Unable to get a signal!

Problem is that my user is root, and remote root login is blocked. Oops.

Nor am I able to see a real signal using Gqrx in a Linux VM using the receiver. I can hear local FM stations, but when I go to 1539.875 I see a waterfall pattern that does not change regardless of frequency change nor moving the patch antenna. Same with or without the 1.542ghz Amp.

Is there some tests I can perform to validate the E4000’s health?

On the amp, is the green light on?

Yes, amp is on. I just restarted Gqrx and did notice some variations in the waterfall when i changed frequency by 1mhz intervals, as well as aiming the patch antenna different ways. So there is certainly something working on occasion.

Put the CHIP back into FEL and downloaded latest zip file of the 2.0a2 from the last couple of days. Flashed new image, and ran through wizard with a regular username (not root – might want to prevent users from using root as username, or at least warn on that wizard pane).

Still unable to acquire signal.

Sshed in, and stopped serving service (sudo su - and then /etc/init.d/S90sdr stop). Ran the command line demodulator (demod).

Here’s what I am seeing:

Most batches are failing to see a signal and State stays as SEARCH. But early on In some batches I get a SigDet and State goes to SIGDET. SNR hits over 1dB. So unless those are false detections it seems like it is finding something, however very weak.

What can I do?

Here are some examples of the SigDet of 1. Appears with similar offsets, etc.

Your signal is definitely too low, and sig det only means something that looks like a PSK signal was detected.

Also - there is no need to stop the sdr service, etc. If you ssh in, and want to look at the demod console, just do “sdr” and when it asks, enter your superuser password. To exit, press ‘ctrl +a, d’.

Yeah, I eventually realized that the init script runs the decoder in a detached screen session, so I’ve been just reattaching to it.

So what to do about this missing signal? :frowning:

At that signal, first step would be to experiment with changing locations, playing around with the antenna direction. Until the signal strength is atleast ~2dB stable, the software isn’t going to be able to lock on.

I spent 7-8 hours on this yesterday, well into the early hours in the morning. Was unable to see any meaningful signals in the 1.5ghz spectrum using the patch and the Outernet LNA/filter. I tried multiple locations inside (by windows), outside, etc. I have not tried it in a completely differently city though.

Kevin,

just a wide open lawn or something would be the best place to try. The signal is really low and shouldn’t be.

Try without the metal box too - it could be causing reflections that interfere with the signal.

Sorry, no specific suggestion comes to mind: its possible there is too much RF interference in your area.

It’s very possible that there is a radio problem. We’ll find out next week.

Hi cbander

Were you able to config the SDR-Play into the Outernet setup, or just using it to check signal strength?

Like yourself, I’m an experimenter and fellow ham, W9MAS - and gotten my feet pretty wet in the world of SDR . . .

I’ll probably start a new thread/post . . . . I’m using Ubuntu X64 on the Oracle Virtual Box, with the RTL-Blog Version 2 dongle (in the silver aluminum case) along with the Outernet “brand” patch antenna and LNA . . . no luck yet!

Mike

Hi i_robot,

No, I just used it the monitor the signal strength. I would like it if it worked with my SDRPlay on Windows, but I am under the impression that the Outernet decoder software is only for the RTL-SDR or E4000 device that they sell (to help fund the project).

… My next project is a portable L-Band antenna which performs better on L-band than the existing patch. I have a 14 inch parabolic dish that I plan to adapt for L-Band soon.

As for Ubuntu / Linux – I do my best to avoid it because I usually end up frustrated after a few days!

Brett (N6BY)

Been trying to get a decent SNR in San Diego for the last day and half. Had issues where the SNR would jump from 2.5 or 3dB to zero often and nothing being decoded. I moved the antenna to the center of my back yard, propped up above the ground on a plastic trash can. That helped get higher SNR (2.5 to 3.5 dB) but still had an issue where it would drop out to 0. Added an FM bcast trap filter and now I don’t have the SNR drop outs, it’s steady between 2.5 and 3.5 dB now.

I see packets being received with a symbol error rate of 0.05 but never have received any files yet.

Russ.

Nevermind, I did start to receive a file.

Next issue, the sun came up and the outside temp has gone up 20 degrees and the PI, SDR, and LNA are all in the sun. This seems to have dropped my SNR down to 1dB, resulting in just errored packets.

@Russ Are you using the E4000 radio? Or the one from RTL-SDR.com? The latter has been vigorously heat-tested to 85C (for over one week).

I’m using the E4000 radio. Something in the setup doesn’t like the sun / heat, the sun has gone down and now I’m getting close to 4 dB SNR vs. during the day of 1 dB and many packet errors.