Search found 41 matches

by Aussie Susan
Thu Feb 27, 2020 2:07 am
Forum: RTL-SDR Discussion
Topic: noaa 19 direct sounder broadcast?
Replies: 4
Views: 2830

Re: noaa 19 direct sounder broadcast?

Where did you get the information from? Looking at http://mdkenny.customer.netspace.net.au/metsat_frequencies.html#noaa, the only mention of BPSK is on the 'Command' section and in the 2GHz range. There is a 137.77MHz mentioned in the TIP section that talks about '8320 BPS bi-phase-level/PM - TIP is...
by Aussie Susan
Wed Feb 26, 2020 2:28 am
Forum: RTL-SDR Discussion
Topic: noaa 19 direct sounder broadcast?
Replies: 4
Views: 2830

Re: noaa 19 direct sounder broadcast?

The NOAA satellites (and others) that work in the 137MHz range use APT (Automatic Picture Transmission). I think you will find that the modulation is a bit more complex the BPSK (binary phase shift keying) but the first step to decoding is to use an FM receiver. That will produce an audible signal (...
by Aussie Susan
Wed Feb 12, 2020 1:28 am
Forum: RTL-SDR Discussion
Topic: usb_claim_interface error -6
Replies: 4
Views: 1415

Re: usb_claim_interface error -6

Glad to hear it. The things that you seemed to be misunderstanding was the word 'driver'. This is a part of the Linux kernel and,unless you blacklist it, it will grab the RTL-SDR interface and expect that all of the user software will use it to talk to the device. This works in exactly the same way ...
by Aussie Susan
Tue Feb 11, 2020 2:33 am
Forum: RTL-SDR Discussion
Topic: usb_claim_interface error -6
Replies: 4
Views: 1415

Re: usb_claim_interface error -6

Did you blacklist the RTL-SDR to stop the default kernel driver from grabbing the interface (the first thing the error message mentioned)?
I also got this message when I accidentally tried to run two of the RTL-SDR apps at the same time.
Susan
by Aussie Susan
Tue Dec 03, 2019 1:46 am
Forum: RTL-SDR Discussion
Topic: I'm losing interest in SDRs... please help
Replies: 3
Views: 726

Re: I'm losing interest in SDRs... please help

It could be that the problem is a little deeper. Take things one step at a time. Give us one example of what you are trying to do and include the type of antenna you are using, the SDR hardware and software and why you need to add filters and LNAs. My suspicion is that this will come down to the ant...
by Aussie Susan
Tue Nov 12, 2019 1:56 am
Forum: RTL-SDR Discussion
Topic: Listening to FM broadcast with HAM IT UP
Replies: 6
Views: 930

Re: Listening to FM broadcast with HAM IT UP

When you mix two signals together, you get the sum and the difference as a result. A Low Pass Filter (LPF) will remove the sum (which will be the higher frequency) and leave the lower one. The two signals that the 'Ham It Up' will be mixing are the 125MHz local oscillator signal and the incoming MF/...
by Aussie Susan
Wed May 01, 2019 2:37 am
Forum: Antennas
Topic: Who has a Discone in the Attic?
Replies: 5
Views: 2745

Re: Who has a Discone in the Attic?

What sort of roofing material do you have?
If it is metallic, then it might cause issues.
I've a discone under a tile roof and it (seems to) work OK.
Susan
by Aussie Susan
Thu Apr 04, 2019 2:57 am
Forum: RTL-SDR Discussion
Topic: Install drivers RTL-SDR on MAC HIg Sierra
Replies: 10
Views: 2962

Re: Install drivers RTL-SDR on MAC HIg Sierra

I'm a bit confused by your question - the RTL devices can be used on a Mac very easily and there are many descriptions on the net as to how to do this. Drivers are generally only needed to provide a way for applications to talk to hardware devices so, given the above, that problem has already been s...
by Aussie Susan
Mon Mar 04, 2019 2:41 am
Forum: RTL-SDR Discussion
Topic: Receiving and decoding asyncronous serial data
Replies: 1
Views: 997

Re: Receiving and decoding asyncronous serial data

You could go that way, or how about something like the Nordic nRF24L01 which directly converts the data provided by SPI interface into a 2.4GHz signal and back again. No need for separate Tx/Rx but you do need a little programming experience if you want to 'roll your own'. I had one connected to a P...
by Aussie Susan
Wed Feb 20, 2019 1:40 am
Forum: User Projects
Topic: How exactly are the IQ channels supposed to be calculated/processed?
Replies: 2
Views: 7326

Re: How exactly are the IQ channels supposed to be calculated/processed?

Just a point of clarification between the two posts (so far). The first post uses 'I' to refer to the 'in phase' component of the original signal. However the 2nd post uses 'i' as the imaginary number (sqrt(-1)). On a screen and reading quickly it is easy to confuse 'I' and 'i' so be careful when re...