Re: [amsat-bb] Satellite Antenna Modeling

[Anthony Monteiro <aa2tx@xxxxxxxxxxx>]

Hi Keith,

1 Siemens = 1 Mho. However, you really should use free-space
to model a helix pointing up at a satellite. Most ground reflection
will generally be opposite sense but EZNEC doesn't handle that
so you are better off just ignoring it by using free-space.

73,
Tony AA2TX

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At 11:50 PM 2/2/2004 +0000, Keith O'Brien wrote:

>Using the antenna modeling program EZNEC to model a 435 MHz RHCP Helix for 
>satellite use, I have a question someone might be able to help me with. 
>With in the program you are able to pick different grounds from which your 
>antenna will operate above. Searching the internet I was able to acquire 
>from the FCC site, that this portion of Florida has a ground conductivity 
>of 4 millimhos per meter. EZNEC is looking for the ground conductivity in 
>Siemens per meter. I have searched and can't seem to come up a answer to 
>my question.  How does millimhos relate to Siemens? Are they one in the 
>same? Is 4 millimhos the same as .004 Siemens? Anyone ?
>
>By the way, does anyone know of a site that might already have antenna 
>modeling files available?  I'm more interested in experimenting with 
>antenna designs then taking the time to build them up within the program. 
>Not really wanting to try to reinvent the wheel, if its already available.
>
>Thanks for your help.. Keith
>
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