FlightAware Discussions

Do I Need A Filter?


Uputronics filter with usb supply to filter

That looks better, might be your bias-t is doing something strange.

How did you switch on the bias-t anyway?

I did use this guide: https://www.rtl-sdr.com/getting-the-v3-bias-tee-to-activate-on-piaware-ads-b-images/

Forgot to mention i’m using the Flightaware Prostick Plus instead of the rtl sdr V3 dongle

I’m confused now :stuck_out_tongue:

Does that combo work for you now?

To deactivate the builtin bias-t:

sudo systemctl stop dump1090-fa
sudo rm /etc/systemd/system/dump1090-fa.service.d/bias-t.conf
~/rtl_biast/rtl_biast -b 0
sudo systemctl restart dump1090-fa

Then you should be able to use the rtl-sdr v3 with the uputronics amp as well.

Looks like it does, but its getting the same results as the LNA,

Setup: PI -> Flightaware Pro stick plus -> Uputronics filtered preamp -> 15m coax -> antenna

Gain is 29.7, percentage of strong messages: 6,053

Results:

I will try this tomorrow, thanks for all your help!

Maybe the problem was only present for the scan.

If you want to do two more scans with the rtl-sdr v3 + LNA combo, then do one scan with the first command issued before the scan and then the second scan with the other command issued before the scan.

~/rtl_biast/rtl_biast -b 0
~/rtl_biast/rtl_biast -b 1

At least one of those scans should be completely black :wink:
And if the not black scan shows noise, then there is a problem that’s either with the LNA or with bias-t.

You said the scan with the v3 + uputronics driven by the v3 bias-t was bad as well, yes?

Yep thats right. Could i do something wrong with activating the bias tee? I did just copy-paste on the RTL-SDR guide for activating.

There are some cases where the activation just doesn’t work.
But i would expect a black spectrum and no planes in that case.

The two scans with manually activating and deactivating the bias-t before the scan should make it clear.

As my soldering iron has fried itself sometimes ago, I used soldering gun to solder the wires from 5V DC adapter to the Bias-T. It seems excessive heat from the powerful soldering gun damaged the delicate copper strip on the PCB, and a little pull on the adapter wire caused the wire to pull out along with the copper strip to which it was soldered :frowning_face:.

Have ordered these two. These do NOT require soldering, as screw terminals have been provided for DC supply wires.

The reason for ordering 2 is that these have different sma terminals. One has female/female, and other has male/female. This gives flexibility in different configurations.

US $4.99 + Free Shipping (on a slow sail boat across Pacific Ocean)

US $5.38 + Free Shipping (on a slow sail boat across Pacific Ocean)

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