On Fri, 7 Nov 1997 16:04:00 -0500 "Doherty, Robert"
<Robert.Doherty@fmr.com> writes:
>We put up a the classic ON4UN 580 ft Beverage Ant..... with the 9-1
>matching torroid exactly a shown in his Low Band DXing handbook,....we
>checked the transformer input with the MFJ259 and a 500 ohm resistor
>on
>the secondary....it was flat SWR for 1 to 10 mhz... we fed it with 75
>ohm RG59, abt 100 ft.....We paralleled some resistors to get about 500
>ohms at about 4 wts.. How critical is selection of the terminating
>resistor?? Can it be anything from 400 to 800 ohms ?? Or does have to
>be
>5% or less.... in my case using the 75 ohm coax it would come out to
>be
>675 ohms.....Is it just nit picking???? or does this REALLY matter????
>Does it NOTICABLY improve receiving performance when the resistor is
>matched exactly??
>Or can it only ....as they say....."Be measured with sensitive
>instruments??
Your last sentence said it all Whitey...if you add : " and in a constant
temperature controlled enviroment and witnessed by 3 committees."
I used anything from 470 to 680 Ohms when I still played with 2W carbon
comps. Never could tell any change with the old ear.
These days I use 10W non-inductive, 3 each 180 Ohm in series since that
is what I found a bunch of at a surplus store. They hold up to WX and
close lightning strikes wheras I was replacing carbons several times a
year.
Enjoy....Carl KM1H
>tnx Whitey K1VV
>
>--
>FAQ on WWW: http://www.contesting.com/topband.html
>Submissions: topband@contesting.com
>Administrative requests: topband-REQUEST@contesting.com
>Problems: owner-topband@contesting.com
>
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Problems: owner-topband@contesting.com
|