[TowerTalk] Why is a reflector preferred over director for 2 element designs?

[David Gilbert]

That shorter element spacing is what makes the tuning more critical and 
the bandwidth narrower than for a RE design.  To actually get the 0.1db 
of extra gain in practice instead of just in your mind, you pretty much 
need to go with something like the tunable 2-element SteppIr.   As a 
corollary, it's easier to get close to a 50 ohm match with a wider 
spaced RE design than with a close spaced DE design.

In any case (using a 20m antenna as an example), I'm not sure how a foot 
or two of boom length makes for a significantly smaller "footprint" when 
the elements are well in excess of 30 feet long.

Dave   AB7E


On 8/25/2011 9:15 AM, Eddy Swynar wrote:
> Hi Don,
>
> That being the case, so does the diminished "footprint" required of a DE vs. a RE design...correct?
>
> ~73~ de Eddy VE3CUI - VE3XZ
>
>
>
> ************************************************************************************************************************
>
>
> On 2011-08-25, at 12:11 PM, n8de at thepoint.net wrote:
>
>> The question asked was why was DE-Refl preferred.  The 0.1 dB loss in gain compared to 5-10 dB F/B makes a difference worth thinking about.
>> 73
>> Don
>> N8DE
>>
>> Quoting Eddy Swynar<deswynar at xplornet.ca>:
>>
>>> Hi Don,
>>>
>>> True enough, but the forward GAIN is less...
>>>
>>> ~73~ de Eddy VE3CUI - VE3XZ
>>>
>>>
>>> *************************************************************************************************************************
>>>
>>>
>>> On 2011-08-25, at 11:53 AM, n8de at thepoint.net wrote:
>>>
>>>> DE-Reflector arrays have better front/back ratios.
>>>> 73
>>>> Don
>>>> N8DE
>>>>
>>>>
>>>> Quoting John Harper<john at ae5x.com>:
>>>>
>>>>> Most 2-element Yagis and quads use a reflector as the 2nd element.
>>>>> I'm wondering what (if any) advantages a reflector has over a
>>>>> director as the parasitic element for 2-element Yagi/quad designs.
>>>>>
>>>>> Thanks,
>>>>>
>>>>> John AE5X
>>>>> http://www.ae5x.com/blog
>>>>> _______________________________________________
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