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Author Topic: Cushcraft MA5b  (Read 2009 times)
N1IZE
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Posts: 5




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« on: August 04, 2008, 08:34:54 AM »

How is this antenna compared to a dipole, a vertical etc?
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AA4PB
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Posts: 12685




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« Reply #1 on: August 04, 2008, 08:59:35 AM »

Just looking at the specs, it has a gain on 20M of 3.6dBi. A dipole has a gain of 2.15dBi so the MA5b is 1.45dB better than a dipole on 20M. That's not very much. I expect that the biggest thing you'll notice over a dipole is its front to back ratio. You'll probably also notice that because it is a shortened antenna, the bandwidth will be much less than a 1/2 wave dipole (i.e your 1.45dB difference will only occur on a very narrow range of frequencies).

Now, if having the MA5b means that you can get it up in the clear on top of a 50 foot tower (for example) whereas your only option with a dipole is down low amongst trees and ground clutter then the MA5b may offer additional improvement.
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WB8YYY
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« Reply #2 on: August 04, 2008, 09:08:19 AM »

Very interesting question.  A quick glance at the eham reviews shows lots of satisfied owners.  

It is a 2 element beam.  its compromises are reducing element length and boom length.  its performance will depend on height above ground, while the vertical will be must less sensitive to height above ground IF it has a clear view to the horizon.  

On 20m it may offer just a little enhancement in gain over a good vertical (if it is mounted high enough), while it more clearly offers some enhancement on 15 and 10 meters.  Note being a beam it will reject signals off the sides, which may or may not be a benefit to you.  

In comparing to a similar vertical (like R5 or R6000) it provides a little benefit, but with the expense of a rotator and need to mount it higher.  It has some gain over a dipole particularly on 10 and 15 meters, and perhaps negliable gain on 20 meters.  If I didnt have a R5 deployed already, I might be tempted to consider it - but its more effort than putting up a vertical.  

Other alternatives?  A Moxon would give you similar or better performance, but with a simple design only one band at a time.  Quads (i previously used one on 10m) requires vertical and horizontal space.  

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AA4PB
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« Reply #3 on: August 04, 2008, 10:30:19 AM »

Note being a beam it will reject signals off the sides, which may or may not be a benefit to you.
----------------------------------------------------
It'll also reject signals off the back by 22dB on 20M.

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N1IZE
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« Reply #4 on: August 04, 2008, 10:38:45 AM »

I have been doing my research and a mosley warc has about 3 db more gain and is several hundred dollars more. The rotor is about 200$ + 200 mount bracket for 10ft section of tower. The thing I like is the rejection off the sides and the directively like a regular beam in the point direction
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WA3SKN
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« Reply #5 on: August 04, 2008, 10:53:45 AM »

The real issue with a directional antenna is not "gain", but the "front-to-back, or front-to-side" ratios... all of which do become useful on the mid to upper HF bands.  You will appreciate it on 20 meters and up when it is crowded, like right now!
73s.

-Mike.
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KA2UUP
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« Reply #6 on: August 04, 2008, 10:53:57 AM »

I have one.  It is not a super duper antenna like one of Cushcraft Boomers, etc. but it has worked well for me for about 6 and 1/2 years.  I have mine mounted on a Yaesu 450 rotator on top of a Rohn 25 tower at 30 feet.  What my MFJ-1798 vertical cannot pick up, this antenna will.

Some caveats:

1)  Read the directions carefully. The capacitance hats (the little rods forming the Xs at the ends of each element) have to be oriented as they say in the instructions to ensure proper SWR readings.  Also, be sure to install the traps with the drain holes down to avoid water pooling on them. Better yet, sealing the joint between the traps and elements with some good electrical tape is an excellent idea.  That way you avoid water getting into the joints in the first place.

2)  Some users have complained that their elements windmill, or rotate, out of alignment.  This will happen if the elements are not tightened properly or if the main boom was not "notched" properly to allow the muffler strap to tighten.  The fix is simple:  just drill and put a screw through.

3)  While the manual gives some measurements to ensure that the antenna is tuned properly on 20 meters (those are the end pieces for the two active elements), mine ended up being about 100 kHz above the frequency I wanted to end up.  I strongly recommend not to follow the measurements and, instead, use an antenna analyzer or an SWR meter on the ground before you raise the antenna up permanently to tune the antenna properly in the area of the band you want to operate in.  An SWR of 2:1 accross the entire 20 meter band should be no problem if you tune right at the band's halfway point.

Remember, all multibanders are compromise antennas.  This one works well for the price and the small size.

I hope this review helps in you decision.

73 DE Bert @ KA2UUP    
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N0MUD
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« Reply #7 on: August 04, 2008, 01:42:32 PM »

Well I've had my three element MA5B up in the air about 3 weeks now and love it.  For Wb8yyy it is NOT a two element yagi but a three element yagi.  For N1ize you dont have to buy a 200 dollor rotor for this beam.  Just a Radio Shack tv rotor will turn it with absolutely NO, None, NADA problems.  So what I did was put the antenna together inside my home, then went out to the back patio porch and put the hats or X's on.  I then had my wife hand all three elements down to me and I walked them to the front of the house where my 30 ft American Standard tower was waiting with the Radio Shack brand new rotor on top of the tower.  Myself and two non hams, neighbors, helped me put it up on top of the tower into the rotor.  I told them both what was needed to be done and they did it for me as I am disabled and couldn't do it myself.  After we got it up and mounted the only thing we had to do was adjust one element to the 45 degree angle the directions call for.  A couple of ham friends that came over two weekends ago to put up my A3 on my 60ft tower asked me why I put the elements in a 45 degree angle and I said that's the way the directions call for.  I could tell they were flabbergasted but accepted it.  I just put the antenna thru it paces this last weekend with the 10/10 ten meter contest.  I used both the MA5B and the A-3 yagis and both of them worked just fine.  You will really enjoy your MA5B if you buy one.  The only problem is it is expensive so if you can find a nice used one on QTH or QRZ then go for it.  Just make sure they can ship it to you.  I have a vertical, a Hustler 6btv and it is just ok.  Used it twice on the 10/10 contest, the signals I needed then were the best on the vertical and not the yagis, go figure.

Any ways FWIW department that's my two cents on the subject.  The most expense is the antenna and use the RS rotor, the antenna is not that heavy and the RS rotor will hold it just fine.

If you want pictures send me your email address to my call sign at arrl.net

Mike, N0mud
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N6AJR
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« Reply #8 on: August 04, 2008, 02:18:48 PM »

I had one up for quite some time and it does work a lot better than you think it would.

I had it at 25 feet on a push up mast.  it is 2 elements on 10, 15, and 20, and a rotatable dipole on 12 and 17.

( it also sorta tunes on 6 meters)

It in not as good as a 3 element steppir or a dedicated 3 element tribander ( mine was a wilson SY-1) but it does tune quite nicely and works pretty darn good for a small antenna.

it is definately better than a wire dipole on 10-20 meters and the rotatable part on 12 and 17 meters is also nice.  if a hustler 5btv is compared to a wire dipole, compared to the ma5b, the vert is usually a 4 out of 10 the wires a 5 out of 10 and the ma5b a 7 oout of 10. the 3 element steppir would be 9 out of 10 and the 3 element tri banders would be about an 8 out of 10. A 10/ 10 would be something like stacked  multi element beams on a specific band.

The MA5B is not stacked 5 element beams, but it is definately worth the price.  I would also use something larger than a radio shack rotor to turn it.

I was happy with the performance of my MA5B , and found it better than expected, part of that is from gsin as a beam and part of that is from rejections off the side of other signals.
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N6AJR
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« Reply #9 on: August 04, 2008, 02:19:53 PM »

http://hometown.aol.com/catfishtwo/N6AJR.html

the ma5b is on the far end of the house.
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WB2WIK
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« Reply #10 on: August 04, 2008, 02:58:36 PM »

N0MUD, assuming you're not joking, the MA5B elements do *NOT* install at a 45 degree angle!  I've assembled a dozen of these and nowhere in the directions does it say that.

The instructions, which are here:

http://cushcraft.com/support/pdf/MA5B.pdf

tell you to install the capacitance "hat" rods (the "X" shaped rods at the ends of the elements) so that they are oriented at 45 degree angles to the elements, and that's true and correct.  But that instruction only applies to the solid aluminum rods that make the "X" hats on the elements, and *NOT* the element-to-boom alignment.

The elements should be horizontal and parallel to the ground.

WB2WIK/6
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N6AJR
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« Reply #11 on: August 04, 2008, 04:36:49 PM »

I agree with Steve.  the little eyepokers are set at 45 degrees ( capacity hats) on the eklements, but the 3 elements are set at 90 degrees to the boom, like any typical yagi.
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W6VPS
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Posts: 369




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« Reply #12 on: August 04, 2008, 07:55:38 PM »

Steve is quite correct about assembly of the MA5B.

One caution he failed to add...check, check again and check a third time...on the location and orientation of the traps  make sure you put the correct ones on the correct booms with the proper orientation.

I checked twice..was about ready to put it up and thought I better check one more time.  WHOA..I STILL had one oriented incorrectly.

I'd also recommend using an engraving tool to mark them with the arrows as the decals show..because the decals wear away in the weather. An engraved arrow solves that problem.

It's a good small foot print antenna. Properly installed it will serve you well.  I'm very pleased with mine.

Good luck / Paul W6VPS
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AH6RR
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Posts: 803




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« Reply #13 on: August 05, 2008, 12:07:00 AM »

I had a MA5B for over 3 years and really liked it. I worked over 100 countries with it. The first qth it was at 40 feet and the second it was at 33 feet. I never had the windmilling problem but I used a RAT Shack rotor and had to replace it after 6 months. I bought a Ham M rotor and no more problems. If this is as big of a antenna you can install then go for it. of course the gain is not the best but if you add a amp that will help also (or move to KH6 land that always adds 6 db to your signal). I have since replaced the MA6B with a A3S that is alot better but no 12 & 17 Sad a Steppir is next.
Enjoy the antenna you will not be sorry at all.

73 and Good DX
Roland AH6RR
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PD2R
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Posts: 131




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« Reply #14 on: August 05, 2008, 03:14:56 AM »

N0MUD, The MA5B does indeed have 3 elements, 2 for 20, 15 and 10, and just one for 12 and 17.

So you could say it's a two element Yagi and a rotary dipole combination.

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