Airspys and Aliens... #sdrsharp


Scott/KC1UA
 

Sounds like a good movie title! While I remain skeptical about such things, they are entertaining to watch from time to time. I went into this one having no idea what I was about to see, but some hardware and software that's near and dear to many of us has a starring role throughout. 

https://www.youtube.com/watch?v=OBzHOJGxhJg

--
Scott - KC1UA
Marstons Mills, Cape Cod, MA USA


paul
 

They should redo this flight with proper Airspy hardware instead of RTL dongles (see 04:17)
RTL dongles generate a lot of "alien" signals ;-)



73
Paul
PD0SWL


Richard Myers
 

Thanks for posting the youtube  video. Skinwalker Ranch is an interesting place I enjoyed watching the video.


Rich NE1EE
 

On 2022-05-22 05:44:-0700, you wrote:
Thanks for posting the youtube video. Skinwalker Ranch is an interesting place I enjoyed watching the video.
I found it ... curious...
I skimmed this vid. It is rife with drama and a lack of detail. Those of us who are hams know about LOS wrt VHF/UHF, and those of use who are pilots are aware of the limitations of ADS-B, especially in remote areas of the country. Flying over much of the western regions of the US is very different from flying over the eastern half of the US.

For an ADS-B message transmitted by an aircraft to be successfully received by a ground sensor, a line-of-sight (LOS) condition must be met. The radio wave from transponders is radiated with sufficient power so that it is safe to assume that the maximum message reception range r corresponds to the radio horizon. Under tropospheric refraction, r is given in kilometers (I'm all metric here) by r = 3.57vke(vh1 + vh2), (check my math) where ke represents the effective Earth-radius factor and h1 (or h2) represents the transmitter (or receiver) antenna height in meters. It follows that a sensor located beyond the radio horizon of a given aircraftís transponder will never receive an ADS-B signal radiated by the latter.

The vid made much of them not showing on ADS-B, but they didn't report their height at the time --- they did mention climbing later --- nor did they mention the location and height of ADS-B receivers. I mention in passing that there are many places in the US where controlled airspace coverage is not possible due to terrain. It might be worth watching the series, but these guys are next to useless. Nice for kids and those w aluminium skull kaps ;-)

~R~
72/73 de Rich NE1EE
The Dusty Key
On the banks of the Piscataqua


Buzz@...
 

Skin walker ranch engineer said he had no idea what was on1.63 gigahertz.1.63 gigahertz  is a satellite to earth, earth to satellite communication frequency. Look at the uhf band frequency chart. Maybe they should start there.

73 de Gary, KF9CM


prog
 

On Mon, May 23, 2022 at 02:10 PM, Rich NE1EE wrote:
For an ADS-B message transmitted by an aircraft to be successfully received by a ground sensor, a line-of-sight (LOS) condition must be met.
The dongle they used was most probably overloaded. 


Zacharias Liangas
 
Edited


Forgot to mention I m referimt to shortwave reception

I have tested the v3 original .
It really generates aliens and ghost reflection signals
Tested in both console and Sharp