The Importance of Material consideration within Yagis

The problem with ham modellers is in general they use software packages using 'wires' only. This means any elements are modelled in 'free space' with no booms, insulators, nuts bolts or mast around them. While there are formulas for predicting (or guessing?) what influence certain materials and components will have, others are completely ignored. It is for this reason that quite often, best possible results are never seen.

In the next issue of DUBUS I start a series of articles explaining the pitfalls even the most experienced and well known ham designers have unknowingly discovered and even with the realisation of my methods and material selections are correct and extremely accurate, find themselves in a very difficult position to admit so as this would result in many years of misguidance having to be U-turned upon.

Take Fabio, HB9FAP as an example experienced builder. He has built many designs from the Internet before and decided to build many 7el 144MHz LFAs for his contest station.

'I have never seen such low or perfect SWR before !!' 
Fabio HB9FAP

Note the above antenna plot is taken between 143MHz and 145MHz and centre design frequency is 144.300MHz. Not bad when you take in to account uncontrollable real world influences such as height above ground and material make-up variation (over what is represented in model).

On of the 7el 144MHz LFAs at HB9FAP

If you would like to join me in my discussion on the above mentioned subject, take a look at DUBUS magazine next time out and remember, you can mail me with any questions you may have at any time!

Some of you may have noticed there has not been too many updates lately. This is due to a big site revamp which has been going on! in addition to the new site skin, the whole site core has been updated too.

I am no web design expert and prefer to spend my time designing antennas rather than writing websites. However, like the research I do on my antennas designs (which means I do not focus on gain) I conducted research to find the right tools for the job before originally setting up this site and selected the content management system Joomla.

The old site was on a old version (1.5) which could no longer be updated, the site now runs on 2.5.

There may be a few things not working right as yet but hopefully, the site developer will have this fixed within a week or two and then we will be back online 100%

Thanks for your understanding until then, take a look at one of the new OWA2 designs soon to be released on this site!