All range optimization steps are useless if you’re already at your geographical limit.
This is how mine looks like with my antenna indoors. I am already at max range compared to my geographical environment. The only improvement i will have with an outdoor antenna and (probably) an additional filter is increasing the message rate because i have some “blind” spots inside the range. The blue border shows the max range at altitude 30.000 feet
Yay finally the cavity filters arrived from sysmocom!!! ( wow what a story that delivery was. First attempting post left them, into Deutsche post and for what ever reason, was returned to them before it even left the country. 2nd attempt posting worked and arrived))
Now for the exciting results !!! N2 > airspy >>>> cavitiy filter >>>>> Uptronic LNA>>>>> antenna
Section A, the rtl sdr triple filter (note, although been working quite well, there is not much signal indication in the 1090 band)
Section B Swapped over to just the Uptronic LNA ( no need to comment…)
Section C. As per above, cavity filter inserted between the airspy and the Uptronic LNA (quite a difference between all 3, with a definite signal indication in the 1090 band.
I have left the other N2 set up to compare tomorrow, the stats of detection’s etc. At this stage, I have not updated to what ever version in the ADSB tweaks that have been going on in the last few days and will not change anything like that till completing comparisons tomorrow. The cavity filter has definitely made a difference, whether improving detection’s, 24 hours will tell.
You have a faulty LNA or the sticker is on backwards or you are not powering it.
There definitely is signal at 1090 MHz you can easily see on a spectrum with the rtl-sdr LNA.
And i can’t imagine that it works “quite well” with that spectrum.
Maybe for the spectrum the bias-t was off?
Ah didn’t and can’t try the cavity filter between the airspy and the rtl-sdr for that reason. Why wouldn’t you power any LNA, via a good USB power source, if mains power source is available, instead of putting more load on something i.e an airspy, to supply bias t power???
it certainly wouldn’t be my first choice unless the LNA has good on-board filtering.
USB PSU’s are SMPS’s and (normally) have no need to be quiet. Injecting noise into your LNA will probably degrade performance.
Replying about the cavity filter. These work great as a filter, and usually have a DC short to ground at the input and output of the filter. Connecting it between the Bias-T source and the low noise amplifier (LNA) will likely affect the Bias-T source and the LNA will not see any power at all. You can use a cavity filter between the LNA and antenna cable, with a small signal loss through the cavity filter. There may be Bias-t compatible cavity filters, but have never seen any design writeups on them. Cavity’s are likely the best filters to remove interfering signals. Love mine.
You can use SpectrumSpy (windows program, is included in the Windows SDR# package at https://airspy.com/?ddownload=3130).
Did a scan some time ago with an Airspy Mini and the RTL-SDR LNA.
Bought a cavity filter that will be mounted on the roof once the spring arrives. Hate running around on frozen, snowy roofs
