Advice Needed SDR USB receivers with KU/C Band and DVB-T ?

[zorrin]

Hi everyone,
I noticed that USB SDR receivers like the RSP1A from SDRPlay could go up to frequencies over 2000mhz.
Have any of you tried plugging one at the back of an LNB or your terrestrial antenna ?
If yes, what is your results , what model and what software did you use?

 

[ozumo]

It is possible, but software demodulation is very processor intensive, some people have used it for reception of QO100 amateur transmissions:

Software DVB-S demodulator - AMSAT-DL Forum

Hi, around last Year i've developed a DVB-S Receiver in Software to learn more about Signal Processing and Multithreading/SIMD Optimization. This software is supposed to be the starting point for experimenting and implementing my own DVB-S receiver on a…

forum.amsat-dl.org

 

[s-band]

It is possible, but software demodulation is very processor intensive, some people have used it for reception of QO100 amateur transmissions:

I tried it a while ago using an AD Pluto SDR. Software DVB-S demodulator (Amsat-DL)
It worked reasonably well but it is limited by the sample rate of cheap SDRs and PC processing power. It's good for low symbol rate (<500s/s) radio etc. There's a new version now which I haven't tried.

SDRs are ideal for looking in narrow band to tweak things on beacons. I don't know of any software that is as good as Crazyscan, EBSPro and the other stuff for normal DVB using PC cards.

If you want high sample rates, you'd need to go to something like GNU radio and an Ettus/National Instruments, if you have money, or even a Lime SDR if you are into self inflicted pain.

@zorrin You need to power the LNB separately and DC isolate the SDR. I've seen some software for demodulating DVB-T but I have no experience of it.

 

[zorrin]

It is possible, but software demodulation is very processor intensive, some people have used it for reception of QO100 amateur transmissions:

Software DVB-S demodulator - AMSAT-DL Forum

Hi, around last Year i've developed a DVB-S Receiver in Software to learn more about Signal Processing and Multithreading/SIMD Optimization. This software is supposed to be the starting point for experimenting and implementing my own DVB-S receiver on a…

forum.amsat-dl.org

Hi @ozumo
I don't want to demodulate,
I just want to see the spectrum and maybe use it as a sat meter.
Thank you for your return

 

[zorrin]

I tried it a while ago using an AD Pluto SDR. Software DVB-S demodulator (Amsat-DL)
It worked reasonably well but it is limited by the sample rate of cheap SDRs and PC processing power. It's good for low symbol rate (<500s/s) radio etc. There's a new version now which I haven't tried.

SDRs are ideal for looking in narrow band to tweak things on beacons. I don't know of any software that is as good as Crazyscan, EBSPro and the other stuff for normal DVB using PC cards.

If you want high sample rates, you'd need to go to something like GNU radio and an Ettus/National Instruments, if you have money, or even a Lime SDR if you are into self inflicted pain.

@zorrin You need to power the LNB separately and DC isolate the SDR. I've seen some software for demodulating DVB-T but I have no experience of it.

Thanks for your experience @s-band
I will try to do some test both on DVB-T and satellite.
Maybe, just for the spectrum a normal pc will be enough, anyway i have a very big server full of xeon and memory if it needed

 

[ozumo]

Hi @ozumo
I don't want to demodulate,
I just want to see the spectrum and maybe use it as a sat meter.
Thank you for your return

In that case you can use the same software as you would with other aerials. There is also spectrum analyser software specifically for SDRplay SDRs which may be what you are looking for:

Spectrum Analyser - SDRplay

Steve Andrew developed this Spectrum Analyser software specifically for the RSP line of products. It is no longer supported.The Spectrum Analyser was developed to work with :RSP1RSP2/RSP2proRSP1ARSPdxRSPduo (single tuner mode)It has not been tested with the RSP1BDocumentation can be found in the...

www.sdrplay.com

 

[zorrin]

In that case you can use the same software as you would with other aerials. There is also spectrum analyser software specifically for SDRplay SDRs which may be what you are looking for:

Spectrum Analyser - SDRplay

Steve Andrew developed this Spectrum Analyser software specifically for the RSP line of products. It is no longer supported.The Spectrum Analyser was developed to work with :RSP1RSP2/RSP2proRSP1ARSPdxRSPduo (single tuner mode)It has not been tested with the RSP1BDocumentation can be found in the...

www.sdrplay.com

Yes this is what i seen.
I will test all possible one for windows.
look at the SRD out of the corner of my eye from a long time but now it's time to try this

 

[zorrin]

@zorrin You need to power the LNB separately and DC isolate the SDR.

I think a splitter like this one will do the job.
One side "out" to a demodulator and the other one to the SDR.

 

[s-band]

I think a splitter like this one will do the job.
One side "out" to a demodulator and the other one to the SDR.

You need one with DC pass on one port only otherwise you risk the SDR
They are available much cheaper but here is an example:

Steren 201-232 2-Way 2 GHz Satellite Splitter One Port DC Power Passing | eBay

2-way splitter, block 1 port, DC passive. These printed circuit board splitters are state of the art and of the highest quality. Tin plated zinc housing and 100% soldered back provides the most effective RF shielding at 90 dB!

www.ebay.co.uk

Also, have a look at this: VMA's Satellite Blog

 

[zorrin]

You need one with DC pass on one port only otherwise you risk the SDR
They are available much cheaper but here is an example:

Steren 201-232 2-Way 2 GHz Satellite Splitter One Port DC Power Passing | eBay

2-way splitter, block 1 port, DC passive. These printed circuit board splitters are state of the art and of the highest quality. Tin plated zinc housing and 100% soldered back provides the most effective RF shielding at 90 dB!

www.ebay.co.uk

Also, have a look at this: VMA's Satellite Blog

I ordered the last one on Amazon USA

 

[zorrin]

I ordered to start my tests this :



and this :


and maybe this in the futur :

 

[Terryl]

Using a splitter will drop your signals from the LNB to the SDR radio by one half, also the impedance miss match on the connector to coax will drop even more. (LNB and it's down lead coax are 75 ohms, coax adapters and SDR stuff are 50 ohms)

You will need one of these

https://www.jfwindustries.com/product-category/test-accessories/impedance-matching-transformers/

inline before you connect any of the SDR/amplifier stuff.

I had signal problems until I re-did all my SDR receiver equipment to all 50 ohm, this was by using RG-214 coax, a true 50 ohm discone wide band antenna and as few connections as possible, the more adapters you use, the less signal you have.

One other bit of info, the SDR Nooelec radios get quite hot, I mounted all of mine on an aluminum heat sink, and also shielded it.

 

[zorrin]

Using a splitter will drop your signals from the LNB to the SDR radio by one half, also the impedance miss match on the connector to coax will drop even more. (LNB and it's down lead coax are 75 ohms, coax adapters and SDR stuff are 50 ohms)

You will need one of these

https://www.jfwindustries.com/product-category/test-accessories/impedance-matching-transformers/

inline before you connect any of the SDR/amplifier stuff.

I had signal problems until I re-did all my SDR receiver equipment to all 50 ohm, this was by using RG-214 coax, a true 50 ohm discone wide band antenna and as few connections as possible, the more adapters you use, the less signal you have.

One other bit of info, the SDR Nooelec radios get quite hot, I mounted all of mine on an aluminum heat sink, and also shielded it.

Ok @Terryl,

First I think you'll be my best friend on this project

Second, I think you've already done everything I'm going to do with this stuff, I'm sure you can help me choose the right software to play smarter.

The splitter is my solution to keep using the demodulator to manage the LNB, I know it won't be the best way to do it, but it's just for the start.
Then I'll use an injector.
For the inpedance, I thought about it from the start. But I don't know if it's usually for the antenna, for the tuner, or for something I don't know.

For the heat, yes I will work on it.

Thanks you so much for your help.

 

[Terryl]

I dont use my SDR stuff on satellite signals, so what I think can be done is to use a dual output LNB, output #1 would go to any reciver/demodulator/PC card, the other LNB output may be able to directly connect to the the SDR radio stuff, (with an impedance matcher) this setup would power the LNB off the main output and you may get the down converted signals on the second output. Just me thinking about this.

Here is my setup with the heat-sink and shield, you ground the heat-sink and shield, the reason I shielded my setup was because it picked up the switching power supply's on the PC's, they added too much noise.


The USB connection is a extender, it has a ferrite core to cut down on all the hash on the data from/to the PC.

 

[zorrin]

Today I received the 50 ohm SMA to SMA cable.



Here is the assembly to see the spectrum of my satellite antenna while remaining powered by my demodulator.




I am considering replacing the demodulator with a bias-T if I have interesting results as advised here.
But the demodulator provides management of current, V / H and frequency band change.
It is very practical.


Test this weekend

 

[zorrin]

One morone more thing...
I started to do tests on the FM since the arrival of the SDR.
I am using CubicSDR at the moment.
but i have no idea how to setup my tests on satellite.
For those who already play with their SDR plugged into their satellite dish.
Can you give me any recomendations and help to start ?

 

[Terryl]

I hope that splitter does not have a reverse DC blocking diode, or it may not work using the input side of it out to the LNB.

 

[s-band]

@zorrin That splitter should be fine and, as you say, it makes setting the LNB band and polarisation easy. Most systems will have plenty of gain without using the extra amplifiers that you showed.

I use SDR# and HDSDR but the basic operation is similar on most software. Attached is a screenshot showing the settings I used for Eshail 2 beacon.

You should be able to see a significant increase in the noise floor when you turn the LNB on. For satellite use there's not much need for wide dynamic range so the RTL-SDR is OK. If you are looking at narrow band signals (<few MHz), which is all you can see with the RTL-SDR type, you really need a PLL LNB or you'll have trouble with the drift of a DRO.

Have a look at his site for lots of beacon plots: Frequency Plan Satellites

 

[zorrin]

@zorrin That splitter should be fine and, as you say, it makes setting the LNB band and polarisation easy. Most systems will have plenty of gain without using the extra amplifiers that you showed.

I use SDR# and HDSDR but the basic operation is similar on most software. Attached is a screenshot showing the settings I used for Eshail 2 beacon.

You should be able to see a significant increase in the noise floor when you turn the LNB on. For satellite use there's not much need for wide dynamic range so the RTL-SDR is OK. If you are looking at narrow band signals (<few MHz), which is all you can see with the RTL-SDR type, you really need a PLL LNB or you'll have trouble with the drift of a DRO.

Have a look at his site for lots of beacon plots: Frequency Plan Satellites

thank you very much for your reply. I should have time to do some tests tomorrow afternoon.
I have a good reception from Eshail 2.
You must talk about the Bullseye LNB ?

I will check with my LNBs to start and move forward later.

I will come back to show my rersult and for more advice.

 

[zorrin]

Hi everyone.
A little update on my project.
I started to prepare a box for the tuner and the possible amps and Bias-Tee. thanks
But first I decided to make the tuner more dissipative ... @Terryl









With the 2-Way splitter to power the LNB Thanks @s-band