Troubleshooting decline in positions reported


#1

This last month the number of positions I am reporting has been on a pretty steady decline. See the attached image.

I am running the FA Antenna on a 20’ mast with about 40’ of LMR400. A 1090 filter into the blue FA dongle. Latest piaware on a raspberry pi. Connected via wifi. Oddly, I changed my wireless AP on 9/3. I can’t imagine why that would lead to a slow decline like this, but it would be on odd coincidence.

My troubleshooting plan:
1 - swap out for a different raspberry pi
2 - swap out antenna for backup antenna to test that part of system

Any other ideas I can test?

I’ll report back if anybody is interested.

Thanks!


#2

wow, that is a clear decline.
Some location taper off after the summer peak but that is a huge difference.
Your range has also decreased significantly. You are now barely getting 80NM.
Check for water or corrosion in the antenna feed line and connectors.

Could you be getting noise from something?
Is the RPI in a metal case(RFI shield). I have my dongles in metal cases to protect them from the noise from the RPIs and power supplies.

Do you have information on the wifi quality? That could also cause a traffic drop off.


#3

Your range dropped, you can check that by selecting dates in the coverage graph.

If the new wifi was to blame it would be a sharp not a gradual drop.
A failing raspberry pi would cut positions regardless of range.

It’s either one of the amplifiers in the dongle going weak or somewhere the connection to the antenna corroding.

Could also be that the coax itself is taking on water internally somehow.

So i would start to check with another dongle and then check the connections towards the antenna.


#4

Just a suggestion. Also do a check on your cable connectors. Maybe there is water inside.


#5

Thank you all. I will hopefully get a chance to tinker with it tonight.


#6

Do you happen to have a picture of your setup? I like this idea and would like to adopt it…but I’m not sure if I am visualizing it correctly.

Is it one RFI shield for the RPi, and then another for the dongle, and yet another for the power supply?


#7

You can get metal RPI cases, with and without fans, on Amazon as well as other sites.
I got the dongle cases from the rtl-sdr website a while ago. They don’t sell them any more.
I use a quality 6” USB 3.0 extension with the dongle. I out an RF choke on it and all leads to reduce noise.

I use dialectric grease inside the coax connectors. I then seal them with self sealing tape. I have read stories of water getting into the FA antenna too.

I am in a very electrically noisy environment. Many WiFi devices and cell towers within a block or two. I do everything I can to limit the noise.


#8

That should get you more than the 50 miles that you seem to have now. I would check the antenna connection (water, corrosion).


#9

That has changed, they do sell them again, with an additional sma side panel, so you can use it as an enclosure for a filter ( after you cut it to size).


#10

That’s right. The $10 eBay SAW filter can have a nice case now. I was already thinking about purchasing one, the case makes it an even stronger option.

I already had my eyes on the RSP1A metal case.


#11

Thanks @biekerc,
I see them now



#12

Make your own case, any shape, any size using cardboard or plastic boxes, PVC pipes etc. The glue is also conductive and you can solder your grounding wire directly to the copper. Or, apply the tape directly over the existing dongle or RPI case.

https://www.amazon.com/Copper-Conductive-Adhesive-1inch-12yards/dp/B018RDZ3HG