[Hi-zreceivingarraydiscussions] Hi-zreceivingarraydiscussions Digest, Vol 20, Issue 2

[Robert Zavrel]

Hello Steve,

On 160 meters most long-haul DX arrives at higher angles than on higher bands...i.e about 20 degrees vs. 3 or 4 degrees on 10 meters (see ARRL Antenna Book). In order to achieve a 20 degree maximum from a horizontal antenna, the height is well over 200 feet, so unless you can get a dipole upo that high, you're better off with a vertical RX and TX antenna.

The crest of the mountains surrounding you will affect the response (block some power arriving from lower angles). Much worse can be how the ground slopes for the first mile or so in any given direction. Suppose, for example, you have an upward slope of 5 degrees for the first mile from your antenna to Europe. IN this situation your take-off angle will be raised by the same 5 degrees in that direction (from models that assume infinite flat ground in all directions). ON the other hand, if the ground slopes downward you LOWER the take-off angle pattern by the same degree amount.

You will have no control over the far field topography and will simply have to live with it. You CAN control the over-all efficiency of your TX antenna, and move to more sophisticated RX arrays....or if you have the energy time and money, use a remote antenna site!

73

Bob Zavrel, W7SX

> From: hi-zreceivingarraydiscussions-request at hizantennas.com
> Subject: Hi-zreceivingarraydiscussions Digest, Vol 20, Issue 2
> To: hi-zreceivingarraydiscussions at hizantennas.com
> Date: Sat, 13 Oct 2012 12:00:06 -0400
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> Today's Topics:
> 
>    1. HiZ3 and low angles (Steve Flood)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Fri, 12 Oct 2012 18:54:41 -0600
> From: "Steve Flood" <kk7uv at bresnan.net>
> To: <Hi-zreceivingarraydiscussions at hizantennas.com>
> Subject: [Hi-zreceivingarraydiscussions] HiZ3 and low angles
> Message-ID: <005001cda8dd$54466230$fcd32690$@bresnan.net>
> Content-Type: text/plain;	charset="us-ascii"
> 
> So after 10 years using the K9AY loops, I bought a HiZ3 triangle setup and
> installed it about 6 weeks ago.
> 
>  
> 
> My initial observations with morning DXing on 160m these past weeks (NH8S,
> 3D2C, 9M2AX, RW0CR, HL5IVL) are as follows:
> 
>  
> 
> 1.       The directivity is wonderful when I first tested it on daylight AM
> BCB stations and early morning 160m stateside and DX.
> 
> 2.      The gain level is quite high compared to the K9AY.   160m band noise
> is S3-S5 on the HiZ.  The same band noise on the K9AY (with 13dB preamp)
> would rarely move the S-meter.
> 
> 3.      The K9AY would always hear better than my omni vertical or my 80m
> dipole, without exception.  This is especially true for the NE path to
> Europe where the vertical or dipole would not hear EU stations at all..
> 
> 4.      While listening to the DX stations over the past weeks, signals were
> as good on the dipole and omni vertical as they were on the HiZ, even while
> the HiZ showed excellent directivity.
> 
>  
> 
> In an email conversation with W7IUV, he explained the HiZ has a very low
> notch angle - around 20 degrees or below.  This is evident on the EZNEC
> plots.
> 
> The K9AY notch is more like 25 to 50 degrees depending on ground conditions
> and termination resistance.  I wish I could set up both the K9AY and HiZ for
> comparisons but I don't have the space.
> 
>  
> 
> Here's the upshot:   I am surrounded by mountains that block my horizon up
> to 20 degrees to my NE, 14 degrees to my SW, and 10 degrees to my NW and SE.
> 
> I am wondering if perhaps the HiZ is not the best antenna to use for my deep
> valley location, since most all of the signals I am going to hear are at
> higher angles.
> 
> Is this why I have not had an "Oh Wow!" moment yet with the HiZ?
> 
>  
> 
> Thanks for any tips,
> 
> Steve KK7UV  
> 
> 
> 
> ------------------------------
> 
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> End of Hi-zreceivingarraydiscussions Digest, Vol 20, Issue 2
> ************************************************************