The 10m 8-Element ‘Needlebender’ Yagi
Here’s an all-out big gun antenna for 10m. It’s a big ballsy, no compromise affair with no regard for space, real estate and the like. It’s a pileup buster to beat pile-up busters.
I was asked a while back to model an antenna for an operator who had virtually no limitations, so this build focuses on that. He wanted one band and everything focused around that band he used.
Whilst we can all dream of 100-foot boom lengths and the like, a tower to hold this monster could and would be exorbitantly expensive. So, the idea here was to model a more manageable 😊 boom length of around 66 feet [just under 20m].
Even so, this is not a build for the faint hearted!
1.5 to 1 SWR bandwidth is approximately 900khz and forward gain is 13.44dbi in free space with a very respectable 31.65db front-to-back rejection based around 28.400Mhz.
This figure can also be improved upon by about 2.5db by reducing the end tips of D#6 by 2cms on each tip. This produces a a super deep null on the rear [approx 90 degrees of azimuth] to over 34db without affecting the SWR and impedance plot. Beamwidth is super-narrow at 38.8 degrees.
When examining the plot, the side and rear rejection is over 30db for more than 225 degrees around the azimuth. So, if its gain and rejection you want – and if you have the real estate – then here’s your chance to be band-king!
Natural impedance of the array is around 28-ohms so can be matched either with a
hairpin match or a DK7ZB 28-ohm match.
With the current band conditions [Feb 2023] vastly improving, you’ll be heard easily in interstellar space [and may be a little further]!
As always, our info is based on a home constructed design using 16mm diameter [centre] tubes and 12mm diameter outer end-tips. Thumbs up if you decide to build this!
FILES:
Download the EZNEC File here
Download a simple Excel document showing measurements and data here
Don’t have EZNEC? – EZNEC Pro/2+ is now free to download from the author W7EL here
Good luck with your build.
73 – Steve G0UIH
Q82.uk
