FM-DX Antennas

(2011-06-27) PE1ITR
7 elements 89MHz LFA Yagi
7 elements 107MHz OWA Yagi
5 elements FM Band 2 Yagi

7el 89MHz LFA Yagi

This design is based on this antenna: A 7 element LFA Yagi for 70MHz with a 6.89mtr boom. I rescaled the values for low part of band 3 and simulated (with 4nec2) the result. Just for fun and to see I could manage this.
Bandwidth: 87,5 - 90,5MHz



Design

BoomElementsHalf ElementsDiameter
R0165482710mm
S1215138069012mm; loop end 10mm
S2520138069012mm; loop end 10mm
D1958154677310mm
D21860149874910mm
D32993147273610mm
D44249144872410mm
D55384142071010mm







First tests 2010-12-31




The first results. Adjusting the dipole loop is important. First I had a bad swr and a second even better dip around 93 MHz but with some tuning it became better. I will improve this when wetter is better.
The antenna is lower in frequency than calculated.



Funny. I found the error and could more or less simulate it. Below the simulated swr graph with the loop error. It seams that the loop is a few centimeters to small.


Changed dipole loop


Here are pictures of the LFA yagi in action.

7 elements 107MHz Yagi OWA yagi antenna

Data and pictures of the enginering model.
Bandwidth: 104 - 108 MHz
















5 elements FM Band2 Yagi


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