Interests and experiences
My current location is in a small village with houses having solar panels, inverters, bad switching mode power supplies, not to mention all the electronic equipment I have in my own house. I have some directions where there are more noise than other directions, and it would be good to somehow visualize that.
The idea about the "SkyScanner" was born. This is a "project under development" and somewhat experimental. If it ever will be finished I don't know, at least I have/will learn something during the development, which is pretty much why I do stuff like this :)
The need got bigger and triggered me to do something about it when I installed my 70cm EME system. On EME, every 0.1 dB counts, and as I always try to optimize whatever I'm doing, I started the SkyScanner project.
SkyScanner is basically a PC (Windows) application that will control a Az/El rotor for your antennas (supports PstRotator, Yaesu GS-232 and my own URC RotorController), sample the audio from a transceiver (via soundcard or built-in soundcard in the radio) and present the measured "noise" from the transceiver and map this on a "dome".
Once the "sky has been scanned", the idea is that you can leave the application running, it will then always show you the current antenna position (by coloring the zone green the antenna currently points to). SkyScanner also shows the current position of the sun (orange zone) and the moon (dark gray zone) position on the dome.
The audio from the transceiver is sampled via Windows sound system, so no special needs there.
As mentioned, this is a project "under development", so expect some things to be changed along the way. Be sure to check this page for new versions once in a while.
Below you will find a couple of screenshots and a video showing the fundamental operation.
The application has a window that will allow you to monitor the noise level currently received. The application uses a soundcard interface to sample the audio, filters this and calculates the RMS value from this. It is VERY important that you DISABLE AGC completely when doing this, only by disabling the AGC the measurements will make any sense. It is also VERY important that the receive chain is linear in the range of the noise measured, clipping/limiting by the receiver will make the measurements invalid!
Using the controls to the left, you can select the dB per division and the width of the graph in seconds.
Pressing the "Delta = 0" button will take a snapshot of the current measured noise level. The "Delta(dB)" number just below the button, will show the delta between the snapshot and current noise level (The "snapshot" used will also be save in settings, so the next time the application is started, this stored value will be used as the basis for the delta value). Pressing "Pause" will pause the update of the graf, the data collected will be inserted once the button is pressed again. Right click with the mouse inside the graph area to bring up a submenu.
Some installations might have limitations on where the antenna(s) can be pointed. This can be due to cable restrictions, you might not be able to access the area around north from the ground to zenith because of cables or mechanical limitations.
In SkyScanner, you can define a list of "keep out zones", SkyScanner will not show these zones that are included in the areas, and the antenna will not be able to be commanded into this area either.
The algorithm behind this is not super clever, so you might end up needing to move the antennas to the area being scanned yourself, its not so that SkyScanner does a lot of route planning etc to get to a certain point. It will just command the rotor(s) to move to a specific Az/El.
But, it will monitor the current rotor position, and if it enters one of the defined "not allowed" zones, it will stop the rotor, you then have to move the rotor out from the area again before continuing.
The screenshots below shows a complete scan from south to west, horizon to zenith. The zones not measured was too close to the sun and was automatically skipped by the program. I can the re-visit these once the sun is out of the way. The full scan too 1 hour on my 70cm EME array.
After the sun moved out of the way, the last zones were selected and scanned.
The single "gray" zone is the current moon position and the lonely orange is the current sun position.
The screenshots below is from a scan I did with my 70cm EME antenna. In the "Download" section below you can download the database with these measurements in, and experiment with the controls of the program, zoom, pan etc.
Please notice that some of the videos below is from the first beta version of the program, some of the features have been changed in the application since the video was recorded.
Although you can select which zones (and the order) to scan using the mouse while holding the ALT key down, it becomes a bit tiresome when you need to select many zones. You can use the "Select zones" window to help with the selection.
Below is a small youtube video of the function.
The data that is being collected by SkyScanner is saved to a database, I'm using LiteDB, a small and relatively simple database. You can use the data in the database(s) for your own usage too if needed. Each record has information about the azimuth, elevation, timestamp, validity of measurement, the resolution of the zones measured (more on that later) and the measured noise level (in dB).
If you need to use the data from the database, the class in C# that holds each record looks like this:
SkyScanner will soon be available for download here!
Example data (from my 70cm EME array)
SkyScanner runs under Windows operating system. There are no installation to be done. The program consists of a single .exe file, simply download this, copy it to a folder and execute it from there.
SkyScanner will create a configuration file in the folder it is located in, this file contains all settings you do in the program.
2024-10-xx SkyScanner - Version 1.0.0.0
2024-10-xx - Version 1.0.0.0