[600MRG] Coax shielding effectiveness

[Gedas]

See if this will get you started.

http://www.repeater-builder.com/antenna/andrew/andrew-shielding-effectiveness.pdf

Gedas, W8BYA

Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.

On 12/9/2019 2:23 PM, david vanhorn wrote:
> I knew fsj1-50 would be good but I haven't found data from anyone at 
> these low frequencies. Any pointers would help.
>
> On Mon, Dec 9, 2019, 12:14 PM Gedas <w8bya at mchsi.com 
> <mailto:w8bya at mchsi.com>> wrote:
>
>     Hi Dave. Funny you should ask. I am right in the middle of making
>     a video where I test about 10 different (and common) coaxial
>     cables specifically for their SE. The project is on and off as I
>     just have too many pokers in the fire right now.
>
>     It is not as simple as one may think to measure the SE accurately
>     esp if the cable is of high quality and has a high SE. If I were
>     still employed and had access to my old lab and shielded
>     enclosures and able to generate & measure known RF fields from DC
>     to daylight it would be a much, much easier task. Having to do it
>     in my basement lab makes it a much more challenging project. In
>     the end I chose to arrive at the SE by measuring the cross-talk
>     between two identical coax cables.
>
>     My methodology is to lay two identical cables of equal length next
>     to each other on a plywood table. Both far ends of the coax cables
>     are terminated in 50 ohm loads. One cable is driven with a
>     tracking generator (then broadband power amplifier) while the
>     other coax fed into the input of my spectrum analyzer. The amount
>     of cross-talk between the two cables can then be used to directly
>     see what the SE was. It gets hairy if the cables have a high SE as
>     the SA has a limited sensitivity (NF) and I can only generate
>     several watts of broadband RF from DC to about 1 GHz.
>
>     Until that video is done you will have to go by OEM data. FSJ1-50
>     will have an extremely high SE (well over 100 dB). If you need
>     some help looking up the exact OEM data just hollar. 73
>
>     Gedas, W8BYA
>
>     Gallery athttp://w8bya.com
>     Light travels faster than sound....
>     This is why some people appear bright until you hear them speak.
>
>     On 12/9/2019 1:37 PM, david vanhorn wrote:
>>     I've been searching around without much success.
>>     I'm trying to find data sheets or good measurements of shielding
>>     effectiveness of the various coax types, including FSJ1-50 for
>>     this band.  I'm not seeing anything talking much below 100MHz.
>>
>>     Can someone point me in the right direction?
>>
>>     -- 
>>     K1FZY (WA4TPW) SK  9/29/37-4/13/15
>>
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