Radar enhancers

[jamie N]

Echomax active X:
PERFORMANCE RESPONSE

Zero degrees 111.36M2
+/-10 degrees of heel 78.96M2
+/-20 degrees of heel 20.80M2
* Stated performance level - QinetiQ Anechoic Chamber Funtington 13th March 09
Exceeds ISO 8729-2 effective 22nd July 09 X band performance requirements
7.5M2 @ 10 degrees of heel for motor vessels and 20 degrees of heel for sailing vessels.

Having something onboard that makes my wee Folkboat more obvious, alongside having the AIS transponder, is good news. Having anything less would concern me..

 

[prv]

It might be nice having a sectored display as I think some military aircraft have?
Klingons on the starboard bow etc....

I'm sure I've seen at least one radar detector that had that. Possibly a French device that's no longer made?

Pete

 

[Topcat47]

That's the problem - they're seriously patchy! My solution id to use a 2" Plastimo tube (certainly for making a racing boat reg compliant), but to add one of those clunky Echomax 230 jobs when when cruising. As you say the tri-lens is prob best of the passives, but my thinking is that the Echomax augmented by a skinny Plastimo tube approaching vertical as the boat heals is prob another way of achieving much the same.

PM sent.

 

[dom]

I once worked in a lab where other people were working on Radar Warning Receivers.
It might be nice having a sectored display as I think some military aircraft have?
Klingons on the starboard bow etc....
The alarm thresholds might give big ship at say 2NM, small boat/fishing boat at 0.5NM.
Of course the military have them linked to chaff rocket launchers and so forth....

As a matter of interest where are we currently on the phased array stuff? The military bods are always waxing lyrical about the massive improvements in size weight and power (SWAP) profiles and I'm wondering if a leisure seaborne application is in sight at a "reasonable " price? Would also save on the chaff if one could take out undesirable incomings at will.

 

[Topcat47]

Phased arrays require huge amounts of computing power, well beyond what a sailing boat is able to support at the moment. Don't hold your breath.

 

[prv]

Phased arrays require huge amounts of computing power, well beyond what a sailing boat is able to support at the moment. Don't hold your breath.

I've no real idea what phased arrays are, but if it's just a question of computing power then Moore's Law ought to knock that obstacle down in short order if it hasn't already.

Pete

 

[Lucky Duck]

I'm sure I've seen at least one radar detector that had that. Possibly a French device that's no longer made?

Pete

C.A.R.D.

As I recall this hasn't been in production for a little while now

 

[lw395]

As a matter of interest where are we currently on the phased array stuff? The military bods are always waxing lyrical about the massive improvements in size weight and power (SWAP) profiles and I'm wondering if a leisure seaborne application is in sight at a "reasonable " price? Would also save on the chaff if one could take out undesirable incomings at will.

Still comically expensive AFAIK.
It has made it into civil air traffic radars and weather radars, and AFAIK, some satellite borne systems.
A lot of the phased antenna beam steering technology is proposed for 5G phone base stations, so that could drive the costs down.
Likewise the digital processing will be less and less ICs as time goes on.

 

[Lyndsey Doyle]

Good afternoon, I've an Echomax X-band, mounted on a bracket on a spreader.

I don't have the manual in front of me, but the current consumtion is tiny, IIRC a small fraction of an amp @12v, and a solar panel would definitely keep up with the demand.

It uses much less leccy than an AIS install of any variety I'm fairly sure.

Any experts care to comment on this: I saved money by getting the X-band only model, rather than X plus S.

My reasoning was, all ships will be on X band radar when 1) near the coast or 2) there is a chance of a risk of collision situation developing.

While S-band ship's radar radar will be switched on when the ship is right out on the open ocean, where yes, I might be hove-to having a nap for example, but the chances of meeting a ship is much less, due to the vast distances involved.
As an aside I did the RYA syllabus radar day at Gravesend Nautical college, they have a realistic bridge sim, highly recommended!!
Enjoy the sun LD

 

[Supine Being]

I went to a really interesting talk by the boss of Echomax recently. Basically, as a previous poster mentioned, you need the large size passive to ensure you're seen. The smaller passive, although convenient, gives a much smaller target (I can't quote figures, I'm afraid). The interior of the Echomax seem to be very well made indeed. We were shown a stripped down competitor that happened to be the same as mine, and it was clearly not up to the same standard. And, even then, it was the smaller size reflector, so not great in any case.

If you have those small tube-shaped reflectors, he reckoned you'd be better off raising a frying pan up your mast for all the good it'll do. He recommends the active Echomax, of course. The power draw is tiny, and you can mount it on the pushpit and it will still be effective.

Of course, all this from the boss of Echomax, so caveat emptor and all that, but what he was saying seemed to tally with what I've read elsewhere.

 

[dom]

I saved money by getting the X-band only model, rather than X plus S.

My reasoning was, all ships will be on X band radar when 1) near the coast or 2) there is a chance of a risk of collision situation developing.

I don't think this is right. Bigger ships (>30,000) GWT must carry S and X. The big advantage of S is that it sees through weather systems far better than X and for this reason a watch holder may primarily monitor S only (perfectly lawful) in rain/fog, etc. Some advanced systems are able to integrate X and S into a single image; not all.

The trouble with this is that due to the different frequency used by S-band, standard radar reflectors return about 10% of the X-band cross-section. I don't think an X-band Echomax will help at all if painted by an S-band radar, though happy to be corrected on this. The trouble here is that this unsatisfactory state of affairs occurs just when we need to be spotted most! - i.e. fog, when our tiny cross-section reflections to not provide the requisite number of bounce backs to trigger an image on the ship's radar screen.

 

[lw395]

Echomax 23mA resting, 155mA transmitting
Nasa AIS Radar 50mA, or 100mA with the backlight on.

Neither is exactly demanding in the power department!
Of course the Nasa unit needs a gps input perhaps another 40ma at 12V?
All small compared to plotters etc.

 

[Lyndsey Doyle]

I don't think this is right. Bigger ships (>30,000) GWT must carry S and X. The big advantage of S is that it sees through weather systems far better than X and for this reason a watch holder may primarily monitor S only (perfectly lawful) in rain/fog, etc. Some advanced systems are able to integrate X and S into a single image; not all.

The trouble with this is that due to the different frequency used by S-band, standard radar reflectors return about 10% of the X-band cross-section. I don't think an X-band Echomax will help at all if painted by an S-band radar, though happy to be corrected on this. The trouble here is that this unsatisfactory state of affairs occurs just when we need to be spotted most! - i.e. fog, when our tiny cross-section reflections to not provide the requisite number of bounce backs to trigger an image on the ship's radar screen.

Hello Dom, that's very interesting, is there a standard proceedure, eg visibility below a certain threshold, for the bridge team/ watchkeeper to move from X to monitoring S?
Yes that's right, the Echomax X-only model does not paint on S-band radars.
Thanks for yr comments LD

 

[Lyndsey Doyle]

Echomax 23mA resting, 155mA transmitting
Nasa AIS Radar 50mA, or 100mA with the backlight on.

Neither is exactly demanding in the power department!
Of course the Nasa unit needs a gps input perhaps another 40ma at 12V?
All small compared to plotters etc.

Very interesting, thanks

 

[prv]

Echomax 23mA resting, 155mA transmitting
Nasa AIS Radar 50mA, or 100mA with the backlight on.

Not really a valid comparison though - the NASA unit is a receiver only, whereas the proper equivalent to an Echomax would be an AIS transmitter.

Pete

 

[lw395]

Note that the Echomax active units have effective echoing areas that drop severely at increasing angles of heel:
X BAND RADAR SPL
(ISO Standard 7.5m2)
Zero degrees: 118.33m2
+/-10 degrees: 65.07m2
+/- 20 degrees: 19.49m2

Which suggests a significant null before 30 degrees.
Even at 20 degrees it's still in similar territory to some passive units when you put it into the fading model that QinetiQ used.
Potentially significant dead areas in sea clutter.
Then there's the potential for such a slim unit to be shadowed by the mast etc.

These are great aids, but not an absolute guarantee of being seen every time.
Statistically I suppose it makes being run down less likely, and it was never that likely in the first place.....
I still don't like fog whatever aids are on the boat!

 

[Topcat47]

I've no real idea what phased arrays are, but if it's just a question of computing power then Moore's Law ought to knock that obstacle down in short order if it hasn't already.

Pete

It's not the place to go into a long explanation of Phased array radar. The computing power is derived from the need to summate all the inputs from an array of sensors operating (in the case of military radars) across a wide band of frequencies. I'm not sure of frequency agility is a necessary feature for a phased array, just that it is a feature of military versions. Trust me, Moore's law has a long way to go to catch up on the computing requirements for one of these babies.

 

[Topcat47]

I don't think this is right. Bigger ships (>30,000) GWT must carry S and X. The big advantage of S is that it sees through weather systems far better than X and for this reason a watch holder may primarily monitor S only (perfectly lawful) in rain/fog, etc. Some advanced systems are able to integrate X and S into a single image; not all.


The trouble with this is that due to the different frequency used by S-band, standard radar reflectors return about 10% of the X-band cross-section. I don't think an X-band Echomax will help at all if painted by an S-band radar, though happy to be corrected on this. The trouble here is that this unsatisfactory state of affairs occurs just when we need to be spotted most! - i.e. fog, when our tiny cross-section reflections to not provide the requisite number of bounce backs to trigger an image on the ship's radar screen.

You're right about that, Dom. I still think anything's better than nothing and the lens systems still give a repeatable return which may not be isolated by anti-clutter software. I"ve been out of the game for too long to be certain of this.

 

[Tranona]

I've done a fair bit of work on the subject in the past, including prior work with the guys at Funtington. The cyclops and tri-lens reflectors return a fairly consistent echo. While my yacht might well give a larger return under ideal conditions, the consistency given by my chosen reflector means that there will always be a trace on a radar screen which means that it is less likely to be confused with clutter. The standard tri-lens was quoted at 4.2 square meters. The iso "recommendation" is 10. To carry a passive enhancer with this reflective performance on a small yacht is not possible, the large EchoMax is almost the size of a dustbin. I can't find anywhere to fit bigger than 85ah batteries or more than two on my boat. My judgement was (and is) that reliance on electronics is not a safe and sensible option. I'm happy to live with my choice, by all means go with yours.

Was not necessarily advocating an active rather than a passive system, just pointing out that you passive system is poor in relation to what is recommended as you well know. Simply saying that ships see you does not necessarily mean they would not see you if you did not have the reflector. The only way you can know if it is making a difference is to do with and without tests in a wide range of conditions - probably impractical.

As it happens I rely on a passive reflector (and an AIS) as I think the chances of not being seen and me not being aware are very low in the type of sailing I do.

 

[Topcat47]

Was not necessarily advocating an active rather than a passive system, just pointing out that you passive system is poor in relation to what is recommended as you well know. Simply saying that ships see you does not necessarily mean they would not see you if you did not have the reflector. The only way you can know if it is making a difference is to do with and without tests in a wide range of conditions - probably impractical.

As it happens I rely on a passive reflector (and an AIS) as I think the chances of not being seen and me not being aware are very low in the type of sailing I do.

I agree, you pays yer money and takes yer choice. I'm still swithering about a PLB. Were money no object, I"d have a modern 35'er with all the toys. It's not, and I manage do do quite nicely with my 60's yacht with mostly 70's technology. You do the best you can with the kit you have.