Active Radar Reflectors

[SailingWill]

Morning All!

I am about to purchase an active radar reflector and will probably go with the Sea-me as it keeps on being recommended but i have just noticed that Sea-me now makes a reflector that operates on X-band and S-band radar. Does anyone already have one and is it worht the extra money?

Thank you

 

[shmoo]

We have thought for a while we should have an active transponder but were put off by the Sea-me only being single band. Now they do a dual band version I will very likely get one. Thanks for drawing the improvement to my attention.

 

[Twister_Ken]

One of the mags recently tested Sea-Me vs the new Echomax active transponder.

Echomax produced a much stronger return, especially at bigger angles of heel.

Both were single band, but it might be worth waiting to see if Echomax also launch a dual band.

 

[ign]

Does having a normal radar in operation do effectively the same thing as a sea me radar reflector by transmitting a signal?

 

[timbartlett]

Does having a normal radar in operation do effectively the same thing as a sea me radar reflector by transmitting a signal?

No.

 

[Piers]

I believe the IMO regs are changing and will require X and S reflections. The only one which does this is the new Sea-Me.

So, if you want to bide by the regs, and / or if you want both X and S radars to see you, Sea-Me!

 

[hoverjumper]

Good Article

One of the mags recently tested Sea-Me vs the new Echomax active transponder.

Echomax produced a much stronger return, especially at bigger angles of heel.

Both were single band, but it might be worth waiting to see if Echomax also launch a dual band.

An excellent PBO article, very interesting.

But it left me thinking that it is pointless fitting a single band transponder if so many ships are only monitoring S band. I assume an AIS transponder give an AIS tag on a ships radar screen such as name of Yacht, etc? If so surely this is the ultimate solution? (must admit I haven't compared prices, AIS transponders are probably much more pricey)

 

[hoverjumper]

Prices

(must admit I haven't compared prices, AIS transponders are probably much more pricey)

OK, so a quick look online reveals rough prices as follows:

Single band Sea-Me / Echomax = £430
Dual band Sea-Me = £780
Digital Yacht AIS B Transponder = £500

Given my ever limited budget I would be inclined to keep my existing passive reflector and go for an AIS transponder.
Thoughts?

 

[hoverjumper]

Does having a normal radar in operation do effectively the same thing as a sea me radar reflector by transmitting a signal?

My limited knowledge of radars tells me that your operating radar is looking for a reflection of its own discreet signal. So transmissions from other radars, with different signal characteristics wont be processed. Even if they were, the distance would be all wrong as your radar is timing how long it takes for its "ping" to "pong" back. Someone elses "ping" is useless to your radar without knowing exactly when it was, um, "pinged".

I think I need to lie down.

 

[saltwater_gypsy]

I sailed down to the Med. in 2004 and had quite a few scares on the way.
I fitted SeaMe and, on the way back this year , although we went through some busy shipping lanes, we had no problems at all. We noticed that when we had right of way, large vessels were making appropriate course alterations and it was all very satisfactory. From talking to a professional seaman (first officer) I understand that if a vessel gets a strong steady signal such as you get from SeaMe they MUST take avoiding action when appropriate as the whole sequece is recorded. Having seen the weak intermittent signals from a typical yacht on my own radar , I don't think there is much choice in the matter. Passive AIS has little advantage over MARPA if you already have radar and requires constant vigilance .

 

[fireball]

IMHO Class B AIS transmitter is currently next to worthless - most of the big boys are not using AIS for collision avoidance (yet) and many will have the minimum info required displayed on a 3 line screen ....

 

[Rivers & creeks]

I assume an AIS transponder give an AIS tag on a ships radar screen such as name of Yacht, etc? If so surely this is the ultimate solution?

No they don't appear on any screen, certainly not on a radar screen. Class B (and class A) AIS signals are displayed on the ship's bridge with their lat and long on a three line text display. Ships use radar for collision avoidance. Quite frankly there is a case for suing those who sell class B on the grounds of misleading advertising. You don't appear on any screen, - you have to hope that someone looks at a 3 line text display and then goes and plots your position on their radar screen and updates it every few minutes 'cos that's going to happen! Your class B AIS will show up on some yachts' plotter screen but only if they have the latest AIS gear. So, not really worth £500 and counter productive as any feeling of safety is an illusion and may cause you to make decisions based on the ship seeing you.

 

[Skysail]

This comment from Deputy HM Southampton is relevant:

http://www.yosc.org.uk/html/announcements.html#navigationaids

 

[Piers]

My limited knowledge of radars tells me that your operating radar is looking for a reflection of its own discreet signal. So transmissions from other radars, with different signal characteristics wont be processed. Even if they were, the distance would be all wrong as your radar is timing how long it takes for its "ping" to "pong" back. Someone elses "ping" is useless to your radar without knowing exactly when it was, um, "pinged".

When an active radar unit senses a pulse from a radar, it immediately enhances the return pulse with no timing issues to give false bearings/distances.

So rather than a weak or no return from a passive reflector, the active reflector ensures a strong return.

Most leisure radars are X band. Larger ships tend to have both X and S band radars.

With the new IMO regs demanding reflectors to respond to both S band radars as X, the Sea-Me is the only reflector meeting the new standards.

So, what do I use? Radar for me to see others as best as poss, and an active Sea-Me to help others see me by returning a strong signal to their radar screens.

I use the maxim - see and be seen.....

By the way - no connection to the company apart from using their products.

 

[SailingWill]

Thank you for all your comments!

With an unlimited budget I would probably go for the Sea-me DualBand and an AIS system - unfortunatley this is not the case!

After reading through all the helpful advice I think The Sea-me Dual Band is the best option. I have made some enquiries and Echomax do not have a dual band system at present.

 

[Piers]

Good decision, SailingWill.

 

[wotayottie]

Does having a normal radar in operation do effectively the same thing as a sea me radar reflector by transmitting a signal?

No - the radar which is looking at you needs in effect to see its own signal reflected back. Thats what the active thingies are doing - amplifying the signal and squirting it back.

 

[rivonia]

No they don't appear on any screen, certainly not on a radar screen. Class B (and class A) AIS signals are displayed on the ship's bridge with their lat and long on a three line text display. Ships use radar for collision avoidance. Quite frankly there is a case for suing those who sell class B on the grounds of misleading advertising. You don't appear on any screen, - you have to hope that someone looks at a 3 line text display and then goes and plots your position on their radar screen and updates it every few minutes 'cos that's going to happen! Your class B AIS will show up on some yachts' plotter screen but only if they have the latest AIS gear. So, not really worth £500 and counter productive as any feeling of safety is an illusion and may cause you to make decisions based on the ship seeing you.

Hmm I find that most odd as we have AIS send and recive. All ships at night and day altered course. We on our radar can see eveyone elses AIS. So I would think if we see them on radar they also will see us on radar,.

Peter

 

[hoverjumper]

Every day's a school day

All very interesting, I'll be saving up for a dual-band sea-me then!

 

[doris]

Sea-Me

I have had a SeaMe for 4 years and it has proved excellent.

Does anyone know if one can upgrade a single band unit for a dual band rather than throw it away and buy a new dual band.