[MLB-WIRELESS] Excellent cable

Ben Ryan ben at bssc.edu.au
Fri Mar 8 14:07:27 EST 2002


> Derr, I quoted Quickform 141, not Quickform 86

> Quickform 86: Loss per 100m 1GHz 0.64dB  10GHz 2.26dB  20GHz 3.42dB
> Outer diameter 2.14mm, so it's small, which is nice.  Min bend radius is 
> 7mm, being semirigid yet very flexible and all.

> I'd say due to it's small diameter it's not good for high power to which 
> the LMR series is better suited.  But for 802.11 it's perfect.  Silver 

sadly I can't attend, I reside 200km north... makes it hard.

Do you, or does anyone else, know how it achieves such a low loss figure??
I thought it was directly related to distance between conductors and capacitance
of the dielectric!
Now it seems my understanding is incomplete/flawed...

I have had people ask me, they thought it was related to shielding - I know it's
not "on lo-rent cables, the screen isn't as good and your signal leaks out",
well I thought that was false.

Can anyone tell me the main factor that defines loss, and in light of the above
info, how a smaller OD cable can exhibit lower loss than a larger OD cable??


Also, (tony!!??) can somebody point me in the direction of literature that
explains the mechanics of RF at microwave frequencies?
I understand the ARRL antenna handbook is interesting, but doesn't specifically
mention microwave stuff, other than "just scale the dimensions of these designs
according to wavelength".. I have searched the net and came up empty-handed
(apart from Uni courses ;))
Can I walk into Dymock's and/or Borders and get a book that has all the
relevant stuff in it - why some connectors exhibit non-linear impedance at high
freq's, the theory behind say a quarter-wave "stub", and why a DC short circuit
actually works when fed microwaves as a radiator???

I just need a source for info, I can answer most of my questions myself if I
just had the right info available...

I gotta find out this stuff because it turns out that for our emerging
bendigowireless group I seem to have acquired the job of tech guru (now I just
have to find out what the hell I am talking about)
:)



thanx


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