Архив за 28.06.2019

Comment on Raspberry Pi 4 Released: Improvements to CPU, Networking, USB, RAM and more by Mark Tomlin

Seems there is a software issue, that is going to need to be fixed.

https://www.raspberrypi.org/forums/viewtopic.php?&t=243982

KerberosSDR • Re: Update rate not showing

I have all 4 tuner tests working on my ubuntu VM. And I've found that the program hangs on this line:

CODE:

byte_array_read = sys.stdin.buffer.read(read_size)
inside of hydra_receiver.py

Statistics: Posted by stasia327 — Fri Jun 28, 2019 10:24 pm


SDR that can transmit in 100kHz range?

I have a project in mind for sending light signals using a signal generated by an SDR as the base for turning an LED on/off but want to transmit the light signals at a carrier of 100kHz.

The HackRF One says its lowest frequency is 1MHz, the LimeSDR says it goes down to 10kHz but i'm not sure if thats reliable info or not.

Does anyone have any experience generating signals in this frequency range with SDR?

submitted by /u/Byte_Farmer
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Comment on Raspberry Pi 4 Released: Improvements to CPU, Networking, USB, RAM and more by Mark Tomlin

As a follow up to my previous post, the error that I’m getting is -7, according to it’s value within libusb_error enum, -7 is LIBUSB_ERROR_TIMEOUT. I’ve been told that -6 (LIBUSB_ERROR_BUSY) is due to a lack of power on the USB Bus, perhaps that’s the same problem here? But that seems very unlikely given that this Pi is meant to have a lot more power delivery capability towards the USB ports. I’ve had it plugged into the USB 3.0 ports and the USB 2.0 ports both resulting in the same error. I’m also using the official Raspberry Pi 4 USB-C power adaptor, so it should be able to fully power the unit, regardless of load CPU load state of USB peripheral count. But to be sure, I removed everything but the RTL and then SSH’d into the Pi4B. Still no luck.

As a sanity check, I plugged the dongles that didn’t work on the rPi4B into a rPi3B+, both are running up to date versions of Raspbian Buster as of about 30 minutes prior to this post. I went though the install test from Raspberry Pi Stretch Install process that I wrote for the trunk_recorder wiki. Installed all dependencies and compiled all of the software from the last master versions on their official public git repositories. And … It works completely fine on the rPi3B+. I’m at a loss as to what to do next? A powered USB Hub, I guess. At least I can rule that out …

Saw-Filter + LNA Combo for 137 Mhz supporting Bias-Tee

Hello all,

is there a combo as explained in the title? If not I would like to make my own PCBs. But I am not familiar with layouts for HF applications. Is there any advice? Or would it even be enough to make a sheet of aluminium for protecting the electronics from interference?

Would be nice if anyone else is interested in doing something like this :)

submitted by /u/salmonelle12
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Comment on Meteor M2 is Currently Experiencing Orientation Issues by Happysat

The old Meteor M-N1 orientation show 🙂 https://yadi.sk/i/8_MzJgRdeJaas

Comment on Meteor M2 is Currently Experiencing Orientation Issues by Happysat

Meteor M-N2 is stable and back on normal operations http://happysat.nl/home/Treated-UTM-2019-6-28-11-18-44-925_123.jpg
Last year something similair did happen to M-N2, no need to panic 🙂

The resurrection of M-N1 was a temp fix in the control systems, speculation about the batteries was not true M-N1 has no power problems, only orientation.
Last year it was still sending a unmodulated carrier on S-band..

KerberosSDR • Re: Update rate not showing

I have about the same supply going to the additional power port of the kerberos.
I believe I have a short, high quality cable.

What is a "short high quality cable" in your terms?

Statistics: Posted by stasia327 — Fri Jun 28, 2019 2:44 pm


Comment on RTL-SDR Tutorial: Listening to TETRA Radio Channels by Bill

Hello Estdomii,

I’m not 100% sure but if Air_interface_encryption=1 then it is encrypted and you wont be able to decrypt as far as i Know.
I can only relate to the Swedish TEA2 encryption “RAKEL”, which is impossible to decrypt as it is sort of a two-way encryption.

Unfortunatly I think you’re out of luck on this one.

Comment on RTL-SDR Tutorial: Listening to TETRA Radio Channels by Estdomii

Since i’m from northeastern Europe…
Then i’ve seen something like this on every tetra cahnnel over here… both fields are equal to 1
Registration_required=1
De_registration_required=1
I know that 0 is false and 1 is true
Also Air_interface_encryption=1
TTT with with single and dual mode made no difference…
No group calls no nothing only encrypted voice…
Since they use TETRA in here as a 4th mobile network called “ESTER”
Should i try this method as this post?

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