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Categories | Antennas: HF Directional: Yagi, quad, rotary dipole, LPD, etc | Cushcraft XM240 Big Thunder 40 meter Monoband Help

Show all reviews of the Cushcraft XM240 Big Thunder 40 meter Monoband

You can write your own review of the Cushcraft XM240 Big Thunder 40 meter Monoband.

VE9OX  Rating: 5/5 Apr 16, 2014 11:57  Send this review to a friend!
Great Big Antenna!  Time owned: more than 12 months
I have had my MFJ XM-240 Big Thunder up at 74 feet for almost 3 years.

Typical front to back ratio exhibited is 15db with good forward gain.
You can easily hear a big difference when turning the antenna against or toward strong signals.

I use mine on CW and SSB from 7.000-7.200 Mhz with a Palstar 5K manual antenna tuner between the XM-240 antenna and my HP amplifier to ensure safe 1:1 SWR.
If you don't use an amplifier, use your radio's auto tuner instead.
If you use the upper SSB portion of 40M, then assemble the antenna for that part of the band.

I did not use the balun supplied by MFJ.
I purchased a 5KW rated DX Engineering heavy duty specialized Yagi balun instead.

All stainless hardware is stock.
All heavy duty brackets and good quality elements are supplied.
I preferred to use two small Gates Hose clamps (instead of one) on the end elements.

I tuned it to mid-band for my preference.

The SWR is as Cushcraft (MFJ) advertised without the tuner.
Of course with a good tuner, it is possible to realize a 1:1 SWR from 7.0 to 7.2 Mhz.

The instruction manual is good -no problems to report on the assembly process.
I put the beast together in a day on a 2" dia 4 foot mast pounded into the ground to measure the elements carefully.

Be certain to measure approximately 2 Ohms across each of the 4 coils before it goes up your tower for proper "Q" to ensure good forward gain and proper front to back ratio.

What a huge difference from using a dipole or an inverted V or a vertical or even two phased loops!

This is an excellent performing monoband 40M Yagi antenna make no mistake.
I am usually one of the first to break through the pileup using this antenna IMO.

'73.
VE9OX. 
Product is in production.
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