B Tuned Antenna. Gain setting was set to max. See sample photo below:
Nothing changed except the new roof. It is a storm-fortified roof, since I am coastal, so extra steps were taken to help strengthen the roof (plastic layering over sheeting, etc, etc). I just find it surprising how MUCH the new roof is attenuating the signal, after I saw how far traffic was reduced:
It would be really nice if Flight Aware incorporated some controls for gain setting within the local SkyAware IP page so users could fine tune adjustments on the fly. I’ve seen a separate thread where the coding for that was done, but I think that was for older versions of PiAware, and I don’t consider myself that adept enough to be messing with code.
I run the special version of Piaware Skyaware that incorporates the gain adjustment menu. I believe it came from Abcd567.
1 Like
Ah that sounds perfect, means you can have the LNA near to the antenna too if you have the relevant cables and connectors and so on.
I’ve found that every new situation benefits from a review of the gain setting. For example a friend of mine recently fitted a UPS HAT to the RPi, and it seems to have improved his numbers a bit. We’re assuming that the UPS is covering all the power and LNA requirements perfectly, whereas before perhaps they were on the edge of what the PSU could provide. The end result is it’s worth another look at the RSSI spread and seeing if the apparent improvements merit a tweak of the gain value to extract maximum use from the SDR.
In your case it sounds like the new roof has had a big effect, but if you’re moving the antenna outside the roof then it’s a case of finding the right value in that configuration which maximises the RSSI spread and message rate. I guess once these scenarios are set they don’t need tweaking, hence the limited value of having a gain setting in the web UI.
With the antenna above that roof and the Uputronics filtering and amplifying, and the gain set to present the optimum RSSI spread and message rate to the Nooelec, I suspect you’ll be back to your previous numbers, and quite likely smashing them with the newly optimised LNA.
I believe it came from Abcd567.
I believe you are correct. I am guessing here it’s compatible with PiAware 8.2 then?
Yes, it is compatible with piaware/dump1090-fa 8.2 and 9.0.
https://github.com/abcd567a/set-gain/blob/master/README.md
2 Likes
The opposite, actually. This adventure started here. The abridged version is below:
- I used an old satellite dish mount on my old roof to mount an external adsb antenna
- Found the coax port in the house it connected to and used this dicussion page to solicit suggestions
- This setup worked well for 5 years.
- Since I was having a new roof installed, I wanted to do away with the dish mount and move the antenna to the attic, based on the “Featured Host of the Month” in the October 2024 Flight Aware News Network. I thought it was a fair compromise, since I no longer had a way to mount the antenna externally
- I moved my antenna indoors with the old roof and found I had BETTER performance, as the antenna was mounted higher than where it was when it was outside on the roof
- With the new roof installed, the reception dropped, which lead to my troubleshooting on this forum
My outside testing will only be temporary as to confirm the loss in range is due to the roof. I suspect is it now, but want to eliminate the variable. However, this experience while stressful on the front end has been a nice learning experience. I find myself appreciative and humbled by the help of others here in the FA community. You all rock!
2 Likes
It looks very nicely presented. Wooden beams are always welcomed in this hobby!
Apologies for the delay. Weather has inhibited my ability to conduct outdoor testing until today. After some brief testing, I was able to determine that the reduction in signal is in fact attributed to the new roof.
I set up my antenna outdoors and connected both the RTL-SDR Blog LNA and the Uptronics LNA and ran them for 5 minutes each, taking a screen shot of traffic. Upon accessing Skyaware via the local IP, I once again saw that the range greatly increased, seeing targets as much as 150nm out. Message rate increased exponentially as well. I did not bother to adjust gain settings as this was only a temporary rig, but the dynamic range DID increase. See photos and screenshots below:
Temporary rig
RTL-SDR Blog LNA after 5 minutes
Uptronics LNA after 5 minutes
It’s unfortunate that the new roof is attenuating the signal so much, as I didn’t want to have the antenna mounted externally any longer, and I’m not seeking to do so. I don’t want to drill any holes in the new roof, or the house. I’m just going to have to settle for the reduced performance. However, the learning experience has been an enjoyable one. Bottom line, an outdoor rig is the BEST rig.
Thanks all!
3 Likes
I used to use the same LNA+filter with most of my DIY antenna verification together with f***ing cheap 5 meters of cable.
Most interestingly: with the CoCo-7-element-plus-shortcut-tip you introduced many years before, I must not use this amplifier. The antenna gain is so high, the amplifier seams to overload the signal. This LNA is worth the price. But finally, the CoCo without LNA is seeing the same number of planes compared to my DIY GP antenna with 8 radials plus the LNA. 200 nmi at 1st floor rooftop.
The only drawback is the length of CoCo: it is about 4 feet (1.2 meter), while spider GP is 4 inches (10 cm).
1 Like
Ugh, this is very low range!
I have in one location a 45€ clone of the Ten-90, mounted 1 meter under my roof top and get 340 km range. Note: this is below concrete roof tiles, rock wool, vapor barrier, plasterboard.
[edited km from nmi after @dvsvejk reported the mistake]
The USB stick is the black “BLOG V4” in this case.