[Antennas] WxAU Balun

[Joe]

I see there may be some confusion? I know I am,  between W2AU  and W2DU.

I've used W2AU baluns for decades.  And have never ever had a problem.  
But my mind is drawing a total blank on W2DU,  very similar,  but is it 
the same company?  or whats going on with a similar product and similar 
callsign?

Joe WB9SBD

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 1/2/2011 11:08 AM, Barry Sherwood wrote:
> Some of those reviews are scary! But, they do have a flashy website.
>
> On Sun, Jan 2, 2011 at 9:21 AM, Terry Conboy<n6ry at arrl.net>  wrote:
>
>> On 2011-01-01 7:20 PM, Ron Youvan wrote:
>>> John Hensley wrote:
>>>> I recently took down a trap dipole which had been up for a couple of
>> decades.  Cleaning up the balun which is also serving as a "T" shaped center
>> support, I realized I had no idea how to check it.
>>>> I would enjoy hearing from anyone who has messed with these things.  I
>> have no idea what is inside.  The caps are black, the body is gray PVC about
>> 1.5" diameter.  Grounding strap runs down the side.  I used to see these at
>> every hamfest I went to.
>>>> Before I forget the performance was lousy but then again, I winged it.
>>>      A piece of coax (min-8 = 8X) or RG-141 or some such with 20 or 30
>> ferrite beads around it between
>>> caps, the inner goes to one eye bolt, the shield goes to the other.  They
>> (usually) can only be hurt
>>> with super QRO or corrosion.  The 1:1 balun is used to reduce feedline
>> radiation (making your signal
>>> just horizontal instead of H + V) and reduce the effects of a nearby
>> conductive object unbalancing
>>> your dipole so much.  I have never heard of them hurting a station.  I
>> use one on my 40 meter dipole.
>>
>> What Ron describes is a W2DU balun, which is a "current" balun.  It has
>> a longer body than the somewhat similar W2AU balun, which is a "voltage"
>> balun, which probably has a trifilar winding on a ferrite rod inside.
>> The W2AU balun come in both 1:1 and 4:1 variations, which look the same
>> on the outside (other than labels).  These are all made by
>> http://www.unadilla.com/
>>
>> With an ohm-meter, the W2DU will appear open-circuit between the antenna
>> terminals.  The W2AU models will look like a short.  You need to test
>> with a dummy load (200 ohms for the 4:1 model, of course) and measure
>> the SWR or impedance at the coax input to see it it's OK.  It's a lot
>> harder to test to see if it is actually providing proper balance and/or
>> isolation.
>>
>> In general, a good current baluns are normally preferred, but make sure
>> you check out the comments by Walt Maxwell, W2DU, at
>> http://www.eham.net/reviews/detail/2300 .
>>
>> 73, Terry N6RY
>>
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