VK Logger Ham Radio Forum Archive

Check this out: "loop fed array" from G0KSC.http://www.g0ksc.co.uk/

"5 element 50MHz LFA in use is 4.7 metres long, has just over 11dBi forward gain and 22dB front to back ratio at worst. More importantly, the antenna shows a 1:1 flat SWR curve from 50 to 50.50MHz and a return loss no lower that -30dB down, peaking at -60dB down."

Wonder what the specs on a 9 el would be? My guess it would be over 16DB!

73

Wayne VK4WDM

Hi Wayne,

Indeed. This is a very big improvement over a standard yagi.
There quite a few advantages I see in this design.

Firstly clean pattern. No Energy in or out into unwanted directions.
This is mostly an RX improvement. Less noise with the same signal, means an improvement in signal to noise ratio.
Hence you can copy weaker signals. This is very good in the noisy suburbs and will reduce the noise level.

Secondly it appears that these yagis have a little bit more gain, which is nice.

The third advantage is less static and a 50 Ohm direct to the yagi.
Getting rid of the 4:1 balun is a good thing. It should not be that lossy, but if you count all the connections, take corrosion into account,
than you know it is going to be lossy.
At the end of the day this also means more gain.

Good to see some innovation.

Keep an eye on his home page, I noticed that the designs he published in Dubus are not yet on his home page.
You need to look at the LFA. The 18 element (2m) monster LFA is too big for me.

Well done G0KSC.

Ron
VK4DD

Interesting.
It almost has as much gain as M2's 6M5X.

I wonder why he is using such thick tubing?
With all this unnecessary extra weight, more strain on tower and rotator, and increased wind-loading, this is a big step backwards, in my books.
I had an ATN 8 element 50MHz LPA Dummy Load in the early 90's, and it too was a big heavy monster.
G0KSC could learn a lot, by having a closer look at the M2 designs.

Hi Adam,

Firstly I am a fan of the M2 yagis. Have used them for a decade, and have quite a few of them.
Operated with the 6M5, 6M5X, 6M7JHV and various 2m and 70cm yagis of them.

But as far as G0KSC... I think has already learned a lot from the M2 designs....
Along the North Sea the winds are terrible and nothing compared with what we have here in Brisbane.
200Km an hour and even beyond that is not that rare in winter.
And I can count the times my mast has been blown down... not to mention severe antenna damage.
At that speed nothing will resist.... even the thicker elements...
But there is certainly a need to build a stronger yagi's along the North sea cost.... and some other areas on this planet.

Technically I all I can say is that element are one of the easiest things to change on an antenna design.

As far as the optimum element diameter... I think it probably depends on where you are on this globe.
If there is Ice, wind, birds etc all these factors can play a role..

The fundamentals of this design are really good, and that is all what matters.
This new antenna concept will beat the M2, no problem.
The M2 designs haven't been updated for ages, and I think there are better designs out there...

There is only one disadvantage of a super clean antenna..... you need a dipole as a second antenna to monitor...
Just to be aware what is going on around you..

73 Ron
VK4DD