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Low cost ADS-B options for VFR aircraft


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There is a difference between what FlightRadar24 and the Airservices systems will display because they are entirely separate systems. The link to the Airservices ADSB coverage maps show what the ATC system will see. In some areas this may be better than what FR24 is capable of, but in many areas, FR24 is capable of much better coverage due to a higher number of receivers provided by community input.

 

In the way of a couple of examples:

Kalgoorlie WA. ATC system nearest receivers are Leonora and Esperance, lowest level coverage at Kalgoorlie is around 10000-12000 feet. FR24 has a local receiver with coverage to the ground.

Learmonth WA. ATC system has coverage to the ground, FR24 does not (not sure of actual coverage floor there but it didn't show RPT jets at around 5000ft when I was there the other week).

 

This can provide a lead in to the question 'why can't ATC extend their network by using FR24?'. The answer to this the system integrity and redundancy requirements that need to be met in order to ensure its accuracy. There are very specific standards for this equipment.

Each ADSB receiver site is not just one single receiver, but requires additional infrastructure to support it. Each site will have the antenna mast with two separate antennas with separate cabling feeding independent receivers. Each receiver is powered by a main power source with battery UPS backups capable of providing power for several days. There are also redundant signal paths for the data to travel to Melbourne/Brisbane centre via terrestrial and satellite links. As much as I would have loved to have better coverage in the ATC system, sadly the costs involved are not trivial.

 

 

All this is to say, ADSB is a great tool, but don't expect that just because you can see it on FR24, ATC can see you on their screens.

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Wow I am surprised at how little coverage there in in ASA system..The hummock and Roma and norther NSW...no wonder its 5000ft they quote and why FR24 is so much better. I actually have a FR24 system that FR24 sent to me to install up at my farm...I havent done it yet but will be very shortly

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Actually you are right..I now remember I was told that he got onto FR24 and got it fixed for his R number
Try HERE, it's the FR24 forum where you can post database corrections. All 719 pages of it so far! :P
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Wow I am surprised at how little coverage there in in ASA system..The hummock and Roma and norther NSW...no wonder its 5000ft they quote and why FR24 is so much better. I actually have a FR24 system that FR24 sent to me to install up at my farm...I havent done it yet but will be very shortly

 

Strqnge: there seems to be a really heavy concentration of ADSB infrastructure in the North Eastern quadrant of Tasmania, compared to the rest of the nation.

 

(Marty had better get ADSB on his CH 701)

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IS that ADS-B equipment or MLAT? I have a vague memory they (ASA) introduced MLAT down there before ADS-B as a cost-cutting measure many years back. Anyone else have a similar recollection?

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Yes will be ok for a plastic fantastic but a all aluminium and steel cage is a whole different matter

 

That external antenna mod is looking better and better

 

I have to say the CASA rego office to get your hex number is on the ball....I got mine literally in 2 hours from the first email to them

 

 

I also received my codes in less than 2 business hours. Well done to the aircraft registrar at CASA.

 

Maybe I don't need this device but anything to improve my safety is a worthwhile investment to me.

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I agree, it's about safety. I purchased a PCAS once, now the company is broke, I know why, doesn't work well if at all and plenty of ghosts.

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My Skyecho works great (Ozrunways Ipad) unless you change the wifi settings and/or try to add a password. It's not really a huge problem as most aviators won't mess with it but I like a little security at busy locations.

For Around $900 bucks everyone should be carrying these thing's.

Also means the old school map an nav's exercises need to be reviewed and replace with electronic flight bags.

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Of course, they only really help if you respond to a radio call directed at you.

 

Some muppet was flying about in VH-DDS last week (ADS-B visible to Center), transmitting ZK-MVP on OzRunways (Visible to me) and blithely ignored both my calls (on Area & 126.7), and BN Center's calls trying to deconflict with him for the descent - tried both callsigns and we were both ignored. Turns out ZK-MVP is an ATR-72....:bash:

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Re external antenna...

I have found that simply plugging in a USB cable into the Skyecho, (no charger/battery pack etc on the other end of the USB cable - ie leave the other end unplugged) definitely improves its detectability (YMMV)

 

I have only just discovered this by the fact that it can be detected by my FlightAware unit when I plug the cable in, but not detectable without the cable.

 

(Background to this - I seem to have a fault with the SkyEcho battery led - the YELLOW battery level led doesnt light up - so I wrapped the Skyecho in aluminium foil to prevent any extraneous transmission, and ran it till about flat battery. I then plugged in the USB cable prior to recharging, and the Skyecho appeared on my local Flightaware page - removed cable, the Skyecho disappeared- this was repeatable many times)

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Maybe some sort of capacitve radiation into the lead but at 1090 mhz the antenna is very short and the USB cable is long...I dont know why..maybe more power to the transmitter when attached to the USB

 

Picture attached of the inside of the SkyEcho...its super easy to connect a external antenna. The antenna on the left is the Flarm/UAT antenna on the pcb and the one on the right is the ADS-B 1090 mhz antenna. You can see 2 small connectors near each antenna. These have a switch inside them for when they are tested. If you clip on the antenna coax tail it cuts out the onboard pcb antenna and then your signal can go out to a proper Transponder antenna

IMG_8871.thumb.jpg.a928156ed2b24903f4fd7d9869f00b7b.jpg

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Watching that Bertorelli video about ELTs (just posted in another thread) I'm reminded that another advantage of ADSB transmission is that it leaves a breadcrumb trail for SAR. He mentioned that (in the US) authorities keep a record of all the data for at least a number of days. I suppose that's similar here.

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From what I have read Aireon, who run the space based ADSB system will also provide tracks when requested by SAR agencies.

 

Which is probably the only way you could get a track in Australia if you disappear in aremote area.

 

Would be interesting to one whether the sky echo is picked up by the space based system.

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No the SkyEcho is not designed to do that. Its a different antenna design also 250 watts compared to to 20 watts. Path loss to geostationary satellites is horrendous at those frequencies and 1 or 2 dB is the difference between silence and hearing. Just the power output difference alone is about 11db or so

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...Which is probably the only way you could get a track in Australia if you disappear in a remote area...

OzRunways have a good record of providing track info to search authorities; I presume AvPlan could as well.

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You can wrap it in foil but that only works when the shield is wholly encasing the device.

As soon as you connect the USB cable, the radio fields of the outside world comes to the inside 'shielded cavity' , along the outside of the cable... The shield now has a sample of the outside world.

 

Yes, the wavelength is short and so it acts as a multi wave long antenna, and may be quite efficient.

 

The shield of the USB cable must be terminated (attached) to the shield (of foil) where it entered the foil shield,

 

If you need to test this stuff without it getting out, use a fully seam-welded box (or screws on the seams no more than 2.5cm apart .

 

as for getting a cable into it, run the cable through a piece of narrow (say 10mm ID) metal tube say 300mm long into the box. the tube should be well attached to the box (welded or soldered or otherwise bolted/riveted etc) . soldering it up with brass sheet and brass tube works OK. or copper clad fibreglass PCB and copper/brass tube. or a nice box.

The cable shield should be terminated (attached) to the tube open end.

 

Glen.

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Glen

I am not sure if you know what the SkyEcho 2 does but its a neat relatively cheap device for being really only for local aircraft to aircraft ops. So it is a short range device somewhere between 10 and 40 nm. It would be far better as you know not to have the onboard microstrip antenna to get increased range as this may be better for the ground station visibility. When I got mine I had a look at it to see how easy it would be to fit a proper external transponder antenna to it...which by the way in the paperwork says you are not to modify it in any way..but we all know what that means :)

 

These micro style connectors are pretty sweet for this purpose they are designed so of course to tune and check parameters directly there are special push and hold in coax connectors into the females you see on the pcb that of course just go to the test gear for setup and alignment. That connector has a small wafer inside so it totally disconnects the pcb antenna. After much searching I found the company who makes the connector..never heard of them before but they are quite large apparently. I got a couple of samples but they were the wrong size too big :(... so between myself and the rep from the company we found the right one but the bummer is they do not make the small attachment connector for that size that we can use a tail for. They only make the push on test connector. So still easy enough to add a external antenna just not as simple as plugging a tail into it its a soldering jobIMG_8936.thumb.jpg.31920f0f0e3ea70fc163a6de380fdc8e.jpgIMG_8935.thumb.jpg.af299224c26a79ca0d9ccc4d95f49869.jpg

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Hi Mark

Looks like an MHF4 connector (1.3mm across the receptacle cylinder..). Ipex originally. but some variation.

 

Is similar to a U.FL connector (1.8mm width receptacle cylinder) I use alot of U.FL . MHF4 are a bit of a pain. too small. good for like 5 cycles.

 

I have various cables like this if you need something . be sure to lever up from behind- under the crimp and tilt forwards

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