Cheap ebay antenna outperforms FA antenna?

FlightAware ADS-B Flight Tracking
1

I’ve been on FA for awhile, but just recently got back into sharing data and upgrading my old RTL dongle with the stubby antenna.

I picked up several Raspberry Pi Zero W’s (amazing deal for what they can do) and switched the setup out to the FA Pro stick with filter built in and FA antenna on Amazon with 15 feet of RG58 N to SMA cable.

I have alongside it another RPi0 with another FA Pro stick with filter built in with this ebay antenna on 15 feet of RG316 MCX cable running through two 50 ohm. SMA to MCX converters.

They are mounted right next to each other on my roof and I’m seeing the cheapo eBay antenna outperform the 4x more expensive FA antenna, even with the better RG58 cable. I just changed it out so I will continue to monitor I suppose before possibly sending the FA antenna back I thinks.

https://www.ebay.com/itm/1pcs-ADS-B-PCB-Antenna-1090Mhz-antenna/263637935957?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

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2

Just for ‘fun’, loosen the N plug on the antenna side to see if it makes any difference. Also, just to be sure, check that the male SMA plug is not of the RP-SMA type.

Yes, I’m paranoid about plugs and adapters now.:rofl::rofl:

3

Yes for sure, not RP-SMA, I made absolutely sure after I read a thread here.

Will try to loosen the N a bit.

4

if this cheapo antenna is out performing Flightaware 26" antenna, then there is something wrong with your FA Antenna installation: connectors most likely, as @Dxista has already pointed out.

Just for ‘fun’, Do loosen the N plug on the antenna side to see if it makes any difference.

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5

Will do so, what is the rationale in backing the N plug off a bit?

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6

Backed the N plug off a bit. Still seeing about 10% more messages on the ebay antenna setup, but similar hourly planes numbers. PiAware Skyviews are pretty much identical except a couple planes are different. I can try getting a N to MCX adapter to really rule out the RG58 cable I suppose, but very interesting so far.

7

gain too high?

there are numerous threads on gain so just take a look if you don’t already know what to do :slight_smile:

8

For this test, dont compare FA antenna with cheapo antenna.

Compare
FA antenna, N plug fully tightened
vs
FA antenna, N plug fully loosened

If both give same message rate, then either the connector is bad, or the antenna is bad.

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9

Gain is stock, haven’t played around with that on either RPi installations. I will look for those threads.

10

Loose as in plugged in and like the smallest turn to engage threads?

11

@aigochamaloh

Compare message rates in following 3 configurations:

  1. N-connector plugged-in and threads fully tightened
  2. N-connector plugged-in but threads loose, smallest turn to just engage threads.
  3. N-connector fully unthreaded and cable disconnected from antenna.
12

At the current time:

  1. 260 m/s
  2. 118 m/s
  3. ~3 m/s

Ebay antenna currently doing 300 m/s.

13

N-connector seems OK.
Problem may be In:

  • Cable (sudch as water/mosture inside ??)
    or
  • Connectors at dongle end
    or
  • The Antenna
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14

Hmm, both cable and antenna are from Amazon, maybe I will get both replaced and try again. Thank you for your help.

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15

The default is automatic gain control?
Anyway if you want to get the maximum out of your gear you will need to adjust the gain.

Try a gain of 30 as a start.
If you have no signals in skyview which are greater than -10 then you can start back up but my guess would be that 30 is about the correct gain for that antenna and stick.

There are more detailed explanations of how to set gain but this should be a good baseline.

Also with strong interference from other signals you might need filters before you can fully use the gain of the FA antenna.

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16

This is a very important point which I overlooked bugs%20bunny%20doing%20a%20facepalm

.

Please see this thread: Do I Need A Filter?

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17

Even more so than the filter built into the FA pro stick?

18

Some planes that fly overhead show up on Skyview in the -2 and -3 dBFS range.

19

YES, with a high gain antenna like FA 26" antenna, ProStick Plus (with built-in filter) may need an external filter also at locations with strong Cell / Mobile signals.

Pro_Stick_Plus_Needs_External_Filter

.

.

Low gain antennas, such as Spider, Cantenna or Cheap PCB antenna work OK with Pro Stick Plus’s built-in filter, without an external Filter.

ProStick-vs-ProStick-Plus_Spider-and-FA-Antenna
ProStick-vs-ProStick-Plus_Spider-and-FA-Antenna800×441 173 KB

20

Thank you! Very informative. Will switch out the antenna, play with the gain settings, maybe pick up the FA filter.