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I recently put up a Cushcraft MA8040V with 8 buried radials -just as documented in their manual. I'm very happily surprised at the performance. I've been testing the antenna during the grey lines and at night using 100 watts.

I placed this vertical 35' away from a 36' steel mast that is a reflector for a 20M K1WA parasitic array that I am VERY pleased with. The MA8040V is fully extended to cover the low end of the 80 and 40M bands. I wanted to see if I could get the MA8040V to get a south facing 3 db(ish) of gain on 40M. I'll take whatever on 80M as a bonus - since I've already worked DXCC on 80M (ugggh) and enjoy 40 and 30M much more.

I have a 40M Bruce Array that is broadsided slightly NE - SW (perpendicular to the plane of the MA8040V "parasitic array"), and found that the single MA8040V did a very good job as a parasitic element on 40M.

I was hoping that the Bruce would show a 3 db improvement over the MA8040V in the NE - SW path, and that the MA8040V would show a 3 db improvement over the Bruce in the Southerly direction.

To my surprise, the MA8040V equals the Bruce Array NE - SW, and beats the Bruce by 3 db in the Southerly direction. The Bruce Array has no radials and no ground screen - so I think I'm learning how much better buried radials are.

I am going to get another MA8040V and do A-B tests using buried radials and 4 elevated radials - 2 per band using ladder line - with a 33' and 66' counterpoise radial on each side.

If that goes well I will look into making a 2X2 rectangular cardioid array - switching 2 sets of phased MA8040V's - for 40M.

I did a site survey this weekend and can't put up a 4 square - so I'll try something else. But these are really cool antenna's that hold a lot of promise.

[NI0C]

Rich, if memory serves me correctly, you once used a Butternut HF-2V in your quest for 80m DXCC.  I wonder how the new Cushcraft compares with the HF-2V?  I just downloaded the MA8040V manual from Cushcraft's web-site.  (BTW I was amused by the apparent typo in the spec sheet-- "easy to turn.")

It's shorter (27 ft. vs. 32 ft.) than the Butternut, but has the advantage of being top-loaded.  Looks top-heavy, though, as a result.  Do you recommend guying this antenna?

I also wonder why they recommend only 8 radials?  Isn't this a quarter-wave vertical?  

73,
Chuck  NI0C
 

[AB0SI]

I think there are several reasons why they suggest the "4+4" radial arrangements.

Sales:
  Certainly "sounds" better than 60 or 120 or ... Also, they inclue the 8 radials in the package.

Practical:
  With some creative "wiggling" quite a few people can find room for 8 radials. Finding room for 60 (30...) is another matter.

Technical:
  Better match to 50 ohm feedline than using a "full"  sprrad of radials.

What I found intersting was that they do not even mention evevating the antenna and using tuned elevated radials.

Paul  AB0SI

[NI0C]

Paul, I suspect you are correct on all points.  Perhaps the reason they supply four 33 ft. radials and four 66 ft. radials is in case one does choose an elevated installation.  Otherwise, the lengths are not that critical for ground mounting.

73,
Chuck  NI0C

I actually took my HF2V and turned it into a "killer" short hatted vertical dipole for 40 and 30M. I moved the coils to center and added an insulator there. I added 2 4' hats and had 12' each side of the center insulator. I tuned the antenna for 8 mhz. I worked over 100 on 40 and over 100 on 30M 2 winters ago.

For 80M I made a homebrewed short hatted vertical dipole with 36' center and 50' hats. I wound 10 turns copperweld on schedule 30 PVC (3") for a center insulator. I then used a pair of K9AY loops for receive. That was superior to both the HF2V and this new MA8040V. Last winter I went from 40 entities to over 100 and that included A61, V51, 6W, XV, F, G, CU and some other "really" good 80M DX for the West Coast. Oh - I never used more than 200 watts . . .

But on 40M with only 8 radials, this antenna does very well on 40M. I think it also is a bit better than the HF2V that I tried with 4 elevated radials - 2 on 80 and 2 on 40. I think a better ground radial system and some top loading wires on the HF2V would have made the HF2V really shine. I know it is a good antenna - but I finally am admitting that you CAN NOT shortcut the ground radial system. Especially with clay soil!

I plan on greatly expanding my radial system to at least 16 radials, probably 32. I just need to find a good power edger - since I used a manual hand edger in clay soil and tucked the wires in the folds on my hands and knees this past weekend - ouch!

I forgot - that was 10 turns copperweld on a schedule 30 form on each side of that 80M SHVD. I then added a bead balun right at that center inductor. Email me if you want the plans . . .

The MA8040V is very lightweight and VERY well balanced. I still added 3 lengths of 1/8" dacron rope as guys - just for those "over 30 mph" days where I don't want to see this antenna bend like crazy in the wind - and I am sure it would in a heavy wind. But it is very well constructed, very stealth, and this is the first Cushcraft antenna in a long time that I am really happy with (I don't like traps after one failed on me on an MA5B I had about 3 years ago).

I am thinking about using ladder line and cutting it with a 66' and 33' radial and running a bunch of these under ground about 4" or so. Anyone ever try this "shortcut"?

I know more than 8 radials will change the feedpoint impedance - but will also increase its efficiency - so I will use an L network or a tuner to tune that.

[NI0C]

Rich,
Thanks for the info on your HF-2V conversion, as well as the MA8040V.  I've also heard good things about the MFJ top-loaded 32' vertical.

As far as radials are concerned, if they are at ground level, they do not have to be cut to any particular length, nor must they be buried under ground.  The more and the longer the radials, the better off you will be.  Most of mine are just stretched out on the ground, some are strung over a covered swimming pool, and some extend into my driveway, with the ends held down with bricks.  Of course, during the Spring and Summer months, many of them have to be taken off the antenna and stored for the next season.  I wouldn't bother with the ladder line unless you elevate the radials.  I purchase 500 ft. spools of wire at home depot (14 ga. or 16 ga. both work fine).

73,
Chuck  NI0C

I've phased two of these (40 / 140 degrees broadside) and they work VERY well in this arrangement. They are 1/2 wavelength apart on 40, 1/4 wl on 80.

Right now I just have them phased with a "T" connector, and will have even more fun when my Comtek Stackmatch switch arrives - which will let me switch between endfire and broadside.