Архив за 24.09.2019

На УКВ на 8дБ точноне надо из головы придумывать -он априори не может слышать лучше на укв ,чем такой же свисток с r820t…

avenger7812 пишет:
На УКВ на 8дБ точноне надо из головы придумывать -он априори не может слышать лучше на укв ,чем такой же свисток с r820t2 -вся разница в txco и наличие прямой оцифоровки кв -где обычный донгл глух как...
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Широкополосный приёмник из DVB донгла - Страница #575

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Police radios

I'm in east Europe and wondering is police radios here encrypted digital analog and where can I find more about them. Thanks for any advice

submitted by /u/AdNine87
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Antennas • Re: What is a good wide range antenna for desktop sdr

in my experience there is no antenna that could work "right to your desktop".

There is too much RFI in the house, LCD TV, Neon lamps, electronics...
Into your house you can at best get the broadcast radio, especially if you live in a city.

If you put the antenna in the balcony, at least at one meter by the wall you will already get superb improvement of the signal.

I suggest also to put the receiver right under the antenna and arrive to the pc with a long usb cable (not more than 5 meters)
If you live in a city and have unfiltered sdr, it is better to buy a BCFM bandstop filter.
Last, put ferrite beans at the end of the coax.

About the antenna, i started with the rtl-sdr blog dipole, i still use it in some cases and i will rebuy it 100 times, i received communications far more than 150km from my house and i live in a city with really much noise. This dipole is also good to receive voice communications and SSTV by the ISS so i will use it tonight too :D

Hope it helps

Statistics: Posted by Jekko — Tue Sep 24, 2019 4:28 pm


RTL-SDR Discussion • RTl-SDR V3

Hello,

Anyone have a problem turning the Bias T on and Off. My dongle about 1 year old now will not turn Bias T off. I have tried in Linux and in Windows.

Any Ideas?

Thanks
Tim

Statistics: Posted by toolman60 — Tue Sep 24, 2019 3:48 pm


KerberosSDR • Re: Feature requests / development ideas

In the DF process, as you get closer to the source it would be beneficial to insert attenuation into the Antenna system to counter increased multipath. (of course those changes would require stopping and re-calibration with any antenna changes.) What do you think about an auto increase of "Minimum Required Power" in the Android App as you DF closer to Signal origin? Also, what is the range the software will accept for 'Minimum Required Power' ?

Statistics: Posted by myke — Tue Sep 24, 2019 3:26 pm


Off-Topic • Re: GPS Jamming detection

Not experimenting with DF for GSP Jammers at this time. Just considering the possibilities ... BTW - your link is very interesting equipment. Thanks

Statistics: Posted by myke — Tue Sep 24, 2019 2:56 pm


Drifting RFI issue

Drifting RFI issue

Hey guys,

once again I've got an issue I can't seem to figure out how to resolve it.

The problem is that several times a day, so it comes and it goes, I've got some RFI that seems to be drifting on the band. The time of day this arrives is never the same neither.

See this photo:

https://i.redd.it/naqalklx3jo31.png

Now I can't figure out what causes this RFI. It must be received by my antenna, cause when I power down the entire house and run my system on batteries I see exactly the same.

To give an impression of what I've done so far to kill RFI:

- air choke of 6 windings

- 6 ferrite beads in a row in the middle of the H155 coax run (total coax run is about 5m)

- Ferrite snap-on on on the 5v power feed to my RPi running twice through the snap-on.

- Ferrite snap-on on the 230V power line feeding the 230 > 5v converter for my RPi.

All this has lowered the noise floor a lot, and it's filtered quite some static RFI. But this drifting one I can't get it out.

Also, I've noticed that as long as there's no sunlight my noise floor is like 5db lower. With the speed of sunlight arriving, the noise floor goes up. Generally from -55 to -50. I assume this is because of a el cheapo inverter of the solar panels one of my neighbours might be using?

submitted by /u/theakito
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RTLSDR for ADS-B — University Final Year Project Survey

Firstly, thanks to the moderators for allowing me to post a survey on this great sub.

For my Final Year Project in University I want to create a mobile app that will gather the data a user is submitting to FlightRadar24 and present that on a mobile device. The application will show the user, on a map, what they are submitting in real time as well as historical data.

This idea is in it's infancy and I'm still working on the idea. If you could fill out this very short survey (2 mins max), I would be very appreciative of this.

Survey: https://forms.gle/n7rF7b9qFtNYvVgD8

submitted by /u/theinvisiblesquid
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Help with Trecking DDE / orbitron settings

hi everyone,

since i got my NOAA filter im realy into making the capture of Weather images as automatic as possible, but im having some problems.

while ussing Trecking DDE 1.2 i can never

  • stop the radio (does nothing)
  • set modulation (wfm fm etc gives error)
  • set simbollrate to auto (gives error)
  • launch external app (does nothing)

another problem that i have is that orbitron sometimes jumps from a perfect align satelite to another, is there a setting that i can use to prevent that other than minimal elevation?

This is settings in DDE for meteor M2-2

radio_modulation_type<wfm> radio_Start radio_center_frequency_Hz<137570000> radio_frequency_Hz<137900000> radio_bandwidth_Hz<100000> M2_decoder_init_Line <rgb=123.jpg> M2_decoder_init_Line<path=D:\SDR\Meteor\ImagesM2_2> OQPSK_demodulator_Start send_tracking_frequency_On start_program_Path<D:\SDR\Meteor\LRPT_Decoder\Decoder_m2-2.bat> 

send_Tracking_Frequency_Off OQPSK_demodulator_Stop radio_stop 

thx in advance

submitted by /u/rjSampaio
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Off-Topic • Re: CB Superbowl 11 Meters 27 MHz

Hi here in Europe i use a legal CB with 12w SSB and the sound Modem thinks work for om Vienna to Germany, France, Spain,... It really depend what Kind of antenna you use and how the athomsoheric condition are. Why not try to put a sound Modem on and see how far you reach?

Statistics: Posted by Username — Tue Sep 24, 2019 9:10 am


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