Carl Reade

You could make one. It is just an RF choke and a capacitor. Nothing to them really.

Hi the dementions of the can stay the same no matter what dish size, however I use a biquad feed there is a link to it's calculator in earlier post. http://www.setileague.org/hardware/feedchok.htm The bias fee was from eBay as long as it's within the frequency range any will do. This one is 0.5 - 2000Mhz.

Hi here is a diagram and pic of what I put together. There are a lot of different cable connectors at play due to components being different. Most LNAs are SMA connectors and for the coax (WF100) F type connectors. So plan what adapters you will need to put whatever components you use together. I.E SMA male to female F etc. For example the dongle will need a male SMB to female F connector tail lead. Carl

Yes it's the same one should be fine. The satellite shop should have 20db line amps. Have you thought about a feed for the dish?

Hi you cannot use a LNB for hydrogen line. The LNB is receiving 12 GHz however the H line is 1.4 GHz. So you will need the can made to receive 1.4 GHz. In the link he is using a very good LNA on the dish with a noise figure of 0.3 dB as well. Half the work is in the software using smaller dishes. For a minimum start I would go for, 1m dish, 20db LNA, 20 dB line amp, dongle and you should be able to detect hydrogen. This LNA has been used successfully, it's 20db gain and ( important noise figure of 0.6db) https://www.ebay.co.uk/itm/LNA-50-4000MHz-SPF5189-RF-Amplifier-Signal-Receiver-For-FM-HF-VHF-UHF-0-6dB-UK/263793459193?epid=19021137313&hash=item3d6b50bff9:g:ss4AAOSwiNxbO2sL&redirect=mobile You will need to put a dish feed together as well. Happy to help will have a diagram up soon. Carl

Hi on this site there is a link to a spreadsheet for the calculations for a can feed horn. http://www.setileague.org/hardware/feedchok.htm Carl

Hi no boring questions at all, Here is a link for filters at a reasonable price I would use one at least to start with and next to the LNA. https://redirect.viglink.com/?format=go&jsonp=vglnk_154137269185016&key=e6d017f13f6a6e8cc619287ca1b92ca3&libId=jo3hfox701013trd000TA1f6l0dvz&loc=https%3A%2F%2Fstargazerslounge.com%2Ftopic%2F319651-anyone-doing-hydrogen-line-observing%2F%3Fpage%3D2&v=1&out=http%3A%2F%2Fadsbfilter.blogspot.com%2F2015%2F06%2Fhydrogen-line-1420-mhz-filter.html&ref=https%3A%2F%2Fstargazerslounge.com%2Fforum%2F75-radio-astronomy-and-spectroscopy%2F&title=Anyone doing hydrogen line observing%3F - Page 3 - Radio Astronomy and Spectroscopy - Stargazers Lounge&txt=http%3A%2F%2Fadsbfilter.blogspot.com%2F2015%2F06%2Fhydrogen-line-1420-mhz-filter.html Your looking a noise figure of 1db or less on the LNA not sure if that one is. If you can get one screened on the board that is also ideal. Wideband LNAs amplify everything. SDR is fine Line amps fine You will also need various connectors, SMA etc I will put up what I put together soon which should help. Here is a link which is excellent and helped me a lot with software http://parac.eu/projectmk3.htm Carl

Hi, I would think the can type would be better as it would reject interference better but I have not seen a comparison between the two. I decide on the biquad as I had the materials at hand. Yes LNA it's amplification. As someone once put it, you are making an impossibly weak signal into a rediculisly weak one. The aim is to get the hydrogen line out of the noise. The inline amps are to eliminate gain loss in the coax and filters and multiple connectors used. The difference between these and LNAs is probably the noise figure which is around 4 dB so no good at the dish but fine for second stage amplifiers. yes bandpass filters you may get away with one as long as you don't have local interference. The LNA I use is filtered then I have one just before the dongle. I use the Egoo cheap SDR dongle. From reading they all are around the same noise figure 6db but that is irrelevant to the system noise figure. Would definitely cool it with a heatsink as they get very hot and heat is bad.

Ok best advice i would say is, Get the biggest dish you can! You will likely have to make the dish feed yourself either the the one on this thread or the can type (measurements online). Next is a good low noise amplifier (LNA). Around 30db gain and the lowest noise figure you can get. This noise figure will be the benchmark for the system. You will need probably two 20db satellite line amplifiers these are cheap and work fine. You will need filters in line as well to keep out interference. You can get these on the LNA4ALL site. You will need a power supply 12V and a DC inserter to power the amplifiers. You will need a receiver, a SDR dongle is fine A computer and software. Once you have a working scope then you can improve it as you go along. Carl

Hi what sort of observations are you wanting to do, Hydrogen line, sun moon? You can make a basic radio telescope from the following, A small dish 50cm. A universal LNB An analogue satellite meter A 12 Volt power supply This would enable you to take readings from the sun and moon to start with.

I take it part of your question is how to amplify the signal to a useable level? Carl

Yea I know I don't have the test gear to make them even. Haven't been on the air myself in a while. I'm guessing there is a build in the pipeline? Carl

Hi Robin, it's a specific one made by Radio Astronomy Supplies. I think it was +/- 15Mhz. The label has came off over time. (Photo) I should also mention the LNA is the SBA1300-1700 from RF Design (G8FEK). The guy Adam who sells LNA4ALL also now makes H line filters at 20 Euro I have ordered before with him and good to deal with. http://adsbfilter.blogspot.com/2015/06/hydrogen-line-1420-mhz-filter.html. Carl

More playing with data and contour graphs the green areas and all within is hydrogen. Even between the two arm sweeps hydrogen is present. The centre Freq should read 1.420410Ghz. Carl

Hi all let the scope run from around 17:30 through to 09:30 this morning. This would pick up two sweeps of the galaxy. Excel seems to struggle with 3d graphs but managed to put one together. There are two interference bands and in-between them the milkyway peeks. The rear peek is the strongest I have seen so I will check where it passed later. The gragh is 2.4 MHz wide spectrum over the time period.