- G4CQM Homebrew/DIY Antenna Specialist -
VHF/UHF/SHF HAM (AMATEUR) RADIO YAGI AERIAL DESIGNS
4X1UN - SIMPLE 3 ELEMENT 144MHz (2M) YAGI
Breaking News...
Today June 6th 2007 at 16:24 UTC Shalom Cohen 4X1UN (KM72JB) with his 3 Element Yagi had a record breaking contact working CT1HZE (IM57NH). A staggering distance (QRB) of 4008.06KM! To date Shalom has had QSO's with 30 countries: Israel, Egypt, Jordan, Syria, Turkey, Russia, Ukraine, T9, Z3, LZ, HA, I, YO, SP, OK, YU, HV, OE, DL, EA6, CT, SV, SV5, SV9, 5B4, ZC4, 9A, 9H, ER and S5, all worked with this Yagi. Well done to Shalom!
If you're just starting out on 144MHz take note, Shalom's results are testimony to what can be achieved with a simple setup.
73's from Derek G4CQM
Construction
Shalom Cohen 4X1UN asked me to design for him a simple Yagi that could be constructed from materials in his junk box. It is based on 'Direct Feed' also known as 'Direct Connect', the element lengths and spacing delivering a natural 50 ohms feed impedance. It will produce a forward gain of 7dBi and 20dB F/B.
Use 15mm pipe/tubing for the elements. They need to be located above a metal boom and insulated from it. Alternatively, use a non-metallic boom and attach the elements directly or pass them through the boom, drilling large holes to do so.
Element Position Element Length
0 Reflector = 1036mm
466mm Driven Element = 970mm
737mm D1 = 840mm
The Driven Element dimension is end to end, so cut two pieces 480mm long and
provide a 10mm gap. Although many text books say you need to include a 1:1 Balun, in reality
this Yagi works without. However, if you can find any suitable Ferrite slugs
slip one over the feeder at the feedpoint.
The Yagi is what I call a 'Flat Liner', having a broad frequency
response, gain and impedance characteristic. Finally, remember that this design is based on FREE-SPACE dimensions, so make sure the elements are either mounted on insulators above the boom or use a non-metallic boom!
73's from Derek G4CQM
Shalom Cohen 4X1UN and his three element Yagi
Components used by Shalom
Seen here are the components used by Shalom and what he had to say!
"Well, thanks to your kindness I have built the 3 element yagi for 2m.
It is wonderful! It is even better than I expected. I get almost always a few S
Points more than before and now I can talk to my father 4X6UN clearly."
SITE NAVIGATION MENU
6M (50MHz) YAGIS
2. 6M (50MHz) 1WL VK3VG 6ELE YAGI
2M (144MHz) YAGIS
3. 4X1UN - SIMPLE 3 ELEMENT 2M (144MHz) YAGI
4. 2M (144MHz) 1WL G6HKS 6ELE YAGI
5. 2M (144MHz) 2.5WL 9ELE YAGI
6. 2M (144MHz) 3.4WL 11ELE YAGI
7. 2M (144MHz) 4.6WL 16ELE YAGI
70CM/23CM (432MHz/1296MHz) YAGIS
8. 70CM (432MHz) 5WL 14ELE YAGI
9. 23CM (1296MHz) 10WL 26ELE YAGI
CALCULATORS - STACKING YAGIS/CABLE LOSSES
10. Stacking Yagis etc
11. Coax Cable Losses
YAGI PARTS
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