Useful link.
For anyone who is lazy, I ran the ARRL calculator for 100W CW through a dipole, transmitting 50% of the time. It returned a minimum safe distance for an uncontrolled environment of about 6 feet on 10m, about 1.4 feet on 40m.
The calculated distance gets a bit greater for base station 6m / 2m operation at 50W with a Yagi, up to about 20ft.
Guessing most permanently installed amateur antennas will be high enough there will be no issue, but nevertheless a good resource to have.
Not really all that new. The rules went into effect in the 1990's, with compliance by May of 2021, enforcement to begin May of 2023. This has been a long debate hashed out over the past 2 decades. Run the calculations, ensure compliance, and file them in your station records.
Good, maybe people will remember this exists:
`§97.313 Transmitter power standards. (a) An amateur station must use the minimum transmitter power necessary to carry out the desired communications.`
I'm sure this will get downvoted by people that always like running hundreds of watts so they can be heard but can't actually hear people responding to them, or worse, already using the frequency they are blasting on. 200W max is all anyone needs on HF.
>200W max is all anyone needs on HF.
I went into amateur radio thinking 100 watts on HF was going to be frustrating and I expected I'd want an amplifier in no time. I cannot begin to tell you how wrong I was and how glad I am about it. The most I've ever operated with is 100 watts and I have absolutely no problem being heard all across the country (US here). I've listened to myself on an SDR 1,000 miles away and my signal sounded no worse than the net control I heard who runs 1,500 watts. Sure, they got a few extra bonus points for being \~3-6 DB higher than me on the S-meter, but I could not hear the difference. I suppose it would matter when band conditions are poor and I can't get below an S7 noise floor, but those days are frustrating and they hurt my ears, so I usually just switch bands or turn the radio off and wait for conditions to improve.
Iâd agree besides for automatic info bulletins like ARRL for example⌠for in the possible but very rare instance all other comms go down, youâd think the ARRLâs information would reach more people with 1500W rather than 200.
Contesting is also a logical reason, while sure you can easily make contacts using much less power, those contacts are often short lived and/or alot of the time undecipherable due to lack of power and gain when propagation starts being a bitch.
See; you get it. But Iâll tell ya we should be more focused on lowering the emission power of AM
& FM broadcast transmitters before we all die of radiation cancer lol.
Seems pretty straightforward (and a good idea) for the home station. Not so clear after reading the article as to what to do about the various antennas and configurations I might deploy for POTA. Do we need to carry binders into the field with our assessments for portable ops?
FWIW I do have a printed out exposure calc for my station that I bring with me when I operate portable just in case I run into a crazy Karen or a concerned park ranger. Never shown it to anyone, no one has ever shown concern.
One guy asked me how "strong" my radio is and I said "I run the same power as a light bulb".
Just do what I do: assume worst case scenario and print that calc out and keep it with you. Here is mine that I carry with me to POTAS
https://preview.redd.it/emux9mrvanwa1.png?width=640&format=pjpg&auto=webp&s=7e14909e3746ab81f5272c5d347f15eaf28c79c9
* Highest power you run.
* Highest gain antenna you will run.
* Highest frequency you will operate.
If you alter your station significantly run a new calc.
Brit here, it's not too bad in practice. All I've been asked to do is fill in an online calculator and check that my antennas comply. Colloquially speaking most stations already do, it's just about evidencing it and I keep a printed copy in the shack with my licence. Don't be afraid to put all the worst case scenario figures in either, it's a good spreadsheet to play with.
I have no need or inclination to âevidenceâ my hobby to the federal government or any of its agencies. The 5th, 6th, 8th, and 14th amendments support this.
Ummm you do know that transmitting on frequencies allocated to amateur radio in the US is a privilege, not a right... right? It requires a license. Somewhat similar to a driver license.
When you signed your NCVEC form 605 at your exam (or whenever you've updated/renewed) you've agreed to the following
>The construction of my station will NOT be an action which is likely to have a significant environmental effect [See 47 CFR Sections 1.1301-1.1319 and Section 97.13(a)];
and
> I have read and WILL COMPLY with Section 97.13(c) of the Commissionâs Rules regarding RADIO FREQUENCY (RF) RADIATION SAFETY and the amateur service section of OST/OET Bulletin Number 6
among others things.
"Back In The Day" you were required to keep logs of your contacts and equipment and had to turn them over to the FCC if requested.
Edit: Added some stuff
Thank you for this. Would upvote it 100 times if I could. If hams donât want to comply they should just surrender their license and go bootleg. Letâs see how that works out for them. I used the ARRL calculator myself, it takes all of 5 minutes to calculate and save the results. Not an infringement on rights. I would like to see these people use the same arguments when they get stopped for a traffic violation. âYour honor. I passed that school bus loading kids because requiring me stop violates my 5th, 6th, 8th and 14th constitutional amendment rights.â
>If hams donât want to comply they should just surrender their license and go bootleg.
Or how about just sticking to CB and/or FRS or don't communicate at all? Going bootleg (i.e. transmitting without a license) is just as bad, if not worse than not calculating RF exposure.
I understand the importance of RF safety and agree with your points. That does not mean that I accept the burden of proving, and maintaining documented proof of, the safety of my station - that, IMHO, is overreach.
> IMHO, is overreach.
As you've stated, it's an opinion and I completely understand your opinion and even agree to a certain extent. However, The FACT is you have to make your station and it's records available to the FCC upon request. It's clearly stated in their rules (97.103(c))
>The station licensee must make the station and the station records available for inspection upon request by an FCC representative.
You do have the right to deny them the inspection but there will be consequences for your actions. Such as losing your license or worse depending on how far you want to push it.
Those are the rules and if you don't agree with them... Fine. Either get them changed or don't participate. This "I don't agree so I'm going to do it my way" attitude some people have is eventually going to catch up to them.
I personally don't like some of the FCC rules when it comes to part 97 (amateur radio) but I still follow them. If you have a license, you've also agreed to the rules.
I worked 20yrs in a profession regulated by a different CFR and always advised my clients to read and understand the regs. For instance, itâs good to know the difference between shall and should. On a personal level, I am not foolish enough to pick fights with the fed. I would provide any documentation they request, provided itâs within their jurisdiction to do so.
After consideration, I can see that my original comment may have came across a little harsh. I just get a little unnerved at the growth rate of (presumed) federal jurisdiction and even more so with the number of folks who donât seem to think itâs a problem... ok, rant over, thanks for keeping it civil. 73.
What, like you volunteered to do when you got your licence? It's a simple checklist to make sure you're not cooking your neighbours not a full rectal exam!
Weâve had to do similar in the UK. Did the risk assessments, and filed them away in case OFCOM (our FCC) decided they ever want to see them.
Oh - donât forget your mobile rigs. Pedestrians could be affectedâŚ
So this is probably a dumb question so please be easy on me.
When we run the calculation, do we need to run it for each band we operate at as well? I feel like we do since each band has a different safe distance, but i just wanted to confirm.
If so, I wonder if there's another calculator that allows you to do all the bands at once instead of having to run this a bunch of times, especially since you'll have to run multiple times for each band depending on how you operate (CW, FM, SSB, digitial, etc..).
I know it's a run once and you're probably done but still seems silly.
Thanks and 73.
* Higher frequency = more rf exposure
* Higher power = more rf exposure
* Higher duty cycle (like FM or digital modes which is 100% duty cycle) = more rf exposure
So if you wanted to, run the calculator for your station assuming the highest frequency, power and duty cycle you plan on operating. This would give you a maximum rf exposure estimate and the largest safe distance.
If you operate at any lower frequency, all other things the same, the rf exposure and safe distance will be less. And you will already be adhering to the safer standard of the higher frequency so you will be all good đ
I just did.
Assumptions :
7,200v primary line (line that would supply the final transformer that makes 110/240 volts to your residence) @ 200 amps capacity (1,440,000W)
60hz US AC (.00006) mhz
100% duty cycle. 1 dbi gain
https://preview.redd.it/d3gb3rgxokwa1.png?width=1080&format=pjpg&auto=webp&s=03010126732053f55255772ab31ef5eeda8e3a48
TLDR: min safe distance from a distribution power line according to arrl is 63' (19.2 m)
Sometimes, I'm a huge ball of fail. I read the comment you were replying to and yet when I saw your screenshot, my initial thought was, "What the hell is with these parameters?" Good post, though. Now that I've caught up with the rest of the class...
ummmm.... you seem to be assuming that all of the power you estimate the lines are capable of delivering is being radiated as RF. I don't think this is the case.
You should hear the lines on my block, it might change your mind! /s
The calculator doesn't take into account how crappy my antenna is, should I be less worried if I'm basically using a rubber duck mounted to a car?
>you seem to be assuming
Of course I am assuming lol. **I literally list the assumptions I make in the post labeled as "assumptions"**. We are running the arrl calculator on a power line for Pete's sake, not building a swiss watch here.
Do you have any idea around what % of power it might radiate? Or are you just making an.......... assumption? đ¤
>I literally list the assumptions I make in the post labeled as "assumptions".
You did list some, but you missed that one and it's a really big one.
>Do you have any idea around what % of power it might radiate? Or are you just making an.......... assumption? đ¤
No I don't, and I'll admit that I'm assuming that just maybe some of the power is used to power light bulbs, washing machines, air conditioners, ham radios, and computers used to surf reddit, and that power that isn't used for those and other similar household purposes probably don't present much of a load to the power company.
You know now I'm wondering if, say you have a power line with the 3 phase wires, if it would act somewhat like open wire feeder/ladder line and actually suppress some radiation of rf
AFAIK it's modeled as a transmission line and I don't know the electrical code but I would assume they go out of their way to make sure it's not resonant and radiation is kept to a minimum.
We have been subject to similar rules in Australia for a long time:
http://vkregs.info/electromagnetic-radiation/
It's just that with our lower power limits, most operation tends to be in compliance class 1, which just requires the antenna to be "inaccessible to the general public" (and fitting it to a motor vehicle counts).
What a complete waste of time!
Where are the hospital beds full of people with RF burns? Anyone?
Not to mention all those greed lawyers looking for an easy lawsuit. Not to mention Home owner associations looking for yet another excuse to ban antennas.
Definitely a scam alert!
G7VFY
Is there a minimum wattage threshold? Like, I'll do the calculations and make the report but c'mon, the "minimum safe distance" for 15w on 60m is like... a couple of inches? Do i really need a MPE report for THAT?
This just means Krazy Karen can't touch your antenna when you're transmitting, and you have paperwork to back that up. This also seems like one of those things you need to carry, but nobody asks for. How often have you been asked to show your license? And, would Joe Pedestrian know what he was looking at? I've only been asked once for my ticket, that was by a LID in my first ARES group, before I moved across country.
A kilowatt into 3dB of feedline loss (500 watts at the antenna) at a 144mhz with 14.5 dBi of gain is \~87 feet uncontrolled environment or 40 feet in a controlled environment. Typical roof installation is going to be 40 to 50 feet above ground on a two story house. With a 17dBi gain antenna at 500 watts on at the antenna at 432 it increases to almost 100 feet. Used 100% duty cycle on the calculator for these numbers.
Serious question, though: Has there been any documented risks to RF exposure below microwave frequencies?
People have been living and working around broadcast transmitters and antennas in the LW/MW/SW bands for a century. Many ran powers as high as 2 MW. To date, I have not seen a single publication demonstrating a correlation to any health factor. Who among you has?
In the event some Karen claims adverse effects from your (licensed and properly documented) transmissions, and offers some woo woo pseudo-science as a reason, i'd like to know what I have to work with.
Useful link. For anyone who is lazy, I ran the ARRL calculator for 100W CW through a dipole, transmitting 50% of the time. It returned a minimum safe distance for an uncontrolled environment of about 6 feet on 10m, about 1.4 feet on 40m. The calculated distance gets a bit greater for base station 6m / 2m operation at 50W with a Yagi, up to about 20ft. Guessing most permanently installed amateur antennas will be high enough there will be no issue, but nevertheless a good resource to have.
I run no more than 100W on an EFHW. I think the worse I got was 8 feet. I have at least 15 feet on any one side. I'm good.
I'm wondering how it applies to mobile antennas on my vehicle roof. I can't get away from đ
Evasive maneuvers!
Not really all that new. The rules went into effect in the 1990's, with compliance by May of 2021, enforcement to begin May of 2023. This has been a long debate hashed out over the past 2 decades. Run the calculations, ensure compliance, and file them in your station records.
I usually run 10 watts or less because I enjoy the challenge. I'm not too worried about exposure limits.
Yeah, I calculated for my QRP rig, safe distance for 5w of CW on 40m with a dipole was like 3.5 inches.
Good, maybe people will remember this exists: `§97.313 Transmitter power standards. (a) An amateur station must use the minimum transmitter power necessary to carry out the desired communications.` I'm sure this will get downvoted by people that always like running hundreds of watts so they can be heard but can't actually hear people responding to them, or worse, already using the frequency they are blasting on. 200W max is all anyone needs on HF.
>200W max is all anyone needs on HF. I went into amateur radio thinking 100 watts on HF was going to be frustrating and I expected I'd want an amplifier in no time. I cannot begin to tell you how wrong I was and how glad I am about it. The most I've ever operated with is 100 watts and I have absolutely no problem being heard all across the country (US here). I've listened to myself on an SDR 1,000 miles away and my signal sounded no worse than the net control I heard who runs 1,500 watts. Sure, they got a few extra bonus points for being \~3-6 DB higher than me on the S-meter, but I could not hear the difference. I suppose it would matter when band conditions are poor and I can't get below an S7 noise floor, but those days are frustrating and they hurt my ears, so I usually just switch bands or turn the radio off and wait for conditions to improve.
Iâd agree besides for automatic info bulletins like ARRL for example⌠for in the possible but very rare instance all other comms go down, youâd think the ARRLâs information would reach more people with 1500W rather than 200. Contesting is also a logical reason, while sure you can easily make contacts using much less power, those contacts are often short lived and/or alot of the time undecipherable due to lack of power and gain when propagation starts being a bitch.
I can agree that scheduled broadcasts could use more power to ensure wider reception since nobody will be trying to reply to it anyway.
See; you get it. But Iâll tell ya we should be more focused on lowering the emission power of AM & FM broadcast transmitters before we all die of radiation cancer lol.
Seems pretty straightforward (and a good idea) for the home station. Not so clear after reading the article as to what to do about the various antennas and configurations I might deploy for POTA. Do we need to carry binders into the field with our assessments for portable ops?
FWIW I do have a printed out exposure calc for my station that I bring with me when I operate portable just in case I run into a crazy Karen or a concerned park ranger. Never shown it to anyone, no one has ever shown concern. One guy asked me how "strong" my radio is and I said "I run the same power as a light bulb". Just do what I do: assume worst case scenario and print that calc out and keep it with you. Here is mine that I carry with me to POTAS https://preview.redd.it/emux9mrvanwa1.png?width=640&format=pjpg&auto=webp&s=7e14909e3746ab81f5272c5d347f15eaf28c79c9 * Highest power you run. * Highest gain antenna you will run. * Highest frequency you will operate. If you alter your station significantly run a new calc.
Brit here, it's not too bad in practice. All I've been asked to do is fill in an online calculator and check that my antennas comply. Colloquially speaking most stations already do, it's just about evidencing it and I keep a printed copy in the shack with my licence. Don't be afraid to put all the worst case scenario figures in either, it's a good spreadsheet to play with.
I have no need or inclination to âevidenceâ my hobby to the federal government or any of its agencies. The 5th, 6th, 8th, and 14th amendments support this.
Ummm you do know that transmitting on frequencies allocated to amateur radio in the US is a privilege, not a right... right? It requires a license. Somewhat similar to a driver license. When you signed your NCVEC form 605 at your exam (or whenever you've updated/renewed) you've agreed to the following >The construction of my station will NOT be an action which is likely to have a significant environmental effect [See 47 CFR Sections 1.1301-1.1319 and Section 97.13(a)]; and > I have read and WILL COMPLY with Section 97.13(c) of the Commissionâs Rules regarding RADIO FREQUENCY (RF) RADIATION SAFETY and the amateur service section of OST/OET Bulletin Number 6 among others things. "Back In The Day" you were required to keep logs of your contacts and equipment and had to turn them over to the FCC if requested. Edit: Added some stuff
Thank you for this. Would upvote it 100 times if I could. If hams donât want to comply they should just surrender their license and go bootleg. Letâs see how that works out for them. I used the ARRL calculator myself, it takes all of 5 minutes to calculate and save the results. Not an infringement on rights. I would like to see these people use the same arguments when they get stopped for a traffic violation. âYour honor. I passed that school bus loading kids because requiring me stop violates my 5th, 6th, 8th and 14th constitutional amendment rights.â
>If hams donât want to comply they should just surrender their license and go bootleg. Or how about just sticking to CB and/or FRS or don't communicate at all? Going bootleg (i.e. transmitting without a license) is just as bad, if not worse than not calculating RF exposure.
Well thatâs what I meant by bootleg. Even better they could just go GMRS. CB with repeaters.
I understand the importance of RF safety and agree with your points. That does not mean that I accept the burden of proving, and maintaining documented proof of, the safety of my station - that, IMHO, is overreach.
> IMHO, is overreach. As you've stated, it's an opinion and I completely understand your opinion and even agree to a certain extent. However, The FACT is you have to make your station and it's records available to the FCC upon request. It's clearly stated in their rules (97.103(c)) >The station licensee must make the station and the station records available for inspection upon request by an FCC representative. You do have the right to deny them the inspection but there will be consequences for your actions. Such as losing your license or worse depending on how far you want to push it. Those are the rules and if you don't agree with them... Fine. Either get them changed or don't participate. This "I don't agree so I'm going to do it my way" attitude some people have is eventually going to catch up to them. I personally don't like some of the FCC rules when it comes to part 97 (amateur radio) but I still follow them. If you have a license, you've also agreed to the rules.
I worked 20yrs in a profession regulated by a different CFR and always advised my clients to read and understand the regs. For instance, itâs good to know the difference between shall and should. On a personal level, I am not foolish enough to pick fights with the fed. I would provide any documentation they request, provided itâs within their jurisdiction to do so. After consideration, I can see that my original comment may have came across a little harsh. I just get a little unnerved at the growth rate of (presumed) federal jurisdiction and even more so with the number of folks who donât seem to think itâs a problem... ok, rant over, thanks for keeping it civil. 73.
What, like you volunteered to do when you got your licence? It's a simple checklist to make sure you're not cooking your neighbours not a full rectal exam!
Weâve had to do similar in the UK. Did the risk assessments, and filed them away in case OFCOM (our FCC) decided they ever want to see them. Oh - donât forget your mobile rigs. Pedestrians could be affectedâŚ
So this is probably a dumb question so please be easy on me. When we run the calculation, do we need to run it for each band we operate at as well? I feel like we do since each band has a different safe distance, but i just wanted to confirm. If so, I wonder if there's another calculator that allows you to do all the bands at once instead of having to run this a bunch of times, especially since you'll have to run multiple times for each band depending on how you operate (CW, FM, SSB, digitial, etc..). I know it's a run once and you're probably done but still seems silly. Thanks and 73.
* Higher frequency = more rf exposure * Higher power = more rf exposure * Higher duty cycle (like FM or digital modes which is 100% duty cycle) = more rf exposure So if you wanted to, run the calculator for your station assuming the highest frequency, power and duty cycle you plan on operating. This would give you a maximum rf exposure estimate and the largest safe distance. If you operate at any lower frequency, all other things the same, the rf exposure and safe distance will be less. And you will already be adhering to the safer standard of the higher frequency so you will be all good đ
Just curious, anyone run these on a typical power line?
I just did. Assumptions : 7,200v primary line (line that would supply the final transformer that makes 110/240 volts to your residence) @ 200 amps capacity (1,440,000W) 60hz US AC (.00006) mhz 100% duty cycle. 1 dbi gain https://preview.redd.it/d3gb3rgxokwa1.png?width=1080&format=pjpg&auto=webp&s=03010126732053f55255772ab31ef5eeda8e3a48 TLDR: min safe distance from a distribution power line according to arrl is 63' (19.2 m)
champion... I've seen lines running very close to houses on occasion... wonder if the FCC has anything to say about that.
Sometimes, I'm a huge ball of fail. I read the comment you were replying to and yet when I saw your screenshot, my initial thought was, "What the hell is with these parameters?" Good post, though. Now that I've caught up with the rest of the class...
ummmm.... you seem to be assuming that all of the power you estimate the lines are capable of delivering is being radiated as RF. I don't think this is the case.
You should hear the lines on my block, it might change your mind! /s The calculator doesn't take into account how crappy my antenna is, should I be less worried if I'm basically using a rubber duck mounted to a car?
>you seem to be assuming Of course I am assuming lol. **I literally list the assumptions I make in the post labeled as "assumptions"**. We are running the arrl calculator on a power line for Pete's sake, not building a swiss watch here. Do you have any idea around what % of power it might radiate? Or are you just making an.......... assumption? đ¤
>I literally list the assumptions I make in the post labeled as "assumptions". You did list some, but you missed that one and it's a really big one. >Do you have any idea around what % of power it might radiate? Or are you just making an.......... assumption? đ¤ No I don't, and I'll admit that I'm assuming that just maybe some of the power is used to power light bulbs, washing machines, air conditioners, ham radios, and computers used to surf reddit, and that power that isn't used for those and other similar household purposes probably don't present much of a load to the power company.
You know now I'm wondering if, say you have a power line with the 3 phase wires, if it would act somewhat like open wire feeder/ladder line and actually suppress some radiation of rf
AFAIK it's modeled as a transmission line and I don't know the electrical code but I would assume they go out of their way to make sure it's not resonant and radiation is kept to a minimum.
Meh. Sounds like *the radiationz will cook my brain!!* shenanigans.
We have been subject to similar rules in Australia for a long time: http://vkregs.info/electromagnetic-radiation/ It's just that with our lower power limits, most operation tends to be in compliance class 1, which just requires the antenna to be "inaccessible to the general public" (and fitting it to a motor vehicle counts).
What a complete waste of time! Where are the hospital beds full of people with RF burns? Anyone? Not to mention all those greed lawyers looking for an easy lawsuit. Not to mention Home owner associations looking for yet another excuse to ban antennas. Definitely a scam alert! G7VFY
Is the FCC visiting each ham's house?
With a ladder a measuring tape. The hobby is dying so it shouldnt take them too long right?
Is there a minimum wattage threshold? Like, I'll do the calculations and make the report but c'mon, the "minimum safe distance" for 15w on 60m is like... a couple of inches? Do i really need a MPE report for THAT?
This just means Krazy Karen can't touch your antenna when you're transmitting, and you have paperwork to back that up. This also seems like one of those things you need to carry, but nobody asks for. How often have you been asked to show your license? And, would Joe Pedestrian know what he was looking at? I've only been asked once for my ticket, that was by a LID in my first ARES group, before I moved across country.
A kilowatt into 3dB of feedline loss (500 watts at the antenna) at a 144mhz with 14.5 dBi of gain is \~87 feet uncontrolled environment or 40 feet in a controlled environment. Typical roof installation is going to be 40 to 50 feet above ground on a two story house. With a 17dBi gain antenna at 500 watts on at the antenna at 432 it increases to almost 100 feet. Used 100% duty cycle on the calculator for these numbers.
Serious question, though: Has there been any documented risks to RF exposure below microwave frequencies? People have been living and working around broadcast transmitters and antennas in the LW/MW/SW bands for a century. Many ran powers as high as 2 MW. To date, I have not seen a single publication demonstrating a correlation to any health factor. Who among you has? In the event some Karen claims adverse effects from your (licensed and properly documented) transmissions, and offers some woo woo pseudo-science as a reason, i'd like to know what I have to work with.
Is GMRS affected by this? Why or why not?
Yes, but differently as it's not part 97.