FlightAware Discussions

New Antenna and nothing... HELP

So I just got a new antenna.


Upgrading from the little 12" wire one with the magnetic base.

I’m getting nothing now all of a sudden.

I have my antenna going into a Type N/Type F adapter to about 30 feet of good RG-6 to a Type F/SMA adapter going into my Blue FlightAware dongle connected to my Raspberry Pi V2 runnning PiAware 3.7.2

With my old antenna I wasn’t getting much outside 50 miles but at least I was getting something.

Anyone have any ideas of what I might have done wrong?

I’m thinking I either need to get a Raspberry Pi V4 to get some more processing power, maybe one of the inline 1090 filters. Maybe an AMP??? I would love your suggestions.

Thanks in advance.

The Pi should be enough to receive something. The blue FA dongle has a filter and an preamp.

Maybe check the connectors, try it without the coax, or a shorter run.

There have been issues with different types of n connectors, 50 vs 75 ohm.

Did you change anything else? A new install will give you a new site unless you change the feeder id.

Check if it has a pin in the SMA side. (might have gotten RP-SMA)

One other possibility is that you are picking up strong cell tower interference or something like that.
With the better antenna and mounting it properly sometimes the interference picked up is stronger and the ProStickPlus can’t always handle that well.

I’d recommend that you create a spectrum scan with the new antenna connected:
Do I Need A Filter?

The SMA connection hasn’t changed at all. In fact with the new antenna all that has really changed cable wise is I cut out the 10 feet of tin coax that came with the old antenna. The Pi did recently update but it ran for a few days with the old antenna.

I’ll try the info in the link in the morning. That was one of my thoughts was that the filter in the dongle wasn’t doing the trick cause I’ve heard its not that great of a filter so maybe i needed an extra inline filter.

If using the FA pro plus stick (the blue one) and receiving nothing is very unlikely
The stick already has an amp and a filter built in. Not the best one but better than most other sticks.

Even without antenna the stick is able to show “something”.
I changed the antenna location yesterday and plugged it off from the stick for some minutes.
There were still 2-3 aircraft displayed and the message rate was not zero.

That’s not true.
The LNA actually makes it more likely than a stick without LNA going deaf.

Interference is no joke. Mobile antenna tower on same level as your antenna, two or three houses away, and you’ll receive nothing.

But why was it working with the previous antenna? Would reducing gain work?

Not necessarily.
I’m pretty sure it’s the LNA itself which sits in front of the filter which gets saturated.
If that happens, gain change won’t help you.

What helps is either a filter or an antenna that’s worse and not picking the signal up that strong.

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Ok, it’s been a while since I last used Putty to log into a Pi.

I’m putting in the IP address and leaving the port default which is 22. I’m getting “Network Error: Connection Refused” I’m sure it’s something super simple I’m forgeting

Enable SSH access

  • For security reasons, SSH access is disabled by default on new PiAware SD card installs, starting with version 3.3. To enable SSH, create an empty file on the /boot partition of the SD card with the filename of “ssh” only (no file extension). When this file is present, SSH will be automatically enabled.

https://flightaware.com/adsb/piaware/build/optional#wifi

Running the scan now. Thanks for the help. I’ll post the results when complete.

Yep, sure looks like interference.
LNA overloaded.

You’ll need a filter.

Some examples:

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Great! Thank you again for helping me through that.

@tripppn

Click on image to see larger size
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:astonished::open_mouth:

That’s probably the clearest example of out of band interference I’ve seen on one of those scans. I’m not surprised you aren’t seeing anything at all.

Should a filter clean it up. I already ordered it so I guess we’ll see in a couple days. I’ll run the scan again with the filter and let you guys know.

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A filter will help, but man that’s a lot of interference right at 1090.
Filters get rid of stuff that’s around 1090 while trying not to touch the small range right at 1090. but you’re just solid all round that whole range.

That’s probably not quite correct.
Due to the SAW filter any noise outside that band will be attenuated.

Now if the LNA is overloading and producing broad band noise, then this is what it looks like.
There isn’t any specific noise in that band.