Alfie168
Well-Known Member
Well what about including aluminised strips in sails. I've no idea if it would work. Perhaps the static charge would make the crews hair stand on end /forums/images/graemlins/laugh.gif
Tim
Tim
Hoisting octahedral radar reflector
- Thread starter Gazza
- Start date
ShipsWoofy
Well-Known Member
I have twin back-stays and the last time I stepped the mast I fitted two old blocks to them, my intention is to attach elastic to them and swing the reflector between them, using the elastic to raise the reflector, with a string to pull it back down.
I have not actually tried this yet, but I am hopeful it will work..
I have not actually tried this yet, but I am hopeful it will work..
lw395
Well-Known Member
The octohedral UPRIGHT has a higher return over a wider range of angles, than catch rain. The ARPA and clutter reduction in most radars makes consistency of return more useful than peak rcs. The 4inch tube type is v good when exactly upright.
All these devices are 'not to be relied on 100%'.
Do not rely on them for your survival! They are just one sensible precaution.
I am a little sceptical about kinuseless's graph implying that the radr is utterly blind at a range of 4nm, perhaps a ship radar user will confirm this?
It has been pointed out before that while yachts make crap radar targets, the ships that try to run us down make very good ones.
So fitting the radar to the yacht might be the better option. In radar speak, a seeme is only a few dB cheaper than a radar nowadays.
I think the best approach is often an AIS receiver, which puts the onus on the yacht to do the avoiding. The vessels not transmitting AIS probably won't be looking too hard at radar either.
To return to the point, suspending an octo on the kite halyard, with a downhaul to corner of the transom for me.
If it ends up touching the main leach, move it to the other side.
I had a tubuar jobby as a permanent fit for clear weather to meet regs.
All these devices are 'not to be relied on 100%'.
Do not rely on them for your survival! They are just one sensible precaution.
I am a little sceptical about kinuseless's graph implying that the radr is utterly blind at a range of 4nm, perhaps a ship radar user will confirm this?
It has been pointed out before that while yachts make crap radar targets, the ships that try to run us down make very good ones.
So fitting the radar to the yacht might be the better option. In radar speak, a seeme is only a few dB cheaper than a radar nowadays.
I think the best approach is often an AIS receiver, which puts the onus on the yacht to do the avoiding. The vessels not transmitting AIS probably won't be looking too hard at radar either.
To return to the point, suspending an octo on the kite halyard, with a downhaul to corner of the transom for me.
If it ends up touching the main leach, move it to the other side.
I had a tubuar jobby as a permanent fit for clear weather to meet regs.
awol
Well-Known Member
At the risk of actually answering the OP's question - I mount mine with the flag halyard to one corner of one square plate, two shackles to two of the other corners of the same plate running up the cap shroud and the downhaul on the 4th corner.
While you lot are moralising about reflectors do remember that for any to be seen requires other vessels to switch on a correctly set up and maintained radar and then have someone available to react to any alarm. Better is to keep your own watch.
While you lot are moralising about reflectors do remember that for any to be seen requires other vessels to switch on a correctly set up and maintained radar and then have someone available to react to any alarm. Better is to keep your own watch.
Marsupial
Well-Known Member
Vic,
Have another read, the octahedron out performed most of the other passive types, the difference between the best of the rest (discounting the reference unit) and the octohedron is the thin end of nothing, the difference between the worst of the rest and the octohedron is significant therefore IF you have a passive reflector there is really no point in fitting anything other than an octohedron. IF it wobbles a bit as boat heals it will probably outperform all of "the fixed" types at heal so the jobs as good as it gets in the passive world.
It WILL be INVISIBLE to S band as is a Sea Me but it should make the boat more visible on X band, more of the time.
/forums/images/graemlins/smile.gif
Oh yes hoisting, make a bridal up with a short stainless wire strop at the top so its in the catching position and hoist it with the signal halyard and attach another line to one of its corners and make it to a staunchion or handy cleat to stop it from spinning.
Have another read, the octahedron out performed most of the other passive types, the difference between the best of the rest (discounting the reference unit) and the octohedron is the thin end of nothing, the difference between the worst of the rest and the octohedron is significant therefore IF you have a passive reflector there is really no point in fitting anything other than an octohedron. IF it wobbles a bit as boat heals it will probably outperform all of "the fixed" types at heal so the jobs as good as it gets in the passive world.
It WILL be INVISIBLE to S band as is a Sea Me but it should make the boat more visible on X band, more of the time.
/forums/images/graemlins/smile.gif
Oh yes hoisting, make a bridal up with a short stainless wire strop at the top so its in the catching position and hoist it with the signal halyard and attach another line to one of its corners and make it to a staunchion or handy cleat to stop it from spinning.
Refueler
Well-Known Member
[ QUOTE ]
It WILL be INVISIBLE to S band as is a Sea Me but it should make the boat more visible on X band, more of the time.
[/ QUOTE ]
Where do you get that an Octo reflector - a passive REFLECTOR will not reflect S band ? Why does a passive item choose what it reflects ? The only reason S band is less responsive to an octo or any other other passive reflective radar device is the wavelength characteristic requiring a larger surface area of reflector. In fair weather and uninterupted line of sight - the octo reflects ALL RF that hits it !
Sorry but I read some comments and I do wonder where they come from.
It WILL be INVISIBLE to S band as is a Sea Me but it should make the boat more visible on X band, more of the time.
[/ QUOTE ]
Where do you get that an Octo reflector - a passive REFLECTOR will not reflect S band ? Why does a passive item choose what it reflects ? The only reason S band is less responsive to an octo or any other other passive reflective radar device is the wavelength characteristic requiring a larger surface area of reflector. In fair weather and uninterupted line of sight - the octo reflects ALL RF that hits it !
Sorry but I read some comments and I do wonder where they come from.
S
Skyva_2
Guest
How is that conclusion reached when reading the Summary of results, Conclusions and Recommendations of the Qinetiq report?
The octahedral is certainly good value for money, but others outperform it for consistency.
The octahedral is certainly good value for money, but others outperform it for consistency.
Scotty_Tradewind
Well-Known Member
Sea-Me
current consumption in quiescent state 150ma
current consumption when transmitting 350ma
current consumption in quiescent state 150ma
current consumption when transmitting 350ma