Traffic Scopes
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Joined: Mar 2004
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From: UK
Traffic Scopes
Has anyone out there parted with hard earned cash and fitted one of those fancy Traffic Scope black boxes that Transair are selling?
Are they any good? And do they only give height and range information or can they give indication of azimuth as well?
Are they any good? And do they only give height and range information or can they give indication of azimuth as well?
Joined: Feb 2004
Posts: 113
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From: SE UK
Not tried one but seen the advert, browsed their website.
They seem to work by listening out for transponders replying to third party interogation (ATC or TCAS). The strength of the signal received is used to estimate the distance, and the altitude is available if that aircaft is squawking mode C. Since there's no other position information in a transponder transmission, it has no idea of azimuth. It can estimate closing rates based on the rate of increase in signal strength, and can track multiple signals (aircraft). Or it least it can if they are squawking different codes. I don't know how/if it can differentiate between multiple aircraft squawking 7000...
Might be more useful when we all forced to have mode S?
They seem to work by listening out for transponders replying to third party interogation (ATC or TCAS). The strength of the signal received is used to estimate the distance, and the altitude is available if that aircaft is squawking mode C. Since there's no other position information in a transponder transmission, it has no idea of azimuth. It can estimate closing rates based on the rate of increase in signal strength, and can track multiple signals (aircraft). Or it least it can if they are squawking different codes. I don't know how/if it can differentiate between multiple aircraft squawking 7000...
Might be more useful when we all forced to have mode S?
Joined: Jun 2003
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From: EuroGA.org
Without azimuth info, you better have a very flexible neck, not to mention an aircraft with 360 degree vision 
It doesn't take many flights under a radar information service to realise that without azimuth, most warnings will be useless. Even with an RIS one cannot spot most of the traffic mentioned if the visibility conditions are less than great.
On top of that, most PPL flights have no transponder, or have it switched off, often deliberately. This means that you have to maintain practically the same lookout as before.
Personally I would save the money and put it towards a really good top-end GPS, with an external aerial - suction cup job if you cannot get one screwed down on the roof.
It doesn't take many flights under a radar information service to realise that without azimuth, most warnings will be useless. Even with an RIS one cannot spot most of the traffic mentioned if the visibility conditions are less than great.
On top of that, most PPL flights have no transponder, or have it switched off, often deliberately. This means that you have to maintain practically the same lookout as before.
Personally I would save the money and put it towards a really good top-end GPS, with an external aerial - suction cup job if you cannot get one screwed down on the roof.
Thread Starter
Joined: Mar 2004
Posts: 224
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From: UK
Thanks for the replies guys. I'm not in the market to buy one, but a couple of other threads on useful/useless gadgets got me thinking. However it is nice to see technology progressing and maybe before too long, there will be a more useful affordable version of TCAS available to the masses.
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Joined: Jul 1997
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From: Europe
the best thing about TCAS is that it shows you which direction to look.....without an azimuth display I wouldn't waste my money.
TCAS systems in use (TCAS I and II) do not provide horizontal avoidance advice. TCAS III intended to use the TCAS directional antenna to provide horizontal avoidance but was abandoned by industry as not being good enough for the job due to the bearing inaccuracy mentioned above.
TCAS IV should improve this accuracy by including positional information sent from the target aircraft (encoded from GPS or similar onboard source) and so will also offer horizontal avoidance advice.
Joined: Oct 2003
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From: Finding Out on 121.50
I was a bit worried that a "budget" low end TCAS could in the GA VFR community cause complacency and lead the user not to look out as much.
I sail a boat with a radar system that has a closing alarm. When I first got the system I used to set the alarm to 0.5NM and closing and drift along letting it do it's job. Well after it had been running for a couple of weeks and worked well I relied on it..............untill a very close shave with the Isle of White hover craft!
Perhaps I am giving a glum opinion of a device that may improve safety and would be interested to see what other people think.
I sail a boat with a radar system that has a closing alarm. When I first got the system I used to set the alarm to 0.5NM and closing and drift along letting it do it's job. Well after it had been running for a couple of weeks and worked well I relied on it..............untill a very close shave with the Isle of White hover craft!
Perhaps I am giving a glum opinion of a device that may improve safety and would be interested to see what other people think.
Joined: Feb 2002
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From: Dubai
The best TCAS for light aircraft under VFR is the Mark1 Human Eyeball.
Its another piece of equipment that will keep pilots heads inside the cockpit and not outside.
I would spend the money on several hours of flying.
Just my two cents worth.
Nosey
Its another piece of equipment that will keep pilots heads inside the cockpit and not outside.
I would spend the money on several hours of flying.
Just my two cents worth.
Nosey
