[TowerTalk] coax attentuation

Mike & Coreen Smith ve9aa@nbnet.nb.ca
Tue, 8 Jan 2002 18:28:19 -0400


Wanna sell some of that coax?
;-)


Michael, Coreen & Corey Smith
(VE9AA,  VE9AAA & Baby-VE9)
271 Smith Rd
Waterville, NB
E2V 3V6
Canada
http://members.tripod.com/~ve9aa/index.html
http://www.geocities.com/RainForest/Vines/2174/

----- Original Message -----
From: Al Williams <alwilliams@olywa.net>
To: <towertalk@contesting.com>
Sent: Tuesday, January 08, 2002 5:50 AM
Subject: [TowerTalk] coax attentuation


>
>
> ----- Original Message -----
> From: "Al Williams" <alwilliams@olywa.net>
> To: <Topband@contesting.com>
> Sent: Monday, January 07, 2002 11:21 PM
> Subject: coax loss
>
>
>  I have been trying to determine signal loss in coax by using a dual trace
> oscilloscope (Tek 465) connected to the input and output of the coax.
> However, instead of a loss I
>  am observing a gain!
>
>    My setup is using a MFJ-249 SWR Analyzer as the source and a BNC 51 ohm
>  resistor connected to the source.  The opposite end of the coax is
> connected
>  to the scope and a 51 ohm carbon resistor with short leads.  Both
resistors
>  measure low swr (<l.2) with the MFJ.
>
>  The waveforms on input and output of the coax appear undistorted
sinewaves
>  but the output is greater than the input for frequencies up to about 30
> mhz. The output
>  increases as the coax length increases being about 20% greater with 130'
of
> LM400.  The MFJ
>  measures SWR of about 2:1 (note; the two 50 ohm resistors at input and
> output are in
>  parallel.
>
>  Has anyone used this method?  What might be wrong with my setup?
>
>  k7puc
>
>
>
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>


________________________________________________________________________
This list is sponsored by the new eHam.net Store.  When you buy products
like ICE filters, Array Solutions StackMatch, or M-Squared Antennas from
the eHam Store for the same price you pay direct, a portion of the sale
price goes to support this list.  Check it out at http://www.eham.net.

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