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@contesting.com
>>[mailto:towertalk-bounces@contesting.com] On Behalf Of Keith Dutson
>>Sent: Tuesday, January 09, 2007 4:23 PM
>>To: towertalk@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@contesting.com
>>[mailto:towertalk-bounces@contesting.com] On Behalf Of Cecil Moore
>>Sent: Tuesday, January 09, 2007 2:17 PM
>>To: towertalk@contesting.com
>>Subject: Re: [TowerTalk] W2DU Balun Bead Source
>>
>>
>>
>>>From: "R. David Eagle" <kb8nnu@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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