New antenna, no increase in gain.

[cs.dk]

My Pi has been running for a week now, and everything seems to work great.
Bought a new antenna, hoped for longer reach. But it seems like it's worse then ever. Is there any way to test the antenna?

This was the old setup; https://shop.jetvision.de/epages/648...Products/53200
New antenna; https://shop.jetvision.de/epages/648...Products/67121

[Oblivian]

Start doing tests here


https://forum.flightradar24.com/foru...ignals-in-area

And then lead into testing gain

[cs.dk]

Sorry for my next-to-nothing knowledge about this. But what folder is the output stored in? EDIT: Found em, they are in /home/pi

Scan is with the small indoor antenna, scan2 is with the bigger outdoor one.

[cs.dk]

Scan.png
Scan2.png

[abcd567]

Your scan shows interference in 900 MHz ~ 960 MHz range. This is signal transmitted by GSM900 Cell/Mobile phone tower in your area.
It is overloading your receiver (DVBT) causing it to perform poorly. You need a Filter to remove this signal.

https://thepihut.com/products/flight...ass-sma-filter

[cs.dk]

Thanks, i'll order a filter.. But don't you agree the noise is worse with the small antenna, if i understand the heatmap correct.

[abcd567]

Thanks, i'll order a filter.. But don't you agree the noise is worse with the small antenna, if i understand the heatmap correct.

(1) You posted Scan and Scan2, but did not specify which scan is for which antenna.

(2) The scan shows the presence or absence of signal in the range of frequencies scanned, but does not show their strength. The better (high gain) antenna picks both the 1090 mhz and interfering signals stronger than the inferior (low gain) antenna, overloading the dongle.

(3) Please reduce gain setting from default " --gain -10 " to " --gain 40 ". This will help in reducing overload of dongle and reception is likely to improve. Try other values of gain like 49, 45, 40, 35 etc to find which gain setting gives you better reception.

[abcd567]

(3) Please reduce gain setting from default " --gain -10 " to " --gain 40 ". This will help in reducing overload of dongle and reception is likely to improve. Try other values of gain like 49, 45, 40, 35 etc to find which gain setting gives you better reception.

[cs.dk]

I wrote it in #3, but the forum seems to have problems at the moment;

"

Sorry for my next-to-nothing knowledge about this. But what folder is the output stored in? EDIT: Found em, they are in /home/pi

Scan is with the small indoor antenna, scan2 is with the bigger outdoor one."

"--gain 40" - is that the complete command to run?

Thanks

[cs.dk]

Got it.. Google sorted it (I think you are the OP on this to) Do you need specific values, or are both ie. 45 and 46 usable?

Step-1:
Open file /etc/default/dump1090-fa in nano to edit it
sudo nano /etc/default/dump1090-fa

Step-2:
In the line starting with RECEIVER_OPTIONS, change the gain value from -10 to the required value. In this example it will be changed to 30.

Line before change:
RECEIVER_OPTIONS="–device-index 0 –gain -10 --ppm 0 --net-bo-port 30005"

Line after change:
RECEIVER_OPTIONS="–device-index 0 –gain 30 --ppm 0 --net-bo-port 30005"

After changes are made as above, save changes (Ctrl+o) and close file (Ctrl+x)

Step-3:
Restart dump1090-fa to implement the newly set gain value
pi@raspberrypi:~ $ sudo systemctl restart dump1090-fa

.
Step4:
Verify that the new value of gain is actually implemented
pi@raspberrypi:~ $ sudo systemctl status dump1090-fa -l

The last line of output of above command will show gain actually set
piaware dump1090-fa[1254]: rtlsdr: tuner gain set to 29.7 dB

[abcd567]

"--gain 40" - is that the complete command to run?

The gain setting method depends on what is your install.

(1) If you have installed Pi24 image, then in your browser go to Settings page following address:

ip-of-pi:8754/settings.html

You will see one of the fielde titled "Process arguments". Most likely it already has --gain -10. It may also be empty. Whatever is the case make it --gain 40. Click the Save button, then Restart button. Both these buttons are at bottom right of settings page.

(2) If your install is not Pi24, but something else, please let us know as gain setting demethods depends on it. Example of other installs are (a) Raspbian image with package install of dump1090-mutability or dump1090-fa, and (b) Piaware image.

[cs.dk]

Something is wrong.. Installed the filter and new antenna yesterday. They're located right next to the small whip in a window. The smaller one gives me more range. I won't put in on the roof before i'm sure it works OK.

Graphs1090

Scan3

[wiedehopf]

Either really strong interference, is there a satellite receiver nearby?

Also check that you don't have any RP-SMA stuff, that misses the pin and you loose the whole signal basically.

[cs.dk]

No recievers nearby that i know of.

No RP-SMA, and i have tested the cables for continuity thay're OK.. Something comes to my mind. The window the antenna is located behind, (maybe) have a metallized film coating. You know the silver-colour sun film. Wonder if thats some of the problem.

[ylis]

Isn't the small antenna behind this same window ?

And maybe its my eyes but I don't see any signals around 1090 on your scan 3 ...