Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: Prev 1 [2] 3 Next   Go Down
  Print  
Author Topic: RF Radiation Danger?  (Read 9464 times)
K1CJS
Member

Posts: 6013




Ignore
« Reply #15 on: July 14, 2012, 07:53:42 AM »

...I pay no attention to this RF filed BS that is the result of one man's 15 minutes of fame like the idiot who was able to bring the world to using the word Hertz instead of cycle.

I agree with 'AXW.  Yes, by all means have some method to protect people from coming in contact with the antenna when you're transmitting, but don't stop doing what you enjoy just because of people who scream "The sky is falling."  You can get a lot more exposure from some microwave ovens--frequencies that can REALLY hurt you--than you can from a transmitting antenna.  

TV and radio towers located in residential areas have been around for years, putting out thousands of watts of power, and there are absolutely no reports of increased cancer or sickness relative to the area surrounding them.

File (in your station records) the required paperwork concerning RF radiation, then enjoy the hobby.  Life is altogether too short to worry about something that has been around us for years--with no ill effects.
Logged
G3RZP
Member

Posts: 4502




Ignore
« Reply #16 on: July 14, 2012, 11:30:58 AM »

I could not agree more with 'AXW and 'CJS. The evidence, such as it is, is somewhat selective, although there may be a case for for avoiding long term exposure to a cellphone handset because it is so close. At HF, the problems are more RF burns from the antenna or from any ungrounded metal work that could be energised.

Some 30 years ago, there was a GCHQ site a mile or so away: at one stage they had a one mile long array with some 30kW around 17 MHz for OTH radar tests - that got abandoned, but that's another story. However, farmers with buildings 'in the beam' (my neighbour is one) were warned to avoid corrugated metal roofs because of the possibility of arcing between the metal sheets causing a fire.

That site is now a nature reserve.....
Logged
KG4NEL
Member

Posts: 373




Ignore
« Reply #17 on: July 14, 2012, 12:14:18 PM »

I prefer being medium-well to being rare anyway.  Grin
Logged
K7KBN
Member

Posts: 2788




Ignore
« Reply #18 on: July 14, 2012, 12:49:35 PM »


I pay no attention to this RF filed BS that is the result of one man's 15 minutes of fame like the idiot who was able to bring the world to using the word Hertz instead of cycle.

Cycle:  one complete alternation of a periodically-repeating function without any specification of time.

Hertz:  a measurement of frequency equal to one cycle PER SECOND

Cycle ≠ Hertz
Logged

73
Pat K7KBN
CWO4 USNR Ret.
K0ZN
Member

Posts: 1544




Ignore
« Reply #19 on: July 14, 2012, 02:38:25 PM »

 The dog will only sniff that antenna ONCE if you are on the air.

 Trust me..... in the REAL world, you have a LOT more things to worry about in terms of your kids safety than radiation from a 100 W HF transmitter.

  Are you going to let them use cell phones when they grow up?! Let me re-word that: How are you going to PREVENT them from using cell phones??
  How about dental and medical X-ray's? They will get far more "injury" playing outside on a bright sunny day for a couple of hours than they ever could
  from your station.  I would rate riding in the car with their friends and the exposure to other traffic hazards as about 500,000 times more dangerous.
  Gonna let them ride bicycles ??  It is all relative.........  Tell the kids to stay away from the antenna and tell them why, I am sure they will understand
  and comply.  The odds of your dog dying from radiation exposure from your antenna is many times higher than your chances of winning a major lottery!
  
  Bottomline:  It is a non-event.

  73,  K0ZN
« Last Edit: July 14, 2012, 02:39:57 PM by K0ZN » Logged
W4FID
Member

Posts: 132




Ignore
« Reply #20 on: July 16, 2012, 01:38:00 AM »

A plain vanilla florescent bulb will light when transmitting. Had one electrical taped to my dipole for a while. It was fun to see it blink. Feed point = higher current portion of the antenna. Ends = higher voltage portion. Position the bulb so it gets enough voltage to light nicely (will depend on actual voltage on your actual antenna and the size/length/wattage of the bulb you choose).

However THAT'S NOT REALLY THE POINT. RELIABLE SAFETY IS THE POINT. Make it an attractive nuisance and it will draw kids -- and liability. Tell them to stay away till you're blue in the face -- do you think 100% of the time they and their friends will? Do your dogs comprehend "if the light is on my antenna will hurt you?" The not too bright one you mentioned probably won't get it when you tell him/her and telling them may encourage the kids to experiment. Kids do that. Adults need to protect them.

RF burns are nasty and slow to heal. Worse than a hot pan on the stove burn. A jolt across the chest can be fatal. NOTE: from a hand or a dog's nose thru the body to the feet they are standing on -- that path -- includes the chest. You need RELIABLE way(s) to avoid them.

Put a "sleeve" around each one -- or a fence around the area. Signs and or lights are only effective for thinking reasoning mature people ............... probably not effective enough to be safe for dogs and kids.

You can do the radiation calculation but I'll bet it will show little danger from brief exposure to 100 watts. Touching and getting burned is the issue ................ unless someone has a medical device (pacemaker, monitoring device, hearing aid, Rx pump, etc) they may be in a different category.
Logged
G3RZP
Member

Posts: 4502




Ignore
« Reply #21 on: July 16, 2012, 05:50:55 AM »

The standards for medical implants and the like at HF are currently 10V/m: there's a move to increase this to 60V/m. Not sure why, since that is beyond the ICNIRP levels.
Logged
WA9UAA
Member

Posts: 313




Ignore
« Reply #22 on: July 16, 2012, 06:49:58 AM »

Why not get some of that plastic fencing and place it around the verticals so that the kids and dogs can't even get close to the antennas?

^^^^^^^^^^^^^^THIS!^^^^^^^^^^^^^^ and use the mulch!
73,
Rob
Logged
K8AXW
Member

Posts: 3780




Ignore
« Reply #23 on: July 16, 2012, 10:19:55 AM »

OK, RF radiation must be monitored to satisfy FCC regulations.  A given.  However, the FCC regulation we're talking about was caused by questionable "research" resulting in media hysteria, which seems to be the norm these days.

The reason I say this is because of working in the broadcast field.  Every since day one, most radio stations were located right under the antenna tower and the stations were running everything from a KW up.  I have read no research results indicating that broadcast engineers or station staff suffers a higher cancer rate than anyone else.

Now, all at once we have hams being required to monitor RF exposure not only to themselves but to the neighbors.

Putting a "TRANSMITTING" sign in your back yard is just asking for trouble from your neighbors.  You can bet you donkey that eventually you're going to find yourself in court proving that you didn't give your neighbors or their dog cancer.

Protect your family and pets with a fence and training or install antennas that anyone can touch.

 
Logged
W0BTU
Member

Posts: 1651


WWW

Ignore
« Reply #24 on: July 16, 2012, 11:15:07 AM »

OK, RF radiation must be monitored to satisfy FCC regulations.  A given.  However, the FCC regulation we're talking about was caused by questionable "research" resulting in media hysteria, which seems to be the norm these days.

The reason I say this is because of working in the broadcast field.  Every since day one, most radio stations were located right under the antenna tower and the stations were running everything from a KW up.  I have read no research results indicating that broadcast engineers or station staff suffers a higher cancer rate than anyone else.

Protect your family and pets with a fence and training or install antennas that anyone can touch.

Very well said. Start reading this thread here (on page two): http://www.eham.net/ehamforum/smf/index.php/topic,81271.15.html .  Draw your own conclusions and do what you want; but I could not find a single piece of hard evidence in that very long IEEE paper referred to there that is the basis for this excess of caution below 30 MHz.
« Last Edit: July 16, 2012, 11:19:57 AM by W0BTU » Logged

G3RZP
Member

Posts: 4502




Ignore
« Reply #25 on: July 16, 2012, 11:19:42 AM »

Read '8AXW - 'You know he makes sense!'
Logged
K4SAV
Member

Posts: 1840




Ignore
« Reply #26 on: July 17, 2012, 05:01:47 PM »

Putting a "TRANSMITTING" sign in your back yard is just asking for trouble from your neighbors.  You can bet you donkey that eventually you're going to find yourself in court proving that you didn't give your neighbors or their dog cancer.

Not if you are in compliance with the FCC rules governing RF exposure.  It then becomes the complaint's problem of proving that levels below the legal limit cause a problem, which is almost an impossible task.  However if you are in violation of the rules then you have a problem.
Logged
K7KBN
Member

Posts: 2788




Ignore
« Reply #27 on: July 17, 2012, 06:13:59 PM »

OK, RF radiation must be monitored to satisfy FCC regulations.  A given.  However, the FCC regulation we're talking about was caused by questionable "research" resulting in media hysteria, which seems to be the norm these days.

The reason I say this is because of working in the broadcast field.  Every since day one, most radio stations were located right under the antenna tower and the stations were running everything from a KW up.  I have read no research results indicating that broadcast engineers or station staff suffers a higher cancer rate than anyone else.

Now, all at once we have hams being required to monitor RF exposure not only to themselves but to the neighbors.

Putting a "TRANSMITTING" sign in your back yard is just asking for trouble from your neighbors.  You can bet you donkey that eventually you're going to find yourself in court proving that you didn't give your neighbors or their dog cancer.

Protect your family and pets with a fence and training or install antennas that anyone can touch.

 

Am I reading this right?
Logged

73
Pat K7KBN
CWO4 USNR Ret.
KK4AXX
Member

Posts: 119


WWW

Ignore
« Reply #28 on: August 20, 2012, 11:08:31 PM »

I fenced off the verticals, added appropriate warning labels to the radiators, planted some nice flowers and called it good.

Now, on the light thing... I'm having fun.   Grin  I reached into a box and pulled out a coil.  Something like 16ga wire with about 20 to 25 turns and an ID of 1.25 inches.  To this I clipped a red LED, then added a random resistor (turned out to be 4.7K) between the other leg of the LED and the other end of the coil.  Then I walked the mess out to the picnic table in the backyard that is about 6 feet from the new protective fencing and simply laid it on the near end.  That night I answered a call on 20M and immediately noticed the LED flashing on each spoken word!  Same thing on 40M, but nothing on 17M.  Thinking that I smoked the LED or something was loose I tried 20M again and it worked fine.  Just something about that coil/LED/resistor combo that doesn't like 17...

It is silly, but fun nevertheless!

OH! My neighbor noticed me fooling with the verticals and asked if they were HAM antennas.  Wincing, I said they were.  His answer was re-assuring.  He said he had had no problems on his end and hoped that if a storm rolls through here this season that I'll be around to help get word to his family in Nova Scotia.  We talked and I found out when & where (roughly) his brother listens and I promised to keep listening and offered to forward a message anytime I can be of service.  Don't think he's going to mind a few more antennas...
Logged

George U. Potter Lodge, #912, F. & A. M. of Alabama
A.A.S.R., S.J. - Valley of Mobile, Orient of Alabama
Dave Langham Chapter, #536, Order of the Eastern Star
Order of DeMolay, Mobile Chapter, Adult Advisory Council
KB3HG
Member

Posts: 404




Ignore
« Reply #29 on: August 21, 2012, 09:23:27 AM »

A couple minor points, Verticals feed at the bottom,  low voltage high current point. If one was worried split thin walled PVC pipe around the base exposed antenna would form a barrier from that rf burn.  Next magnetic field would probably be high at the base.
And old folk lore, studies from the OTs that worked 75m phone at high power exposed to high level rf showed a very very low occurrence of a rare form of leukemia after a lifetime of operating. 50 + years. 1kw rf in the shack.  From arguments when they were thinking about the exposure regs.

Tom
Logged
Pages: Prev 1 [2] 3 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!