# Ham Radio General Class Lesson 8.2, RF Exposure

Here’s your video introduction to ARRL General Class License Manual for Ham Radio, Section 8.2, RF Exposure. (Rats! I just realized the video says it’s the introduction to section 8.1! It’s really 8.2!) These videos are meant as introductions to the material and are not a substitute for reading the book and answering the various sample tests questions. After you are done reviewing this video and the material in the text, you may return to the list of General Class videos by clicking here.

Two URLs are listed in the video. The first is on the ARRL web page for RF Exposure and can be found by clicking here. The second is to an RF exposure calculator at hintlink.com, and can be found by clicking here.

I add here a caveat. This video is about safety, but it is not a comprehensive lesson on safety. I don’t cover everything you need to know to stay safe with regard to RF exposure. This is merely an introduction to the material in Section 8.2.

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### 3 Responses to Ham Radio General Class Lesson 8.2, RF Exposure

1. Dave says:

Hi Mark, sorry for the delayed reply. The answer lies in Figure 9.2 in the latest Tech manual, which provides the exposure curve for maximum permissible exposure. You’ll see that in the 144-148 MHz region, the curve is flat (level). So in that region, the exposure is not dependent on the frequency. That is not true of the 420-450 MHz region, which is on the slope that goes from 300 MHz to 1500 MHz. In this region, as the frequency goes up, the permissible exposure goes up. Hope that helps! 73, Dave, KEØOG

2. Mark says:

Hello Dave,

Great job on the videos. I used your Tech series to help me pass the exam. Now I’m using your General series for the next step.

I do have a question pertaining to your video “Ham Radio General Class Lesson 8.2 RF Exposure”. When using the suggested power density calculator I found that the numbers for 2meter VHF are the same for 144.1 and 148.0 using the same wattage and gain for both (10W, 4.5 gain, 144.1 & 148.0 Ctrl=2.536 Un-Ctrl=5.6089). I also noticed that the 70cm UHF calculation results for 420 (10W, 7.2 gain, Ctrl=2.9171 Un-Ctrl=6.4609) is higher then calculations for 450 (10W, 7.2 gain, Ctrl=2.2.8198 Un-Ctrl=6.2435).
I was just wondering why?

Keep up the great work.

Mark

3. Baset says:

Sir…coming back to this hobby after about 2 decades, i dont have words to appreciate how ur videos are helping me out in clearing lots and lots on concepts which would nt have been easy to do so without…..its a big favour ur doing to hamkind…. Thanx and again much appreciated