During the weekend i successfully optimized my VHF Groundstation. I want to share some of the steps i went through.
I use a Raspberry PI3B+ using the Ethernet connection. SDR is a NooElec NeSDR at highest gain. In front 15 meters Ultracell-7 cable and a NooElec Bandstopfilter.
- Antenna: Wimo Turnstile TA-1 @ 11m above ground.
After installing this antenna last week i thought, lay back and enjoy the results. I did several mistakes.
a) The wiring inside the antenna is that the cable shield and the centre wire are connected. (I asked Wimo and they confirmed that).
So for instance if you made a mistake during soldering the connector it is hard to find the error. I double checked this an went to another connector, where i was sure, everything is fine.
b) The manual says: "Stay away at least 2-Meters from metallic stuff.
This was my first installation resulting in poor results.
I removed everything below the TA-1 and the results got much better.
- Heatmap / rtl_power
The breakthrough at least was using rtl_power.
I followed the instructions here:
I followed option one and did all on the RPi.
So this resulted in the following pictures:
At the end the culprit was the power supply at the RPi.
Changing to wifi, switching HDMI off, did not show noticeable changes.
Good luck and 73 Oliver