New hardware worked for a few days and now low signal

I mounted the patch antenna on the front of a plastic board with the amplifier, receiver, and
raspberry pi 3 on the other side. I am powering it with the Raspberry pi wall power supply. The
first few days I had a reasonable signal of around 3 db and signal state of 3 to 4. I was receiving
ok with the weather data, wiki posts, aprs, pics and stuff like that.

My signal had gone down to around 2 db with a signal state of about 3. I have tried re positioning
the antenna but am stuck around these values. I am setup inside the apartment house looking out
the window and have taken the setup outside with about the same results.

I also notice quite a bit of interference from the computer and monitor since the setup is about 4
feet from the system. So I keep the computer off when taking the readings and positioning the ant.

WOW, what’s going here? I thought I was only one having problems. I’m the one waiting for new Tuner (arrive today). I first replaced LNA. Thought I fixed it, Had a SNR of 5. Then, maybe 15 minutes later, trouble came back. Lower SNR and getting worse. Went back old LNA, the same, Figured Tuner bad. Ordered one.

What platform (CHIP or RPi3) are you guys using and what is the power source? Have you tried using a different cable, battery pack, and/or wall adapter?

I am using a RPi3. The power adapter that came with the RPi3 says 2500 Ma. I have also used
the battery pack as well. The USB cable is direct with the wall adapter and the battery pack has
its own USB cable.

I am only seeing some peaks to about 2.5 db and dips to around 1.5 db at times. The receiver
is plugged directly into the RP and the amplifier directly to the receiver. The assembly is mounted
to the back of a plastic sheet with the antenna in front.

The antenna is looking out a window. I have tried taking it outdoors with no obstructions looking
at the 98 west satellite here in southern California with about the same results. The first few days
it appeared to be working well. I think I was seeing SNR dance around 3 with a signal state of
3 to 4.

I also note that if the computer and monitor in my room is turned on it severely degrades the SNR to around 1 and signal
state to 3. I live in a large apartment complex and am wondering about interference from other units.
I am also tempted to separate the RP, receiver, and L-Band amplifier away from the antenna as a
next step.

They all say 2500 mA on the wall adapters, 1A+2.1A on the battery packs, etc. Which battery pack is it? Published specs on these don’t matter, they never follow them - you need to either test it yourself or find information from someone that has tested it.

If the radio or LNA is at fault, we will definitely replace them.

In my experience with small Arm based computers and RTL dongles the key issue is VOLTAGE and VOLTAGE DROP.

I made some special 5 volt dedicated adapters for my Orange PI Arm mini computer. The Orange Pi would not boot. The power supply was EXACTLY 5.0V regulated.

I got a Cigarette lighter adapter to USB phone charger and powered my Orange PI with that. It was regulated at 5 plus Volts.

Lesson. if you power this stuff with exactly 5.0 it will have issues.

If you power it with 5.2 volts which I think is what a Cigarette USB charger puts out it seems to work better.

My CHIP and RTL are now powered by a single Cig/USB 5plus volt charger.

I no longer need a powered hub in between.

If you are unable to get it to work try a powered hub in between the RTL dongle and the CHIP/Raspberry. I successfully used a USB 3 powered hub for weeks when I first started.

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The battery pack was a RavPower 10050 Ma. I have talked with another person and they had
about the same signal readings so I decided to take the antenna and receiver assembly off the
plastic mounting sheet. I took a deep dish baking pan and placed the antenna inside. I am now
back up and receiving data again with a SNR bouncing from about 2.5 to 3.5. I am powering it
from the wall power supply for now.

I think the receiver and L-Band amp are Ok. I have yet to put a meter on it to see what the voltage
level is from the Wall supply or switch back to the battery because everything is propped up and I
do not want to disturb it for now.

It could be that the more metal under the antenna made enough difference to get it going again
or the deep dish pan is shielding the antenna from electronic noise. I also have the receiver, L-Band
amplifier, and RP separated from the antenna and shielded by the baking pan. I may ever try the
powered hub as another experiment. A some point I would like to experiment with a different style

I will probably order another amplifier and receiver to swap out and compare and build a second unit
but for now I will experiment a bit.