FlightAware Discussions

Does the FlightAware 26" 1090Mhz have built in groundplane?


#1

I am only used to magnetic mounts that I stick on a metal plate. If I buy that 26" antenna for 1090Mhz from FlightAware, for indoor use, would it be simply prop up, plugin, go? Or would it need grounding either by an earth connection or a separate metallic ground plane? If so, what would be required for optimum functionality within an upstairs bedroom?


#2

I used it in a ground floor bedroom for several months by simply propping it up along a big window without any grounding. The obvious caveats apply. Data will flow but…

Regards.


#3

How effective was it for you? Could you compare it to any other antennas in the same kind of placement?


#4

I have placed the Flightaware 1090 Mhz 66" antenna in a large window, touching the glass all along its length. I have placed besides it at 1.5 ft (50 cm) away horizontally (also almost touching the glass), following two antennas, and FlightAware 66" antenna proved better than both in terms of plane count and maximum range.

  1. Mag mount antenna of DVB-T, whip cut to 67mm (1/4 wavelength) and placed over food can 80mm dia.

  2. Quick Spider.

Note
Due to strong Cell/Mobile signals in my area, I am using a filter with prostick plus. Without filter the performance of FA antenna becomes poor. You need or dont need a filter depends on how strong cell/mobile signals are in your area.


#5

Any antenna, for optimum functionality needs to be grounded.
Might be at antenna, or other end. At those frequencies, grounding can be via a capacitor, like the ones included in the power supplies.
So no need for dedicated ground, but tying the metal part to ground might help. More reading:
http://www.hard-core-dx.com/nordicdx/antenna/ground/ground2.html

Now, there is another type of grounding - for lightning protection. If the antenna is high enough, it should be considered:


#6

This is the comparison of FA 26" /66 cm Antenna with DIY Cantenna which I did in June 2016.


#7

You don’t need any ground plane for the FA antenna

Not sure why someone would talk about electrically grounding the antenna, it’s not relevant to the question “does it need a groundplane”.
The link provided by Sonic mainly talks about antennas with much lower frequencies, so most of it is not really applicable. Connecting the antenna to the dongle is all you need.

Would suggest one of the following dongles / filters:
Blue FA dongle with FA filter.
rtl-sdr blog v3 dongle with their LNA.


#8

No groundplane is needed for this antenna.

(nb: there is a bit of confusion in some replies about grounding vs. groundplane; I’m specifically talking about a groundplane here, typically used to turn a monopole into a dipole by reflection; see https://en.wikipedia.org/wiki/Monopole_antenna#Radiation_pattern. The FA antenna isn’t a monopole and doesn’t need a separate groundplane)


#9

Well the question is indeed about ground plane.
But that implies that the metal is grounded electrically, hence the “ground” in the name.
The shield of the cable is not always all that’s needed.

That’s why I mentioned the other issue. No confusion.


#10

I am not an antenna, nor RF expert. But I have found that electrical grounding and a ground plane may have connections between their benefits but one does not imply the other. Before I post this, I just did a quick google and found this on wikipedia for Ground Plane:

“In telecommunication, a ground plane is a flat or nearly flat horizontal conducting surface that serves as part of an antenna, to reflect the radio waves from the other antenna elements. The plane does not necessarily have to be connected to ground. Ground plane shape and size play major roles in determining its radiation characteristics including gain.”


#11

Fully agree. :+1: :+1: :+1:

.

@ittechtal
I use Flightaware Antenna Indoors.
(1) No groundplane for FA Antenna.
(2) No grounding of antenna or coax shield.
With above setup, It’s performance is excellent :smiley:

NOTE: The Monopole (Cantenna) has a groundplane in the form of Coke Can

CLICK ON PHOTO TO SEE LARGER SIZE
CLICK AGAIN TO SEE FULL SIZE_


#12

That is not true. A balanced antenna, such as a balanced dipole, does not need to be grounded.
In fact, it should not be. A balun (balanced to unbalanced transformer) is used to convert the balanced signal to an unbalanced one if fed with coax cable.
I believe the FA antenna incorporates a sleeve balun as part of its design in order that it can be fed with coax cable.


#13

Thank you for that great image. Is that ground level or like, upstairs or something? Also what kind of range do you get with that FA antenna? Mine currently I am getting my best coverage south east and I am using a telescopic antenna that I collapsed and then sawed a little bit off to make it 1/2 wavelength and it’s still sat on the same 15cm circular ground plane. I am getting a good 120 miles. Do you think if I were to upgrade to the FA antenna that I may expect better performance?


#14

Fully Agree :+1:

.

TRUE
I feel there are TWO Sleeves
(a) First one made of brass, just below the Coil (Length of Sleeve = 1/4 Wavelength)
(b) Second one made of stainless steel just above the N-connector (Length of Sleeve = 1/4 wavelength)
The rigid coax between two sleeves is also 1/4 wavelength.

CLICK ON PHOTO TO SEE LARGER SIZE
FA Antenna from inside


#15

It is in my apartment which is about 60 feet above road level :slight_smile:

.

Over 250 nautical miles, but less than 300 nautical miles.

.

I have another one similar to yours, cut to 67mm (1/4 wavelength), gets me over 200nm but less than 250 nm.


#16

Quick answer, yes, I think it would.
I use the FA antenna indoors, it is just tie wrapped to a rafter in the loft.


I do have some additional filtering as I have some very strong Mobile Phone signals here but it seems to work quite well. Much better than my results using smaller antennas.
This is my site if you want to look at the stats:


#17

The so-called balanced antenna is actually two unbalanced antennas in phase opposition. The ground is happening inside the receiver, middle point.
An antenna that has no way to drain the static electricity is a dangerous thing if installed outside.
The fact that might “work” indoors is just because there are very few static charges and because the dingle have internal diode to clamp any dangerous voltage build-up. But that diode has it’s limitations and on an outside installation, a ground wire should be used.
Unless you like the chances of getting an electric discharge routed inside the house.


#18

Thanks. Although in my position I have no access to be able to put things in our loft, so I have to makedo with putting the antenna in my room. It is a big chunk of money for that antenna and cable but I am considering it. I am just not sure if it will make much difference covering the east side of the UK where I tend to get less hits due to geography I suppose.


#19

Geography? Just less planes there. Or there might be another building/tree in the way?

Anyway you can check the geography here: What is the Maximum Range I can Get?


#20

Thanks. It seems I am not at what I could be. Although I bet this is calculating open air vs in a house at the same elevation etc. But I am on the verge of purchasing it.