[AMRadio] ground sticks again

david knepper collinsradio at adelphia.net
Mon Jun 5 10:11:54 EDT 2006

If I could add my "two cents" to this discussion.  Any ham who has the 
slightest thought that a large oil filled capacitor is charged should bleed 
the voltage to ground through a 100K  resistor, acting as a bleeder 

By the way, be very careful not to assume that your bleeder resistor is 
functional.  Lots of folks, including myself, got nipped by a bleeder that 
opened up!  Thank goodness it was only a few hundred volts but what if ....

A shorting stick should be in evey hamshack.  The one that I have is made 
from a phenolic rod about a foot long with a insulated copper braid with a 
clip attached to a hook rod at one end that I drape over the filter 
capacitors when working on the amplifier.  It was issued to me when I was in 
the Air Force working on 5 KW transmitters.  If the sergeant saw you without 
your "Jesus stick" you might get your butt kicked.

Crazy story:  I had a friend who used to charge up a 100 mfd/4000 volt oil 
filled capacitor to see how long it would stay charged!!  He wasn't too 

Dave, W3ST
Publisher of the Collins Journal
Secretary to the Collins Radio Association
www.collinsra.com - the CRA Website
Now with PayPal
CRA Nets: 3805 Khz every Monday at 8 PM EST
and 14255 every Saturday at 12 Noon EST
----- Original Message ----- 
From: <W4AWM at aol.com>
To: <amradio at mailman.qth.net>
Sent: Monday, June 05, 2006 9:42 AM
Subject: Re: [AMRadio] ground sticks again

> In a message dated 6/5/2006 0:25:48 AM Eastern Daylight Time,
> k4kyv at hotmail.com writes:
>> it can ruin the capacitors with excessive
>> instantaneous current surges.  Better to first discharge through a
>> resistance to limit the discharging current, then apply the "coup de 
>> grace"
>> by shorting  directly.
> How do you intend to handle the resistor while doing the discharging? You 
> are
> still going to need a shorting stick. If the initial charge opens the
> resistor, tyou are still going to have a huge discharge when tou roun the 
> cap
> directly.  It is much better to take the slight chance of discharging the 
> cap the
> direct way than messing around with some Rube Goldberg resistor 
> arrangement. If
> the Great Electron Gods had intended for capacitors to be discharged 
> through a
> resistor (other than a bleeder) before working on a circuit, them he would
> have made discharge sticks with built in resistors. I have never seen one, 
> have
> you?
> Transmitting caps are not that hard to find, not that expensive.  You can
> find them at nearly every hamfest. At the Manassas, VA hamfest yesterday, 
> there
> were 2 large piles of them at one vendor in the flea market and he would 
> almost
> pay you to take them home.
> 73,
> John,  W4AWM
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