Carl Reade

Good stuff. You should be able to get false colour in the settings as well.

Not bad at all. You will get passes like that and others will be a lot better.

Basically these satellites orbit constantly transmitting live weather pictures. So the aim is to wait for it to pass overhead, tune to it's frequency, decode the signal using software and produce a picture.

Just a horizontal V and LNA. I used WXtrack software to look at the passes.

Software is fine. To improve a quad helix or turnstile would help both not easy to build. Overall I found I generally I got one decent quality pass a day. Here are my decent ones.

I was referring to your first post😀 On the weather one the best results I've had was using a horizontal V antenna and a LNA4ALL preamp and a decent pass helps a lot.

Looks way too narrow for station. Check if noise level changes when aerial connected. Would also widen the band to the max.

Nice webpage and concept. Just a couple of questions, points, The user is going to need the co ords of the telescope to know when and what it will drift through. Is the scope going to be Alt Az mounted in order to look at different locations of sky? Maybe an idea to point users to software ie Stellarium in order to plan a scan request. I take it you will be carrying out requests manually? Carl

Glad to see your getting results. I don't think the line amp would be any advantage with only 3m of coax. Yes pointing is important, depending where you point and arms in that direction. The above graph was a drift scan of Cassiopeia. If your getting a big jump and small bump it's safe to say Cygnus area has passed through the scope. I use the off method for all the graphs that brings out the details and should give you results. To seperate different objects would be difficult as the resolution of the small scope simply is not good enough and there is a lot of hydrogen up there. Maybe using other frequencies than hydrogen would be useful to do this. I have still to put the total power bit of the scope together to see if it works or not.

Yea PI needs to be shielded or away from the rest of electronics. Not sure if the LNA is water proof so I boxed mine and sealed all the connectors.

Is the PI on?

You want to be doing two things. All of your RF chain should be shielded in metal enclosures. There's not much point in having shielded coax with the line amp open to RFI. So in the RF chain it's to keep RFI out. That would leave RFI only getting in from the antenna and where filters come in. With the PI your trying to keep its RFI in an enclosed area so it's not interfering with anything else. Bit like a microwave oven. So doing both greatly reduces the PI and external sources interfering with the signal your after. However another issue is cabling which can carry RFI so cables ie USB should also have a ferrite core on as well. Computers simply are not screened for RF. Amplifiers are dumb if they see it in their range they will amplify it, hence the use of filters.

A metal box would be ideal. You could line the box in foil and attach the RF ground to it and also foil up the pi seperate, ideally the pi would be best away from the RF amps. Be a matter of testing.

I think you will need to move the PI away from the rest. Not sure what's going on with the line amp and filter perhaps a power issue when they are in the chain. Could it be that the LNA isn't getting power when they are connected? I prefer the satellite inline amps as they and the LNA are just fed off the coax. Keep posting your results.

LNAs always work better cool. It's more RF interference from the PI I was thinking of.

Hi shouldn't make any difference, however not so sure about having a PI so close to the amps but that will just need testing.

No there would be no signal your looking for just random stuff whatever the circuit board metal would pickup, like a bit of tin foil at the end of the RF chain. A volt meter at the LNA will reveal all.

First thing I would check is voltage getting to the LNA and all connections good.

There's your answer it's the wire. The spikes would remain if it was the power supply. Try it with the feed horn. I would stick to what works adding a wire is a random element. If you change something keep the rest the same. It makes life easier.

What sort of supply is it? I would also suspect the simple wire antenna was it grounded? Was the pi on for the first time? Suspect everything that changed since your last successful detection not just the filter. No the FFT won't deal with that. Carl

Hi yes you could do that however the switch and wiring would become part of the RF chain on the filter and be susceptible to interference. Best thing to do is remove it if not required and just power the line amp and LNA with a plus wire. Looking forward to the Pi plan. Carl

Short answer no. That would mean the voltage going both ways and bypassing the biastee circuit and dead SDR! Why bypass the filter it's only a benefit to the system? Carl

Hi, yes + to centre pin. 12 Volts and enough current to supply both and your good.

Sounds good yea the analyser will be well worth it. Lots of concrete and pictures of the dish mounts before dismantling 😉

You could do some serious RA with that!