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KerberosSDR • Re: Bias-T on KerberosSDR?

OK, so are the antenna inputs decoupled or do I need to protect them from DC on the coax?

Just asking, I guess I'll go for an LNA (or rather four of them) that has an external bias input and feed the power to the LNA via a separate line.

Statistics: Posted by Stromeko — Wed Jun 19, 2019 8:09 pm

KerberosSDR • Single radio failure on my KSDR?

Hello, this is my first post on the forums!

I received my KerberosSDR about a month ago and I have been having a great time learning about RDF and SDR.

However, it looks like the first radio has developed a fault.

I can see the blue light for radio 1 come on when I set the DIP switch, but it no longer appears as a USB device (using lsusb).

There is no problem with the other three radios.

I have tried it on my Ubuntu PC and my laptop but radio 1 doesn't come up on either device.

I have visually inspected the PCB but I can't see any obvious faults with components.

Has anyone had a similar issue, or can anyone suggest fault-finding or repair steps? I would be very grateful for any assistance!

Statistics: Posted by lukestuts — Wed Jun 19, 2019 4:36 pm

RTL-SDR Discussion • Re: Advice Please. GNRadio, Osmocom Libraries, Straight Python?

Have you tried decode345 on GitHub? It seems to do most of what you ask. It is designed for Honeywell sensors, but would probably be adaptable to your needs.

Statistics: Posted by crrkrieger — Wed Jun 19, 2019 11:43 am

KerberosSDR • Re: Update rate not showing

So I always have the kerberos connected to my pi before boot up but if I have all 4 switches on before boot up the whole pi freezes. If I leave them off(while connected), wait for the pi to boot, then turn all of them on everything is fine in terms of system freezes - however, even in this procedure I don't get any results. I know all 4 SDRs are connected to the pi by simply doing an lsusb. :(

Statistics: Posted by stasia327 — Tue Jun 18, 2019 2:22 pm

Antennas • Re: Strangest thing with my antenna!

Yep - I'm planning on experimenting with building my own. If the experiments don't go well, I'll buy one.

BTW, the antenna amp is powered from a power supply.

Yeah - I know it's not the best scenario, but it won't be long until I've built/bought another antenna ;-)

Statistics: Posted by Donniesito — Tue Jun 18, 2019 2:20 pm

KerberosSDR • Re: Clock oscillator on KerberosSDR?

Would the creators of this unit be interested in adding a 10MHz ref in? I Ordered one and would love to connect it to fury gpsdo for increased precision.


Statistics: Posted by Docdailey — Tue Jun 18, 2019 10:48 am

Antennas • Re: Another Double Cross Antenna build (went wrong)

Hey guy's, sorry that it took me that long to answer, i was busy doing other stuff!

So, i did try to extend the antenna away from the satellite dish, sadly that didn't help either. No, it made it even worse! The reception got so bad, that i decided to remove the antenna from the roof. The satellite dish wasn't the problem, more likely the geometry of our roof.

I placed the antenna in our backyard now. Even though decoding is now only possible at a min. elevation of around 12 degrees, all the null's disappeared completely. The signal stays stable over the whole pass, which is all i was ever looking for.

So, thanks again to all of you who helped me out!

Statistics: Posted by swarl3s — Tue Jun 18, 2019 10:04 am

Antennas • Re: Strangest thing with my antenna!

That sounds like the most likely scenario.

As admin says, the yagi is unidirectional, but it is also tuned to the TV frequencies and may not perform well outside this band.

Additionally the amplifier may also contain a filter to reject out of band signals.

Some amplifiers have a second input for an FM antenna(80 to 110MHz). This is normally used to connect hi-fi radio receivers. But again, this may be filtered to block out other signals.

Statistics: Posted by HighSNR — Tue Jun 18, 2019 2:40 am

Antennas • Re: Strangest thing with my antenna!

Yes that could be happening. The inner conductor should actually be shielded, so if you can somehow connect the outer shield of the coax cable to your SDR if might work even better as that is more exposed to the RF. Really you want a proper antenna like a Discone or dipole up in your attic though.

The TV antenna itself might not be so great. First there is an amplifier in line, and I assume that takes bias tee power from a unit plugged into the TV. Without that unit the amplifier would be unpowered. Secondary, TV antennas are usually Yagi's, which are directional antennas. So it will only receive well in the direction that it's pointing.

Statistics: Posted by rtlsdrblog — Tue Jun 18, 2019 1:10 am

KerberosSDR • Re: Update rate not showing

stasia327 wrote:
Mon Jun 17, 2019 8:42 pm
Well I'm positive I'm getting enough power. Here's another thing. It's recommended to connect the kerberos with the pi before booting up the pi but if I do so, I cannot turn all 4 antennas on because the CPU usage jumps up to 80%+ and the whole system freezes
Ah well if you're not connecting the KerberosSDR to the Pi3 before booting then that is definitely the problem. On the images the software loads on boot and connects to the RTL-SDRs. If it's not connected it will not be able to connect, and there is no way for it to connect after the software loads.

You can try closing the software, then plugging the unit in, then restarting it manually.

But the real question is why is your Pi3 freezing on boot when it's plugged in. That is not normal. Are you sure that your Pi3 is getting enough power with a high quality 3A supply? The KerberosSDR might be fully powered, but the Pi3 has problems if it itself cannot get enough power, since then the CPU will throttle down.

Statistics: Posted by rtlsdrblog — Tue Jun 18, 2019 12:34 am

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