YAGI vs Dipole

 Yagi vs dipole


My full size 4 element 20 meter Yagi was a good antenna at 70 feet. However it only had a gain of less than 2 S-units over a dipole at the same height. Its elevation angle profile would be the same as the dipole at the same height. Most likely its gain was about 2 dB less than two S-units. A properly installed 4 element Yagi has a gain of about 10 dB over a dipole while 12 dB is two S-units.

Under some conditions that is a lot. However under good conditions, signals can be S9 or better and it’s hard to tell the difference by ear. When DX stations are weak and right at the noise level, only one S-unit can make the difference. For general amateur use I find the dipole works just fine. I don’t miss my 4 element Yagi at 70 feet enough to go through the time, money and work to put up a tower again. Frankly I have worked more QSOs in a contest weekend and more countries in a contest weekend with dipoles than I ever did with the Yagi. Some of that is due to experience and just simply being on the air more. 

I much prefer using a remote antenna switch to instantly switch to a dipole pointed in a different direction than to using a slow rotator. In addition my remote switch is at ground level instead of 70 feet in the air. Much easier to install and work on! The cost of the antenna switch is less than a rotator not to mention the cost of a tower.

If you run 100 watts that 10 dB in transmission gain can be easily made up for with a power amplifier. I frequently use 500 watts in a contest, but my everyday power level is usually 50 watts. Even my portable operating power is only 20 to 50 watts using mobile antennas. I occasionally use 5 watts both portable and at home.

Picking the right band and time to be on the air can make more difference than just 10 dB. 

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