Antenna construction cross Yagi, VHF band, 6 elements, 2 meters long, circular polarization, 9dB gain

Useful links:
Notes on 6-Element Wide-Band 2-Meter Yagis
http://on5au.be/content/a10/vhf/32m.html
Antenna Circular Polarization
https://www.qsl.net/sv1bsx/antenna-pol/polarization.html
Yagi Uda Antenna Calculator
https://www.changpuak.ch/electronics/yagi_uda_antenna_DL6WU.php
Coaxial Power Split Calculator
https://www.changpuak.ch/electronics/coaxial_power_split.php
Calculate the extra length of coax feeding the other dipole for circular polarisation
http://dg7ybn.de/Building/xpol.htm

Drawings…
VHF antenna design, 6 elements, 2 meters long, 9dB gain


UHF antenna design, 2 meters long, 12 elements, 12dB gain

Be aware of the cable loss!!!
I used this Antenna (Vector-Network) Analyser to measure the cable loss…
Here you see the loss of a 15m long, RG58 (50Ω, Ø4mm, ordinary) cable.
The loss is considerable in VHF – 5dB, and enormous in UHF – more than 9dB.
-9dB means that only 10% of your power is passing thru.
Almost the entire antenna gain is lost over the cable.
So a high quality, thick, expensive cable is mandatory, especially in UHF. RG58 is to be used for short connections, of less than 3 meters.

Leave a Reply

Your email address will not be published. Required fields are marked *