[TowerTalk] RF Safety Worksheet, Rev. C

[David O. Hachadorian]

Here is an updated version of my RF Safety Worksheet. There were
no errors in Rev. B (as far as I know), just some enhancements in
this version. I hope you find it useful. Let me know if you find any
mistakes.

Dave Hachadorian, K6LL
K6LL@juno.com
Yuma, AZ
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     SAMPLE RF SAFETY WORKSHEET (Not Officially Sanctioned) Revision C.
     (Not for repeater or multitransmitter use) K6LL, author.
(K6LL@juno.com)

	A. Callsign: AA7AAA

	B. Frequency, MHz: 21.45
	
	C. Maximum PEP transmitter output, watts: 1500

	D. Type of feedline: RG-213

	E. Length of feedline, feet: 80

	F. Feedline loss, negative dB:  -.8
	   Look this up in a book, or use the program TL

	G. Line F divided by 10. (It will be a negative number).  -.08

	H. PEP power delivered to the antenna: line C antilog line G 
		1500 antilog (-.08) = 1248 watts
		Scientific calculator keystrokes:
		.08, +/-, inverse, log, times, 1500, equals
		
	   Note - Evaluation is not required if line H does not exceed:
	   160/80/40m, 500w; 20m, 225w; 17m, 125w; 15m, 100w; 12m, 75w;
	   10/6/2/1.25m, 50w; 70cm, 70w; 33cm, 150w; 23cm, 200w; 13cm and
	   shorter, 250 watts.
			 
	I. Worst case (highest) Emission mode duty factor: .4(cw/proc.
SSB)

		FSK, RTTY, AFSK SSB, FM Voice: 1.0
		Conversational SSB, heavy speech processing: 0.5
		Conversational CW: 0.4
		Conversational SSB, no speech processing: 0.2

	J. Transmit/Receive duty cycle over six minutes: .5
		Longest conceivable percent transmit time in six minutes,
		expressed as a decimal.

	K. Transmit/Receive duty cycle over 30 minutes: .5
		Longest conceivable percent transmit time in thirty
minutes,
		expressed as a decimal.
 
	L. AVERAGE power to antenna, controlled case: H x I x J = 250

	M. AVERAGE power to antenna, uncontrolled case: H x I x K = 250

	N. Antenna Gain, dBi: 9.5 (large tribander)
		Sample gains from OET Bulletin 65, supp B:
		3 el triband yagi 20m/6.5 dBi, 15m/7 dBi, 10m/8 dBi
		quarter wave vertical 1 dBi
		half wave dipole 2 dBi
		1/4 wave vhf/uhf whip or GP 1 dBi
		5/8 wave vhf/uhf whip or GP 4 dBi
		17 el yagi on 5 wavelength boom 16.8 dBi
		Discone 2 dBi
		
	O. Closest CONTROLLED human proximity to antenna, feet: 46

	P. Closest UNCONTROLLED human proximity to antenna, feet: 51

	Print this worksheet, and Proceed to the University of Texas
World
	  Wide Web Site:  http://www.cs.utexas.edu/users/kharker/rfsafety
	Select "Include Ground Reflections."
	Input items L, N, O, B (controlled case). Print the output sheet.
	Input items M, N, P, B (uncontrolled case). Print the output
sheet. 

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