[OKDXA] DX, on 160

Thu, 21 Nov 2002 09:39:25 -0600

Hi everyone,

I'm a new OKDXA member, but I couldn't help chiming in on 160.  I live 
about 5 mi SE of Tinker AFB in a rural area on a 2 acre lot. It's a quiet 
160 m location, something I learned to determine off of W8JI's site. 
Briefly, record the daytime noise level S-meter reading and compare it to 
the night-time level.  If the level is higher at night, you're in a quiet 
location.  This is because in the daytime we hear only local noise, but at 
night the band is open and lightning noise is propagated.  Because the 
location is quiet, I'm looking forward to playing a bit on 160.

I have ordered a Force 12 Sigma 80 vertical dipole for 80 m.  I talked with 
Force 12 about using this antenna on 160 m, and they assured me that, aside 
from a serious mismatch, it would handle full legal power with a 
tuner.  With a slightly souped-up AL-80A (beefed-up HV supply), I can 
generate only about 600 W output on 160, but a vertical dipole is about as 
efficient a transmit antenna as I am ever likely to get for 80 or 160 
m.  Force 12 tells me they have been working on a vertical dipole for 160 
m, but they haven't released it yet.  Vertical dipoles would make a killer 
4 square array, but the Force 12's would be expensive (proposed price is 
about $1k each; the 80 m version costs $580).

Initially, I plan to try operating with just the vertical dipole, even 
though I'll my receive capability be pretty limited that way.  Someday, I 
hope to put up a Beverage antenna, but our current lot is heavily treed and 
I'm not sure I could do it now as things stand.

Anyway, I think 160 m is the most challenging band for DX, with all of its 
odd propagation modes and inherent unpredictability. I have only about 
three countries on it right now, but the 160 m DX test is always a good 
candidate for nabbing a few more.

73,

Kim Elmore, N5OP

At 10:51 PM 11/19/2002 -0500, you wrote:
>Good stuff Jay.  I use electric fence wire from Home Depot for 
>radials.  At the end of the season I take it up and throw it away because 
>you cannot keep it straight, ha.
>
>160m is busy tonite with contest stations getting ready for the weekend.
>
>Jim
> >
> > From: "Jay Bromley" <[email protected]>
> > Date: 2002/11/19 Tue PM 01:27:06 EST
> > To: "Clifton Sikes" <[email protected]>,
> >       <[email protected]>
> > Subject: Re: [OKDXA] DX, on 160
> >
> > Hi Clif and gang again,
> >
> > One thing I forgot to comment on is the radials.  More smaller ones are
> > better than a few long ones.  Elevated ones are better than those on the
> > ground.  Radials on top of the soil  have less loss than ones buried.  Try
> > to put out 40-70 radials and cut them to 75ft.  If you have the room and
> > wire then by all means make then a 1/4 wave long which is around 120 feet.
> > The ideas is to have very low loss at the bottom of the antenna were the
> > current is.  So more is better here, not just one long one!  Elevated feeds
> > can get by with 2 to 4 radials if the ground losses are low and it also
> > depends on the height of the ground plane antenna
> >
> > Also on your inverted L, if you are using a 1/4 you might want to try a 3/8
> > wave.  It will move the current up a little and the losses at the base are
> > not as great.  You match it with a simple series capacitor at the 
> base.  You
> > could go to a 1/2, but most folks don't have the support to make the center
> > vertical,  so the 3/8 is a good compromise!  If I remember a 3/8 on 160m is
> > 177 to 180 feet long.  Matching a 1/2 on 160m is no fun with high power
> > because you are voltage feeding!
> >
> > If anyone needs the exact measurements of the radials, capacitor, or any of
> > the above I can e-mail them later.
> >
> > Have fun and 73 de jay..
> >
> > _______________________________________________
> > OKDXA mailing list
> > [email protected]
> > http://mailman.qth.net/mailman/listinfo/okdxa
> >
>
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                           Kim Elmore, Ph.D.
                        University of Oklahoma
         Cooperative Institute for Mesoscale Meteorological Studies
"All of weather is divided into three parts: Yes, No, and Maybe. The
greatest of these is Maybe" The original Latin appears to be garbled.