[TowerTalk] lp V stepIR

[Roger (K8RI)]

Robert wrote:
> Can this dialogue be continued elsewhere, like perhaps to a more appropriate 
> LP reflector?
>   
Antennas and towers... certainly falls directly within the group 
charter...how could it be OT?  Starting to get monotonous, but not OT. <:-))

73

Roger (K8RI)
>
> ----- Original Message ----- 
> From: "Gene Smar" <ersmar at verizon.net>
> To: "Tower and HF antenna construction topics." <towertalk at contesting.com>
> Sent: Sunday, January 24, 2010 11:16 AM
> Subject: Re: [TowerTalk] lp V stepIR
>
>
>   
>> Gents:
>>
>>     Fig. 5 in the URL is a good depiction of how only a few of the total
>> elements are actually active on any one frequency.  If one could run 
>> similar
>> models for increasing frequencies across the design BW of the LP one would
>> see the peak current move from the back of the LP (longer elements) 
>> towards
>> the front.  It is for this reason that the gain of an LP is considerably
>> lower for a given boom length than a similar Yagi - only a few elements 
>> out
>> of the six or eight or ten are active at a time.  However, the SWR is
>> maintained at a low level throughout the entire BW, the main advantage of
>> LPs over Yagis.
>>
>> 73 de
>> Gene Smar  AD3F
>>
>>
>> ----- Original Message ----- 
>> From: "jimlux" <jimlux at earthlink.net>
>> To: "Tower and HF antenna construction topics." <towertalk at contesting.com>
>> Sent: Sunday, January 24, 2010 1:30 PM
>> Subject: Re: [TowerTalk] lp V stepIR
>>
>>
>>     
>>> Stuart Browne wrote:
>>>       
>>>> Has anyone built an inverted LPDA?  Not practical unless you have the
>>>> land
>>>> and towers to support it but looks cheap to build and rugged. If you had
>>>> the
>>>> height it looks practical for 7-30 mhz.
>>>>
>>>> http://plasma.newcastle.edu.au/plasma/research/tiger/venice/Inv_V_antenna_paper.pdf
>>>>
>>>> Stu,
>>>> WH6H
>>>>
>>>>         
>>> This kind of thing is a mainstay of the commercial HF broadcasting
>>> world.. take a look at the TCI website.  They even make ones that
>>> rotate! (you move the base around)
>>>
>>> A HF broadcast station near me (KVOH) has something that looks much like
>>> this, using two towers.
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