[amsat-bb] Yagi Stacking,

Wed Feb 22 14:20:19 UTC 2017

Awesome Greg,

Thats what I was thinking, 1/2 of each's capture area. added together 
makes them minimum apart.

You made ( or someone) made a comment about 10 meters screwing up NO-84.

Does it really attenuate it that much?

I have been playing with NO-84 for quite a while.

Reason asking is My 10 meter side has been no problem, even 5 watts, is 
enough to activate her. My weak side has been the recv.

But Sunday I put together a 70 cm 9 ele beam and listened and on both 
passes not only was it full quieting it was FULL SCALE!!

Then at the Monday passes this I was ready for transmit too.

I listened first and heard nothing, about mid through the pass way I 
started transmitting, and nothing at 5 watts, 20,, 50  and even 100 not 
once did she come awake.

Does this happen?

joe WB9SBD
Sig
The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com
On 2/21/2017 11:04 PM, Greg D wrote:
> Hi Dave, Joe,
>
> According to the fine print, the formula is for antennas more than about
> 10 elements, and boom lengths 2 wl and longer.  Dave's 3 element 2m beam
> doesn't quite qualify.  Joe, you're probably ok, but still...
>
> I'd put them as far apart as is practical, and not worry so much about
> the math.  How long is your cross arm?  6 or 8 feet?  Start there.
> These are relatively blunt instruments; don't over-think it.  :)
>
> To Joe's numbers, two of the 65's would be placed 65 (what, inches?)
> apart, or about 5'.  By the ideal different bands diagram, the mixed
> pair would be half of 65 plus half of 123, or 94 apart, or about 8'.
> But the different bands practical diagram says, basically, anything
> farther than half of whichever is the higher band's distance, so if
> that's the 123 antenna, about 5'.  So, like I said, 6-8 feet is probably
> fine.
>
> Greg  KO6TH
>
>
> Joe wrote:
>> Now when using that formula on that page,
>> And you get an answer of 65 for one antenna and 123 for another,
>>
>> Now if they were identical antennas IE the 65, I would place the two
>> 65 apart correct?
>>
>> Now if one is 65 and the other is 123, what should be the optimum
>> spacing?
>>
>> Joe WB9SBD
>> Sig
>> The Original Rolling Ball Clock
>> Idle Tyme
>> Idle-Tyme.com
>> http://www.idle-tyme.com
>> On 2/21/2017 2:44 PM, Mike Thompson wrote:
>>> I replied to this earlier, but I thought it would be worth sending to
>>> the
>>> whole board.
>>> The idea is to get each antenna out of the aperture of a smaller
>>> antenna as
>>> much as possible.
>>>
>>> Hope this helps.
>>>
>>> http://www.ifwtech.co.uk/g3sek/stacking/stacking2.htm
>>>
>>> On Tue, Feb 21, 2017 at 1:01 PM, Dave Mann <cwo4mann at comcast.net> wrote:
>>>
>>>> Same Question here, RE placing the two 2-M Yagis directly next to each
>>>> other and 90 degree angles.
>>>>
>>>> I read where I can put both of my Cushcraft 3-element Yagis together,
>>>> spacing the elements on one so that they are ahead or behind the
>>>> other set
>>>> of elements.  Then binding the two Yagi booms together.  Feed line
>>>> would be
>>>> one 1/4 wave and one 1/2 wave, "I think".  Then the two feed lines
>>>> would be
>>>> soldered together and attached to a PL-259.
>>>>
>>>> I put a couple of photos of my construction project on the AMSAT
>>>> Facebook
>>>> page, but it only shows the 70cm Cushcraft Circularly Polarized Yagi
>>>> at one
>>>> end of the cross-boom and a single 3-element Cushcraft Yagi at the
>>>> other
>>>> end of the cross-member.
>>>>
>>>> I originally placed the second 2-m Yagi at a 1/4 wavelength away
>>>> from the
>>>> end Yagis, but saw some pretty high SWR readings on both the 70cm
>>>> and on
>>>> both 2-m Yagis.
>>>>
>>>> This is more difficult to explain in writing than to actually do.  I
>>>> will
>>>> get some photos up to my Ham Radio DropBox account and post the link
>>>> here,
>>>> "real soon now".  Photos here might be more illustrative than my
>>>> written
>>>> explanation (pun intended).
>>>>
>>>> I appreciate all of the comments and other advice received here and
>>>> on the
>>>> Facebook AMSAT page.
>>>>
>>>> -------------------------
>>>>
>>>> Esto es para mis amigos de habla hispana:
>>>>
>>>> La misma pregunta aquí, RE colocando los dos Yagis 2-M directamente al
>>>> lado del otro y ángulos de 90 grados.
>>>>
>>>> Leí donde puedo poner ambos de mis Cushcraft de 3 elementos Yagis
>>>> juntos,
>>>> espaciando los elementos en uno para que estén por delante o detrás del
>>>> otro conjunto de elementos. Luego se unen las dos barras de Yagi. La
>>>> línea
>>>> de alimentación sería una onda 1/4 y una onda 1/2, "creo". A
>>>> continuación,
>>>> las dos líneas de alimentación se soldarían juntas y se unirían a un
>>>> PL-259.
>>>>
>>>> Puse un par de fotos de mi proyecto de construcción en la página de
>>>> Facebook de AMSAT, pero sólo muestra los 70cm Cushcraft circularmente
>>>> polarizado Yagi en un extremo de la cruz-boom y un solo 3-elemento
>>>> Cushcraft Yagi en el otro extremo de la cruz- miembro.
>>>>
>>>> En un principio colocé el segundo 2-m Yagi a una longitud de onda 1/4
>>>> lejos del extremo Yagis, pero vi algunas lecturas bastante altas de
>>>> SWR en
>>>> ambos los 70cm y en ambos 2-m Yagis.
>>>>
>>>> Esto es más difícil de explicar por escrito que hacerlo. Voy a obtener
>>>> algunas fotos hasta mi Ham Radio DropBox cuenta y publicar el enlace
>>>> aquí,
>>>> "muy pronto". Las fotos aquí pueden ser más ilustrativas que mi
>>>> explicación
>>>> escrita (juego de palabras).
>>>>
>>>> Agradezco todos los comentarios y otros consejos recibidos aquí y en la
>>>> página de Facebook AMSAT.
>>>>
>>>> 73's
>>>>
>>>> Dave
>>>> N4CVX
>>>>
>>>>
>>>>
>>>>
>>>> On 02/21/2017 10:23 AM, Joe wrote:
>>>>
>>>>> OK using this image as a reference,
>>>>>
>>>>> http://i67.tinypic.com/28mpzkh.jpg
>>>>>
>>>>> Ok the yagis are 8 elements on 2 meters and 21 elements on 70 cm.
>>>>> Similar boom lengths.
>>>>>
>>>>> Now when vertically polarized and stacked side by side as in the top
>>>>> picture how close can they get to each other before starting to mess
>>>>> with each other.
>>>>>
>>>>> Same thing in next image but horizontally polarized so above and below
>>>>> each other.
>>>>>
>>>>> Now if they are 90 deg in rotation IE: one is vertically polarized and
>>>>> the other horizontal, I'm thinking they could even be on the same boom
>>>>> correct?
>>>>>
>>>>> So that brings in the third drawing same antennas but at 45 deg to the
>>>>> horizon but 90 to each other, How close can they get without
>>>>> bugging the
>>>>> other?
>>>>>
>>>>> Now with the 45 deg angle thing,  how much will a metal cross boom
>>>>> mess
>>>>> with them?
>>>>>
>>>>> Joe WB9SBD
>>>>>
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>>> _______________________________________________
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>> _______________________________________________
>> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
>> to all interested persons worldwide without requiring membership.
>> Opinions expressed
>> are solely those of the author, and do not reflect the official views
>> of AMSAT-NA.
>> Not an AMSAT-NA member? Join now to support the amateur satellite
>> program!
>> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
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>
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