SDR Help Please!

[screamin72]

Amazon is good but you are paying 2-3 dollars more than going to NooElec and buying it for the original price. That's what I did. Registered at nooelec.com and Nooelec does not store debit/credit card information. You only provide it at check out. They do store your street address and name. I feel safer that way. Just personal preference.

@john1969
I am guessing you are wanting to know if you can 'go between the channels'. Essentially you can tune in 1hz increments which is way finer than needed because for broadcast the signals are very wide in comparison to a narrow fm signal say on 162.400 NOOA weather radio(my local WX frequency). Those 1hz steps are good for single side band and CW fine tuning. If you are strict on tuning a station exactly on the frequency the transmitter is tuned at you can use HDSDR which has a tuning indicator that turns green for perfect tune. I don't think SDR# has that maybe it has another way. Usually any radio will have a slight shift in frequency when it comes to fine tuning. It may read higher or lower than it's advertised frequency. AFC or Automatic Frequency Control does this for you. I never saw a option for AFC in SDR#.

For some basic band plans look here. Since you are in USA I will provide you this link
http://www.w2aee.columbia.edu/fcc-bandplan.html

For a good discussion on channel spacing
http://forums.radioreference.com/ge...109184-channel-spacing-channel-bandwidth.html

@takedownman5150

and everyone else buying this type of SDR

May I stress LNA LNA LNA LNA low noise amplifier. These dongles are great little low cost entry into SDR. I do have to tell you since you asked for more info that when you increase the RTL gain it also increases the noise level. With a low noise amplifier it amplifies the signal and you dont need alot of gain which makes the signal seem quieter with far less noise. That being said these dongles have a high noise floor.
I managed to use a RCA LNA you can buy at Walmart for 15 dollars with a set of tv antenna rabbit ears.

 

[takedownman5150]

Thanks Gentlemen......I havent been this impatient in a long time. Its shipping from Chattanooga Tenn. and im in the s/e Cali desert....so we will see.

 

[takedownman5150]

Why I Love this Hobby !!!

Amazon is good but you are paying 2-3 dollars more than going to NooElec and buying it for the original price. That's what I did. Registered at nooelec.com and Nooelec does not store debit/credit card information. You only provide it at check out. They do store your street address and name. I feel safer that way. Just personal preference.

@john1969
I am guessing you are wanting to know if you can 'go between the channels'. Essentially you can tune in 1hz increments which is way finer than needed because for broadcast the signals are very wide in comparison to a narrow fm signal say on 162.400 NOOA weather radio(my local WX frequency). Those 1hz steps are good for single side band and CW fine tuning. If you are strict on tuning a station exactly on the frequency the transmitter is tuned at you can use HDSDR which has a tuning indicator that turns green for perfect tune. I don't think SDR# has that maybe it has another way. Usually any radio will have a slight shift in frequency when it comes to fine tuning. It may read higher or lower than it's advertised frequency. AFC or Automatic Frequency Control does this for you. I never saw a option for AFC in SDR#.

For some basic band plans look here. Since you are in USA I will provide you this link
FCC Frequency Band Plan

For a good discussion on channel spacing
http://forums.radioreference.com/ge...109184-channel-spacing-channel-bandwidth.html

@takedownman5150

and everyone else buying this type of SDR

May I stress LNA LNA LNA LNA low noise amplifier. These dongles are great little low cost entry into SDR. I do have to tell you since you asked for more info that when you increase the RTL gain it also increases the noise level. With a low noise amplifier it amplifies the signal and you dont need alot of gain which makes the signal seem quieter with far less noise. That being said these dongles have a high noise floor.
I managed to use a RCA LNA you can buy at Walmart for 15 dollars with a set of tv antenna rabbit ears.

The people here and some of the groups are so helpful,though the sdr# blogsite seems to be in a titter lately....thanks for the links also.
Rich

 

[takedownman5150]

? I have an antennacraft sts wideband antenna on the roof and have the adapter bnc male to mcx,,,,,does the LNA go between there somewhere,,,sorry in advance for stupid questions. lol.

 

[screamin72]

? I have an antennacraft sts wideband antenna on the roof and have the adapter bnc male to mcx,,,,,does the LNA go between there somewhere,,,sorry in advance for stupid questions. lol.

Some put it between the antenna and coax. Mine is midway in the coaxial line. One more point is don't use a LNA that is powered via the coax. Those kind will burn out the dongle in a jiffy. If you are tech savvy with a soldering iron you can feed its power bypassing the coaxial power feed.

http://www.hdsdr.de for hdsdr if you want to try it. It needs the ExtIO_RTL2832.dll for rtl dongles which is supplied at that site. just put the dll in the hdsdr install folder.

 

[takedownman5150]

LNR

Some put it between the antenna and coax. Mine is midway in the coaxial line. One more point is don't use a LNA that is powered via the coax. Those kind will burn out the dongle in a jiffy. If you are tech savvy with a soldering iron you can feed its power bypassing the coaxial power feed.

HDSDR Homepage for hdsdr if you want to try it. It needs the ExtIO_RTL2832.dll for rtl dongles which is supplied at that site. just put the dll in the hdsdr install folder.

Will a LNR with an AC power supply work ? like this one ?Amazon.com: Antra AT-PAA28 Low Noise Pre-Amplifier HDTV Pre-amp Signal Booster for UHF VHF Antenna 28dB Adjustable Gain Excellent for Long Cable running: Electronics

 

[br0adband]

Some put it between the antenna and coax. Mine is midway in the coaxial line. One more point is don't use a LNA that is powered via the coax. Those kind will burn out the dongle in a jiffy. If you are tech savvy with a soldering iron you can feed its power bypassing the coaxial power feed.

HDSDR Homepage for hdsdr if you want to try it. It needs the ExtIO_RTL2832.dll for rtl dongles which is supplied at that site. just put the dll in the hdsdr install folder.

RTL sticks sold by NooElec have a protection diode on the antenna input to block voltage - I can't say precisely how much voltage, but it's considered to be an electrostatic protection diode so, perhaps it would be enough in such a situation. Not all of the rest of those "cheap TV tuners" have that diode in place; a lot of them don't but they have the same packaging as the NooElec sticks - they just don't say NooElec on them directly but everything else is the same. NooElec is the only supplier that guarantees the sticks they sell have that electrostatic protection diode.

Regardless, good advice is still to avoid using a line-powered LNA (where the voltage to power the circuit is sent through the feedline itself) unless someone specifically has experience with this and offers up their particular advice (and even then I'd still probably avoid it myself unless absolutely necessary).

Putting the LNA closer to the antenna end of the feedline ensures you get a better and perhaps cleaner signal (in terms of SNR) than having it at the receiver end - the LNA's amplification would help negate any potential line loss if your feedline is considerably long, say 100 feet or more, and so will using low-loss feedline too.

 

[slicerwizard]

RTL sticks sold by NooElec have a protection diode on the antenna input to block voltage - I can't say precisely how much voltage, but it's considered to be an electrostatic protection diode so, perhaps it would be enough in such a situation. Not all of the rest of those "cheap TV tuners" have that diode in place; a lot of them don't but they have the same packaging as the NooElec sticks - they just don't say NooElec on them directly but everything else is the same. NooElec is the only supplier that guarantees the sticks they sell have that electrostatic protection diode.

That's a lot of words to say "I don't know."

If a DC blocker is not present, which is unlikely, one of the protection diodes will present a near dead short to the LNA's power supply. Either the DC supply or the protection diode will eventually (or perhaps quickly) fail. A failed shorted diode will do wonders for a dongle's sensitivity.

Regardless, good advice is still to avoid using a line-powered LNA (where the voltage to power the circuit is sent through the feedline itself) unless someone specifically has experience with this and offers up their particular advice (and even then I'd still probably avoid it myself unless absolutely necessary).

It's not good advice at all. Coax-powered LNAs use a power injection module or coax jumper that includes a DC blocking cap that protects all downstream devices from the DC current riding up the coax to the LNA. Of course, if someone doesn't read the directions and connects the hot side to their receiver, well maybe they shouldn't handle anything more dangerous than a lollipop. Seriously, is this too complicated to follow?

http://www.winradio.com/home/bt-650-install.jpg

Putting the LNA closer to the antenna end of the feedline ensures you get a better and perhaps cleaner signal (in terms of SNR) than having it at the receiver end - the LNA's amplification would help negate any potential line loss if your feedline is considerably long, say 100 feet or more, and so will using low-loss feedline too.

LNAs belong right next to the antenna. Kind of pointless to invest the time in installing one if it's not where it belongs.

 

[screamin72]

I have 3 NooElec RTL2832U R820T SDR dongles. They all have the protection diode and no do not remove the diode use a LNA. Static electricity is in your house and if on outside antenna you need antenna protection. If you remove the diode and it fails you will know why. Sensitivity is fine I can receive a NOAA weather radio broadcast from 40 miles away on a indoor antenna with the diode in place without LNA on.

My purpose for a LNA is to have enough signal amplification to turn down the RTL Tuner gain enough to drop the noise level a lot and to have enough signal to work with. Signals are strong with the LNA mid line coax but its only 7 feet long over all with RTL tuner gain at 20. No noise.

 

[takedownman5150]

So is the lna link I posted one that will work with jumpers for Ftype to bnc antenna conection?

 

[screamin72]

So is the lna link I posted one that will work with jumpers for Ftype to bnc antenna conection?

You will need a BNC to MMCX adaptor.

This one is best because it is in the L shape to reduce strain on the mcx female connector on the dongle and it has a run of cable in between.

Amazon.com: RF coaxial coax cable assembly BNC female to MCX male right angle 6'': Electronics

If you ever have seen a mcx connector in person its really tiny. Don't run thick cable right up on it. For a good size comparison it is smaller than a SMA connector.

Now you need to know that you have to have a FM trap ion line as well. Basically 12 inch run of coax will kill the fm broadcast intermod if you see it. Normally below 50 mhz where it is prominent on the dongle. I saw a video on it the guy showed how he did it now I cannot find it lmao

 

[takedownman5150]

got cha.....fm trap...this is fun lol. Just looked up the tracking on my dongle and good old amazon..it said out for delivery and my heart rose and then it said it was out for delivery in a city 3 driving hours from here so now they say if i don't receive it by 5-25 let them know and they will reship. Might as well have ordered from china. <<<<<< frustrated.

 

[takedownman5150]

btw, i have that very conector right there from amazon....now if i could use it....this is worse than being a kid and waiting for xmas.

 

[screamin72]

found the youtube video

Using Coax Stub Notch Filter - YouTube

 

[SCPD]

I was recommended the "Newsky" version of these dongles. supposedly less drift and heat.
i.e. Newsky TV28T V2 USB DVB T Rtl SDR Receiver RTL2832U R820T Tuner MCX Input | eBay

$15, free & fast shipping. USA seller. Took 3 days to get to Oregon. Pic below is what I got in the mail today. My 3rd SDR dongle.

If the $5 difference is worth it to you, Amazon has RTL-SDRs even cheaper at times. Less than $10 right now.
Can't speak for the seller, but such a deal!

Amazon.com: RTL-SDR, FM+DAB, DVB-T USB Stick Set with RTL2832U & R820T. Great SDR for SDR#, HDSDR, and Other Popular SDR Software Packages!: Electronics

 

[takedownman5150]

K2 and scream.....thanks for more info on this...because of the amazon screw up with my order and not getting here until the 25th, i ordered one from nooElec direct today lol. It will probably get here before amazon. I also bought the 2 SDR e-books from kindle and i wish i could print them out. A friend told me duh..you cant record netflix, same with kindle...proprietary I guess. Can kindle e-books be printed ? Anyway, this waiting sucks.

 

[KCoax]

K2 and scream.....thanks for more info on this...because of the amazon screw up with my order and not getting here until the 25th, i ordered one from nooElec direct today lol. It will probably get here before amazon. I also bought the 2 SDR e-books from kindle and i wish i could print them out. A friend told me duh..you cant record netflix, same with kindle...proprietary I guess. Can kindle e-books be printed ? Anyway, this waiting sucks.

Use the Amazon computer version and take screen shots. heheh

 

[takedownman5150]

OIC...lol. Thanks !

 

[john1969]

I've played around a little with this and thanks to all your help! Can't rec. AM or Natl' Weather Svc. Can get FM.

 

[joeuser]

I'm enjoying SDR radio, I use 2 dongles, Unitrunker, & DSD+ Works very well.

Sent from my Nokia Lumia 928 - Windows Phone 8.1 using Tapatalk