Hi Guys. Thought this might be of interest to some of us newbies. To avoid this happening, , you old hands may want to look the other way
I installed a PiAware setup with DVB-T Dongle and stock aerial a little over a week ago. Was pleased with the results but thought I could do better so I built an 8 element collinear and stuck it to the window with duct tape. Quadrupled the reports but thought I could do better so I put the collinear in a PVC pipe on top of a two meter mast outside on the roof with 360 degree views and 600 feet up on a ridge with a 5 metre 75ohm coax lead. That was a mistake. Reports dropped to a couple of thousand. So I brought the aerial back inside and stuck it to the window again. Reports are now back up to where they were. I must have screwed something up with the outside install but anyway the main purpose of this post was to point out a pretty extraordinary range (for me anyway) that I got tonight with the reinstalled (to the window) aerial.
251NM !!! 8)
My usual hits are in the 210 -230nm range on this particular airway but I have recieved a few 240-242nm reports on nearby airways.
Radio horizon from my site to FL390 is approx 236nm though reports on this airway usually begin or end in the 210-230nm range. So 251nm is pretty extraordinary and had to reflect some kind of OTH ducting or tunneling.
This long range hit was on a WSSS-NZAA flight inbound on the A464 at FL390 at 2100 on 21 May 2015. Rain radar showed a belt of moderate to heavy rain between my site and the reporting aircraft lying parallel to the airway.
According to ‘The Basics of Radio Wave Propagation’ by Edwin C. Jones, MD, PhD (AE4TM) Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200):
“Inversions that occur along frontal systems support propagation along a line parallel to the weather front, and radio amateurs using frontal inversion often point their antennas parallel to the frontal system to take advantage of this form of propagation.”
I have noted that other 240nm+ reports on the R599 and B333 airways which have also occurred during bad wx and wondered if wx had anything to do with it.
Here’s a picture of the report (the yellow circle) and my ADS-B site. That’s New Zealand in case you were wondering. The airway is the A464.
And here’s an image of the Auckland rain radar at that time. You’ll not how the front lies parallel to the airway.
So I thought that was pretty neat. To get a 251nm hit made me fell like this;
I told my wife I can now see around corners but a vacant stare was all I got. She’s a bit bewildered by all the aerials going up and down, things getting taped to the window, me running outside and reeling off data about passing aircraft and multiple computer screens that look like something out of the Matrix!!