[Elecraft] More antenna problems

Tue Jul 27 12:07:43 EDT 2004

Wingkeel at aol.com wrote:

> My antenna is a 100' length of wire fed by 50' of RG8X Mini.  The
> feed point is at 10' off the ground through a balun.

This doesn't have anything to do with your noise problem, but you should
realize that you probably have a relatively high SWR on the feedline and
balun on most bands, even though the KAT2 reduces the SWR seen by the K2
to a manageable level.  As a result, loss in the coax and balun is quite
high (the balun is worthless in this situation, and probably
significantly reduces performance).  I know you say that you get out
well, but believe me you would get out better with a resonant antenna or
  one fed with ladder line.

> There is a power line at the same height as the balun just over the
> property line, (about 12' away).  The noise blanker has no
> appreciable effect on noise, so I doubt if power line noise is having
> much effect.

Power lines conduct noise from devices connnected to them, and from
actual faults (cracked or dirty insulators, etc.) on the line.  12' is
very close.  Your noise could be coming from someone's pump half a mile
away or a fluorescent light in your kitchen, etc.  Some kinds of noise
are reduced by the NB, others not.

My suggestion is to replace your antenna with a 40-meter dipole or a
multiband dipole (using either traps or parallel elements for each
band).  The antenna should be resonant on the bands on which you plan to
operate.  If you feed it with coax, use a 1-1 balun at the feedpoint.
If you use ladder-line, use a 4-1 balun at the entry to the house, and
then run 50-ohm coax to the K2.  Try to locate the antenna as far as
possible from the power line, and (most important) oriented at 90
degrees to it.  The balanced line or isolated coax line will then reduce
pickup of noise by the feedline itself.

This system will have minimal noise pickup and maximize efficiency,
important for QRP operation.

> I'm seriously thinking about buying as 5-band Hustler to ground mount behind 
> my shack.  I've been told that my signal to noise ratio would improve 
> considerably by a salesman at a local store.  He suggested either the Cushman or the 
> Hustler and indicated that for the $350 difference, the Hustler receives almost 
> as good as the Cushman. 

A vertical antenna will probably pick up MORE noise than a horizontal 
one, since local manmade noise appears to be primarily vertically 
polarized (I'm not sure why this is so, but it is).  In addition, if you 
can get the horizontal wire up to about 30' at the center, it will 
perform much better than the vertical for most QSOs.  If you do get the 
Hustler, make sure you have a good radial system (either elevated or 
in-ground) -- without it, it will be a dummy load.  An acceptable in- or 
on- ground radial system for this kind of antenna (40 m and up) can be 
constructed of 16 20' radials; an elevated system should have 2 resonant 
radials for each band that you intend to work.  I think you would get 
much better results at lest cost with the horizontal system I've outlined.

I know I've touched on a number of religious issues in this post, but so 
be it.

-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco

  My K2 also has the KAT2 which matches up at 1.3:1 on
> 40-meters.  My power supply is an Anstron SS30 which is about 4' away
> from the radio.  The power supply has no effect on a computer about
> the same distance away. The noise seems to be white in nature and not
> the 60-cycle hum. Periodically, the noise will fluctuate about 2
> s-units which I attribute to scatter effect.
> 
> Several people have indicated that I have busted through pileups with
>  10-watts out.  Others have indicated that I had the strongest signal
> out there at times...Usually in Utah and Texas.  I live in Boulder,
> CO.
> 
> My problem is that I cannot hear the incoming signals very well
> through the 5-7 S-units of noise between 1830-2100 when I can get on
> the radio.  I just completed realigning my receiver with the
> Spectrogram software.
> 
> I have not been able to work anything outside of the US since I
> finished my K2 and got my General license about 4-weeks ago.  I also
> cannot work anything or anybody between 0500-1830.  Sometimes I can
> find a weak signal but I can never get back to them on 5-10 Watts.
> Is this the norm for this cycle?
> 
> I'm seriously thinking about buying as 5-band Hustler to ground mount
> behind my shack.  I've been told that my signal to noise ratio would
> improve considerably by a salesman at a local store.  He suggested
> either the Cushman or the Hustler and indicated that for the $350
> difference, the Hustler receives almost as good as the Cushman.  Any
> thoughts?  I'm getting pretty desperate.  I can use all the Morse
> Code programs in the world but it all gets boring after about
> 5-minutes, otherwise, I can talk for hours to real people!  For a
> newcomer, its kind of like fishing...you never know what you've got
> till you bring it in.  One of the most fun aspects is looking them up
> in the ARRL database to get an address to send a QSL card to.  At 54,
> I thought I'd done it all...LIFE IS GOOD!
> 
> Thanks all
> 
> 73 de Terry - KC0QZX _______________________________________________ 
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