Topband: Monopole Elev Pattern w.r.t. Earth Conductivity

Mike Armstrong armstrmj at aol.com
Wed Oct 24 23:08:19 EDT 2012


Dang Tom..... I just sent out a more wordy version of what you just said.  This is getting strange.  Not sure why it hasn't been disseminated yet (my email), but I swear I sent it just moments before  your email hit my system. 

You just added some fuel to my fire.  Short version: I, with my rather inexperienced eye (160 experience, that is) is seeing a pattern that seems to indicate what we would call low radiation angles aren't really optimum for long range 160 communications.  The other email goes into a little more detail in why I am thinking this way.  Morning enhancement, especially with high angle radiators (like mine) where I am working Japan and Chile on a radiator that can very truthfully be called an NVIS antenna.  On higher frequencies, a scaled version of my antenna wouldn't radiate a signal out of the southwest region, much less thousands of miles distant.

Just a thought!  Again, my other email expounds a little more, but this was the conclusion in a nutshell.  Maybe "low horizontal" antennas really ARE better on 160 than they should be..... Given our experience with low antennas on the higher bands, it seems counter-intuitive..... But there it is.

Mike AB7ZU

Kuhi no ka lima, hele no ka maka

On Oct 24, 2012, at 17:12, "Tom W8JI" <w8ji at w8ji.com> wrote:

>> If we knew those, then we could calculate the location and distance of the
>> signal hops. That might give us some insight as to why some people have
>> found a taller monopole to be worse than a shorter one at a given distance.
> 
> Back in the 70's or 80's there was speculation a low angle was lossy from grazing along, based on others having poor experiences with taller verticals. The top of my tall tower had some antennas and side arms which top loaded it a bit, but not much. Certainly the wave refracts gradually at a minimum, and so I think distance would not tell anyone much. There have been a host of theories since the 1960's, even some from Stew the real W1BB. :-)
> 
> I don't know what happens when it gets up in the soup, although people like K9LA should be pretty well versed on it. I only know things behave differently all the time, and what antenna generally works most of the time.
> 
> For example, at sunrise most of the time almost anything reasonably efficient works about the same here. It's more a matter of ERP at any not-too-low angle and any polarization.
> 
> 73 Tom 
> _______________________________________________
> Topband reflector - topband at contesting.com


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