[TowerTalk] Mosley

Fri Aug 24 16:06:19 EDT 2012

Geez,

Its the USA... there is no truth in advertising.  Why should Mosley be any 
different than GM, Ford, Johnson and Johnson, McDonalds, etc. I do suspect 
they get many repeat customers who may provide input as to the fact that 
they are replacing a previously puchased Mosley antenna...

Instead of bashing them why don't you ask them how they arrived at the 
conclusion?

I had one of Mosley's first 2 ele 40m Vest Pocket beams.  It had a steel 
boom, redwood spreaders, 4" ceramic insulators, center loaded link coupled 
driven element and center loaded reflector using 32 foot elements.  It was 
fun antenna; had noticable forward gain and 10-15db front to back... great 
fun!

I'm glad Mosley still builds amateur radio antennas.... they make their 
profit building commercial antennas.  Those dual boom 48ft x 3" x .250 wall 
log periodic antennas that we see hovering 150ft in the air located on 
military bases...

https://encrypted-tbn2.google.com/images?q=tbn:ANd9GcRLuCRiHnhn1YeQnEcayrYzLN_WoKQtxLlyScrNgh8Seq-SgHft

73,
Dave
wa3gin

----- Original Message ----- 
From: "David Gilbert" <xdavid at cis-broadband.com>
To: <towertalk at contesting.com>
Sent: Friday, August 24, 2012 2:53 PM
Subject: Re: [TowerTalk] Mosley

>
> The point here is not whether some Mosley antennas will hold up for 27
> years.  The point is that there is no way on earth that Mosley has the
> statistically valid data to support their claim that the average life
> without maintenance of their antennas is 27 years ... to one year
> resolution, no less.  It's an irresponsible claim, and their eagerness
> to make it should make potential customers a bit skeptical about their
> other claims, such as those for gain.
>
> But in case that doesn't register with you, here is a more direct
> comparison that might.
>
> I own an Optibeam OB16-3 tribander.  It has four full size elements on
> 20m, four full size elements on 15m, and eight full size elements on 10m
> ... all on a 31 foot long boom.  All sixteen elements are separate and
> they are more or less optimally spaced within the constraints of the
> boom length.  On 10m the element spacings sacrifice a small amount of
> gain in order to be able to cover a wider bandwidth, so I consider it to
> be approximately the equivalent of a six element yagi instead of eight.
> I assembled the antenna myself and I can say with great certainty that
> there are minimal resistive losses anywhere in the antenna itself,
> although there could be some small losses in the balun.  Here is a link
> to a closeup picture of the feed system so that you can understand why I
> say that.  As a scale factor for viewing the picture, the square boom is
> three inches on a side.
>
> (the picture can be found at the top of this page ...
> http://www.ab7e.com/AB7E_Antenna_Page_4.html)
>
> The published gain figures for the OB16-3 are 7.1/7.5/8.5 dBd
> (20m/15m/10m).  I took all of the dimensions of the OB16-3 (element
> diameters, stagger, element lengths, element spacings, etc) and loaded
> them into the EZNEC 5+ antenna modeling program and got almost exactly
> the same calculated profiles for gain and SWR as the published plots
> from Optibeam.  With the help of a ham friend who lives about 40 miles
> from me I carefully plotted the azimuth gain profiles of my OB16-3 on
> all three bands and got almost the exact same pattern profiles as the
> published plots from Optibeam.  My measured SWR plots match the Optibeam
> plots almost exactly.  Taking all of that into account I tend to believe
> that the published data from Optibeam is reasonably accurate for gain.
> My antenna height (73 feet) is even virtually the same as used for the
> Optibeam specs.
>
> By comparison,  the Mosley TA-34 with a claimed gain of 8.2/9.1/9.5 dBd
> has traps on all elements.  The TA-34 has only four elements on a much
> shorter boom (21 feet) and the elements are not a full wavelength on 15m
> and 20m.  The element spacings are a compromise for the three bands and
> are not optimized for gain or bandwidth on any single band.
>
> There is simply no way I can think of that the TA-34 could have more
> gain than the OB16-3 when mounted at the same height above ground, and
> in fact the physical comparisons make me strongly suspect that the
> actual results would be the other way around by a considerable margin.
>
> To clarify, I am not suggesting that the TA-34 or any other Mosley
> antenna is not a decent antenna, or that any other antenna would be a
> better choice in any particular situation.  Compared with the OB16-3,
> for example, the TA-34 is less expensive, weighs less, and has a shorter
> turning radius ... all valid reasons why someone might choose it.
> However, this message thread started with someone being inclined to
> choose the TA-34 over the products from other manufacturers based
> primarily upon Mosley's published gain specs, and in my opinion that
> would be a highly flawed rationale.
>
> 73,
> Dave   AB7E
>
>
>
>
> On 8/23/2012 6:49 PM, Mike Krzystyniak wrote:
>>     I agree with John.  I have had several Mosley Pro 57 and Pro 67 
>> series antenna here in north Texas.  All we bought used and they all 
>> disassembled on site easily due to the initial application of penetrox 
>> anti-ox.  And after applying a fresh coat of the gray goup they went 
>> right back together.  Some were up for a few years, one old Mosley I 
>> bought was up for 20 years (and it came from the Texas coast line).  No 
>> issue on element or bracket disassembly.
>>
>>     For many days of the year MY Mosley beams are steadily pressed by our 
>> prevailing southern winds.  We also get high winds from fast moving 
>> t-storms or straight line winds from microbursts or collapsing cells. 
>> The Mosley beams came through it all.  The real test a couple years ago 
>> when an ice storm delivered 1 inch ice followed by winds.  Many locals 
>> lost or had damge to most every type of beam you can think of.  The 
>> Pro-67C3's I have held up and stayed up.  And after the ice dropped off 
>> the beams came right back to original form.
>>
>>     Regarding 27 years without maintenance, with proper assembly and 
>> application of a few other sound assembly techniques I would not be 
>> surprised they are close to that.  As always YMMV.
>>
>> 73  Mike K9MK/5
>>
>>
>
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