NooElec ADS-B 8.5cm Antenna Bundle gain JOKE

Thanks for your detailed reply!
Re NooElec disassembly: Did some twisting and bending. The top will need some (or more <g>) force to come off.

Re coiled whips: So the whips are connected to signal and the base to ground / shield!? No coils or sth. in the base?

Re measurements: Costly, yeah, what I heard in Andreas Spiess’ YouTube videos.

Is it worth it to try some tweaking? Saw some antenna-related settings in the SW, but can´t find them any more.

Re FA vs. AirNav: Planning to stick the AirNav onto some tube to raise it above the roof-top. (ca. 50 cm)
How much above the roof should the antenna-base be and does the tube material matter?

And: Would you shorten cables? Need a meter or two (depending on model and mounting).
The coiled whip has 3m, the AirNav seemingly 10m.

Thanks again for your help
G.

@gue22 - Definitely worth tweaking. There are some threads around here about those coiled wire antennas. People shorten them up to a specific length and stick the magnet mount on round metal lids to cookie tins or similar. The metal lid gives the antenna a ground plane and shortening up brings it better in tune for 1090. Not sure what to search for but you can optimize those wire coil antennas. When properly tuned, an antenna can help pull in signals of interest while “rejecting” noise.

Lots upgrade to different antennas like a discone or the FLightAware stick. I use the 26” FlightAware stick and it made a huge difference to my range and numbers of aircraft tracked. It was just a connect up and go kind of thing but i did need to also get coax and a proper adapter connector.

If mounting antennas outside, you may also want to look into lightning protection.

Those antenna settings you found - maybe to enable LNA power on the antenna cable? I think the Nooelec’s have that capability.

On shortening cables, it depends. There is per-foot/meter loss in coax and you can improve signal strength, but if the cable isn’t too much longer than needed, it gives you flexibility while sorting out your station. Hand wavy but hard to answer without knowing your coax and the length you are planning to cut.

Regarding the FlightAware vs AirNav antenna… I have both. It seems like the AirNav one are getting me more planes. Note: They are still indoor, placed 20 cm apart, and a lot of trees, buildings, etc. are in the way at the moment. The setup is the same for both. Antenna > Uputronics LNA > AirNav green stick > Pi 4B.
The persistence mode was enabled at the same time this morning to see the difference.

AirNav/RadarBox. Max range is ~155 nm

FlightAware. Max range is ~100 nm

No coils inside base. Only lower part of threaded
brass stud, to which core of coax is soldered
Please see details of base here.

Thanks for the schematic! This simplicity opens up a lot of options. Got the Mag Mount thread already open, but didn´t get around to it.

Possibly stupid q: If I don´t use the base I´d use a ground plane or where do I hook the shield?
I think I remember some VERBALLY grounded radio with a flat antenna (300 Ohms?) cable from my youth (for AM radio?). <grin>
Nothing else than the mains ground??

You´re also confusing me with your Quick Spider article. The RG6 apparently is 75 Ohms and not 50, like the RG174.

And is there a reason that the stuck-in radial part is 21 mm?

Lotsa q!
G.

Guess 150 NM and all kinds of obstacles is some accomplishment in Denmark. What´s your elevation?

I remember my flight instructor wanting me to find the highest “mountain” in Florida, called Mount Trashmore, a cultivated ex-dump, 150 feet “HIGH”. <rofl>

I´m on 300 m with unobstructed view of Alps peaks. :wink:

Cheers
G.

My elevation is ~300 feet over sea level - Denmark is quite flat though.

I’ll get better performance, when I get the antennas up. But lucky as I am, looked for a mast/pole at 11 meter, but it was sold already. I’ll find another one :slight_smile:

Use any of these to connect the shield of coax:
In first one, the SO-239 connector and radials form ground-plane, in second one the tuna-can lid acts as ground-plane.

NOTE:
The “ground” and “antenna ground-plane” are two different things.
The “ground” uses rods driven into ground.

 

The tin can looks like from “The Day After” - if there weren´t the cozy, clean houses in the background.

Thanks, ground plane vs. ground was clear. The question was how weird would it be to use the mains plug ground.

And that you use a 75 Ohms RG6 when else is 50. No reflections?

Just tried the NooElec vertically as suggested with no success. Sent the pic to support.

BTW: Would I need to restart dump1090-fa (for AGC) when I change antennas on the fly?

Thanks again
G.

In transmitters this mismatch can cause reflection of power which are in the range of few watts to several hundred watts, and to compensate one requires a transmitter with larger power output, which is a costly affair.

In receiving senario like ours, the power levels are in mili or even micro watts, and any loss can easily be compensated by a LNA which is not costly (FA ProStickj has one builtin with 18 dB gain). In terms of dB, the loss caused in each transition from 50 to 75 or 75 to 50 is only 0.177 dB which is easily compensated by Gain of Dongle and/or LNA

The receiver DVB-T is actually designed for TV reception (DVB-T = Digital Video Broadcast - Terrestrial). As the TV systems use 75 ohms Antenna with 75 ohms TV Receiver, the DVB-T’s input impedance is 75 ohms, and NOT 50 ohms.

SUMMARY: Dont worry, be happy. Just ignore the 75 vs 50 ohms issue

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As far as i know, Flightaware and Flightradar as well are delivering different antennas depending on the country.
In Germany the kit is shipped often with the well known antenna from Jetvision.

Yeah I think a lot of the old-skool HAM guys are more concerned about Ohm’s Law than they should be for a receive only system for ADS-B. To boot, I don’t think many here have very long cable runs (like 100M or more) so the perceived mismatches really don’t have an impact as they would for an Rx/Tx setup.

Being more concerned about keeping the components running cool and without interference should be top priority when putting a system together, don’t sweat the small stuff. Get the antenna as high as feasible for your location and the rest is back-fill.

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Sorry for the confusion. I bought the antenna directly from Jetvision, just refered to it as FlightAware, since they use it.

For everyone´s info:
NooElec support was quick to reply, but now they´re acting stupid by requiring a screenshot with the zero planes I get with their antenna, not sufficing with the one I sent them with the coiled whip mounted.

Refusing to change again to prove nothing.

But I just tried to stick a 68x1mm wire directly into the vertically mounted FA, here with the coiled whip


but 1 mm seems too thick. Need to try a wire from an RG6 tomorrow.

Good night Just saw I forgot to post this with all the NooElec ballyhoo. Good morning
G.

RG6 core wire has diameter of 1 mm, so wont go into hole of ProStick connector.

Straighten a small paper clip. It will fit the thin hole of ProStick plus. I have done it.

 

Radials from straightened paper clips
2019-01-07 21.44.41

After the NooElec support nonsense demand of an empty plane list in PiAware SkyAware when I use their antenna (Doesn´t show anything that I use their antenna or specific reception data) I think I found some culprit when I changed antennas several times:

I had two distinct coverage experiences with the coiled whip:
For some days I had a poor coverage of up to 160km and after some tinkering I had up to 400 km. (e.g. Sunday)

The antenna position was practically the same. (see attic picture)
The difference seems to be that I just screwed the SMA tighter than before.

Maybe the connector male pin just gets close and doesn´t make real contact when not screwed with some considerable force.

Wadayathink?
G.

I think you could use some more free-space around your antenna, no matter what you end up using. I’m willing to wager that you will see better results since surroundings have a direct effect, especially solids.

I pasted some side-by-side tests that included one of them coil antenna’s and they are truly trash. Grab an FA antenna and be done with brain-bleeding that portion of things, you will save in the end, money and heartburn. (I don’t work for FA or get anything by recommending their antenna, I just haven’t come across a cheaper alternative that performs as well, so until I do, I’ll continue to recommend them)

The Flightaware Antenna with Plastic Pipe Removed

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Best antenna to date for me :grinning: