Comments below
On 1/7/2022 6:23 AM, Roger Kennedy wrote:
<SNIP>
But I picked up on people saying that EZNEC doesn't model these antennas
near the ground very well.
This is very true of EZENEC based on NEC -2....EZENEC PRO 4 based on
NEC-4 depending on attention to detail and uniformity of soil conditions
can produce results for models near ground that represent reality.
NEC-5 was intended to address the lack of uniformity in the ground
medium ( i.e having half your ground plane consumed by 3 story apartment
building as an example) but the modeling could becomes quite an
exercise. Unfortunately the father of NEC-5 passed away unexpectedly and
left its development in limbo and a fair share of questions and
possible bugs. When last I talked to LLNL they were still searching for
a replacement for Jerry
<SNIP>
I think part of the reason is that DX Propagation on 160 is usually much
higher angle than on 80m . . . but I also think that there is more low angle
radiation from my Dipole than EZNEC would suggest !
This is very true especially near gray line. I have noticed on numerous
occasions the the F/B on my Beverage and BOGS becomes very poor at
gray-line only to return to expected performance later in the evening.
Popular wisdom suggests that most 160 DX occurs at 15-25 degree arrival
angle . I suspect that gray line propagation arrives due to "ducting" at
even higher angles. I am toying with the idea of building a loop on a
gimble that would allow rotation not only for azimuth but for elevation
as well. I suspect however that I will find that the arrival angle can
change quite rapidly making it hard to track and is one of the reasons
for deep QSB
Dave
NR1DX
--
Dave Manuals@ArtekManuals.com 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
|