Satdump software & wxsat reception

[Satspot]

One other thing to note is that some of the passes have both the NOAA satellites and the Meteor satellites in the same orbital time frame, the NOAA birds have a much stronger signal then the meteor's and will wipe them out, also when the NOAA bird are in close orbit to each other you will get zip as far as a usable signal on one or the other.

This photo shows that NOAA-18 is going to wipe out the signals from Meteor M2-3 on the next scheduled pass of both as it is only 12.5 KHz away in frequency.

View attachment 156354

Thanks for that. Much appreciated.

It was mind blowing looking at the different antenna options available both off shelf (some of them damn expensive) and the DIY alternative too.

Reminds me of the analog to digital switchover when they were selling digital aerials. As it transpired in my case a good old fashioned metal coat hanger did the trick

 

[Satspot]

A very easy solution is the Turnstile antenna.
I built the one described in THIS POST and i got good result. Since some comment on the picture are in italian, please feel free to ask if you need any information.

Thanks for that. I’ll have a read through it this evening. I’m getting the general idea of what I need to do the job.

 

[Terryl]

Back again. How about some recording tips? My gut feeling tells me that I need to record RF using 120 kHz bandwidth.
I've been recording so far with maybe 3.8 MHz and squeezing the IF bandwidth down to 120 kHz in HDSDR.
It has been awhile but using the last SDR# that works with my radio with the Metoer demod plugins. And all of the steps needed to get a final image. I was able to.
And as far as RF gain. I am able to get a "screaming" signal using my proper QFH antenna and the radio preamp on.
NOAA APT sats. are never an issue even approaching the horizon fringes. Overhead and close to passes using wxtoimg always come out sweet.

It's getting the RF levels correct that seem to be an issue in getting a good OQSPK constellation. So far I get just blobs of green scatter in the window.
Is there any leeway or AGC built into sat-take-a-dump that handles not so perfect recorded input files?
Tips? Anyone?

I've had to sit and play with the gain, decimation and sample rates to get a good pass on both the Meteor's and NOAA birds, it was time consuming but I'm retired and have nothing else to do.

On satdump there is a setting in the configuration for the Meteor's that will try and fill in the missing data, it seems to work OK on some passes.

 

[Terryl]

Finally got delivery of the Nooelec v5 USB dongle and installed it in Windows 10. Drivers installed and Satdump. The Nooelec terminates in an SMA female so I got an SMA male to BNC male adapter just to use an old whip antenna I had lying about. All seems to be in working order and Satdump is clearly receiving signal.

My question is, what would be a suitable antenna to use for receiving the 137x MHz band. I’ve seen some off the shelf very simple and inexpensive solutions and some very convoluted and expensive solutions so not really sure what route to take from here. I can cut and solder on the DIY side so that could well be an option. All suggestions welcomed.

Nooelec makes some very nice LNA amplifiers for the USB dongles, they even have one with a 137 MHz bandpass filter to knock down the FM radio broadcast signals, some of you may have problems with the local FM radio broadcast stations, the signals from these stations can cause problems as they are quite strong if you are close by to one.

I use the Nooelec SAWbird+NOAA filter (137 MHz bandpass) it works quite well in my case, I use it because as I was listening in on the decoded audio on one pass I heard music in the background, come to find out it was a station about 35 miles from me, so I got the filter, no more problems with FM radio.

 

[Satspot]

I've had to sit and play with the gain, decimation and sample rates to get a good pass on both the Meteor's and NOAA birds, it was time consuming but I'm retired and have nothing else to do.

On satdump there is a setting in the configuration for the Meteor's that will try and fill in the missing data, it seems to work OK on some passes.
View attachment 156355

Yes I’ll have to have a proper read of the Satdump docs to find out exactly how the different settings are applied.

In the meantime I was rummaging through some old boxes in the attic and came across this. From my hand scanner days. 1988 vintage. Discussing the use of the good old BBC Micro connected to the scanner via serial port. I think I still have the old BBC Basic programs on disk somewhere. Even discusses the building of an antenna.

 

[pontiend]

Another nice Meteor 2-4 pass this afternoon.14.12 UTC EL88.25 .

 

[pontiend]

This is different. I usually get a good scan from the M2-4 afternoon pass.
14.27 UTC EL71.02

 

[Terryl]

It could have been interference from something it the 137mhz band, or a harmonic or mix with another signal.

 

[Terryl]

This is what I got on the last M2-3 pass, but nothing on the M2-4's last pass.

 

[Terryl]

And here is the same pass but the RGB composite version, with all the other junk cropped out, you can almost see my house.

 

[Terryl]

I have a pass on M2-4 in about 56 min, will report back then.

And no other birds in the area on this pass, it's by it's self.

 

[Terryl]

OK, it looks like something is going on with M2-4, as I got the same type of download as Pontiend did on his last pass.

 

[pontiend]

A good M 2-4 pass at 1405 UTC this afternoon EL 82.43. Almost over the top.Hopefully a good one.

 

[pontiend]

A very good one today. 14.05 UTC EL 82.43.

 

[Terryl]

Good one, I got zip on the last pass of M2-4.

 

[pontiend]

At is a bit weird Yesterdays scan was rubbish todays very good..

 

[Terryl]

There are a lot of other satellites up there that we are not tracking, so it could very well be interference from another bird (or more) on the same path and orbital timing.

 

[Terryl]

And I had a good pass on M2-4 this afternoon, I still can't figure out what is causing the dead bands, (at the top) I have scanned everything from 30 MHz to 1 GHz and didn't find anything that would be even strong enough to cause a drop out that could cause those dead bands.

 

[pontiend]

I do not know what is causing the dead bands.The M2-4 13.44 UTC pass this afternoon has one.The satellite was well East and low down.
EL58.78 probably some thing getting in the way of the signal
I do not get that problem when the satellite is high and over the top.
Edit I forgot about the scan at #427 that was in a different league though.

 

[Terryl]

I'm thinking that it may be caused when the satellite is low in the horizon, thus the signal is edge on to the antenna and that causes a drop out.

I might mess with building a helical antenna, that would take care of any edge on problems, but I don't have time to do that as I'm now neck deep on a 1939 Chevy refurbishment.



I don't want to hijack the thread on this, so I would start a new one on it somewhere else.