Topband: Beverage Question

[David Harmon]

Jim.....confirmed on Herb's comments.
In preparation for installation of the DXE I had a long conversation with
Rod about the impedance and he assured me that it would be difficult to
match the impedance with wire which would degrade the performance.
In the end....I did not put up the DXE because of this reason.....I did not
want the 450~ ladder line flapping in the breeze and causing maintenance
problems.
I could be wrong about the maintenance....but that's the excuse I told to
myself.


73

David Harmon
K6XYZ
Sperry, OK

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Herbert
Schoenbohm
Sent: Saturday, September 20, 2014 9:34 AM
To: topband at contesting.com
Subject: Re: Topband: Beverage Question

Jim, The DXE boxes are designed for 450 ohm ladder line which has a much
higher impedance than WD1-A wire.  Using the DXE boxes may work but Gary's
boxes (KD9SV) will work better as they are designed for the 100 ohm
impedance of WD-1A.  I also understand that DXE may now sell the boxes
designed for WD-1.

Herb Schoenbohm, KV4FZ
On 9/20/2014 10:06 AM, Jim Garland wrote:
> I want to replace the 450 ohm ladder line for my two DXE 720 ft long 
> bi-directional beverages with two lengths of WD-1/TT field telephone wire.
> The wires will be secured only at the ends, but will be suported along 
> their length by ceramic insulators mounted on 4x4 posts spaced every 
> 60 ft.  The spacing between the parallel wires will be about six 
> inches. Here are my
> quesetions: First, does anybody know what the likely impedance is of 
> this configuration, or if not, how to measure it?  Second, if I keep 
> the DxE matching trnsformers used with the 450 ohm ladder line, will 
> beverage performance be degraded noticeably with the new wures if, 
> say, the impedance of the new line turns out to be 600 ohms or so? In 
> other words, as a practical matter how important to performance (e.g., 
> F/B ratio and
> low-noise) is it to make sure impedances are matched.
>
>   
>
> Finally, a mechanical question. I want to have a pulley at one end of 
> the parallel wires to equalize the tension in the wires. I've not been 
> able to find a good pulley with a five or six inch diameter, except 
> for nylon pulleys used for clotheslines. Do you think one of these could
be used.
> There will be no motion of the pulley, since it is only used to 
> equalize tension. The field telephone wire is rated at 200 lbs maximum 
> tension, and I'm guessing the actual tension will be about half that.
>
>   
>
> Thanks!
>
> Jim W8ZR
>
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