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Old 02-21-2009, 13:36   #1
clemtiger00
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2 Meter Newbie question

I am planning on setting up a 2Meter Radio, IC-2200H at home, and i am looking at mounting a J pole antenna in the attic. Are there any RF safety issues with operating this at 65W power. Anything else to consider? Thanks.
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Old 02-22-2009, 09:28   #2
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http://n5xu.ece.utexas.edu/rfsafety/

There ya go. a J Pole is 5.15dbi gain 100% duty cycle on FM, so you put in the full 65 watts.

I personally wouldn't worry about it.
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Old 02-22-2009, 19:23   #3
RED64CJ5
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It's a responsible question, no doubt about it. Most hams don't even think about it!

You should not worry with the configuration you have described.
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Old 02-23-2009, 18:43   #4
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Quote:
Originally Posted by G23Adam View Post
http://n5xu.ece.utexas.edu/rfsafety/

There ya go. a J Pole is 5.15dbi gain 100% duty cycle on FM, so you put in the full 65 watts.

I personally wouldn't worry about it.
It's not as simple as all that!

http://www.fcc.gov/oet/info/documents/bulletins/#65

ERP, Controlled and Uncontrolled areas need to be factored into the "What is Safe" equation.

It specifically states that any amateur station transmitting power >50 Watts (except mobiles) on 2 meters must do a station evaluation. The method of evaluation must be documented and kept at the station. If the evaluation determines that RF levels in controlled and uncontrolled areas are below established limits it's OK to use the power for which evaluated. Otherwise power must be reduced to limit RF exposure to less than established exposure limits.

That said, I don't think the FCC is out hunting for violators. This rule was established to appease the State of New Jersey that wanted to tax Amateur transmitters to the tune of $200 per. If I lived in Jersey, I couldn't afford to be a ham if that law was passed.
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Old 02-25-2009, 15:14   #5
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Did you even click that link?

Didn't think so....

It's a calculator that tells you about MPE. Most hams at the technician level aren't taught nor know how MPE works, therefore that is a good start.
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Old 02-25-2009, 18:10   #6
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Quote:
Originally Posted by G23Adam View Post
Did you even click that link?

Didn't think so....

It's a calculator that tells you about MPE. Most hams at the technician level aren't taught nor know how MPE works, therefore that is a good start.
Did you know any of his particulars, like distance of concern, feed line specifics? He may be OK according to "your" calculator, but he still needs to document his results if the PWR at the antenna feed point >50W. He needs to do this for both Controlled and Uncontrolled areas.

Yes I did open the link. I don't think it covers all the bases. Did you read my link?

When anyone applies for a license or upgrade by signing the 605 for they agree to evaluate their station per OET 65. I agree that tech aren't taught enough however, ignorance is no excuse, right?
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Old 03-03-2009, 09:57   #7
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Quote:
Originally Posted by EUPHER49 View Post
Did you know any of his particulars, like distance of concern, feed line specifics? He may be OK according to "your" calculator, but he still needs to document his results if the PWR at the antenna feed point >50W. He needs to do this for both Controlled and Uncontrolled areas.

Yes I did open the link. I don't think it covers all the bases. Did you read my link?

When anyone applies for a license or upgrade by signing the 605 for they agree to evaluate their station per OET 65. I agree that tech aren't taught enough however, ignorance is no excuse, right?

I had put a long and drawn out explanation here, but felt it would be lost on someone too wrapped up in FCC pdf's to understand that there's ways to make life easy for the amateur operator these days.

I bow to your knowledge of where the rules are and how you dole them out without any explanation of how they apply to any circumstance, nor any useful implementation of them in any example.
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Old 03-03-2009, 19:42   #8
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Quote:
Originally Posted by G23Adam View Post
I had put a long and drawn out explanation here, but felt it would be lost on someone too wrapped up in FCC pdf's to understand that there's ways to make life easy for the amateur operator these days.

I bow to your knowledge of where the rules are and how you dole them out without any explanation of how they apply to any circumstance, nor any useful implementation of them in any example.
I'm not wrapped up in FCC PDFs. In fact I'd think that the FCC would be concerned if they questioned you about the safety of your station, I don't think they'd take kindly to your not being wrapped up with them.

The link you provided can provide calculations to insure that MPEs aren't being exceeded provided you know what the power is at the feed point of the antenna, the distance to people in the area that you can control (your family and friends), and the distance to the area to which you can't control. (your neighbors. One must take these into consideration, according to my beloved PDFs.

I'd be happy to provide how to apply this calculator to the OP's situation if I had it. He really didn't supply any of it. How much and what type of feed line, the distance from the base of the antenna to the closest occupied area in his home, and the distance from the base of the antenna to his property line, or his closest neighbor if he lives in an apartment. You didn't have that information when you told him to go ahead and have fun. (Unless he contacted you off forum) It may be as simple as saying that he has so much of a certain feed line and its loss from the TX to the ANT is >1.1dB. Not many hams know how to calculate that either.

The calculator is basically correct but one needs to know how to justify its results. My PDFs from the FCC can do that.

Oh and I'd like to hear your long drawn out explanation...

Judging by the number of replies to this thread, I'd say not many other hams here know how to evaluate their station.
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Old 03-04-2009, 07:34   #9
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Quote:
Originally Posted by EUPHER49 View Post
I'm not wrapped up in FCC PDFs. In fact I'd think that the FCC would be concerned if they questioned you about the safety of your station, I don't think they'd take kindly to your not being wrapped up with them.

The link you provided can provide calculations to insure that MPEs aren't being exceeded provided you know what the power is at the feed point of the antenna, the distance to people in the area that you can control (your family and friends), and the distance to the area to which you can't control. (your neighbors. One must take these into consideration, according to my beloved PDFs.

I'd be happy to provide how to apply this calculator to the OP's situation if I had it. He really didn't supply any of it. How much and what type of feed line, the distance from the base of the antenna to the closest occupied area in his home, and the distance from the base of the antenna to his property line, or his closest neighbor if he lives in an apartment. You didn't have that information when you told him to go ahead and have fun. (Unless he contacted you off forum) It may be as simple as saying that he has so much of a certain feed line and its loss from the TX to the ANT is >1.1dB. Not many hams know how to calculate that either.

The calculator is basically correct but one needs to know how to justify its results. My PDFs from the FCC can do that.

Oh and I'd like to hear your long drawn out explanation...

Judging by the number of replies to this thread, I'd say not many other hams here know how to evaluate their station.
The measurement isn't from the base, it's from the center of the antenna. For most hams, feedline loss is a wash when under 100 watts, it's not worth calculating for a safety check, just grab the antenna gain and input power.

And most hams never evaluate their station. These are the same morons who tune up their amp on the DX or net freq, and pretty much trash 80M from 3800 up.
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Old 03-04-2009, 09:40   #10
RED64CJ5
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Quote:
Originally Posted by EUPHER49 View Post
Judging by the number of replies to this thread, I'd say not many other hams here know how to evaluate their station.
Quote:
Originally Posted by G23Adam View Post
And most hams never evaluate their station. These are the same morons who tune up their amp on the DX or net freq, and pretty much trash 80M from 3800 up.
Guys, the OP posted a very legit question and both of you tried to help him. While you may disagree on some matters, you both apparently share a love for the hobby and radio technology.

Both of you sound like elitists in your quoted messages above. You have no idea what kind of people are on GlockTalk or lurking. There might be some of the top radio engineering minds in the world here, but you instead decide to put yourselves up on a pedestal with Marconi and Hiram P Maxim himself.

Chill out a little bit, please.

Look at item #4 from this link:
http://www.arrl.org/acode.html

73
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Old 03-05-2009, 19:34   #11
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Thanks for all the replies, I didn't have notification, and didn't realize it was still going. I decided to mount my antenna outdoors with a roof mount. It is about 17' from the ground, not at the peak of the roof, but still outside. I live in a single story home, and next to me is another single story home maybe 12' away from the side the antenna is on, with a similar roof profile. I used about 50' of Belden RG8 to get from radio to antenna. I don't have my radio yet, so I can't say how it works yet. We will see.

I guess I am not sure how the RF pattern is vertically up and down as opposed to going out horizontally. Or is the RF pattern omni directional, and you need to take that into consideration as far as a safe distance from controlled and uncontrolled areas in the RF calculations.
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Old 07-02-2013, 03:12   #12
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Forget the plain Jane "J" pole and build a Modified "J" pole (SilmJim) out of 1/2" hard copper tubing. Go here: http://www.hamuniverse.com/2metercopperslimjim.html

With this antenna and the same radio I talked barefoot 50 miles with this antenna 18' in the air. This antenna sends the signal a lot straighter than a "J" pole.
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