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Discussion Starter · #1 ·
Has anyone tried the following Antennacraft UHF Yagi:


Maxus UHF Series


Featuring quadrature drive that develops extended resonance and optimum impedance match across the entire UHF band, and a precision, stagger-tuned director array that produces compounded gain elevation!


MXU59


For Extreme Deep Fringe Areas


100" Boom Length


59 Electronic Elements


List Price $54.25



 

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I haven't tried the antenna but let's take a look at what the marketing pitch is really saying.

Quadrature Drive- Normally the drive is a dipole, quadrature drive implies 2 dipoles undoubtedly one for the high end (short length) and one for the low end (long length). The driven elements are the ones the wires are actually attached to. Essentially the dual dipoles gives you a broader bandwidth which they are terming, Extended Resonance. Nothing is free and by broadbanding the antenna they do give up some gain.

Optimum Impedance Match- These dipoles should have 300 ohm impedance across the band. A single length dipole will not have a perfect 300 ohm match across the entire band. By using 2 dipoles one will be more dominant at the high and one at the low ends of the band.

Precision Stagger tuned director- The directors are the elements in front of the driven element. Adding directors adds gain and narrows the bandwidth. Having not seen the antenna they imply that they have staggered the directors probably for each of the 2 driven elements and by adding these elements, voila...we have Expanded gain elevation or in simple terms more gain.


In general, all of these antenna manufacturers are following the same laws of physics in designing these antennas. I live in a very mild weather area of California. (no snow, ice etc) As a result, I don't have to have as rugged of an antenna as someone living in Indiana or Minnesota. Channel Master is a top brand in terms of design, construction and ruggedness. Antenna Craft I would put in the category of Radio Shack whereas its electrical performance should be good but it may not have the ruggedness to withstand severe weather. I personally use a UHF long boom Radio Shack antenna and it has performed extremely well for about 4 years. It cost me about $35 and it has very high gain.

Hope this helps..


Doyle
 

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Discussion Starter · #3 ·
Here http://antennacraft-tdp.com/uhf.htm is the pix and pitch.


The Antennacraft factory claims a average gain of 15+ for the MXU59.


Seems along the lines of an extended CM 4248.


I wonder whether a multi-bay like a CM 4228 or CM's 4251 Para Scope would do any better in my in-direct line of sight (read reflected signals) at a distance of 36 miles?


Murray Kerdman
 

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Doyle, thanks for the extended reply on the "quadrature driven" techno-babble. Even before I read your post, I had decided to order one of these Antennacraft MXU59s in an effort to get two recalcitrant stations in southern California (KCOP and KTLA). It'll be another week, presumably, before I get it. Murray Kerdman's heartening results that he reported in another thread were sufficient to prod me into action. I, too, have the RatShack 15-2162 "long" UHF antenna I believe you referenced. It, too, (at least in the iteration I purchased three months ago) has two dipoles of differing length (apparently to optimize gain for the entire UHF spectrum), so would reasonably be of quadrature design. The RatShack 15-2162 lists 37 elements to the Antennacraft MXU59's 59. Presumably the additional director elements in the MXU59 would translate to both higher gain and better multipath rejection. Interestingly, RatShack's antennas are manufactured by Antennacraft, or so the fellow at the other end of the line assured me when I ordered directly from Antennacraft. He also mentioned to me that they had offered this antenna to RatShack, but RatShack would only consider carrying it if they could get it at the same price they currently pay for the 15-2162. (C'mon, RatShack, given the developing interest in HD, and your boast that "We got answers", get with the program!) Again, thanks for the concise and understandable explanation of the jargon.


[This message has been edited by Ray H (edited 05-22-2001).]
 

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The description of this antenna sounds like something that you'd need to see a doctor in an emergency room to get treated.


I have never heard the term "compounded gain elevation" - that's definitely marketing BS.


The esiest way to make an antenna broadbanded is to use a full-wave loop or folded dipole as the driven element. This has been known for decades. The bow-ties seen on many UHF antennas are simply modified full-wave loops.


Half-wave dipoles are typically not as broadbanded.


A log-periodic antenna (like the small Silver Sensor) is another approach - as the desired frequency goes up or down, the elements on a log-periodic antenna can function as directors or reflectors. Not a lot of gain will be had, but it will be broadband.


This antenna looks like a simple yagi with corner reflector. There is a law of diminishing returns on the number of directors - I'd be surprised if the 59-element version has substantially more gain than their 37-element version.


Tapering the directors is a clever trick, and may make the antenna behave somewhat like a log periodic.


KC

 
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