1090 Antenna real or Fake?

Discuss commercial and home made antennas.
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Username
Posts: 482
Joined: Sun Oct 09, 2016 7:27 am

1090 Antenna real or Fake?

Post by Username » Sun Dec 09, 2018 1:38 pm

Hi
Everyone who travel from time to time on a plane know there is no better place to track other Aircraft. :D
The problem the Antenna must be "Stealth" to hide it behind a window shade. ;)
I found on Ali this: https://www.aliexpress.com/item/10-piec ... 9b767b65bf
https://www.aliexpress.com/item/5-dbi-S ... eee71477b8
https://www.aliexpress.com/item/10-dbi- ... eee71477b8

are the genuen or just relabled LTE Antenna?

HighSNR
Posts: 45
Joined: Mon Sep 18, 2017 8:14 am

Re: 1090 Antenna real or Fake?

Post by HighSNR » Sun Dec 09, 2018 2:00 pm

There is no way to tell without some sort of measurement. Many antennas I get from reputable brand name suppliers dont come close to meeting their performance specs.

EmilK
Posts: 5
Joined: Sun Dec 09, 2018 1:51 pm

Re: 1090 Antenna real or Fake?

Post by EmilK » Sun Dec 09, 2018 3:36 pm

I would say its a fake - the 10 db statement - my 10 db antenna has 1.8 m length. The one in your post has 37 cm.

snn47
Posts: 180
Joined: Tue Dec 27, 2016 11:00 pm

Fake 1090 Antenna

Post by snn47 » Sun Dec 09, 2018 7:13 pm

There is a difference between theoretical and real meassured gain, and here it is a placebo gain to bait buyers, because you can't cheat physics.

To give you an idea of the necessary size for an vertically polarized omnidirectional antenna with meassured 10 dBi gain look at https://www.kathreinusa.com/wp-content/ ... 715986.pdf. The active antenna length is about 1945 mm.

An increase in gain will either limit the beamwidth in azimuth or elevation, as you can see from the narrow elevation pattern.

Some antenna, e.g. 1/4 wave-length monopoles are smaller, but require a ground plane of sufficent size to operate, e.g. aircraft blade antenna for 960 - 1215 MHz, while small in size require a 4 ft by 4 ft as ground plane (source DME/SSR MOPS) see also L-Band receive antenna (960 MHz to 1215 MHz) viewtopic.php?f=6&t=1516 .

Furthermore in order to obtain the gain requires that an antenna is clear ob obstacles, any non-conductive and conductive in the direction to the source you want to receive, The closer they are to an antenna the more distorted the antenna pattern and the lower gain is.
Last edited by snn47 on Sun Dec 23, 2018 4:04 pm, edited 1 time in total.

rtlsdrblog
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Joined: Mon Nov 19, 2012 11:54 pm

Re: 1090 Antenna real or Fake?

Post by rtlsdrblog » Sun Dec 09, 2018 10:33 pm

The first one doesn't even have the right connector, it's using an RP-SMA connector meant for WiFi devices.

The whip type antennas are quite trash unless you're actually in a plane. Go for a FlightAware antenna or similar. Should still be small enough to hide behind a window.

Username
Posts: 482
Joined: Sun Oct 09, 2016 7:27 am

Re: 1090 Antenna real or Fake?

Post by Username » Mon Dec 10, 2018 10:31 am

Which one?
I know only that: Image

rtlsdrblog
Site Admin
Posts: 2368
Joined: Mon Nov 19, 2012 11:54 pm

Re: 1090 Antenna real or Fake?

Post by rtlsdrblog » Tue Dec 11, 2018 4:39 am

Username wrote:
Mon Dec 10, 2018 10:31 am
Which one?
I know only that: Image
https://www.amazon.com/1090MHz-ADS-B-An ... lightaware

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