TopBand: Re: Sloped Beverage Terminations

[km1h @ juno.com]

On Tue, 21 Oct 1997 19:49:41 -0400 (EDT) Frank Donovan
<donovanf@sgate.com> writes:
>Charles,
>Here are some direct answers to your questions:
>
>On Tue, 21 Oct 1997, Charles H. Harpole wrote:
>> 1.  just how long should it be (not in wavelengths, not in meters, 
>but in
>> gud ole American FEET) for 160 meters????
>
>Based on computer models, and on-the-air experience, good choices are 
>580,
>880 and 1160 feet. If these are inconvenient for you, use what you 
>can.
>Lengths less than 500 feet perform significantly poorer than longer
>lengths.
>
>> 2. what should be on the far end?  a carbon resistor?  or what? and 
>of
>> what wattage value?  and of what resistance value?
>
>Use a 470 ohm carbon composition resistor.  If you have an antenna
>analyzer, you could optimize the resistor value for flat VSWR across 
>the
>range 1.8-10 MHz.  If you don't have an antenna analyzer, don't worry
>about it, just use 470 ohms!  VSWR flatness indicates minimal 
>reflections
>from the far end.  Wattage value is not critical, I've used everything
>from 1/2 watt to 2 watts and none have ever failed at my QTH.

Yeah, but you roll it all up during T Storm weather season Frank. I used
to blow at least 4 2W carbons every summer; just from induced voltages. 
Finally went to three 180 Ohm 10W non-inductive in series. No problems
all this year. The 180 Ohm value was just what I found at a "junk store"
in quantity AND cheap. 


>You will need a 9:1 transformer to feed the Beverage, and suitable 
>ground
>rods at each end. 
>
>Lay the feedline on the ground or bury it.  If you must raise the 
>feedline
>above ground it will also behave like a Beverage and you will need to 
>take
>special precautions to isolate the antenna currents on the feedline 
>shield
>from the Beverage feedpoint ground.

If you have various critters in the woods they may destroy soft coax in a
few months. I lost some nice runs to bite marks that sucked up the water.
The worst time was in the winter with a deep snow cover. The little
monsters did their work under the snow and when it melted I wound up with
700'  attenuators. 
Finally went to CATV hardline. 

73  Carl  KM1H



>73!
>Frank
>W3LPL
>donovanf@sgate.com
>
>
>
>
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