A Short Boom 3 Element Super Lightweight Yagi for 10/11m

A Short Boom 3 Element Super Lightweight Yagi for 10/11m

Here’s a simple project for the 10/11m operator who needs performance, but has a very limited amount of space to play with.

The project is an 11m 3 element Yagi on a shortened boom of just over 2m. In addition, there’s enough bandwidth to cover into the lower half of 10m [up to around 28.500MHz] albeit with a reduced front-to-back ratio.

With a boom length of just over 2m, this makes for a nice and compact dual-band solution

The array employs a hairpin match to tune the array from its natural low impedance of around 25-30 ohms to 50 ohms.

Forward gain is just over 7.00dbi and the front-to-back ratio is impressive at well over 35db across the main portion of the 11m SSB operating frequencies, making it ideal for reducing unwanted QRM.

At some frequencies it peaks at over 50db.

Matching is achieved using a hairpin match with rods coming off each side of the driven element

Construction is super lightweight but very strong and given the prices [as of January 2023], we estimate that this antenna can be constructed for under £100.

The array has element plates bolted directly through the boom with 2 x M6 stainless bolts through each plate. This saves both weight and also removes the need [and cost] of expensive U-Bolts that are not really needed for this type of antenna.

A split-dipole centre is used to feed the array. To note, this image was taken from a 2018 version which had U-Bolts on the element mounting plates. For a simpler and cheaper home-brew design, drill the plates directly through the boom with 2 x M6 stainless hardware.

We’ve based the construction around 16mm aluminium tubes which form the inner sections of the elements and 12mm tube which forms the outer sections. Clamps used are 16mm Stauff Group 2 [either 216PA or 216PP] will do the job.

Alternatives such as Ehrco clamps from companies such as ‘Designation‘ in Peterborough who also offer an over the counter trade counter service come in fairly cheep at around £1.30 per clamp.

Download the EZNEC file here
Don’t have EZNEC? – then download it from W7EL’s site as from Jan 2022 it’s totally FREE!