978 Mhz UAT in the US

I dont know about others, but I use a Cantenna with Whip 76mm, and a drink can also cut to height 76 mm. I use 330 mL /12 oz Pepsi can (dia=68mm). Unfortunately there is very little UAT 978 traffic around Toronto, so I rarely catch any fish … oops plane :slight_smile: .

For 1090 Mhz also I use Cantenna made of above noted size Coke can, but the whip & can are both cut to 69 mm.

Please note that:
@1090 Mhz, 1/4 wavelength = 69 mm
@ 978 Mhz, 1/4 wavelength = 76 mm.

At the moment I use the crappy telescopic unit that comes with the dingle. Fully closed.
Once I move the setup to the attic(and antenna to the chimney), I will buy this to match their 1090Mhz version I have
dpdproductions.com/page_vhf_ … #978adsout

I haven’t seen many good commercial options.
FA has talked about a 978Mhz antenna. It has not yet appeared.

I have a COCO that I built specifically for 978. was getting 40-50 flights a day last summer. Not currently running it but will one day get it back up. Currently focusing on 3x20 mile triangle of 1090. 2 of three feeding very well and getting ready to install 3rd. After that I will throw the 978 back up and start tuning.

Cheers!
LitterBug

PS: I have used my 1090 COCO antenna to recieve 978. Not as many flights, but it is better than the stock antenna…

I have their 1090 antenna and it works great. Zero issues with it. For 978, I just have a clipped OEM antenna. It only provides a 10 mile radius. I will also be getting the DPD 978 antenna this spring.

I’m using a splitter with my amplified 1090 coco which is mounted about 40 feet up. It has seen 978 traffic up to about 50-55 miles away even though I’m surrounded by tall trees. I’m also planning a dedicated 978 antenna eventually.

As others have mentioned, there isn’t a large volume of 978 traffic in the US yet. I usually see about a dozen or so aircraft a day, but I am not located in a busy area.

I’m still having a problem with 978 traffic showing up on 1090. Sometimes it does and most times it doesn’t. I eventually ended up using jprochazka’s scripts at: https://discussions.flightaware.com/ads-b-flight-tracking-f21/ads-b-feeder-project-setup-scripts-t36532.html
It allow you to set up everything, dump1090-mutability, dump978, flightaware and performance graphs fairly easily. All the different setups which I have tried still have a problem with most of the 978 traffic not showing on the 1090 map. I’m still working on that.

Thanks everyone. I’ll give the 76mm Cantenna a try.

I have a FA antenna on my roof for 1090Mhz and a DPD AIS antenna for AIS. Both of which I am pretty happy with.

@johnhawkes2030 how have you found the DPD 1090Mhz antenna? Do you know of any comparisons between that and the FA antenna?

@bakerkj
Sorry, I am a few weeks away from using the DPD Antenna.
Even when I do, it won’t be a fair comparison.
The FA antenna is in my bedroom(2nd floor U.S. counting of floors), behind a corner dresser that has a 40" LCD on it. I suspect the TV may interfere with the piaware when it is on.
The DPD antenna will be outside, mounted on the Chimney on a 10’ pole. It will be 10-15’ above the FA antenna and outside.
The chimney is such a pain to get to(I have to borrow a tall ladder) that I only want to do it once.

The other pain for me is running conduit from the basement to the attic for the cat5e STP. I will use POE so I don’t need to have power in the attic.
I may be able to compare the antennas once I run the cable to the attic. I can test them both inside the attic, making a fair comparison.

I live in an apartment with no balconies. The building management does not allow to install antenna on roof top, or an antena poking out of a window. My installation is therefore strictly indoor.

I have large wall-sized nonuopenable glass windows. I have installed my antennas near the corner with large glass windows. My own buildind, and adjuscent high rise building blocks nearly 50% of the 360 degree view. However in the unobstructed semi-circle, I get max range 250nm in best direction, and 200nm range in most directions. My system has no amplifier. The brief details below:
Cantenna >> 12 ft / 4m RG6 coax >> F-to-MCX pigtail RG316 >> DVB-T dongle >> RPi >> 15 ft / 5m network cable to router.

For both 1090 Mhz and 987 Mhz, I use Cantenna. The one photographed is for 1090 Mhz, but the 978 Mhz one is nearly same except slightly longer whip & slightly longer can. The dvb-t & rpi are below the antenna on floor (not shown in photo).

Recently I purchased FA antenna, and put it on trial run side-by-side with Cntenna. Result were unexpected: Cantenna out-performed FA Antenna. I suspect that it is due to dodgy N-to-F connector, or dodgey F connectors on the RG6 coax.I have ordered a N-to-F adapter and a N-to-MCx pigtail, delivery from China by mid March :frowning:

Testing of FA antenna vs Cantenna

https://farm2.staticflickr.com/1665/24776996065_9bcbb7a0be_z.jpg https://farm2.staticflickr.com/1552/24645800311_0f0b9645d1_z.jpg

.

Anyone running two RTL dongles and a usb WiFi stick on the same RPi? If so what power adapter do you use?

I have a Pi2 with two 820T2 dongles and a generic usb wifi adapter. rtlsdr couldn’t access the second dongle until I set max_usb_current=1 in /boot/config.txt. Now it works briefly but the Pi reboots randomly after a few minutes.

I guess my supposedly-2Amp power supply is not up to the task. So I’m wondering if it’s worth it to invest in a better power supply, or do I need to buy a powered USB hub?

The dongles are pretty power hungry - 300mA each, something like that? Between that, the Pi itself, and a wifi dongle you’re probably drawing something like 1A. Many nominally 2A power supplies won’t supply anything close to 5V @ 1A…

They just announce a dual band/frequency antenna for 978/1090Mhz
ads-b-flight-tracking-f21/8dbi-978mhz-1090mhz-antenna-t36003-75.html

amazon.com/dp/B01BKRMGEY
I ordered one.

Amazon.com do NOT ship to Canada :frowning:
Amazon.ca do NOT have this item :frowning:

https://farm2.staticflickr.com/1602/24984083065_f9f2d543c3.jpg

I haven’t seen this before. Usually all I see are local low altitude 978 aircraft. It seem strange that this flight would show up on dump978 at an altitude of 40000 feet. It was also shown on dump1090.

This is a portion of the aircraft.json file:
{
“now” : 1455312570,
“messages” : 9735,
“aircraft” :
{“hex”:“a72844”,“squawk”:“2270”,“flight”:“N560PW”,“lat”:31.559107,“lon”:-78.330159,“seen_pos”:1,“altitude”:39950,“vert_rate”:-128,“track”:198,“speed”:349,“messages”:815,“seen”:1,“rssi”:0
]

I’m having a problem getting most of the 978 aircraft to also show on the dump1090 map, but this is this first I’ve seen of what should be a 1090 aircraft showing up on the dump978 map! I don’t see how it can be a rebroadcast as I haven’t been able to receive a ground station, and this was only one of many 1090 aircraft in the same area.

That N560PW appears to be a private jet. In order to fly above 18,000 feet you must run 1090, but there is no rule against also having a UAT and leaving it on. So you may have actually seen a signal direct on 978. Some people like having all the gadgets.

Thanks. You’re right. I didn’t think of that. I’ve seen it again.

I set up dump978 feeding dump1090 like so:


rtl_sdr -d 1 -f 978000000 -s 2083334 -g 48 - | ./dump978 | tee -a 978.log | ./uat2esnt | nc 192.168.1.123 30001

Works fine for a few hours but then rtl_sdr catches a SIGPIPE error and exits. Is there an easy way to find out who is breaking the pipe? Maybe nc drops its connection.

The signaling pid is rtl_sdr and uid is me, so no help there. I guess I could add a signal handler to uat2esnt to find out if nc is at fault…

I have the same issue. My BandAid solution was to set up a cron job to restart dump978 every hour.

I am not my computer at the moment, so I can not point to a right topic, but search the UAT topics for the script obj posted some time ago. It is piaware such restarting dump1090 if it have not heard from it for a while and that causing the issue

Thanks, that could be the issue indeed.

Last night I caught some uplinks for the first time (the transponder is rather far from my location so I was surprised)

Is there any website or program to decode NOTAM messages like this?


UPLINK:
 Site Latitude:     +29.7025 (possibly invalid)
 Site Longitude:    -96.9007 (possibly invalid)
 UTC coupled:       yes
 Slot ID:           0
 TIS-B Site ID:     12
INFORMATION FRAME:
 Length:            221 bytes
 Type:              0 (FIS-B APDU)
FIS-B:
 Flags:             
 Product ID:        8 (NOTAM (Including TFRs) and Service Status) - Text/Graphic
 Product time:      12/10 21:02
 Data:              22 10 2C C0 98 00 00 D2 54 08 2C 38 F5 01 36 D1 ".,.....T.,8..6.
                    84 0E 02 CC 09 8B B5 BF 5C F7 E2 0C 70 CB 1C 32 ........\...p..2
                    6A 08 46 10 38 35 BF 5C F7 E2 03 02 62 04 C9 12 j.F.85.\....b...
                    05 05 60 14 E0 1D 53 06 80 33 C1 4D 48 12 1C E3 ..`...S..3.MH...
                    2C 78 13 87 30 55 0F 3A F3 01 2C 58 0A 04 32 D3 ,x..0U.:..,X..2.
                    3C EB 20 51 8B 9E 04 C1 58 04 E1 12 24 18 05 24 <. Q....X...$..$
                    72 14 80 41 50 05 25 15 48 5B AE B9 E3 15 18 B2 r..AP.%.H......
                    4E 80 E2 4E 16 01 05 40 14 94 55 21 6E BA E7 8E N..N...@..U!n...
                    06 01 58 0C 54 14 80 63 D2 80 12 52 0D 20 46 52 ..X.T..c...R. FR
                    01 51 54 94 10 14 48 17 25 42 20 4D 52 54 04 23 .QT...H.%B MRT.#
                    05 81 23 81 5A 04 D9 4D 41 4D 81 72 54 22 01 D0 ..#.Z..MAM.rT"..
                    4E C7 8C 18 B8 16 3D 28 0F 55 48 0F 1A 04 C5 49 N.....=(.UH....I
                    62 43 16 E8 31 D7 1C B1 C3 2C 70 C6 DC 76 C3 6C bC..1....,p..v.l
                    37 CB 1C 31 15 35 1E 00                         7..1.5..