[TowerTalk] Do I need to Offset Yagis 90 Degrees?

n8de at thepoint.net n8de at thepoint.net
Thu Aug 25 07:24:38 PDT 2011


Quoting navydude1962 at yahoo.com:

> Also offsetting them minimizes the windload

Oh, really?   And you did what calculations to reach this conclusion?

Windload depends on the direction from which the wind blows in  
relation to the position of the boom & elements.

I have NEVER seen a calculation that says MINIMUM windload occurs when  
two antennas are offset 90 degrees WITHOUT specifying the direction of  
the wind relative to the antennas and what the windload is for EACH  
antenna at EACH different wind direction.

73
Don
N8DE



>
> Sent from my iPhone
>
> On Aug 25, 2011, at 5:31, "Bill Parry" <bparry at rgv.rr.com> wrote:
>
>> I have a 2 element Cushcraft 40 M beam and a Force 12 C3 mounted at the top
>> of my 120 foot tower. The C3 is at 120 feet and the 2 element 40 is at 132
>> feet. They severely interacted until I had the tower guy come back and turn
>> the C3 90 degrees from the 2 element 40.  Now there is little interaction
>> and they both work fine.
>>
>> If I were you I would try it with both pointing the same direction but have
>> in mind that you will probably have to make another trip up the tower to
>> move the bottom antenna.
>>
>> Bill W5VX
>>
>> -----Original Message-----
>> From: towertalk-bounces at contesting.com
>> [mailto:towertalk-bounces at contesting.com] On Behalf Of Williams, Richard
>> (OAG/CPG)
>> Sent: Wednesday, August 24, 2011 8:58 PM
>> To: towertalk at contesting.com
>> Subject: [TowerTalk] Do I need to Offset Yagis 90 Degrees?
>>
>> I would rather point them in the same direction. The 2 ele for 40 will be 10
>> feet above the TH-11DX. Anyone have any experience with this? VE9HF
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