forums
new posts
donate
UER Store
events
location db
db map
search
members
faq
terms of service
privacy policy
register
login




UER Forum > Archived UE Tutorials, Lessons, and Useful Info > Safe MHz range? (Viewed 2035 times)
toqueman 


Location: Saskatoon, SK.
Gender: Male




Send Private Message | Send Email
Safe MHz range?
< on 4/23/2012 12:23 AM >
Posted on Forum: UER Forum
 
Yeah, I've spent about an hour on google before I thought why the heck not? I mean, I'm part of the forum, so why not?
Anyways, yeah, what is a safe Megahertz range?
Theres a tower in my area that is rated as
SaskTel 850 MHz
SaskTel 1900 MHz

Any help is appreciated

Everything happens for a reason. It's just up to you to figure out that reason. So go ahead. Search for the reason. Now you know it's there.
Crypton 


Gender: Male




Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 1 on 4/23/2012 12:55 AM >
Posted on Forum: UER Forum
 
I've spent about an hour on google before I thought why the heck not?


No you didn't.

Mhz cannot be called safe, it's called a frequency.

Now, transmission power can be called safe, which is measured in watts. And can range from harmless (cell phone, RC car) to killing (AM tower, etc.).

Go back to google ;)

SuchundFind 


Location: San Antonio, Texas
Gender: Male




Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 2 on 4/23/2012 5:10 AM >
Posted on Forum: UER Forum
 
Posted by toqueman

Theres a tower in my area that is rated as
SaskTel 850 MHz
SaskTel 1900 MHz



Ok, as the person before me said, MHz is a frequency and not a power output.

So they are not rated this, this is the frequency they use.
Now these frequencies are used in cell phone communication.

Here I will help you a little:
http://lmgtfy.com/...s+of+base+stations


Tastee-Freeze 


Location: Saskatoon. Saskatchewan.
Gender: Male




Send Private Message | Send Email | Polygon Productions
Re: Safe MHz range?
<Reply # 3 on 4/23/2012 5:37 AM >
Posted on Forum: UER Forum
 
I've kind of got a similar question, I read somewhere that 2000MHz is equal to an output of around 33.2 Watts, What is a safe human watt output range? I'm going to take a guy climbing and kind of want to make sure I know what the Hell I'm talking about.

Entry to the rooftop playground is free, if you look up enough to know it's there.
-Dsankt on 'The Crane Style'
Crypton 


Gender: Male




Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 4 on 4/23/2012 11:44 AM >
Posted on Forum: UER Forum
 
I read somewhere that 2000MHz is equal to an output of around 33.2 Watts


No, and once again, read up on what are waves and what is power (and current) in an electrical circuit. ~2Ghz is a very generic band that is used among wifi, bluetooth, and other general purpose devices.

FCC also regulates maximum power output that can be operated at each frequency. And usually, personal network devices output less than a watt.
[last edit 4/23/2012 11:44 AM by Crypton - edited 1 times]

SuchundFind 


Location: San Antonio, Texas
Gender: Male




Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 5 on 4/23/2012 3:18 PM >
Posted on Forum: UER Forum
 
Posted by Tastee-Freeze
I've kind of got a similar question, I read somewhere that 2000MHz is equal to an output of around 33.2 Watts, What is a safe human watt output range? I'm going to take a guy climbing and kind of want to make sure I know what the Hell I'm talking about.


Ok, lets try to explain it as easy as possible.

Lets say you are at the ocean.
You might have seen that there are waves.
Depending on the wind, sometimes you have a long time between the waves, and sometimes they come quite fast.

Radio waves are more or less the same as the ocean waves. The Frequency, is measured in Hz, and this number gives you the amount of waves per second.

Back to the ocean waves. You might have seen that sometimes this waves are quite small, and sometimes they are so strong that they will wash you away. This would be the power, measured in Watts.

As you can see, they both go together, but they are NOT the same.

Tastee, where did you get the information that Hz and Watts is the same?

Now, as we are already here, I show you the only time that Watts is equal to something else. But this has not so much to do with radio output.


Lets talk about power and light.
You might have seen that a light bulb says 100 watts, or 60 watts, or something like this.
Now, as we might have people from different countries, we assume that the voltage that comes out of the wall socket is 110 Volts, one phase only.

Now and this doesn't work with a radio transmitter, I will show you were watts is equal to Volt and Ampere.

If we have a light bulb that says 100 Watts, this means that at a voltage of 110 volts, we need about 0.9 amps.
Amps = Watts/ Voltage
Or
Watts = Amps * Voltage

You can only use this for certain appliances for certain reasons.

Lets assume we have a two way radio that is using about 10 amps on 12 volt.
In general you would say Watts = Amps * Voltage. But as I said this doesn't work. The radio will not have an power output of 120 Watts, even that it might has a power consumption of 120 watts.
A radio doesn't use all it's incoming power to transmit.

I mobile radio for example has an output of 50 Watts and an input of 108 watts.

You might ask what is with the rest, where does it goes?
Some will produce heat, some will be used for the blower that removes this heat. Some will be used by the display, and some will be used by the electronics that make the transmitter transmit.

So even that we know the input power of some devices, this mostly will not be the output power of this device.


Now I tried to explain all of this quite easy.
If you have any question, ask me, or ask Wikipedia.




Banditt 


Location: T.
Gender: Male




Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 6 on 4/23/2012 5:07 PM >
Posted on Forum: UER Forum
 
Sasktel runs UMTS (W-CDMA). They will only be transmitting a couple of watts per antenna face. It's not an immediate danger.

Just watch out for the parabolic dishes. Its like using the sun through a magnifying glass and focusing on an ant. These have hazards in front AND behind, so just steer clear of these. Even the small ones.

And of course, dont fall.

FLICKR
SuchundFind 


Location: San Antonio, Texas
Gender: Male




Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 7 on 4/23/2012 5:24 PM >
Posted on Forum: UER Forum
 
Posted by Banditt
Sasktel runs UMTS (W-CDMA). They will only be transmitting a couple of watts per antenna face. It's not an immediate danger.

Just watch out for the parabolic dishes. Its like using the sun through a magnifying glass and focusing on an ant. These have hazards in front AND behind, so just steer clear of these. Even the small ones.

And of course, dont fall.


A UTMS base station can transmit with about 20 to 40 watts, depending on the manufacture of this base station.
This is not a couple of watts and is not without risk.


Antennas might be directional, but this doesn't mean that they don't have any radiation transmitting outside of it's primary field of operation.



Tastee-Freeze 


Location: Saskatoon. Saskatchewan.
Gender: Male




Send Private Message | Send Email | Polygon Productions
Re: Safe MHz range?
<Reply # 8 on 4/23/2012 10:25 PM >
Posted on Forum: UER Forum
 
Okay, I think I get the idea now, thanks guys, that answers my question. Toque? how bout you?

About the falling...
Lol, not too worried. I take pains to avoid putting myself in that situation, and I've been free climbing for as long as I can consciously remember, so I've had a lot of practice. Also, I was karma's bitch last week, so I should be good.
[last edit 4/23/2012 10:28 PM by Tastee-Freeze - edited 1 times]

Entry to the rooftop playground is free, if you look up enough to know it's there.
-Dsankt on 'The Crane Style'
neptix 






Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 9 on 5/22/2012 7:37 AM >
Posted on Forum: UER Forum
 
The best advice I can give you? If you don't know the details of the transmitter well enough to build it yourself, don't climb it. Not much is known about the effects of long term exposure to those levels of EM radiation, but we do know that the higher the power, the more dangerous it is, and there is some evidence to suggest that it's cumulative, like nuclear radiation. Personally, I'd stick to cranes if I were you.

neptix

SuchundFind 


Location: San Antonio, Texas
Gender: Male




Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 10 on 5/22/2012 6:06 PM >
Posted on Forum: UER Forum
 
Posted by neptix
The best advice I can give you? If you don't know the details of the transmitter well enough to build it yourself, don't climb it. Not much is known about the effects of long term exposure to those levels of EM radiation, but we do know that the higher the power, the more dangerous it is, and there is some evidence to suggest that it's cumulative, like nuclear radiation. Personally, I'd stick to cranes if I were you.

neptix


This would mean that no tower climber should go on a tower, because they don't know how to build a transmitter.

I know how do intermediate maintenance on a high power transmitter, but not how to build it. So I shouldn't work on a transmitter or on an antenna?

Your best advice means nobody should ever climb a tower, unless he is a engineer for transmitters. Show me one person that can build a modern transmitter.


I believe your best advice is useless as it's not realistic.

There are studies about RF radiation, as EM covers everything including light radiation and heat radiation.

Your postings tries to compare apples and oranges and tries to scare people that might not know so much about radio frequencies.

neptix 






Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 11 on 6/28/2012 7:53 PM >
Posted on Forum: UER Forum
 
Perhaps I could have phrased that more clearly. I wasn't talking about being able to design a new transmitter, I was talking about understanding it well enough to put it together from parts, which a competent repairman should be able to do. Regardless, people who don't know why power and frequency are different should not be climbing radio towers.

My experience comes from marine radio and radar systems, rather than the higher power land based towers, but from what I know, the antennae themselves aren't that complicated, just precisely tuned. Are land based systems that much more complicated?

neptix

SuchundFind 


Location: San Antonio, Texas
Gender: Male




Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 12 on 6/28/2012 11:20 PM >
Posted on Forum: UER Forum
 
Posted by neptix

My experience comes from marine radio and radar systems, rather than the higher power land based towers, but from what I know, the antennae themselves aren't that complicated, just precisely tuned. Are land based systems that much more complicated?



Last weekend I talked with a 100 watt radio from West Texas to the Pacific coast.
The Antenna was a long wire hanging from one tree to the next.

So they are quite simple but they have to fit the radio.

Radar can be fun, but you cant grill a flying bird.



Keaven 


Location: 15 miles from the Grassy Knoll
Gender: Male




Send Private Message | Send Email | Yahoo! IM
Re: Safe MHz range?
<Reply # 13 on 6/29/2012 4:13 AM >
Posted on Forum: UER Forum
 
You guys have all given good answers.

There is no relationship between power and frequency, but knowing what the tower is used for is absolutly necessary to safely climb it.


I have a guess where people got the incorrect idea that frequency has some realtionship to watts:

AM broadcast (MW) stations use the entire tower as the antenna. Touching the tower while being grounded can kill you.

FM broadcast stations (VHF) and TV stations (VHF or UHF) do not use the entire tower as an antenna.


Posted by Tastee-Freeze
...I read somewhere that 2000MHz is equal to an output of around 33.2 Watts, What is a safe human watt output range? ...


What is a "safe" level of RF exposure does vary with frequency. The worst frequencies to be exposed to are from 30-300 MHz (VHF). X watts in that range is worse for you than X watts in a lower or higher range. RF exposure is not a simple issue. The FCC has an FAQ on RF exposure at:
http://transition....afety/rf-faqs.html

Posted by Banditt

...Just watch out for the parabolic dishes. Its like using the sun through a magnifying glass and focusing on an ant. These have hazards in front AND behind, so just steer clear of these. Even the small ones.



True not just for parabolic dishes but for all directional antennas.

Posted by neptix

... people who don't know why power and frequency are different should not be climbing radio towers...



I don't think anyone needs to have a GROL, a GMDSS license or a degree in electrical engineering to climb a tower, they need to know have a basic understanding of what to avoid. And for that they need to know what is going on up there.



@ SuchundFind:
Very good explination of what "frequency" means. Also good on the diference between "power consumption" and "power output" (although you didn't use those terms).
Posted by SuchundFind

...If you have any question, ask me, or ask Wikipedia.


Made me laugh! This is a great phrase. Mind if I steal it from you and use it as my tagline? Since I'm one of the guys who likes to jump in and try to help but comes off as a know-it-all, it fits me!

Posted by SuchundFind


...Radar can be fun, but you cant grill a flying bird.




If your birds are coming out too rare, you need to QRO!


SuchundFind 


Location: San Antonio, Texas
Gender: Male




Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 14 on 6/29/2012 5:34 AM >
Posted on Forum: UER Forum
 
Keaven even directional antennas side lobes, especially behind.
That's why the MIM-104 has a shroud, in case you wonder.

And yes we tried to shot a bird with 1Kw radar output, sitting only 500 feet away from the antenna, he was sitting there for 30 minutes and flew away.

Even saw birds landing on higher output radars.

Never saw a dead one.

Keaven 


Location: 15 miles from the Grassy Knoll
Gender: Male




Send Private Message | Send Email | Yahoo! IM
Re: Safe MHz range?
<Reply # 15 on 6/29/2012 2:47 PM >
Posted on Forum: UER Forum
 
Posted by SuchundFind
Keaven even directional antennas side lobes, especially behind.
That's why the MIM-104 has a shroud, in case you wonder.


Yes, I was just agreeing that directional antennas are most dangerous in front, followed by directly behind. People need to understand the basic concept of radiation patterns before they take up tower climbing.


Posted by SuchundFind

And yes we tried to shot a bird with 1Kw radar output, sitting only 500 feet away from the antenna, he was sitting there for 30 minutes and flew away.

Even saw birds landing on higher output radars.

Never saw a dead one.


I was joking about you needing to QRO, but with enough power radar can indeed kill. My former boss operated some kind of over the horizon military radar in Vietnam. He said it was not unusual to have an animal get past the fence and die from RF exposure. I'm sure it was extremely high power, but he has passed away and I can't ask him for additional details.



SuchundFind 


Location: San Antonio, Texas
Gender: Male




Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 16 on 7/2/2012 12:14 AM >
Posted on Forum: UER Forum
 
Posted by Keaven

I was joking about you needing to QRO, but with enough power radar can indeed kill. My former boss operated some kind of over the horizon military radar in Vietnam. He said it was not unusual to have an animal get past the fence and die from RF exposure. I'm sure it was extremely high power, but he has passed away and I can't ask him for additional details.




Could be that other animals died with it, but birds can take it for some reason.
And I know a couple of soldiers that sat on the amplifier tube in a certain radar system, as you might know they are more the size of an engine block, and most of them died on cancer.

They sat on it in the winter time as these amplifiers get nice and warm.


Rosin 


Location: Kingman, AZ
Gender: Female




Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 17 on 2/22/2013 4:30 PM >
Posted on Forum: UER Forum
 
The correct answer is 4.

Underground Twin Cities Minnesota Subterranean adventure
Tunnel kings Action Squad vs plagarism king Greg Brick on minnesota caves and subterranean twin cities
Carvers cave, Fountain Cave, Schmidts cave, stahlmans cellars, channel rock cavern
-Rex- 


Location: Right behind you


Rarely travels in straight lines

Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 18 on 3/3/2013 8:00 PM >
Posted on Forum: UER Forum
 
Having self-studied a lot of electronic circuitry and stuff, I very well know the difference between wattage and frequency. But to slightly go off subject and bring something from science class up, don't the higher frequencies need more power to operate? Ultra-violet/blue frequencies from an LED generally pull in more current but maintain the same average wattage, so couldn't the same thing apply to radio towers?

Also, I was wondering if there are different sorts of towers (Radio, Microwave, etc.), and do these pose different threats themselves?

Agility; Strength; Cunning; Confidence
SuchundFind 


Location: San Antonio, Texas
Gender: Male




Send Private Message | Send Email
Re: Safe MHz range?
<Reply # 19 on 3/6/2013 7:11 PM >
Posted on Forum: UER Forum
 
Posted by -Rex-
Having self-studied a lot of electronic circuitry and stuff, I very well know the difference between wattage and frequency. But to slightly go off subject and bring something from science class up, don't the higher frequencies need more power to operate? Ultra-violet/blue frequencies from an LED generally pull in more current but maintain the same average wattage, so couldn't the same thing apply to radio towers?

Also, I was wondering if there are different sorts of towers (Radio, Microwave, etc.), and do these pose different threats themselves?


I will answer your last question first.
Yes the antenna needs to be different depending on the frequency.
Here you see a PATRIOT radar on a German vehicle base, they work in the GHz frequency and all these little round things are antennas, so they can be quite small and don't need to be large. Ask me if you want to know more about this weapon system.


If you now look at TV antennas or ham radio antennas that work on a smaller frequency you will see that they are larger than these small antennas in the radar. In the very low frequency bands, the ones they use to communicate with submarines (3-30 kHz) the antenna needs to be very long, in general they use a long cable they tow behind them.

So the higher the frequency, the smaller the antenna can be.

Now both types I showed have risks, the radar antenna is very directional, so while you can stand 10 meters behind the PATRIOT radar (with shroud) while transmitting with full power and be under the legal limit of RF exposure, you will not be able to stand next or near a antenna that uses very low frequency as it goes through everything including several meters of salt water.


Now to your first question, about the power requirements for different frequencies.
As we can't change the power output of a transmitter, it actually makes no difference how much power the system draws to produce this amount of output.
The problem with transmitting something depends on the application, and this will tell you how much power you draw.
For example a radar needs a clear signal to get out, so they can only use certain amplifiers that will not mess up the system. They also can not use the maximum output of amplifications as this might mess up the signal as well, so they might use something that needs more power than others. But as there is so much more to it, you can't really say that this amount of input will give you this amount of output. At least not in these kind of applications.

But there might be someone that knows more about theoretical input and output, as you forget that not all the energy that goes in goes out as transmitting power, some goes out as heat and in other ways.

UER Forum > Archived UE Tutorials, Lessons, and Useful Info > Safe MHz range? (Viewed 2035 times)



All content and images copyright © 2002-2024 UER.CA and respective creators. Graphical Design by Crossfire.
To contact webmaster, or click to email with problems or other questions about this site: UER CONTACT
View Terms of Service | View Privacy Policy | Server colocation provided by Beanfield
This page was generated for you in 109 milliseconds. Since June 23, 2002, a total of 737091260 pages have been generated.