XM240 Big Thunder

A few months ago, I installed my first ham radio tower and wanted an antenna with some gain for 40 meters. My requirements were fairly simple. I wanted a "shorty 40" with:

• Relatively decent performance 
  
• Relatively easy to assemble
• Relatively inexpensive

The XM240 seems to meet all of these criteria when compared to more expensive options (such as the Optibeam, Force12, or M2 offerings) while having better performance than bargain basement solutions (wire antennas).

Mechanical  & Assembly 

Assembly was not without some issues. Some of the holes did not line up as expected and tuning for the center part of the band required the antenna to be lowered and the lengths to be reset.  The "hose clamps" from Cushcraft look to be inadequate in the long term and stainless nuts/bolts would have been a sturdier design (although that wouldn't allow for tuning adjustments). 

So far, the antenna has withstood two Iowa icestorms that have caused the elements to droop a bit, but thy have returned to their original shape. The center section is reinforced well, so I expect that it will hold up over time. 

On-air performance

I've used the Cushcraft XM240 in a few contests since the installation. I've had experience contesting with much more sophisticated solutions (full-sized 3 element 40 meter stacks with amplifiers) and with much less firepower (Butternut vertical). I'd say that I'm happy with performance. In CQ WW CW I was able to break several pileups on the first or second call with the XM240 - without using an amp. That's about all I can ask for 100w.  Yes, I could have better results with a stack of full sized 40m yagis, but that wouldn't meet my budget. My XM240 is  installed at about 25 meters and about 3 meters above my 4 element SteppIR. 

Support 

 I had some strange SWR readings when the antenna was first installed. In the end, we determined that the cause was a nearby broadcast AM station that was interfering with the antenna analyzer. However, I did exchange several emails and calls with Cushcraft who provided excellent support. I hope that Cushcraft continues to provide this level of support to their ham radio product lines. 

Modifications, SWR and Installation Pictures 

You can see the modifications I made to my XM240 (including grounding the reflector to the boom) by checking out my blog:

Here is the posting on grounding the XM240 reflector to the boom.

And here is the posting on the SWR battle with my Cushcraft XM-240...

Overall

If I had to do it over again, I would probably buy this antenna. It is difficult to balance all of the requirements to get a high-performance antenna for the 40 meter ham radio band - but the Cushcraft XM240 is a decent compromise in my opinion. If there were a SteppIR 30/40 beam on the market, I would consider that.