[TowerTalk] W2DU Balun Bead Source

[FISCHER,GREG]

I don't remember if it was on this reflector or another, 
but the common mode chokes were discussed in great detail 
with great info from this site:

http://www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdf

Basically.....Buy the cores and make your own.  But as 
stated...it's not going to work on how that antenna was 
setup for 160.

GL
Greg
AB7R




On Wed, 10 Jan 2007 15:30:23 -0600
  K4SAV <RadioIR at charter.net> wrote:
> Well I guess if no one else is going to say it, I will. 
>The reason your 
> balun got hot is because you put in in series with your 
>signal not in 
> series with common mode currents.  You can't put a balun 
>on a 160 meter 
> T antenna.  When you short the center to the shield of 
>your 80 meter 
> inverted vee and feed the whole thing against your tuner 
>ground, there 
> are no common mode currents, everything is single ended. 
> Any balun you 
> put on the coax will be directly in series with the main 
>signal current 
> to the antenna.
> 
> Jerry, K4SAV
> 
> AD5VJ Bob wrote:
> 
>>I tried a Ferrite not long ago and took it off. 
>>
>>I had a relatively small donut piece of ferrite and 
>>placed it over the coax, I didn't wrap it or anything, 
>>just a quick test. Hoping
>>to get rid of any common mode currents on 160Meters and 
>>quieted the noise down on my receiver.
>>
>>The first time I had ever used one.
>>
>>I have an adapter made to make my 80 meter inverted Vee 
>>into a T vertical for 160. It goes to the wire input of 
>>the tuner.
>>
>>I didn't smell anything, but reached over to take the 
>>pl-259 off of the barrel connector to take it off of the 
>>wire input and put it
>>on the other antenna input to my tuner after working some 
>>of the 160 meter contest. 
>>
>>So I could use the antenna for 80 meters again. 
>>
>>I jerked my hand back rather quickly, however, because I 
>>had in no time at all burnt a bluster on my thumb and 
>>forefinger because
>>the ferrite was so hot.
>>
>>Then every time I transmitted for any length of time on 
>>160, the ferrite got so hot that it started making the 
>>insulation on my coax
>>melt I could smell the burning.
>>
>> So I removed it.
>>
>>73,
>>Bob ad5vj
>>
>>  
>>
>>>-----Original Message-----
>>>From: towertalk-bounces at contesting.com 
>>>[mailto:towertalk-bounces at contesting.com] On Behalf Of 
>>>Keith Dutson
>>>Sent: Tuesday, January 09, 2007 4:23 PM
>>>To: towertalk at contesting.com
>>>Subject: Re: [TowerTalk] W2DU Balun Bead Source
>>>
>>>There is a good discussion of baluns in the current issue 
>>>of 
>>>QST written by Ward Silver.  The bead balun is a good 
>>>choice.
>>>
>>>73, Keith NM5G
>>>
>>>-----Original Message-----
>>>From: towertalk-bounces at contesting.com
>>>[mailto:towertalk-bounces at contesting.com] On Behalf Of 
>>>Cecil Moore
>>>Sent: Tuesday, January 09, 2007 2:17 PM
>>>To: towertalk at contesting.com
>>>Subject: Re: [TowerTalk] W2DU Balun Bead Source
>>>
>>>    
>>>
>>>>From: "R. David Eagle" <kb8nnu at yahoo.com>
>>>>Subject: [TowerTalk] W2DU Balun Bead Source Howdy all...I 
>>>>am 
>>>>      
>>>>
>>>looking at 
>>>    
>>>
>>>>constructing 2 W2DU bead baluns as described in ARRL 
>>>>Antenna 
>>>>      
>>>>
>>>book that 
>>>    
>>>
>>>>uses 12 Amidon FB-77-1024 beads.
>>>>      
>>>>
>>>Not trying to change your mind, but you get more balun 
>>>for 
>>>the money with multi-turn toroids. Multi-turn toroids 
>>>yield a 
>>>choking impedance proportional to the square of the 
>>>number of 
>>>turns. Turns are cheap. W2DU baluns yield a choking 
>>>impedance 
>>>proportional to the number of beads. Beads are expensive. 
>>>I 
>>>have the very W2DU chokes that you want to build and 
>>>don't use them.
>>>--
>>>73, Cecil, w5dxp.com
>>>
>>>_________________________________________________________________
>>>Dave vs. Carl: The Insignificant Championship Series. 
>>> Who will win? 
>>>http://clk.atdmt.com/MSN/go/msnnkwsp0070000001msn/direct/01/?h
>>>    
>>>
>>ref=http://dav
>>  
>>
>>>evscarl.spaces.live.com/?icid=T001MSN38C07001
>>>
>>>
>>>_______________________________________________
>>>
>>>
>>>
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>>>    
>>>
>>
>>
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>>
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>>  
>>
> 
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