[TowerTalk] book Tribander comparison test

[Joe Subich, W4TV]

 > Are you telling us that yagi element spacing has no effect on front
 > to back ratio?

Yagi element spacing has minimal effect on front to back ratio as
long as the element spacing is not extreme (all elements compressed
toward one end of the boom) and the elements are *properly tuned*
for front to back.

Of course a five element yagi will have better front to back than
a wide spaced four element yagi of the same boom length.  One has
an extra element and an extra degree of freedom to design for both
gain and front to back.   It is a simple exercise with antenna
modeling/antenna optimizing software to learn the trade-off among
gain, front to back (or front to side) and SWR bandwidth ... or
simply spend some time and re-read the series on yagis by Dr. Jim
Lawson, W2PV from Ham Radio back in the late 1970s.

73,

    ... Joe, W4TV



On 3/1/2011 8:04 PM, Barry Kirkwood wrote:
> Are you telling us that yagi element spacing has no effect on front to back
> ratio?
> If so, not correct.
> 73
> Barry ZL1DD
>
> On 2 March 2011 00:56, Jim Brown<jim at audiosystemsgroup.com>  wrote:
>
>> On 2/24/2011 5:32 PM, Joe Subich, W4TV wrote:
>>> Nonsense!  Some 30+ years ago W2PV showed that a monobander was a
>>> monobander no matter what the element spacing as long as the elements
>>> are properly tuned for their place in the array.  Gain is a product
>>> of boom length as long as there are "enough" elements for the length.
>>>
>>> Tapered spacing only effects the bandwidth and feed impedance of the
>>> antenna and with a SteppIR bandwidth has no meaning since the antenna
>>> is constantly retuned for the operating frequency.
>>
>> RIGHT.
>>
>> Jim K9YC
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