Thanks, Dave. Right you are about the problems of 450 ohm ladder line
flapping in the breeze! I've had to spend several days each autumn
repairing multiple breaks in the lines, even with supports spaced 60
feet apart.
73,
Jim w8zr
Sent from my iPad
> On Sep 20, 2014, at 9:00 AM, David Harmon <k6xyz@sbcglobal.net> wrote:
>
> 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@contesting.com] On Behalf Of Herbert
> Schoenbohm
> Sent: Saturday, September 20, 2014 9:34 AM
> To: topband@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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