FlightAware Discussions

Discussing best 978 MHz hardware setup

Ok I’m really happy that we will get a new toy in coming days - support for 978 MHz UAT ADS-B.

So, let’s discuss the hardware setup. Ok computer part should not be relevant, but:

SDR. Which one? Orange ProStick? rtl-sdr.com? NooElec Smart?
Preamp. Yes, no, which one?
Filter. FlightAware cylinder, something alternative (I saw smaller cheaper ones sold on Ebay), no filter?

Filter wo preamp, preamp wo filter.

Antenna. Length. Types. Is FlighAware antenna good enough? DIY, etc.

About SDRs. There is newer Smart XTR. NooElec say they don’t recommend this one for ADS-B as there’s “a small gap in frequency capability near 1100MHz. As such, we do NOT recommend this device for ADS-B usage.”

About everything else: I’m now experimenting with NooElec Smart + FlightAware filter + different antennas, ordered some online.

I’d probably use the rtl-sdr v3 dongle.

I use the FlightAware pro stick (Yellow/Orange) with the older 1090 filter and into my home made can-tenna cut for 978 mhz. By the info on the graphs I see aircraft out as far as 81 miles. I use RG6 CATV coax.

NooElec Smart + FlightAware filter + NooElec 978 MHz 5 dB antenna.
It’s located outdoors, on the balcony. I live on the hill, so sky view isn’t too bad and I see about 20 airplanes currently on my 1090 MHz.

Well, one (one!) message in the last 20 hours. That’s definitely better than 0, but something is probably wrong.

NooElec antennas or what is sold as a NooElec antenna is often crap.

They are tuned not even close to the advertised frequency.

If you have coax, try and make one of these:
QUICK SPIDER - No Soldering, No Connector

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Crap? Yes, likely. I compared their 1090 5 dB one (I got both 978 and 1090) with cheap 2.5 dB one from Ebay and with paper clip cut to 153 mm. Both cheap antenna and paper clip won. Thinking about returning those. Will try coax.

I replaced NooElec 978 MHz 5 dB antenna with 153 mm paper clip. Now getting few UAT messages, about two per hour. So paper clip is better than their antenna. Will return.

Also I collected the heatmap around of 978 MHz.

rtl_power -f 975M:985M:2k -g 50 -i 5 -e 240m 4.csv drawn with gopow:

What can you say?

76 mm would be quarter wave for 978 MHz.

Then some improvised radials and it should be better than the paper clip.

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Currently I am using these ones

  • Left magmount for 978 Mhz, whip (thin steel wire) cut to 75 mm.
  • Right magmount for 1090 Mhz, original whip cut to 67 mm.

Plan to built & use this one (two pieces)

  • For 978 Mhz: Whip & Radials 75mm.
  • For 1090 Mhz: Whip & Radials 67mm.

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Yup, 76 is quarter wave, and 153 is half wave. Or is quarter better than half?

Have same plan but I need to wait for Type F to SMA adapter to arrive.

.

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I’m getting great results at 1090 with this:

https://ebay.us/MDyc6Z

978 is another story

If you don’t have a spider to compare it to i would be careful in saying that you are getting great results :slight_smile:

If you want a relatively cheap ebay antenna which is good, check out this one:
https://www.ebay.de/itm/1pcs-ADS-B-PCB-Antenna-1090MHz-Antenna-SMA-female-Antenne-CASE/253915016420

I’ve tested it and it performed as good as my quarter wave spider, maybe better.

I already ordered this one (tubeless variant), but will take like 3 weeks to get here.

Note that you need a male to male SMA adapter or pigtail.

Have you tried replacing the whip of the antenna you are currently using? (should unscrew)
Length should be 67 mm from middle of the base to top.

Then some reflector and the whip antennas normally get better.

Maybe you actually got one that is tuned to 1090 MHz but i somehow doubt it.

Will piece of 1/4 wave wire on the whip stand be better that piece of 1/2 wave wire plugged in directly? I’ll try of course. BTW I’m now generating a higher resolution heatmap, I see some hot zones around 978 MHz here, maybe that’s cause of interference.

That one you posted seemed quite narrow and everything in the heatmap didn’t really look like noise, rather just a pattern from the receiver but i don’t know.

Trial Run Results for Three Types of Whip Antennas