1. How Strong Is My Signal?

2. We Would Like A Strong Signal to Beat Losses in the Atmosphere But the little Baofeng radios only Put out 4 watts How do we get “More Power” in our Signals?

3. We Considered Adding An Amplifier 4 watts 27 watts So what did that get me?

4. The dB (decibel) Scale 3 dB = Double the Power

5. Applied to the Test (T5B-09) The Power Doubled so What is the Gain?

6. Answer

7. Try Again (T5B-11) Double Once 20 X 2 = 40 watts gain 3 db Double Twice 40 X 2 = 80 watts gain 6 db Double Thrice 80 X 2 = 160 watts gain 9 db Double Four 160 X 2 = 320 watts gain 12 db 200 is between 9 and 12

8. Your Turn Only This Time We’ll Have a Negative dB gain (T5B-10) 12 to 6 6 to 3

9. Answer

10. So What Did that Amplifier Get Me 4 amps goes to 27 amps How many dB is that? Double 4 4 X 2 = 8 3 dB Double Again 8 X 2 = 16 6 dB Double Again 16 X 2 = 32 9 dB Didn’t quite make it we got about 8 dB

11. So Did I Do the Same With My Range? 7 miles with just the radio Double once 14 miles Double twice 28 miles Double three times 52 miles Remember your sending signals out in Many directions – not one. Remember your antenna is still only As high as the car so the earth could Get in the way. If you have a high clear shot its Probably more like 20 to 25 miles

12. The Value of Antennas One way to increase signal strength is to point our Radio Wave Energy where we need it. We can use a good ½ wave vertical antenna will move power away from straight into the air and down into the ground This gives us a gain of about 2.15 db

13. There is Also the Take Off Angle 5/8 th wave puts the signal closer to the ground To someone on the ground this is about 1.35 gain over a ½ wave Or 3.5 dB gain over an isotropic radiator 3 dB is like doubling the power. How did we go from 2.5 – 3 miles with a rubber duck to 7 miles when We put a 5/8 th wave on top of the car using the same power?

14. So What About Beams? You’ll beat a ½ wave antenna By around 9 dB Double power once 3 dB Double twice 6 dB Double thrice 9 dB 4 watts doubled once 8 Doubled twice 16 Doubled three times 32 watts

15. So Why Not Just Use Beams? Daddy, I’m Ok. Honey – Debris have collapsed across all the exits – I’m trapped Why won’t you Answer! Do you always know where the signal will come from?

16. One More Gain Trick Stack ½ or 5/8 wave antennas On top of each other Its called collinear You can get 7 to 8 dB gain It sends the signal out fairly flat across the ground If you bump into Something your Chances of bending Around it are reduced.