Is this normal?

[Lucas Barclay]

Good evening, I have been trying to observe the hydrogen line for sometime now and I have this curve using IF average.. At the moment the area of the sky I am pointing my antenna at is not emitting many hydrogen emissions but I was wondering if this graph was normal for this, thanks!

[Ed astro]

Hi Lucas, 

yes this looks fairly normal. The three bumps in the graph are an artifact of the SDR and will always be there no matter where you point your antenna. 

The hydrogen line is centered at 1420.406 MHz, and you can usually detect it between 1420 and 1421 MHz (the frequency can vary somewhat due to doppler shift). Your graph spans from 1418.1 to 1420.2 MHz, these frequencies are a bit too low and you will likely have missed the hydrogen line.

Could you shortly describe the setup you are using and/ or post an image of your setup?

Best regards,

Eduard

 

[Lucas Barclay]

On 20/07/2021 at 16:53, Ed astro said:

Hi Lucas, 

yes this looks fairly normal. The three bumps in the graph are an artifact of the SDR and will always be there no matter where you point your antenna. 

The hydrogen line is centered at 1420.406 MHz, and you can usually detect it between 1420 and 1421 MHz (the frequency can vary somewhat due to doppler shift). Your graph spans from 1418.1 to 1420.2 MHz, these frequencies are a bit too low and you will likely have missed the hydrogen line.

Could you shortly describe the setup you are using and/ or post an image of your setup?

Best regards,

Eduard

 

Thank you for the response, I have recently changed the antenna I've been using from a custom built one I made to a generic satellite dish to see if this is any more reliable (I still have yet to test it). In terms of the other hardware Im using, I am using some RG59 coaxial cable, a sawbird H1 and a nooelec nesdr smart V4. Im also using SDR# to read the signal.. Thank you for the help!

 

[Lucas Barclay]

(Here are some images of the setup by the way, and a screenshot of what has come through so far with the new antenna) 

[Lucas Barclay]

Update - I have changed back to my original setup since I just realised that the LNB would prevent me from seeing any activity along the hydrogen line..