Primarily for general aviation discussion, but other aviation topics are also welcome.
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By Miscellaneous
#1846134
@ls8pilot, @lobstaboy as I have said previously I am in agreement that it augments lookout. To that end the way to get the best from it under normal flying conditions is to rely on the audio warning (having established it works :wink:), IMO. From what @Tim Dawson posted on another thread there are a few factors taken in to account to 'activate' an audible warning. One of those being a range of 3 miles and under. That works for me. Not being able to detect traffic at 20 miles plus is not a compromise.

Looking at ranges of 40, 60, 80km is a red herring! :D
ls8pilot, Cub, lobstaboy and 1 others liked this
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By lobstaboy
#1846139
ls8pilot wrote:I wouldn't disagree @lobstaboy , but to be fair my impression is that a substantial percentage of PAW users rely on internal antenna and I've not seen much systematic analysis of how that performs either.

I wonder what is an acceptable air:air warning? With Flarm:Flarm it can quite short head:head, maybe 10-15 seconds (closing speed for two gliders head on typically 120 to 180kt) At, say, 240kt closing speed 4nm range gives you a minute to react, so if SE2 is better than that it should bring benefits.

Unlike TCAS an EC system is meant to augment visual acquisition, so I'm not sure how useful it really is knowing about traffic 10nm plus away?


Yes, agreed. I'm not trying to make a case one way or the other, SE2 Vs PAW.
They do different jobs anyway, since PAW doesn't transmit adsb.
It would be good nevertheless to know from some technically robust trials exactly what the detection ranges are.
I'm firmly in the "anything is better than nothing, but don't give up using the MK1 eyeball" camp.

Flarm came along later than my gliding career, but it was obvious straight away that it was a jolly good thing.
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By lobstaboy
#1846142
Tim Dawson wrote:
lobstaboy wrote:I'm saying we have no data either way.


It isn’t true to say there’s no data available.

Ian did a good review of SE2 and PAw using multiple devices and aircraft, and that contains lots of information on the air-to-air ranges observed, if I recall correctly.


Sorry Tim, that's not data, that's anecdote. As I think I made clear in one of my posts above.

(Time for me to bow out now, I've made my points)
By riverrock
FLYER Club Member  FLYER Club Member
#1846144
Cub wrote:I think there is plenty of evidence from the Flight Information Display (FID) trials that a CAP 1391 device is also acceptable for the ground based, short range detection required to enhance the traffic information provision by a suitably qualified FISO or A/G operator.
So not airspace?
Someone in the past suggested ADS-B TMZs - so presumably not suitable for something like that? What about drone TDAs?

Last I heard, the specification for FID hadn't been finalised? Is any of that public yet?

So should we expect all / some / most CAP 1391 devices to be detectable in all directions at 5 nm? I just remember Ian's much talked about flight test, with various blanking issues, across various systems, some at short distances ("within a few miles"). That doesn't prove anything - but shows there could be issues, even at short range.

I assume someone has walked around an aircraft on the ground, with an SE2 mounted, showing no dead spots using a detector (or stood a few km line of sight of an aircraft on the ground and slowly turned the aircraft round)? At least that could give confidence about all round short range protection in the horizontal plane, of at least one aircraft? A bit more difficult to do that on the other planes, unless you can crane your aircraft so that it sits vertically (etc) so you can check no blind spots underneath at close range. You might say that aircraft would normally move relative to one another, so checking in a single direction isn't required - but that is precisely when a MAC occurs - when two aircraft stay at a constant bearing to each other.
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By gaznav
#1846145
From the SkyEcho2 tech specs: https://uavionix.com/downloads/skyecho/ ... 20V1.8.pdf

Transmits ADS-B on 1090MHz and meets MOPS DO-260B Class A0 25W output power


However, I believe the output is closer to 20W and this is spelt out in the installation manual: https://uavionix.com/downloads/skyecho/ ... EV%20L.pdf

1090 MHz Class A0 transmitter limited to 20W


So either way, this is declared as a device that meets the Class A0 ADS-B transceiver standard - there are 2 separate declarations of that fact.

This is what @leemoore1966 said earlier:

this is what is said in CAP1391
AMC 1391-4.4: ADS-B out requirements Due to the reduced transmitter power of EC devices covered by this requirement, it is accepted that the minimum air-to-air range specified in ICAO Annex 10, 5.1.1.3 for extended squitter transmitting and receiving systems in the classes specified, may not be supported.

This is quite a strange (non) requirement, but from Annex 10, the lowest specified A0 Device must have a minimum performance of 10nm for both transmit and receive.


So that means to me that the device will give transmit and receive at 10nm or more. How you mount it and use it cannot be taken into account. I could take a Class 1 500W transponder and mount it inside a Faraday Cage for 1090Mhz - hey presto, very low range (certainly less than 10nm) if the Faraday Cage is doing its job. So it is all about the capability of the device rather than the performance of the installation - there is no way a manufacturer can guarantee someone else’s installation!

Standby for a picture of the device as requested @Straight Level
By johnm
FLYER Club Member  FLYER Club Member
#1846146
I see that the medieval debate continues :roll:

The only thing that we've established thus far is that ADS-B professionally installed kit does a good job of transmission, but finding a equally good airborne receiver is tricky

Flarm can do an excellent job of both Tx and Rx if proper professional kit is professionally installed but outside the glider community usage is patchy to say the least.

Thus the dog will continue to enjoy its breakfast for a while yet.
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By gaznav
#1846147
@Straight Level

So this is the SkyEcho2 from the other side:

Image

The batteries do not completely obscure the antennae from the back, but this is presumably why uAvionix give this wise guidance in their install manual:

Best performance is achieved when the SkyEcho is placed vertically orientated on the aircraft window mounted with the suction cup mount in a forward or side facing window with clear line of sight visibility in the direction of travel and clear visibility to the sky for GPS reception.


Finally, there is an option to attach external antennae vis these connectors:

Image

However, I would strongly advise against doing so. The reason being is that this device has met the Declaration of Capability and Conformance (DoCC) - for SkyEcho2 it is “UK.CAA.DoCC.000007”. As soon as you start fiddling with this, which transmits in the aviation band of 1090Mhz, then you break that DoCC. That is why uAvionix is quite clear about this in their Installation Manual:

Modifications and use outside of intended scope
This device has been designed and tested to conform to all applicable standards in the original form and when configured with the components shipped with the device. It is not permissible to modify the device, use the device for any use outside of the intended scope, or use the device with any antenna other than the one shipped with the device.


If you did modify it, you are likely to “have your collar” felt by OFCOM and other Authorities. :thumright:
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By gaznav
#1846150
I should also add that reasonable transmission and reception ranges are possible with SkyEcho - here are some longer ranges from one installed in a Cessna 172N.

Image

I have also watched aircraft with ADS-B flying over mainland Europe whilst sat on the ground at Hinton in the Hedges near Banbury.
By johnm
FLYER Club Member  FLYER Club Member
#1846152
I have also watched aircraft with ADS-B flying over mainland Europe whilst sat on the ground at Hinton in the Hedges near Banbury.


Proper installed Mode S ES or something else and how could you tell??
By Straight Level
#1846158
gaznav wrote:@Straight Level

So this is the SkyEcho2 from the other side:

Image

The batteries do not completely obscure the antennae from the back, but this is presumably why uAvionix give this wise guidance in their install manual:

Best performance is achieved when the SkyEcho is placed vertically orientated on the aircraft window mounted with the suction cup mount in a forward or side facing window with clear line of sight visibility in the direction of travel and clear visibility to the sky for GPS reception.


Finally, there is an option to attach external antennae vis these connectors:

Image

However, I would strongly advise against doing so. The reason being is that this device has met the Declaration of Capability and Conformance (DoCC) - for SkyEcho2 it is “UK.CAA.DoCC.000007”. As soon as you start fiddling with this, which transmits in the aviation band of 1090Mhz, then you break that DoCC. That is why uAvionix is quite clear about this in their Installation Manual:

Modifications and use outside of intended scope
This device has been designed and tested to conform to all applicable standards in the original form and when configured with the components shipped with the device. It is not permissible to modify the device, use the device for any use outside of the intended scope, or use the device with any antenna other than the one shipped with the device.


If you did modify it, you are likely to “have your collar” felt by OFCOM and other Authorities. :thumright:


That's a good photo.
I'm guessing that the batteries would have some influence on the transmission / reception in an approximately 60 degree arc.
I'm not sure of the orientation, but if the batteries are towards the rear, this effect would be negligible as the aircraft fuselage would have the same blanking effect anyway, but when mounted on the side window this might produce some noticeable areas of 'blanking'.

I'm guessing the coax connectors are used for final testing. Normally when fitting a coax plug into those (tiny) sockets it disconnects the pcb antenna and matching components so accurate measurements can be made. Many mobile phones have a similar setup.
I'd be quite tempted to whack in an external antenna as a quick test on the ADSB side. One hole in the case and jobs a goodun. The authorities will be too busy feeling much bigger collars to notice. :wink:
I be surprised if external antenna testing isn't already underway.

Hopefully any update to CAP1391 will allow for external antennas and much of this issue would be eliminated.
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By gaznav
#1846159
@Straight Level

I did consider it at one point when a pair of these at £2.43 each would do the job. But my sensible head got the better of me! :lol:

Image
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By Cub
FLYER Club Member  FLYER Club Member
#1846162
Straight Level wrote:Hopefully any update to CAP1391 will allow for external antennas and much of this issue would be eliminated.


I don’t believe CAP 1391 prevents external antennas in it’s current iteration, indeed I believe some approved devices have them. I fact I own two, a SkyEcho 1 and an ATT20B.
By uAvionix-Ramsey
#1846166
A0 within DO-260B describes more than the output power, but it is the lowest output power class defined by that document. When seeking to describe the performance of SE2, we chose to describe it as Class A0 @ 25W output power as being the closest representation to a standard.
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By lobstaboy
#1846168
uAvionix-Ramsey wrote:A0 within DO-260B describes more than the output power, but it is the lowest output power class defined by that document. When seeking to describe the performance of SE2, we chose to describe it as Class A0 @ 25W output power as being the closest representation to a standard.


Are you having a laugh? That is absolutely ridiculous. I can't possibly write what I really think about that statement on a public forum.
Frankly I am incredulous :(
It doesn't meet the standard, yet you claim it does (oh but not at exactly the power output that the standard requires). How does that work then?

(I fully intended not to post on this thread anymore, but I made the mistake of coming back for a peek...)
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