Search found 67 matches

by radiolistener
Mon Mar 16, 2020 12:55 am
Forum: Off-Topic
Topic: Dancing radio-waves :)
Replies: 3
Views: 1632

Re: Dancing radio-waves :)

Not the signal itself, but how it shows the atmospheric movements. This is not atmospheric movements. This is over-the-horizon radar. https://en.wikipedia.org/wiki/Over-the-horizon_radar They are used to detect nuclear missiles at long distance. It changes, because direction and shape of radar beam...
by radiolistener
Fri Mar 13, 2020 11:58 pm
Forum: RTL-SDR Discussion
Topic: Weak GPS reception with RTL-SDR blog V3 bias tee + cheap active GPS antenna
Replies: 1
Views: 1377

Re: Weak GPS reception with RTL-SDR blog V3 bias tee + cheap active GPS antenna

With the auto gain enabled for the dongle in SDR# I'm getting the noise floor at about -30dBm It looks like one of the possible issues is that the antenna is somehow picking noise from the PC, No, this is just because signal is too weak. What autogain doing is just shifting all signals, include noi...
by radiolistener
Fri Mar 13, 2020 11:49 pm
Forum: RTL-SDR Discussion
Topic: Can I observe TV channels using an rtl2832u?
Replies: 6
Views: 3109

Re: Can I observe TV channels using an rtl2832u?

you can see tv channel signals on the spectrum, but you can't see full tv channel bandwidth. Because TV channel bandwidth is too wide and cannot fit into RTL SDR USB bandwidth.

TV channel bandwidth is about 7-9 MHz. But RTLSDR has 3.2 MHz bandwidth max in SDR mode
by radiolistener
Fri Mar 13, 2020 5:04 am
Forum: RTL-SDR Discussion
Topic: Measuring VSWR
Replies: 3
Views: 2904

Re: Measuring VSWR

Victorbktop wrote:
Mon Mar 09, 2020 9:17 am
I wonder how to measure the VSWR of the antenna before tuning and after tuning.
You can buy NanoVNA analyzer and check your antenna impedance at specified frequency.
by radiolistener
Fri Mar 13, 2020 4:58 am
Forum: RTL-SDR Discussion
Topic: Measuring VSWR
Replies: 3
Views: 2904

Re: Measuring VSWR

Does rtl-sdr dongle match the antenna's impedance to 50ohm? or does it just choose the proper frequency by using filter?? I wonder because I think the antenna I bought can't cover all of the HF and VHF frequency. No. It has some curve which depends on selected mode. For example, here is VSWR measur...
by radiolistener
Mon Mar 09, 2020 10:56 pm
Forum: Other SDR Devices
Topic: MSi sdr panadapter problems
Replies: 1
Views: 5685

Re: MSi sdr panadapter problems

These Msi.sdr are Chinese clone of Sdrplay RSP1. But it doesn't have filter and attenuator on the input. These clones are not supported officially, so you will need to fight with problems with no help from customer support. It works bad. I got instance which has terrible pulses at some frequencies, ...
by radiolistener
Tue Mar 03, 2020 4:07 pm
Forum: Other SDR Devices
Topic: Wideband HF SDR
Replies: 2
Views: 2462

Re: Wideband HF SDR

- 28 MHz instantaneous BW - channelized IQ (200 KHz / 2 MHz BW DDC), or SW support to channelise wideband IQ stream - 10.7 MHz IF output (ideal, otherwise an SDR TX just for this is acceptable but overkill - just to feed a DF processor) Thanks if you want to get IF with 28 MHz bandwidth, it will co...
by radiolistener
Sat Jan 18, 2020 4:06 am
Forum: Off-Topic
Topic: More fake units sold on Ebay
Replies: 35
Views: 42197

Re: More fake units sold on Ebay

I think they selling filters with terrible characteristics just because they use cheap component that they have instead of what is required. For example they can put a little different inductors just because they don't have inductor which is exactly needed. The same for capacitors. They can use indu...
by radiolistener
Thu Jan 16, 2020 3:06 pm
Forum: Off-Topic
Topic: More fake units sold on Ebay
Replies: 35
Views: 42197

Re: More fake units sold on Ebay

He meant the original filter RTL-SDR.COM, but component values are trade secret, of course. what is the secret? You can desolder components measure it and solder it back with no problem... :ugeek: I'm asking what component values are used just to put it into simulator and compare how aliexpress fak...
by radiolistener
Sat Dec 07, 2019 1:21 am
Forum: RTL-SDR Discussion
Topic: rtl-sdr dongle V3: Accessing the 28.8 MHz reference
Replies: 5
Views: 933

Re: rtl-sdr dongle V3: Accessing the 28.8 MHz reference

is it correct that extension pin CLK (or CIK) is 28.8 MHz oscillator output?

What is the meaning of the middle pin with no marking?