Well, it seems that I’m starting to have some very first results for SID monitoring using VLF.
The basic idea is very simple (and so the setup for now).
There are a few VLF stations around the world. Usually they are military stations as VLF is used also for sending messages to submarines. In any case what I do is monitor one (or more) signals of those stations and check how the power level of those transmissions changes. Sudden changes in the power level can be a sign of a SID.
The more stations the more “reliable” is the analysis as you can “average” their signal strengths.
I don’t care about the content but only focus on the power level of the transmissions.
My actual setup is not simple… but even more than simple 😀
I use a 3m single wire cable attached to the “LINE” input of the Soundblaster of my PC. That’s it. I’m about to build a “real” antenna and a VLF “receiver”. But this setup is helping me in getting in confidence with the SpectrumLab software.
Here are a couple of screenshots.
The first is the spectrum of about 10 minutes. As you can see I have a loooooooooooooooooot of noise but I can follow a nice strong signal at around 19.1Khz. Still don’t know exactly where it cames from but I’m almost sure that it’s not noise.
Here’s the graph showing the singal Strength over the last 20 hours (time is in UT).
And here is Roma3 radio telescope at the moment. Just for comparison.
During those two days of tests I noticed many correlations in the peaks and valleys of the signals. Hopefully with a “real” VLF setup I’ll be able to have a better signal.
Unfortunately I don’t have the best location for VLF but I’ll try putting a couple of antennas (a loop and a mini whip) on top of the roof.
So far I’m very happy with the results and with what I’m learning.
I’m reading Renato Romero’s book: Radio Nature. GREAT! I love it. Very simple and practical. Exactly what I needed. I almost have all the electronics to start building a receiver so I just need to do some soldering and I should be able to have a better performing setup within a few days… max a week 😉
Weather is good and I should start doing some high resolution imaging but work is still keeping me very busy and I need to focus on it as what I’m doing now is very important for me.
SID monitoring is not very time consuming so I can let myself work on it 😉