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Show all reviews of the Cushcraft XM240 Big Thunder 40 meter Monoband
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of the Cushcraft XM240 Big Thunder 40 meter Monoband.
Apr 16, 2014 11:57
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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.
Product is in production.
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