So how dangerous is radar?

[Sans Bateau]

Little while ago I remember a post on SB where the dangers of the radar scanners output was discussed. With most radomes on yachts set high up the mast there is no danger to crew, with the radome set on a pole or bridge on the aft of a yacht, I remember it was suggested that crew on the fore deck could get a good zapping with radiation.

The reason I mention this is when sailing home (slowly) to Northney yesterday we noticed that on many mobos the radar is fitted to a bridge above the flydeck (?). This puts the radar VERY close to the heads of crew etc. In fact one mobo with a big high output open array was motoring with a bows up attitude, like they do (how the hell can they see anything?), this put the line of the radar straight into the backs of the heads of those on the flydeck enjoying their gin and tonic.

Point is, radar output can't be that dangerous if so many people are subjecting themselves to the transmitted signal, can it? /forums/images/graemlins/confused.gif

 

[jimg]

This has been covered in quite a few articles, but the pulses are of a very short duration and you have to be very, very close for it to be a problem. You are more at risk from your mobile phone when placed next to you head.

 

[Langers]

What I know is based more on the rotating 25KW scanner variety of radar than radome (where its less 5KW perhaps). But basically, in this case, for you to receive a dose of RF that is more than the recommended amount, you would be more at risk of being hit by a rotating object (the scanner) than of cooked brain tissue. This is becasue the radar is pulsed and the mean level is actually only about 12.5 Watts. This would infer that a greater exposure would be recieved from a mobile phone becuase its closer to you and a continuos source of RF power.

 

[graham]

I contacted the HSE about this a few years ago .They consider there is virtually no danger as the scanner would have to be jammed in one place(which would blow a fuse or trip) and then aimed directly at you for a long while to do any harm.

The greatest risk in their assesment are seaman working near a scanner that is switched off getting knocked off the ladder or wheelhouse roof if someone starts it up!

 

[Stemar]

There was some concern over this several years ago at the CROSSMA at Jobourg . The recommendation was that, as a precaution, pregnant women and young children shouldn't be living in the married quarters which were close to the antenna, but there was no measurable risk to anyone else. This involved a radar several orders of magnitude more powerful than anything on a pleasure boat, running 24/7. Unless you're right in line with the beam, for several hours at a time, I doubt very much there'd be a problem.

On the other hand, I know someone who worked in microwave communications who claimed he could cook birds in midflight by turning the focussed beam transmitter on at the right time...

 

[Norman_E]

Modern low power boat radars are probably pretty safe. Early radar was a different matter. I knew a man who had detached retinas as a result of working with radar in WW2, and it appears that microwave energy damage to the eyes was a common problem with early radar. He told me that the radar operators found that if they placed their packed lunches near to the antenna, they would heat up.

 

[jimg]

Hence the microwave oven!

 

[andy_wilson]

\"motoring with a bows up attitude\"

I trust the radar scanner was operating in a bows up attitude also?

 

[Talbot]

The standard small boat radar is 2 or 4 kw. You are in more danger from the rotating antenna (for those with no dome) than of radiation from it. That doesnt mean that all radar is the same, - you would not want to be close to an aegis system if it was concentrating on you!

 

[bruce]

for fun and information, you could attach a hotdog/sausage to the cover and turn on the unit and check it every few minutes to see for yourself, and us, what happens...

 

[Langers]

somewhat contrary to my last post, but I have heard that raytheon point there scanners at a tree and tune for maximum smoke...

 

[ghostwriter]

ah, the radar debate again ... always a nice one

a yearly joke at radio officers school (the ones who also used to be responsible for radar maintenance, at least in my neck of the woods) was to tie a chicken in front of the scanner and have it roast; I can confirm it was yummy indeed, the scanner was the 30kW variety mounted on top of the classroom /forums/images/graemlins/wink.gif

but of course that chicken was constantly and directly in front of the rotating scanner

during first radar electronics classes we were also warned about the dangers of radars, in such a way that I witnessed a guy in my class having to make a run to the nearest vomitorium. biggest dangers were (and still are) (1) as mentioned already ... not radiation but being knocked of a ladder when a nutcase starts the scanner while you are working on it (halelujah for interlocks on the electronics box preventing that) (2) standing continuously in front of a transmitting radar scanner , directly in front of it within a close range (a couple of meters) is not exactly beneficial for your so-called weaker parts : eyes , brains ....goolies get cooked. One of the easiest way to castrate somebody is to dangle his b*ll*cks in front of a scanner and let them roast.

and then there are a load of speculations, learned studies etc... but so far I still have to see something clear and conclusive.
it IS correct that due to the pulsing, due to the specific radar angle there is a quick and big dispersion of the power , resulting in a low average power , and underneath the scanner hardly anything , but I still have to see something conclusive on the question what is the minimum safe distance at which you can stand for hours....

as a side remark : even in front of a microwave oven you won't see me standing for a long time, as there is no guarantee either that they would not be a bit leaky.

better safe than sorry, no ?

 

[pappaecho]

Explains the saying "I have half a mind to buy a MOBO"

 

[bilbobaggins]

We all know about 'radar-assisted collisions', don't we?

A story told within the V-bomber fleet relates that pilots at RAF Waddington started to notice that a group of their EngTechs would gather - smiling and waving - at the end of the long taxiway, close to where the taxiing Vulcans stop for final checks, before taking the runway. This was unusual enthusiasm, and seemed to occur only on Friday afternoons.

Seasoned officers were suspicious, 'cos it didn't seem to fit with the normal, expected 'sullen erks' behaviour. So a quiet inquiry was made.

Then the answer was found. The spot where these grinning Airmen were gathering, a dozen at a time, was directly in line with the aircraft nose - and directly in line with the big attack radar scanner. And that's exactly where the Radar Systems Nav, doing his system checks, turned on the scanner briefly from 'Standby' to 'Transmit', to check the full power output.

The 'folk tale' had spread that a dose of radar frequency radiation, gained in this way, killed the sperms in the testes and tubes, rendering the willing Airmen impotent for a few days. And that's why this happened on a Friday afternoon, before they all went off to London for the weekend...

I remember the horrified looks when the Senior Medical Officer briefed the whole Eng Wing on the true consequences.

That radar's output, in a spot beam and at a couple score of yards, would certainly fry your chickens....
/forums/images/graemlins/laugh.gif

 

[alan_d]

"... rendering the willing Airmen impotent ..."


I think you (or they) meant infertile rather than impotent.

 

[MapisM]

Re: \"motoring with a bows up attitude\"

Not necessarily.
I mean, of course the radome angle follows the boat angle, but in fact many planing boats have the radome fitted on a mast whose angle is calculated in order to keep it (more or less) horizontal at cruising speed.
Therefore, the radome orientation quite often fits nicely the back of the head of anyone helming from the flybridge.
Maybe the idea is that when the radar is needed (i.e. night or rain) it is a sensible choice to helm from lower station.
But actually, I also saw people happily cruising in sunny days, with the whole family enjoing the flybridge and the radome gloriously spinning.
Sometimes I wonder if anyone think of it as a tanning aid?!?........