New to SDR Radio

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billcox5

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Here is my hardware info:

rtl_test -t Found 1 device(s): 0: Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM Detached kernel driver Found Rafael Micro R820T tuner Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6 Sampling at 2048000 S/s. No E4000 tuner found, aborting. Reattached kernel driver

If I want to listen to public safety frequencies like police, fire, EMT, etc which mode do I use: FM, NBFM, WBFM, LSB or USB?

And which mode do I use to listen to CB radio?

PS: Is there a site you know that list frequencies and it's modes so I can use them in GQRX? Thanks
 

robertmac

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We are not mind readers. Where do you live and this may help people giving you proper information. Or you can look at Databases for your area for frequencies and modes. CB is AM or USB or LSB, and as CB is open, there are no rules as to which mode. CB will vary if you really want to listen to the junk that is usual. Public service depends on what is used in your area. FM, NFM if have not migrated to DMR, NEXEDGE, or P25.
 

billcox5

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USA
We are not mind readers. Where do you live and this may help people giving you proper information. Or you can look at Databases for your area for frequencies and modes. CB is AM or USB or LSB, and as CB is open, there are no rules as to which mode. CB will vary if you really want to listen to the junk that is usual. Public service depends on what is used in your area. FM, NFM if have not migrated to DMR, NEXEDGE, or P25.
I live in the USA/New York City.

I already found the frequencies and modes for New York City from RadioReference.com database.

Unfortunately, I can only pick up local FM broadcast stations with the cheap stock antenna.

Can you or anybody recommend a good antenna to buy for a SDR receiver dongle?

Thanks
 

dlwtrunked

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I live in the USA/New York City.

I already found the frequencies and modes for New York City from RadioReference.com database.

Unfortunately, I can only pick up local FM broadcast stations with the cheap stock antenna.

Can you or anybody recommend a good antenna to buy for a SDR receiver dongle?

Thanks
The first thing anyone who buys one of the SDR dongles should do is throw that antenna away! You only received it because the dongle was designed for another purpose before others figure out they could use the dongle for other bands. Before throwing it away, cut off the wire as that has some use for making an adapter if you do not buy an adapter for whatever connector your new antenna has and have to make one yourself. Different dongles have different connectors and different antennas have different connectors so no one here can tell you what adapter you need . Now buy a scanner antenna (mobile or base station). A starting place would be to click the Scanner Master advertisement that you probably see at the top of this page. All the rules for scanner antennas apply--the higher the better. *Nothing* sitting on a desk is going to do very well. In regard to base antennas, a rooftop discone antenna is likely the best if you want VHF/UH "all bands" (some will argue otherwise) but you will get better performance with gain if you buy an antenna bands in which you are interested. No antenna will be good for HF and VHF/UHF. In regard to adapters for the antenna connector, eBay and Nooelec (Google them) are good places to look after you identify what connector your dongle and what connector your antenna have. There is a good chance that you will need a M-MCX to F-BNC, or a M-MCX to F-SO-239 adapter; but instead of MCX, you may have an SMA or PAL connector on the dongle so you need to determine which.
 

BM82557

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The first thing anyone who buys one of the SDR dongles should do is throw that antenna away!
That's not always the case. It depends on what you want to listen to and your receiving conditions. I'm only 2 miles from the transmitting site of the local P25 system that uses the 450 - 460 MHz band and get good reception/decoding of that system using the stock dongle antennas. That frees up my discone in the yard for other more difficult to monitor targets. That's just my situation though. In NYC you most likely won't have that kind of reception.
 

billcox5

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Jan 1, 2017
Messages
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Location
USA
The first thing anyone who buys one of the SDR dongles should do is throw that antenna away! You only received it because the dongle was designed for another purpose before others figure out they could use the dongle for other bands. Before throwing it away, cut off the wire as that has some use for making an adapter if you do not buy an adapter for whatever connector your new antenna has and have to make one yourself. Different dongles have different connectors and different antennas have different connectors so no one here can tell you what adapter you need . Now buy a scanner antenna (mobile or base station). A starting place would be to click the Scanner Master advertisement that you probably see at the top of this page. All the rules for scanner antennas apply--the higher the better. *Nothing* sitting on a desk is going to do very well. In regard to base antennas, a rooftop discone antenna is likely the best if you want VHF/UH "all bands" (some will argue otherwise) but you will get better performance with gain if you buy an antenna bands in which you are interested. No antenna will be good for HF and VHF/UHF. In regard to adapters for the antenna connector, eBay and Nooelec (Google them) are good places to look after you identify what connector your dongle and what connector your antenna have. There is a good chance that you will need a M-MCX to F-BNC, or a M-MCX to F-SO-239 adapter; but instead of MCX, you may have an SMA or PAL connector on the dongle so you need to determine which.
Since the SDR dongle is designed mostly for getting VHF and higher, I'd probably get a scanner antenna or a 2m/70cm antenna and hope that's enough.

That's not always the case. It depends on what you want to listen to and your receiving conditions. I'm only 2 miles from the transmitting site of the local P25 system that uses the 450 - 460 MHz band and get good reception/decoding of that system using the stock dongle antennas. That frees up my discone in the yard for other more difficult to monitor targets. That's just my situation though. In NYC you most likely won't have that kind of reception.
Yes, NYC is RF hell. Of course, I am a bit confused about UHF. I read that UHF signals can work through buildings. Can't figure out why I couldn't get any UHF from the cheap stock antenna. I live one block away from the 33rd NYPD Precinct.

Thanks to all here.
 

dlwtrunked

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Since the SDR dongle is designed mostly for getting VHF and higher, I'd probably get a scanner antenna or a 2m/70cm antenna and hope that's enough.
something to add: A common problem with the dongle and other scanners is neaby FM broadcast stations. Some of us have learned from experience that even though one may not hear them when tuning, they can make the receiver less sensitive. I always advise adding an FM notch filter. Radio Shack used to sell cheap ones that work very well for the cost. Better ones will cost more than the $20 dongles. You will need possibly also adapters to use one.
 

princessthelus

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something to add: A common problem with the dongle and other scanners is neaby FM broadcast stations. Some of us have learned from experience that even though one may not hear them when tuning, they can make the receiver less sensitive. I always advise adding an FM notch filter. Radio Shack used to sell cheap ones that work very well for the cost. Better ones will cost more than the $20 dongles. You will need possibly also adapters to use one.
This can be a plus or negative if you know how to modify your dongle. You can modify an RTL-SDR to use as a passive FM radar. If you can do the math correct there is a program out there to make a radar system using a Strong FM station as your carrier wave and use the triangulation to turn it into a crude passive radar system. its really cool. You can see aircraft and even the occasional meteor. Other than that, yes FM broadcast stations are pain in the arse, if you are just going through the frequencies and just looking at the waterfall.
 
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