SDR reciver issue

Hi all,
Im new to this,
Im facing a problem with SDR reciver with SNR max at 1.5db only with Alphasat satellite.

My SDR model is NooElec NESDR Mini USB RTL-SDR

also with NooElec Amplifier

this is the stats

What are you using for an antenna?

L band antenna

This is my setup

There have been many reports of a signal problem with alphasat, however I don’t think they were that low. Some things you can try:
Check all connections (unlikely since you are getting some signal)
Make sure you have as clear line of sight as you can get
Use ferrite beads on your coax and usb cable (extension between your rtl-sdr and pi if you can)
Separate your pi/rtl-sdr and LNA/antenna
Check for local interference with an sdr software like SDR#

please note that I couldnt find extention from amplifier to SDR so I mount it on the board as shown in the image
plus the weather is cloudy could it be this is casuing the problem.

The exposed center conductor could be allowing noise in I guess. Cloudy weather will reduce your snr, I see a 2.5-3 SNR drop on cloudy days. I would try adding a shield to that connection. Just use foil, being careful not to short anything, and ground the foil on an sma connector, or the shielding on the front of the pcb.

EDIT: I forgot about the sma connection its self. The center conductor is still exposed. Just cover that whole end (or the whole thing) of the LNA with foil.


I have noticed even if I removed the antenna, the SNR value dose not affect that much.

Then you definitely have a connection problem. If you have a multimeter check continuity between the center pin of the sma pigtail and the brass element of your antenna. I have seen a few people say there was a break there.

Do i have to install any drivefs to the sdr usb stick
As i recived an email says its guided me to this website

If you are going to use an sdr software then you will need to install a driver, however you don’t need a driver for outernet. Here is a guide to setup an rtl-sdr in sdr# and a couple others. This is a great way to check for noise that may be interfering with your signal but I think you have other issues.

Do you have power supply on your preamp?

Necesitas alimentar el LNA, ese SDR no tiene salida de alimentación, creo yo.


You need to feed the LNA, that SDR has no outlet, I think.

Power is from power bank to usb stick sdr and i believe its feeding the amplifier.

Wow, I must be really tired if I missed that! @kalattar There should be a light on the LNA if it is powered.

Tu SDR tiene “bias tee”?


Does your SDR have “bias tee”?

I couldn’t find any documentation about the NooElec NESDR Mini having bias tee. In fact the only other sdr I could find with bias t is the elonics E4000.

Pues ese sera el problema.

Well that will be the problem.

I don’t think it is doing that. You used a cheap SDR not the official one that is feeding the amplifier.
You will need to feed it somehow.

sorry to say but you will have really hard time receiving Outernet signal with this, the specification says it doesn’t have TCXO reference clock inside, which means you have about 20ppm precision instead of 2ppm, impossibly to set up the receiver without calibration (which works only in short term due to environmental heat variations and you need expertise / or-and instruments)

the other problem as other noted the lack of bias tee power, so your LNA is off.

will this SDR work ?