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[TowerTalk] More: Antenna Bleed Resistor

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Subject: [TowerTalk] More: Antenna Bleed Resistor
From: wilder@abs.net (Dick Wilder (K3DI))
Date: Sat, 11 Sep 1999 11:34:22 -0400 (EDT)
I would like to pass some comments about this thread.

In the 1950's and 1960's I worked at AM broadcast stations and
would normally see an antenna bleeder system.  I recall a 5 kW 
station had a 100K-ohm  NON-INDUCTIVE resistor at some 100W.  
Other stations, typically 1 kW stations, used an RF choke. 

Prior responders to this thread said:
> > I use a 1 meg ohm wire-wound 25 watter 
> Wire wound???  What freq does that one resonate at?

Good point.  The test is to mount your bleeder device (resistor,
RF choke, or >LC network< ) and leave off the wire for the final 
connection to your antenna lead.  Check the SWR.  (We measured
the Z with a bridge at a BC station.)  Then connect the bleeder
device and recheck to SWR.  If there is no change, then you
know you have a high Z at your operating frequency.

I believe that a bleeder device on a vertical is a must.  On a dry snowy
winter day, the discharge of charge from snow flakes can build up the
voltage until it arcs to ground (or through your receiver).  I understand
that static build up can even result from dust.

73, Dick Wilder, K3DI


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