Search found 36 matches

by Airwind
Fri Mar 22, 2019 11:10 am
Forum: RTL-SDR Discussion
Topic: Yard Stick One - RF Transmitter Raspberry PI
Replies: 2
Views: 616

Re: Yard Stick One - RF Transmitter Raspberry PI

You can probably buy some cheap transmitter module of a given frequency on ebay and drive them with a RPi/Arduino GPIO pin. You will however need to write or get some software or script that will handle the pin output to generate the required signal. For 433,92 MHz there are plenty of cheap modules ...
by Airwind
Wed Feb 27, 2019 6:55 am
Forum: Other SDR Devices
Topic: Hackrf one - increase RX-TX
Replies: 7
Views: 15785

Re: Hackrf one - increase RX-TX

Can you show an RF amplifier [complete module with in and out connectors] that would work for either RX or TX without modification? Not for both ways (who uses that anyway?) or without modification, but scroll down to the HackRF TX mod here: http://lna4all.blogspot.com/ That's a LNA mod for TX only...
by Airwind
Tue Feb 19, 2019 1:40 pm
Forum: Other SDR Devices
Topic: Hackrf one - increase RX-TX
Replies: 7
Views: 15785

Re: Hackrf one - increase RX-TX

Note well, the LNA is for receive (RX) only!! Oh? Citations? I believe a LNA can also be used for TX (provided that you will only transmit through this channel) by swapping the input/output ports so that the output now faces the antenna and the input is oriented towards the SDR TX port. Be careful ...
by Airwind
Thu Feb 07, 2019 6:18 am
Forum: Other SDR Devices
Topic: Hackrf one - increase RX-TX
Replies: 7
Views: 15785

Re: Hackrf one - increase RX-TX

You need a specific band-pass filter for every frequency range you're interested in. For 433MHz you need a 433 MHz band-pass filter. This will filter out strong signals that may even be outside your receiving range, but can still damage your RF hardware. And when receiving be sure to wire the filter...
by Airwind
Mon Jan 28, 2019 5:33 am
Forum: RTL-SDR Discussion
Topic: Long USB-cable vs long antenna-cable?
Replies: 18
Views: 32728

Re: Long USB-cable vs long antenna-cable?

I once asked this exact question for a WiFi card and I was told a longer USB cable is preferred.
But in your case I suppose you could also get away by using a longer coax with an LNA instead.
by Airwind
Mon Dec 17, 2018 8:20 am
Forum: Off-Topic
Topic: More fake units sold on Ebay
Replies: 19
Views: 32172

Re: More fake units sold on Ebay

We've tried issuing takedowns on from Aliexpress and eBay, but as soon as you take one down, three more listings pop up in it's place. Are there not any automated options available that scan for similar products and issue automatic takedown notices? I hear the anti-piracy orgs use a lot of them for...
by Airwind
Mon Dec 10, 2018 1:39 pm
Forum: Signal Identification Help
Topic: Signal Identification Help
Replies: 8
Views: 18769

Re: Signal Identification Help

What exactly is the transmitter for the given signal? The central station or the vehicle itself?
Because if the vehicle is the transmitter then naturally one would expect the signal strength to change as the vehicle travels around.
by Airwind
Mon Nov 05, 2018 8:24 am
Forum: User Projects
Topic: Trying to open my weird Garage with radio at 434Mhz
Replies: 3
Views: 15227

Re: Trying to open my weird Garage with radio at 434Mhz

I haven't experimented with garage doors yet, but does your system happen to use a rolling code (does the transmitted signal change each time you hit the button on the remote)? If not, try adjusting the timings a bit. I have done some tests with a doorbell and certain remote power switches - some of...
by Airwind
Thu Oct 11, 2018 8:51 pm
Forum: Signal Identification Help
Topic: Unknow signal
Replies: 9
Views: 22597

Re: Unknow signal

Wait, what signal are we talking about here?
I assumed it was the strong curvy white one on the waterfall.
Because the waterfall Remon posted seems different although they do seem to sound similar.
by Airwind
Wed Oct 10, 2018 10:39 am
Forum: Signal Identification Help
Topic: Unknow signal
Replies: 9
Views: 22597

Re: Unknow signal

That signal looks screwed. I don't see any data in it unless it's some weird wideband modulation, but why the hell does it jump all around like that and it seems to be poorly filtered? Looks as if some device is constantly restarting itself at irregular intervals.