Build a 157.000 Mhz 4 Elements Yagi for VHF

4 Elements Yagi for 157.000 Mhz

This antenna is 4 elements yagi built for the frequency 157.000 Mhz, in the Philippines most of the users of this frequency bands are Government Organizations, LGU’s, Civic Groups, Fire volunteers and the like. Although most of the requested antenna designs fall on the Amateur Band (144.000 Mhz to 146.000 Mhz) frequency. I decided to published the details of this antenna although not frequently requested. The details of the build is similar to building the 4 Elements Yagi for Amateur Frequency. Elements measurements and spacing are of course adjusted to resonate properly on the 157.000 Mhz band.



Antenna Specifications

Antenna Center frequency 157.000 Mhz
Lowest usable band 152.000 Mhz
Highest usable band 160.000 Mhz
Antenna Gain: 9.52dBi
F/B ratio: 9.87dB
Beamwidth: 60° Vertical / 24° Horizontal

Expected Antenna Pattern Generated by 4NEC2

4 Elements Yagi Antenna pattern 157.000 Mhz
4 Elements Yagi expected antenna pattern at 157.000 Mhz. Generated by 4NEC2

Antenna Pattern Vertical

Vertical antenna Pattern 157 Mhz
4 Elements Yagi expected antenna pattern vertical at 157.000 Mhz. Generated by 4NEC2

Horizontal Antenna Pattern

Horizontal Antenna Pattern 157 Mhz
4 Elements Yagi expected antenna pattern horizontal at 157.000 Mhz. Generated by 4NEC2

Antenna Measurements

4 Elements Yagiat 157.000 Mhz measurements and spacing.

Download PDF Document antenna measurements here.

Material Listing

1. 1″ X 0.5″ Rectangular Aluminum tubing for the boom
2. 3/8″ Aluminum tubing for antenna elements
3. 1cm Outside diameter antenna tubing for elements holder
4. 1pc SO239 connector
5. Pop rivets / Rivet tool
6. #12 AWG Copper wire with insulation (12″for Gamma match)
7. Soldering iron
8. 8pcs Stainless steel nuts and bolts 20mm length 3mm diameter
9. 1, Butterfly nut and 1 bolt 18mm length 3mm diameter
10. Aluminum plate 0.5mm thickness
11. Collapsible tube (shrinkable tubes)

Antenna Matching / Gamma Match

For the antenna matching you may use the Gamma Match for the 4 elements yagi. The measurements of the gamma match and tuning procedure are the same.

Gamma Match 4 Elements Yagi

Finished Antenna Testing

4 Elements Yagi Antenna 157.000 Mhz
4 Elements yagi antenna for 157.000 Mhz

Antenna Calibration Video using NanoVNA

SWR response on the center frequency as confirmed by N1201SA

Antenna SWR at center frequency 157.000 Mhz
N1201SA analyzer readout for SWR/S11 response of the the 4 elements yagi antenna at 157.000Mhz center frequency.



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