I have two receiving antennas on 160: an 8-circle vertical array and a low dipole up 10 feet. I have been noticing that in the first part of the evening, the dipole often hears Europe as well as, or nearly as well as, the 8-circle. This appears to indicate that the signals are arriving at relatively high angles. This might also explain why a transmit dipole at a moderate height can work well for DX. Other times, the dipole is way down from the 8-circle, and I would expect a vertical transmit antenna to do better.
Occasionally in the mornings, around SR, the dipole also hears the DX as well as or sometimes better than the 8-circle. 73, John W1FV -----Original Message----- From: Topband [mailto:[email protected]] On Behalf Of Artek Manuals Sent: Friday, December 11, 2020 9:39 AM To: [email protected] Subject: Re: Topband: EZNEC Ground Errors OR The propagation mode on 160 is not what we have popularly come to "Accept". There is a growing body of evidence that particularly at gray line that signals often arrive at a higher angles. This is often attributed to "ducting" . Maybe a lot more of 160 intercontinental propagation is due ducting rather than the more commonly thought of low angle earth to F layer hop/multi-hop stuff seen at higher frequencies? Where do i get a pair of those glasses that lets me look at radio waves so I actually see them arrive Dave NR1DX On 12/11/2020 8:58 AM, Roger Kennedy wrote: > Guy I have ALWAYS thought that the various Computer-based modelling of > Ground and its effect on Antennas is WAY off . . . > > And surely the errors are MOST significant on 160m, not just because > Antennas are near the ground (in wavelength terms) . . . but also because > even the ground 130 ft deep is still going to have an effect . . . and there > is no way EZNEC can possibly take that into account, even if you KNEW what > was underneath your topsoil ! > > In my particular case it's not the effect on Verticals on 160m that interest > me . . . it's the effect on a Low Dipole. > > Any DX stations I work on 160m will confirm I put out a pretty respectable > signal . . . my signal reports around the world and more recently I am able > to compare my RBN Reports across NA and they tend to be very similar to the > other British DXers. > > However, most people are surprised to discover that for the last 50 years I > have always used a Horizontal Half Wave dipole on 160m, at around 50ft. > > BUT I believe that EZNEC plots showing that most of the RF is just very High > Angle is WRONG . . . that's because in practice the Ground underneath it is > rubbish . . . so the Dipole's effective height above Ground is much higher. > > And in fact, it seems that most people who have Dipoles on 160m mounted over > or near a very comprehensive Radial system DO get poor results using them > for DX . . . but that goes to confirm my theory (which is all based on my > actual experience on Top Band) > > Roger G3YRO > > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector -- Dave [email protected] www.ArtekManuals.com -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
