2M7 Yagi by M2 Antennas
This was a gift from my son-in-law, at the time I didn’t have 2M SSB/CW capabilities so I left it in the box. When we moved to a new QTH I had a local ham loan me a Kenwood TS700SP all-mode rig. Time to get the 2M7 out of the box and up in the air!
First impressions were good, the assembly manual simple to read. Measurements all on one page so it’s easy to stay on track during assembly. Did some quick math and figured out where to push the element retainers to. So far so good.
Once all the elements were in it was time to install the “T” Match Assembly and balun. The “T” match is a great looking part of the antenna. Carved out of a solid piece of aluminum with a CNC. Solid, beefy parts used throughout. This is where I ran into a problem with the assembly of the antenna.
There are 3 of the 8-32, 1.25″ screws in the parts bag, I used two of them to secure the two boom pieces together per the assembly instructions. That left one to secure the “T” match to the boom. The problem with this is that the threaded hole in the “T” Match body is 1/4″ instead of 8-32. The hole in the boom is drilled for the 8-32 screw included in the parts bag. My first inclination was to just drill out the hole and use a 1/4″ SS bolt/screw and be done with the antenna. But I hesitated and I’m glad I did. If you look at the image below you’ll see the the curvature of the “T” Match body does not match that of the rear section of the boom. It may appear that this wouldn’t be an issue except for the weight of the “T” Match and the coax balun. I’m not sure I want to expose this to the wind and find out later it broke free from the boom. I contacted M2 Antennas and was told it appeared more like the wrong parts were in the bag.
So the long and short of it is that I won’t be able to use the M2 antenna in upcoming VHF and up contests the next few weekends. Bummer. Before I started assembling the antenna I almost bought another 2M7 antenna to stack them for a little more kick since I’m only running an 80 watt brick for the amp. Now I’m glad I didn’t. It may pay to dump the 2M7 antenna in favor of a pair of 2M quagi antennas which would be much cheaper and better performing. One other thing about the 2M7 that I found particularly annoying, no end caps for the boom! You just know the wasps will fill the boom up without something to cover up the ends of the boom. A couple of plastic caps such as the ones Cushcraft antennas use couldn’t cost all that much to include in the parts bag.