[Top] [All Lists]

[TowerTalk] Shunt Feed Capacitor for Tower

To: <>
Subject: [TowerTalk] Shunt Feed Capacitor for Tower
From: (Pete Smith)
Date: Fri, 08 Feb 2002 09:24:35 -0500
At 06:50 PM 2/7/02 -0500, Tom Rauch wrote:
> In an earlier message, Tom warned against this problem and suggested
>> modeling the voltage across a small load placed at the top of the
>> tower as a check on the voltages to be expected. 
>You can either place a very *high* resistance load there, or a 
>current source set to *zero* amperes.

Sorry, I wasn't thinking clearly.  That makes perfect sense.  I must have
crossed the two ideas from your earlier post.  

Just for fun, I ran my whole-tower model with a zero-current source at the
junction between the top 40m yagi's reflector and boom.  At 200w input to
the shunt feed (2A @ 50 ohms, if I did it right) the model shows 580v
there, vs only 68 volts across a similar point on the tribander 7 feet
below it.  If the model is reasonably accurate in this respect, it looks as
if I probably only need to ground the 40m yagi elements for 160 meter RF,
and that not until I start to run high power on 160.  

73, Pete N4ZR

Sometimes a tower is
just a tower

Where do you get ICE bandpass filters & beverage matching boxes?  The
same place that pays for the hosting of this list:  The eHam Store.
Order online at

FAQ on WWW:     
Administrative requests:

<Prev in Thread] Current Thread [Next in Thread>