Detection hydrogen using Phased Array and SDR# with IFAverage Plug in and processed using ezRA suite

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andrew....@googlemail.com

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Oct 1, 2023, 6:05:03 AM10/1/23
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processed using ezRA suite

 

At last!

Pretty sure I have now managed to transfer my data to ezRA suite to produce some nifty plots! Waiting for Ted Cline from SARA to confirm – but it seems to me likely the following show hydrogen.

As always comments and constructive criticisms are very welcome!

I am hoping to let this run for few days and then demonstrate varying plot over time.

Andy

­

From last night:

 

The following shows the typical double peak of hydrogen detected via SDR# with IFAverage Plug-in and 50 Ohm dummy load to calibrate:

 

 

When I processed the data from last night from SDR# IFAverage plug-in is processed in ezRA suite, I obtained following results:

 

 

The Doppler shift of -0.4MHz corresponds to the hydrogen peaks seen on SDR# on same system – so even if the Doppler shift itself is erroneous due to some error in system then this data above corresponds to the typical hydrogen trace.

In addition, this peak is +96 degrees galactic longitude which corresponds to when Cygnus crossed Zenith – my Ptarmigan Triffid array is pointed at the Zenith.

 

The peak drops gradually as galactic longitude moves away from +96 degrees so that at +91 degrees see below:

 

 

There is another peak at +152 degrees galactic longitude, smaller than peak above = the Milky Way was now crossing Perseus:

 

 

The above findings correspond to the bright orange strip in the plot below:

 

 

 

image001.jpg
image003.jpg
image005.jpg
image007.jpg
image008.jpg

Alex P

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Oct 1, 2023, 6:41:15 AM10/1/23
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On Sunday, October 1, 2023 at 6:05:03 AM UTC-4 andrew....@googlemail.com wrote:


YES : That is Neutral Hydrogen Data !

What is the configuration of your "phased array' antenna ( photo ? )

Have you tried plotting a few samples via Excel re-scaled in dB relative to cold sky ?
                                    typical plot  w/  vert scale dB
H1_typicalplot.jpg

Alex

Andrew Thornett

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Oct 1, 2023, 7:24:24 AM10/1/23
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It is a Pharmigan Triffid military array 1m in size, see my website www.astronomy.me.uk for photos.

How do I rescale the data relative to cold sky? I don't really know what I am doing here. Vincent and Ted have been marvellous with their support and I couldn't have got this far without them but I would like to do what you suggest- can you give me an idiot's guide on how to do it?

Andy


From: 'Alex P' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Sent: Sunday, October 1, 2023 11:41:15 AM
To: Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Subject: [SARA] Re: Detection hydrogen using Phased Array and SDR# with IFAverage Plug in and processed using ezRA suite
 
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b alex pettit jr

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Oct 1, 2023, 7:43:02 AM10/1/23
to 'Andrew Thornett' via Society of Amateur Radio Astronomers
Here's How to do it.
Inline image

Great Website, .. but the background animation is a bit distracting.

Alex



On Sunday, October 1, 2023 at 07:24:27 AM EDT, 'Andrew Thornett' via Society of Amateur Radio Astronomers <sara...@googlegroups.com> wrote:


It is a Pharmigan Triffid military array 1m in size, see my website www.astronomy.me.uk for photos.

How do I rescale the data relative to cold sky? I don't really know what I am doing here. Vincent and Ted have been marvellous with their support and I couldn't have got this far without them but I would like to do what you suggest- can you give me an idiot's guide on how to do it?

Andy


Andrew Thornett

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Oct 1, 2023, 7:45:29 AM10/1/23
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Thank you.
By cold sky, do you mean the value when Milky Way out of the way?
Background animation is my animation of solar flare taken by myself - I am very proud of it as took ages to work out how to do it!
Andy 


From: 'b alex pettit jr' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Sent: Sunday, October 1, 2023 12:42:53 PM
To: 'Andrew Thornett' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Subject: Re: [SARA] Re: Detection hydrogen using Phased Array and SDR# with IFAverage Plug in and processed using ezRA suite
 
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b alex pettit jr

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Oct 1, 2023, 7:53:11 AM10/1/23
to 'Andrew Thornett' via Society of Amateur Radio Astronomers
Inline image


b alex pettit jr

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Oct 1, 2023, 8:00:01 AM10/1/23
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Cold Sky = Freq Range not influenced by H1 RF Spectrum 
Shown  here ~ 1420.0 MHz - 1420.2 MHz



Inline image



Andrew Thornett

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Oct 1, 2023, 8:18:23 AM10/1/23
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Thanks!!!! Currently visiting Leamington Spa today in UK but when I get home tonight I am definitely going to give this a go!

I can't find any literature on the Pharmigan military array antennae so know little of its characteristics - all I know is that it is a discontinued military communications antenna that was designed for directional battlefield communications.

It would be nice to determine what coverage of the sky it provides (ie how directional) but I dont know how to do it.

Andy


From: 'b alex pettit jr' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Sent: Sunday, October 1, 2023 12:59:57 PM
To: 'b alex pettit jr' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>

Subject: Re: [SARA] Re: Detection hydrogen using Phased Array and SDR# with IFAverage Plug in and processed using ezRA suite
Cold Sky = Freq Range not influenced by H1 RF Spectrum 
Shown  here ~ 1420.0 MHz - 1420.2 MHz



Inline image



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b alex pettit jr

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Oct 1, 2023, 8:34:54 AM10/1/23
to 'Andrew Thornett' via Society of Amateur Radio Astronomers

Hi Andrew,

That is an Interesting antenna, but perhaps not optimized for the ultra low signal levels of H1.
The open ends allow a fairly high pickup of 290K ground noise and RFI from the PC etc.

                                    Motto for low signal level H1 reception :
"  IF  You can see an antenna's feed element(s) they can 'see'  You, your PC , and  all other surroundings. "

Inline image


Thanks!!!! Currently visiting Leamington Spa today in UK but when I get home tonight I am definitely going to give this a go!

I can't find any literature on the Pharmigan military array antennae so know little of its characteristics - all I know is that it is a discontinued military communications antenna that was designed for directional battlefield communications.

It would be nice to determine what coverage of the sky it provides (ie how directional) but I dont know how to do it.

Andy

Andrew Thornett

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Oct 1, 2023, 8:52:41 AM10/1/23
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So.would it worth putting sheet aluminium foil behind it?
From: 'b alex pettit jr' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Sent: Sunday, October 1, 2023 1:34:47 PM
To: 'Andrew Thornett' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>

Subject: Re: [SARA] Re: Detection hydrogen using Phased Array and SDR# with IFAverage Plug in and processed using ezRA suite

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b alex pettit jr

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Oct 1, 2023, 9:03:50 AM10/1/23
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b alex pettit jr

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Oct 1, 2023, 9:18:36 AM10/1/23
to 'b alex pettit jr' via Society of Amateur Radio Astronomers
Here's a good project for you :

>>>>  Compare the Scope in a Box to your Phased Array :

Capture the same part of the Sky with each, save via IF_Ave and plot both on the same chart..
( use an offset for each ( converted to ) dB column by whatever value is needed for Its 'Cold Sky' to = 0dB, but the conversion formula is the same f)

Such As :

Inline image

Alex

Andrew Thornett

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Oct 1, 2023, 9:35:12 AM10/1/23
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What would I gain?
From: 'b alex pettit jr' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Sent: Sunday, October 1, 2023 2:18:29 PM
To: 'b alex pettit jr' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>

Subject: Re: [SARA] Re: Detection hydrogen using Phased Array and SDR# with IFAverage Plug in and processed using ezRA suite
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b alex pettit jr

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Oct 1, 2023, 9:41:07 AM10/1/23
to 'Andrew Thornett' via Society of Amateur Radio Astronomers
You can Quantify the difference in performance ?

On Sunday, October 1, 2023 at 09:35:15 AM EDT, 'Andrew Thornett' via Society of Amateur Radio Astronomers <sara...@googlegroups.com> wrote:


What would I gain?

From: 'b alex pettit jr' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Sent: Sunday, October 1, 2023 2:18:29 PM
To: 'b alex pettit jr' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Subject: Re: [SARA] Re: Detection hydrogen using Phased Array and SDR# with IFAverage Plug in and processed using ezRA suite
 
Here's a good project for you :

>>>>  Compare the Scope in a Box to your Phased Array :

Capture the same part of the Sky with each, save via IF_Ave and plot both on the same chart..
( use an offset for each ( converted to ) dB column by whatever value is needed for Its 'Cold Sky' to = 0dB, but the conversion formula is the same f)


Alex


Eduard Mol

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Oct 1, 2023, 4:46:16 PM10/1/23
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Well done Andrew! That definitely looks like a successful detection of the hydrogen line. Also nice to see someone try this with a different setup than a dish or a horn antenna.
As for ground noise/ RFI pickup via the sides: maybe this is not a big problem if the array elements are arranged in such a way that waves coming in from the sides are effectively canceled out. If it does have serious sidelobes, perhaps you could try putting mesh screens or aluminium foil as reflectors on the sides and see if that further improves your results. That being said, it is always a good idea to have atleast a few meters distance between your antenna and your computer.
I would expect the beam size of a 1 metre array to be comparable with that of a 1 metre dish, about 10- 15 degrees at 1420 MHz. Maybe you could check this by performing a driftscan of the sun.

Anyway, great work, and have fun with your radio astronomy experiments.
Best,
Eduard

Op zo 1 okt. 2023 om 12:05 schreef andrew.thornett via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
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Andrew Thornett

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Oct 1, 2023, 6:17:50 PM10/1/23
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Thanks Eduard!
How do I confirm beam width with drift scan of sun?
From: sara...@googlegroups.com <sara...@googlegroups.com> on behalf of Eduard Mol <eddiem...@gmail.com>
Sent: Sunday, October 1, 2023 9:45:58 PM
To: sara...@googlegroups.com <sara...@googlegroups.com>
Subject: Re: [SARA] Detection hydrogen using Phased Array and SDR# with IFAverage Plug in and processed using ezRA suite
 

Marcus D. Leech

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Oct 1, 2023, 7:15:46 PM10/1/23
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On 01/10/2023 18:17, 'Andrew Thornett' via Society of Amateur Radio Astronomers wrote:
Thanks Eduard!
How do I confirm beam width with drift scan of sun?
You'll need to plot total-power over time during the transit of the Sun, and then figure out how many minutes are between
  the half-power points in that plot.

Roughly 4 minutes per degree for objects on the celestial equator--the Sun is a few degrees below at the moment, but
  probably not far enough to make that much difference.


fasleitung3

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Oct 2, 2023, 5:08:48 AM10/2/23
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Hi,
I am afraid I have to be the bearer of bad news (again ;-)
Your signal shown in the plot from IF average is in the range from
1419.2 to 1419.6. This is around 1 MHz away from the transition of
hydrogen at 1420.405 MHz. This would be a redshift of > 170km/s which
does not occur from hydrogen in our galaxy. Just for the sake of
completenss: There are some so called "high velocity clouds" but these
are too week to be detected with such a small antenna.
So there are two possibilities: Either it is not hydrogen or your SDR's
frequency is way off.
There is some indication that the latter might be the case: Your last
plot shows a signal starting at around 21:00 UTC which very much looks
like a hydrogen signal from the galactic plane, albeit at the wrong
frequency. So you may want to check the accuracy of your frequency.
What I am struggling with are the second, third and fourth plot: The
straight, noise free baseline will not be observed an a real spectrum.

Best regards,
Wolfgang

Am Sonntag, den 01.10.2023, 11:04 +0100 schrieb andrew.thornett via
Society of Amateur Radio Astronomers:
> processed using ezRA suite
>
> At last!
> Pretty sure I have now managed to transfer my data to ezRA suite to
> produce some nifty plots! Waiting for Ted Cline from SARA to confirm
> – but it seems to me likely the following show hydrogen.
> As always comments and constructive criticisms are very welcome!
> I am hoping to let this run for few days and then demonstrate varying
> plot over time.
> Andy
> From last night:
>
> The following shows the typical double peak of hydrogen detected via
> SDR# with IFAverage Plug-in and 50 Ohm dummy load to calibrate:
>
>
>
> When I processed the data from last night from SDR# IFAverage plug-in
> is processed in ezRA suite, I obtained following results:
>
>
>
> The Doppler shift of -0.4MHz corresponds to the hydrogen peaks seen
> on SDR# on same system – so even if the Doppler shift itself is
> erroneous due to some error in system then this data above
> corresponds to the typical hydrogen trace.
> In addition, this peak is +96 degrees galactic longitude which
> corresponds to when Cygnus crossed Zenith – my Ptarmigan Triffid
> array is pointed at the Zenith.
>
> The peak drops gradually as galactic longitude moves away from +96
> degrees so that at +91 degrees see below:
>
>
>
> There is another peak at +152 degrees galactic longitude, smaller
> than peak above = the Milky Way was now crossing Perseus:
>
>
>
> The above findings correspond to the bright orange strip in the plot
> below:
>
>
>
>
> --
> --
>

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