Mode C

[John.Riley]

I have not purchased anything yet, but I am about to purchase the Pilotaware Classic.
Will Runway HD display Mode C transponders in a similar way to Mode S. I realise it will not have the same accuracy.

John

[Ian Melville]

Not with the current software. A better option is to persuade mode C, as well as mode A and non-transponders to get a PAW Classic
 

[Admin]

I have not purchased anything yet, but I am about to purchase the Pilotaware Classic.
Will Runway HD display Mode C transponders in a similar way to Mode S. I realise it will not have the same accuracy.

John

Hi John

Currently Mode-S (Bearingless), Mode-S/ES(ADS-B), and P3I are supported.

Mode-C may be added at some point in the future, but not right now.

Thx
Lee

[John.Riley]

Many thanks both. Wondering if Mode S has over taken Mode C yet in usage.

[exfirepro]

Hi John,

Funny you should say that, I was just wondering the same thing. Do any of you out there have numbers for Mode A / C / and S transponders currently in use in the UK? ...or where I can find this information?

I tried Google, but with limited results.

Regards

Peter

[T67M]

Maybe Lee could add logging of this to PAW which is uploaded during software updates and then publish since summary stats.

[the_top_pilot]

Lee.

I am fighting the PAW Corner but there are people around me who are pushing for Flarm (sorry for swearing) as it has functional Mode C detection. We have 24 Aircraft in the fleet. some will obviously not need anything as they have TAS.
Clearly the price difference £200 against £2000 is not putting them off.

Steve

[Admin]

Lee.

I am fighting the PAW Corner but there are people around me who are pushing for Flarm (sorry for swearing) as it has functional Mode C detection. We have 24 Aircraft in the fleet. some will obviously not need anything as they have TAS.
Clearly the price difference £200 against £2000 is not putting them off.

Steve

Very interesting, do you know how PowerFLARM distinguishes between Mode A/C returns ?
because of course, they are technically the same (google: transponder FRUIT)
There is a convention in the UK (apparently) that SQUAWK codes are not allocated which represent a real altitude for example

The Squawk code of Mode-A 4120, is equivalant Mode-C Alt 3000ft

if ATC's stick to the convention of not allocating Mode-C Codes, this becomes reliable, otherwise, the information
provided could be false

I am very against providing 'bad' information, because it leads to mistrust.
There was a discussion on another thread regarding Mode-S and the fact that we could display the following data

REG + ALT
or
ALT

Now call me a sceptic, but I believe if you are told a REG and an ALT, eg G-ABCD +200ft, you are much more likely to believe the validity of the information as opposed to an <ANONYMOUS> ALT, which I am sure many would put down to bugs / RF noise, if after many attempted sightings, nothing was forthcoming.

I think I could enable Mode-C, but I am concerned about the FRUIT issue.

Open to suggestions, and would like to hear from any ATC's on the forum.

Thx
Lee

[the_top_pilot]

Our Portable Flarm displays mode 'C' as a range ring and a a plus and minus Height difference.
steve

[the_top_pilot]

Mode 'A' just a range ring no height

[Admin]

Just reading up on this, sounds like there are some heuristics involved .....

The Mode-S Transponder can easily be filtered because it carries the ICAO code, which can be programmed to be ignored in software.

Mode-A/C is more difficult - how can you know which is your own transponder in order to ignore it from consideration ?
according to the Other-Systems manual, it listens in, and learns, then discards the highest signal strength transmission,
so I guess it is finding the max strength signal received, then setting a threshold at or below.
Of course this can only be done whilst you are being interrogated, so it means that if you are not interrogated on the ground, you will start seeing your own transponder once in the air and interrogation begins (but you will not know it is you), then after some time, this can be excluded.

hmmm
 

[exfirepro]

Fun isn't it 

Peter

[Paul_Sengupta]

Something I've heard about these Mode C detection and exclusions is that sometimes you can receive ghost alerts if your own transponder emission reflects off something else and is detected. Obviously this would be quite a low signal strength!

[Vic]

I would have thought that by the law of 'Square the RF output power to double the range', any received replies from ones own transponder, even from outside to inside the AC would be a significant order of magnitude higher than anything received from other aircraft and fairly able to eliminate.

This is how the ZAON MRX PCAS works to eliminate 'own aircraft' A friend gave me his to look at as it was only seeing his own aircraft and nothing else. It turned out that the antenna connecter had broken at the pcb, so the device could only pick up the strong replies from the host aircraft (C172) actually on a 2mm track on the PCB of the device! and , seeing this now weaker signal, alerted on it.

Is PAW able to collect 'strength of replies' information from the DVB-T receiver to collect logs from willing volunteers?