Radar waves safe for humans?

[hamburking]

I'm an engineer. i worked at the communications research lab at McMaster university in Hamilton Ontario as a radar research engineer. We developed and tested early versions of ice detection/classification radar, and intelligent radar systems.

And I can tell you, beyond a doubt, with absolute certainty...radar waves are dangerous. Close to the radome is a high concentration of microwaves. Basically its a microwave oven with no door. You need distance to be safe.

We wrapped our work area in a faraday cage to protect ourselves when operating our ground level radar systems.

The radar waves are transimitted horizonally, so putting the radome up high puts you "under the fountain", not directly in the line of transmission. Putting the radome up high also increases the distance to you. So win/win.

The new radar systems use signifacantly less power than earlier versions, but still enough to do damage to the human body at close range.

[Rorzech]

How do you post an image from your desk top to CF ?

[Rorzech]

I have a document that say's that the 3G radar has ZERO Radiation Hazard Period and that it can be installed anywhere on your boat. That means you can mount it on your steering pedestal if you like. I just posted it a minute ago.

[Paul Elliott]

The (fairly new) HiDef / 3G / Broadband / (and other marketing-generated names) radars do put out a very low power signal. These use solid state transmitter circuitry (not magnetrons or klystrons). Simrad's "Broadband 3G" radar puts out a fairly steady 165 milliwatts, compared to the 2KW and 4KW pulses of many traditional marine radars. That's about 20,000 times less peak power for the Broadband units, and yes, that's similar to a cellphone in transmit power, or even less.

I still wouldn't want to sit on one, but to be honest I don't worry that much about carrying my cellphone in my pants pocket...

[Rorzech]

http://www.cruisersforum.com/forums/...1&d=1503707232
This should settle the argument once and for all . 3G Radar Zero Radiation Hazard

[foggysail]

Originally Posted by Tkeeth

Wouldn't it be better to use real info than just ask a bunch of people you don't know?

WHO | Electromagnetic fields and public health: radars and human health

Marine radars can be found on small pleasure boats to large ocean going vessels. Peak powers of these systems can reach up to 30 kW, with average powers ranging from 1 to 25 W. Under normal operating conditions, with the antenna rotating, the average power density of the higher power systems within a metre of the antenna is usually less than 10 W/m2. In accessible areas on most watercraft, these levels would fall to a few percent of present public RF exposure standards.

Yeah, WHO! And notice that the article waited until the very last paragraph to state that "to date, there is no evidence of adverse health effects, including cancer........."

They could have posted that in the first line of their opening paragraph but that would have cost them to lose punch. They spend a lot of type describing different frequencies but little pertaining to marine radar which operates in X band. Be careful of what you read

[foggysail]

Originally Posted by Paul Elliott

The (fairly new) HiDef / 3G / Broadband / (and other marketing-generated names) radars do put out a very low power signal. These use solid state transmitter circuitry (not magnetrons or klystrons). Simrad's "Broadband 3G" radar puts out a fairly steady 165 milliwatts, compared to the 2KW and 4KW pulses of many traditional marine radars. That's about 20,000 times less peak power for the Broadband units, and yes, that's similar to a cellphone in transmit power, or even less.

I still wouldn't want to sit on one, but to be honest I don't worry that much about carrying my cellphone in my pants pocket...

Yes! and they make up for the lost high power microsecond radiated pulses with low continuous power and get better performance at a lower cost. A new low radiated power radar will see its way onto my boat next season.

[guyrj33]

Originally Posted by mrybas

Hi,
My radar used to be mounted on a tall pole well above deck, but I would like to mount it on top of the cabin. I sometimes sit on the cabin top while underway to keep watch. Are there health issues by being on the same level as the radar?

NO RADAR WAVES ARE NOT SAFE for humans, they are microwaves, the same microwaves that boil water in your kitchen and in are capable of boiling the water in your eyeballs.

[Alan Mighty]

Originally Posted by guyrj33

NO RADAR WAVES ARE NOT SAFE for humans, they are microwaves, the same microwaves that boil water in your kitchen and in are capable of boiling the water in your eyeballs.

Ten years or so back, I read several article detailing a surprising number of recreational sailors who reported with cataracts. The argument was that the location of the cataracts in the lens was different from "normal" cataracts. Radiation from a radar antenna mounted above and behind the sailors (as on a post aft of the cockpit) was suspected. I've not seen the issue raised in the literature since.

[Paul Elliott]

Originally Posted by Alan Mighty

Ten years or so back, I read several article detailing a surprising number of recreational sailors who reported with cataracts. The argument was that the location of the cataracts in the lens was different from "normal" cataracts. Radiation from a radar antenna mounted above and behind the sailors (as on a post aft of the cockpit) was suspected. I've not seen the issue raised in the literature since.

I haven't seen the article, or the survey, and I am not an expert in the field of cataracts -- so I should stop right here.

But I won't. Instead I will share some uninformed thoughts on this subject:

* Sailors get a significant amount of glare reflected off the water. This might result in cataracts forming in different locations than with the non-sailing public where the sunlight comes from above.

* Few sailors I know keep their radars turned on at all times, and by a large margin most radars are mounted on the mast far above anyone's head. It seems improbable to me that the resulting amount of exposure would yield any statistically meaningful data.

I would be interested to hear of any follow-up to the reported study.

[Paul Elliott]

Originally Posted by guyrj33

NO RADAR WAVES ARE NOT SAFE for humans, they are microwaves, the same microwaves that boil water in your kitchen and in are capable of boiling the water in your eyeballs.

It depends on the power and frequency. "Microwaves" are radio waves in the frequency range from 300 MHz to 300 GHz.

Our typical marine radar units use the "X-band", which is around 10 GHz.
Cellphones also use microwaves, typically 800 MHz - 2 GHz.
WiFi uses microwaves, up to 5GHz, and even around 60GHz.
Microwave ovens operate around 2.4 GHz.

Traditional marine radar transmits roughly 1000W of power in very short pulses.
Microwave ovens generate about 700W of power in a tightly confined space.
Broadband FMCW radars generate about 0.165W of continuous power.
Cellphones transmit in the 1W or less region.

So you can see that cellphones and WiFi (and many other low-power services) operate in the microwave region and according to virtually all scientific studies these signals cause no biological damage. "Broadband" radars transmit at even lower power than cellphones or WiFi.

So, all microwaves are not created equal. Some can be quite harmless. Traditional pulse radar is not safe for close exposure. Broadband radar is safe, even though it operates in the same frequency range as pulsed radar.

[Alan Mighty]

Originally Posted by Paul Elliott

* Sailors get a significant amount of glare reflected off the water. This might result in cataracts forming in different locations than with the non-sailing public where the sunlight comes from above.

I've not searched for the original journal article, Paul. And I do not know if I still have access to whatever database the article was in. I do have a vague feeling that the story was also repeated in one or more magazines targeted at the boating public.

From what I remember of it, the location of the cataracts was such that it suggested radiation from above and behind the head, i.e. radiation that had penetrated the skull and brain and caused cataracts that were centred at the back of the intra-ocular lens, not the front of the lens.

I think the author of the article linked the phenomenon, based on interviews with the patients, to radar that was mounted aft of the cockpit or to people who spent a lot of time on deck forward of the radar antenna.

I'm not an ophthalmologist. But I hazard a guess that if an ophthalmologist using a slit lamp could determine such a location for cataracts, then the patients were young enough not to have age-related cataracts. And the cataracts must have been small and discrete.

[foggysail]

Originally Posted by guyrj33

NO RADAR WAVES ARE NOT SAFE for humans, they are microwaves, the same microwaves that boil water in your kitchen and in are capable of boiling the water in your eyeballs.

True, microwaves are capable of boiling water anywhere. That does NOT mean radar pulses are going to boil anything unless one's face is directly in front of and almost in contact with a high average power radiated beam. It is average power that generates heat, not peak power.

Average power is calculated by taking the peak power multiplied by the pulse width and then multiplied by the number of pulses per second.

Pulses for marine radar seldom exceed 1 microsecond because the range accuracy is determined by the pulse width. PPS .... not sure about marine radars on pleasure boats but my guess is most likely between 200-500.

Should one stand in front of a radiating radar antenna? I doubt anybody would knowingly want to. Now as to eye cataracts:

Cataracts: 3 Common Types, Causes, Symptoms and Treatments

Age seems to be the most important factor where over 22 million Americans over the age of 40 suffer from cataracts. I don't believe there are that many boat owners in the country.

[MartinMV]

No radar waves are not safe for humans.
But as always, the dosage and orientation is important.

The thing will not send its waves directly to its bottom but in a torso around.
So put it up, you may be outside it perimeter and you also will get better results.

There are a lot of other waves, that ain't particulary healthy for humans either.

The whole picture is called electro smog.

If you happen to live under big antenas or with a lot small transmitters next to you, you may want to check how strong those electromagnetic fields are, that you are living with.

A wifi device will probably not harm you. But living in a house where ten parties that use a hungred of those constantly transmitting and stronger wifi antenas to get a better response for their internet and streaming. That may be a dosage not harmless anymore.

And even for mobile phones there are some that do have way less emission than others. So if you use such a transmitter near your brain or transport it near your testicles, you at least can minimize its long time impact by chosing carefully. And it is a good practice to use a headset.

[Ziggy]

Originally Posted by Paul Elliott

It depends on the power and frequency. "Microwaves" are radio waves in the frequency range from 300 MHz to 300 GHz.

Our typical marine radar units use the "X-band", which is around 10 GHz.
Cellphones also use microwaves, typically 800 MHz - 2 GHz.
WiFi uses microwaves, up to 5GHz, and even around 60GHz.
Microwave ovens operate around 2.4 GHz.

Traditional marine radar transmits roughly 1000W of power in very short pulses.
Microwave ovens generate about 700W of power in a tightly confined space.
Broadband FMCW radars generate about 0.165W of continuous power.
Cellphones transmit in the 1W or less region.

So you can see that cellphones and WiFi (and many other low-power services) operate in the microwave region and according to virtually all scientific studies these signals cause no biological damage. "Broadband" radars transmit at even lower power than cellphones or WiFi.

So, all microwaves are not created equal. Some can be quite harmless. Traditional pulse radar is not safe for close exposure. Broadband radar is safe, even though it operates in the same frequency range as pulsed radar.

While generally true, this is a bit misleading. The FCC/ANSI non-ionizing radiation safety standard at marine radar frequency (X-band) for general public is 1mW/cm^2 average power density over a 6 minute period. In other words, the concern is average, not peak power. Average power for a conventional 2.2kW pulsed radar is about 1W, compared to 0.165W for the 4G FMCW solid state radar. So yes, the solid state radar radiates about 6x less average power, but it's not quite as dramatic as comparing 2.2kW with 0.165W might suggest. Furthermore, in both cases the average power radiated in any particular direction is reduced by the antenna rotation and beam pattern. While I wouldn't want to deliberately sit in front of either radar if I didn't have to, I think both types are safe.