[TowerTalk] Ask the experts

Sat Jul 7 20:11:27 EDT 2007

I can speak about my Mosley experience!

I have owned and used numerous brands of antennas. This includes a homebrew 6 element 15m monobander a long time ago. But most recently, I have been able to compare two antennas.  Be aware my comments are based on "feelings" about how one compares to another. I couldn't A/B test them with test equipment.

Here's the story:

About 15 years ago I had been using a HyGain TH-5DX at 90 feet. I was living in a suburb of St. Paul, MN. I used this yagi for many years. It was not a pile-up buster, but I wasn't the last station to get through either. Of course an AL-1200, then an AL-1500, and finally an Alpha 87A helped get my signal heard using this HyGain. I had no complaints about the performance or construction of the yagi (after replacing the BN-86 fusible link) with the BN-4000.

After awhile I started looking to replace the TH-5DX with a single yagi that would cover 40 through 10 meters on one boom. The TH-5DX is a 10-15-20 meter tribander. At that time the only antenna I could find to fit my need was a Mosley PRO-67B. So I ordered one.

It sat in the boxes in the garage for several years. In the mean time, I bought a new house in a rural area about 30 miles NE of the old QTH. I put up a new 90 foot tower and then installed the Mosley Pro-67B. It had 2-elements for 40 and covered all the other bands (except 30 meters). As the saying goes, "it worked". Even when running high power I wasn't the first person to break pileups. My feeling was it had about the same performance as the TH-5DX. I was pleased I had gained the 12, 17, and 40 meter bands. It was one antenna on one tower with one rotor. It "worked".

Mother nature paid a visit about 8 years later and the tower and Mosley came crashing down. Fini! It was a freak wind shear event that took out many trees in my area. Prior to that, the Mosley survived a severe ice storm (winter 1995 if I remember correct) and relentless winds. The elements looked like U-bolts hanging from the boom! This storm took many towers, trees, and utility poles down in its wake. When the ice finally melted off (2 weeks later!), the elements returned to their normal positions. You would have never known the beating it had taken.

As an aside, some fellows were caught with their crank up towers extended. They couldn't get them down because the storm started as rain and turned into ice as it hit the colder surfaces. By the time they recognized the problem, their towers were "froze" into the extended position and would not retract.

Talk about feeling helpless! My tower was coated with thick ice. I thought I could take a hammer and tap the ice off. Well that was naive thinking on my part! The ice clung just like epoxy to the legs and braces. There was no "tapping" it off! But I was lucky, everything survived that time.

Okay... back to the main point... a few years later (fall of 2005) I installed a replacement tower. I decided 70 feet was "good enough" (and I was no spring chicken anymore). I reasoned a lower profile would provide an extra margin of wind load capacity. (This is a self supporting tower.)

When I started investigating antennas again, now there were a variety of designs to choose from. Mosley had brought out their PRO-67C which added 30 meters. They had other larger designs too. Then there were the new (to me) Force 12 antennas to consider.

I wanted to get on the air quickly once the tower was back up so I started asking around for opinions. One antenna kept coming up in discussions. That was the new (to me) HyGain TH-11DX. MANY of the DXers in this area were using them and were very satisfied with the performance. It just so happened I found a used one for sale in an estate sale so I snapped it up.

I installed the TH-11DX and have been using it for the past 2 years. I "feel" it outperforms the Mosley in breaking pileups. But there's a whole bunch of variables in my comparison scenario. There was a 2-year break in my DXing between the antennas, the TH-11DX is 20 feet lower than the Mosley PRO-67B, I'm using regular RG-8 instead of the 1.5" hardline, and the solar cycle is in the tank right now.

My gut feeling is the Mosley is more rugged and heavier than the HyGain. But I experience better on-air performance with the HyGain. That's even after hearing MANY DXers in the area tell me "you're gonna really like how that TH-11 plays". My pile up experience confirms their statements. I have bought into their bias now too! Of course I gave up the 2 elements on 40 meters.

Yeah I don't like the Mosley bashing either. I do have the comparison reports for both yagis and verticals. The guys put a lot of time, effort, energy, and thought into the field tests and report.

But there has been a lingering question in my mind. If Brand M has maximum forward radiation at 20 degrees elevation and another antenna radiates all it's power at 10 degrees, what is the difference in signal strength several miles in front of these yagis when you're receiving at 0 degrees elevation? Is this comparison really "fair"? I suppose it is if you're looking for the best DX antenna (lower angle is better). But what if you want better local coverage like you get from a NVIS radiator?

I guess the ultimate question is, if I were given a new Mosley for free, would I replace my TH-11DX? I don't think so. I'm satisfied with the performance I am getting with what I have. It "works".

73 de Bob - KØRC in MN

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Message: 1
Date: Sat, 7 Jul 2007 12:01:31 EDT
From: K7LXC at aol.com
Subject: Re: [TowerTalk] Ask the experts
To: towertalk at contesting.com, w1ksz at earthlink.net
Message-ID: <d55.ce872c6.33c112db at aol.com>
Content-Type: text/plain; charset="US-ASCII"

In a message dated 7/7/2007 8:20:09 A.M. Pacific Daylight Time,  
towertalk-request at contesting.com writes:

>  This "Mosley Bashing" has finally hit my button !!
I have  a PRO-57A and am very satisfied with it. It
is my understanding that  subsequent models were
"improved". I have not seen any published data  from
verifiable sources except those peddling their
"comparisons" which  I don't intend to pay for.

    You mean you're not interested in any proof? FB -  go ahead and believe 
the manufacturer's claims which are not only  non-verifiable for the most part, 
but also the figments of some manufacturer's  imaginations.         

    The whole reason for several of us to go to all  the trouble of comparing 
a bunch of yagi and vertical antennas on the air in  comparison to a 
reference antenna is so that there was some sort of  uniform results for everyone to 
see and even discuss. Of course the report  generated some comments but 
generally the results have been accepted as  useful. Also the protocol used is 
published with the report, and if you follow  it and run your own tests (you're 
heartily invited to do so and share the  results with us), you find the results 
are repeatable. 

>  Not every ham has the real estate to put up Mono-
Banders  on Sky-Needles, so, as it is in life, one
must make compromises. But I  cannot accept that the
PRO-57A is that bad, not without  proof.

        I have a theory why Mosley  owners are as adamant as you are. 

        First, "I owned a TA-33 in  the 60's and it worked great. The newer, 
bigger Mosleys should work great  too."

        Next, "I just worked  Scaffolding Reef so it must work great."

        Next "I spent this much  money on it, therefore it must work great." 

        And finally, they have  never compared them to anything. 

        Whoever mentioned N6BT's  article about "anything works" hit the nail 
on the head. 

        Our antenna comparison  reports were published to advance the art of 
ham radio antenna understanding and  use. Obviously your mileage is going to 
vary. 

Cheers,
Steve     K7LXC
co-author of the aforementioned reports available at _www.championradio.com_ 
(http://www.championradio.com)  