Having recently built one of the new (to me) DK7ZB designed yagis for 144MHz I am finding it’s performance to be amazing. It even feels like it performs better than our old array of 2x 19 element MET antennas. So I wondered how they measured up for gain.
The 19 element MET antennas we used back in the 1980s and 1990s and Google was struggling to come up with the good for me to see what they were specified as to compare. I eventually found this advert in a PDF for a construction article from a 1983 Practical Wireless magazine so I thought I would share it for anyone else who might follow the same path.
So our 19 element MET yagi was 14.2dBd from a 6.57m boom.
My new 9 element DK7ZB is 12.5dBd from a 5m boom.
To get 14.2dBd in a DK7ZB requires a 8m boom. Hmmm.
I’m not sure I fully trust the claimed gain on this advert! 14.2dBi maybe, but I am not convinced on 14.2dBd. The ‘feel’ on the air of the new single 9 element DK7ZB is just great comparing to what we used to work on the 2x METs. I am getting great signals from familiar places and people. I am using a new-ish radio (FT-817) though that is not what I would call a top spec VHF contest radio. I am using a lower mast and probably better quality and shorter feeder I guess. I must dig out the Yaesu FT-225RD I used to use and see how it ‘feels’ on that. One thing I have thought of is I know we mounted one MET at top with support below, and one at bottom with support up. I can’t remember if we arranged the feeds to be on same side! So we may not have been operating as efficiently as possible.
All in I am loving the DK7ZB and can see why lots of the contest groups have them.