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Author Topic: New version of RTL-SDR.com dongle now available  (Read 8008 times)

Offline ChuckConner

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New version of RTL-SDR.com dongle now available
« on: August 16, 2016, 1555 UTC »
RTL-SDR.com has just released their improved dongle.   Among other things it includes a direct sampling mode and bias-T function for switching external devices.   http://www.rtl-sdr.com
Chuck Conner
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Offline Josh

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Re: New version of RTL-SDR.com dongle now available
« Reply #1 on: August 16, 2016, 1949 UTC »
Ossum, will have to give on of these a try!
Thanks for the link.
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Offline skeezix

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Re: New version of RTL-SDR.com dongle now available
« Reply #2 on: August 20, 2016, 0005 UTC »
On a lark after reading this on Tuesday, I went to the website to read about it and liked it. So ordered it. This morning receive an email that it was shipped, got home and it was waiting for me.

A very pleasant surprise for the weekend.

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Offline ChrisSmolinski

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Re: New version of RTL-SDR.com dongle now available
« Reply #3 on: August 20, 2016, 0112 UTC »
On a lark after reading this on Tuesday, I went to the website to read about it and liked it. So ordered it. This morning receive an email that it was shipped, got home and it was waiting for me.

A very pleasant surprise for the weekend.


I'm particularly interested in how it performs on HF, if you try it there.
Chris Smolinski
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Offline skeezix

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Re: New version of RTL-SDR.com dongle now available
« Reply #4 on: August 20, 2016, 0142 UTC »
Currently working on some unrelated computer things tonight, but going to get to it tomorrow for sure.

In the package:
- RTL-SDR. In a nice metal case. Unlike my E4000-something or another which is in plastic.
- Antenna magmount
- UHF+ antenna  Extended: 7 7/8"  Collapsed: 2.5"
- HF/VHF antenna. Extended its 5' long. Collapsed its 8"  <--- This antenna was a big surprise. Who does this in 2016?
- Dessicant

As you will notice, there is a gap in the supplied whips between 7 7/8" and 8". I hope this won't be a problem.


Have to say, initial impressions of opening & seeing the physical things, I am happy. Also picked up the assortment of antenna adaptors so will hook up to the various good antennas (most importantly that are away from the house).




Minneapolis, MN

Offline skeezix

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Re: New version of RTL-SDR.com dongle now available
« Reply #5 on: August 20, 2016, 2244 UTC »
Win7 laptop has been searching for updates for ~24 hours now...  ::)


Put the RTL-SDR on there and installed SDR#. Installed fine & receiving FM stations w/o problem. Had to crank up the gain (it came set to 0), which they mention. This seems to be doing a decent job.

Tuned down to MW & SW with just the 5' whip, but heard nothing. I did expect to hear a local 50kW that's ~20mi away and another 5kW pest that's ~5 mi away. Will need to investigate this. Perhaps SDR# (which is made more for the AirSpy SDRs) has to do something special with the RTL-SDR dongle.

Picked up aircraft on their band (incl activity above 134 MHz, which I don't remember there being much around here), weather radio, pagers on VHF-hi band, digital repeaters up on UHF, and I think I may have also just found my shiny new 900 MHz water meter transmitting around ~920 MHz.

Can't do a whole lot on here at the moment as the SWU is taking ~50% CPU.  >:(    Stupid windows.
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Offline skeezix

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Re: New version of RTL-SDR.com dongle now available
« Reply #6 on: August 20, 2016, 2342 UTC »
Got MW & HF going. Had to select Direct Sampling (Q Branch) instead of the usual Quadrature.

With the 5' whip within a few feet of the laptop & its noisy PS-
Picked up two local strong stations stations on MW.
Got WWV at 10 MHz
And Voice of Greece on 9420 kHz. Opa!

Noisy and kind of crappy, but with that 5' whip next to the laptop, that was expected.

While switching to the outdoor antennas, the AC adapter came unplugged and noise went way, way down.

Have two antennas in use for testing for this - Bonito Boni-Whip & Wellbrook ALA100LN loop (~40' of wire), both into a phaser.

With maximum gain, the antennas saturate the SDR and there are images & noise all over the place.

When fine tuning the gain on various stations, the images will go away. Local strong stations sound good. Tried to get 540 WXYG on this (it sounds fantastic on my Yaesu FT-847 with these two antennas, at full gain). SINPO on the Yaesu is 55555 (for a little 850W station ~75 miles away), while on the RTL-SDR, its only 25353. The RTL-SDR struggled a bit with this one. At minimum images, it was a noisy signal, but still listenable.

Went back to Voice of Greece on 9420. When adjusting gain on the antennas, can get it in pretty good. Audio quality is still better on the Yaesu overall, which is not surprising as computer audio is usually mediocre at best. Will have to try this on my other PC that has a SoundBlaster X-Fi in it hooked up to 5.1 speakers.

Visited the 41m band. 7385 kHz was strong, brought up the gain and it sounded much better. No images on 7385, just increase in strength (as one would normally expect). Saw some stations above 8 MHz and tuned there to find that they're MW images. Turned down the gain and they went away.

The driver has RTL AGC & Tuner AGC, plus a gain control. When in Quadrature mode, we can fiddle with all three. When in Direct Sampling, only can check/uncheck RTL AGC, can't fine tune the gain. This would be a problem if we can't control the gain of the antenna. In my case, deselecting RTL AGC gives better signal control.

Also, sampling rate has an effect. 0.250 MSPS just makes noise & finds images, no useful audio. Useful rates are 1.024 MSPS to 1.4 MSPS (at least while listening to 540 kHz). Above 1.4 MSPS, its noise & garbage. Didn't seem to behave like this in the 31m band.

As long as you can adjust antenna gain easily, it seems to do a decent job. Its not a DX machine, but would be perfectly fine for casual listening. For $24.95, I'm not going to complain and will enjoy this device.

Will continue experiments with other antennas & things.


BTW: After composing this, tuned to 43m and saw activity... sure enough its Wolverine on 6940. Sounds fine on this except for a het on 6942.

« Last Edit: August 21, 2016, 0041 UTC by skeezix »
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Offline ChrisSmolinski

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Re: New version of RTL-SDR.com dongle now available
« Reply #7 on: August 21, 2016, 1610 UTC »
Thanks for the report, skeezix.  I wonder if a pass band filter / preselector on the antenna input would help a lot for MW and SW, especially with getting rid of images?

Sounds like a fairly good value for the price.  Speaking of SDRs, I just got my shiny new AFE822x dual input yesterday. I am planning on writing some custom software for it that will do phasing entirely in software. I'm still fiddling with the DGPS software now, however. Too many radio software projects, too little time...
Chris Smolinski
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Offline skeezix

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Re: New version of RTL-SDR.com dongle now available
« Reply #8 on: August 21, 2016, 1856 UTC »
For the preselector, I have a small tuned loop and going to try that thing and see how it works. It has loops for LW, MW, and SW (up to around 6200 kHz). The thing works fantastic for hooking to the Meduci MW-2 PLL. That radio has no preselector and is easily overloaded by stations. Tried the tuned loop and it pulled in 540 WXYG great, in glorious AM Stereo.

This morning, had my dual band VHF/UHF airband whip hooked up. At the antenna, it has a VHF/UHF airband bandpass filter on it.

Noise on VHF airband seems to be too high. Granted the antenna is on the deck, but should be far enough away from noise sources. Or maybe its not. Or something wrong with the coax. meh.


That sounds like a great project with the dual channel SDR. I'd love to write something like that, but, I still need to learn the basics of of the internals of SDRs and write my own simple things. Have a book on DSP and a few others things. The main problem is lack of time.
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Offline ChrisSmolinski

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Re: New version of RTL-SDR.com dongle now available
« Reply #9 on: August 21, 2016, 2030 UTC »
That sounds like a great project with the dual channel SDR. I'd love to write something like that, but, I still need to learn the basics of of the internals of SDRs and write my own simple things. Have a book on DSP and a few others things. The main problem is lack of time.

I'd strongly recommend downloading the source code for cuteSDR, studying it, and even using it as a base for your own projects, which is what I've done. Although I've modified the DSP routines from C++ to objective-c, because C++ makes my eyes bleed.
Chris Smolinski
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Offline skeezix

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Re: New version of RTL-SDR.com dongle now available
« Reply #10 on: August 21, 2016, 2131 UTC »
Source code for various things I have and can get. Its just actually sitting, reading, thinking, and then doing it. Hopefully with summer winding down and PTO stockpiled, I better be able to find time.

I'm going to the GNURadio Conference in a few weeks and hopefully will glean some nuggets from there.

C++: I've tried that and it made my head hurt. I mentioned that I was trying to learn C++ to my Dad, who was in data processing decades ago. He doesn't think much of the object-oriented stuff. But then, I'm also not going to do this in COBOL.  ;D  Although... hooking a bunch of SDRs to a z-Series then having The Beast doing the processing would be wild, possibly insane. Which means it may have to be done (for the same reason that people climb mountains).

I'll prob start with C and try to keep it cross-platform with Mac/FreeBSD/Linux.



BTW: My winderz 7 laptop finally finished checking for updates, after 37.5 hours of continuous "work" (~50% CPU). >:(

Minneapolis, MN

Offline skeezix

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Re: New version of RTL-SDR.com dongle now available
« Reply #11 on: August 21, 2016, 2231 UTC »
Update for MW:

Using DX Tools Quantum DX Loop v3.0.

Found a station on 1690 and was of decent strength. Compared to what my Kenwood TS-690S with Wellbrook ALA1530S+ was receiving and was closer than I expected (as far as SINPO was concerned, not comparing S-meter readings). The TS-690S still beat the RTL-SDR, but they're in the same neighborhood.

The 1690 station went abruptly off and another station was underneath. Tracked that down to an image from local station 690 KFXN.  According to FCC records, KFXN is 500W daytime that's 2.5 miles away, with a directional antenna. Most of it goes to the ESE (away from me), but they have a significant lobe to the back that I'm well within.

Even with the tuned loop, the RTL-SDR is picking up an image.

That was on 0.250 MSPS. Switched to the higher rates and the image went away.  This isn't the first time I've seen this, and this is with two different programs, Studio1 and SDR#.



Update for FM Broadcast:

Antenna are $6 rabbit ears about 6' away balancing on the top of a door.

Had to turn off AGC for RTL & Tuner, otherwise it would overload. Manually set it to 16.6 dB and its doing pretty good. Any higher and can see the images & a lot more noise. At least at the low end of the dial here. Tuned up further and had to decrease the gain further or would get overload. Looks like will have to keep a close eye on the gain for best reception. And the tuner AGC kills it, so that stays off.

Max sample rate of 2.4 MSPS. Any more than that and the stereo & RDS cut out. This is while listening to a 100 kW station about 20 miles from here.

Dialing things back from testing this morning with things maxed, found a few new FM stations. Might spend some time here checking it out. Usually had little interest in FM, but the SDR has made FM fun.
« Last Edit: August 22, 2016, 0157 UTC by skeezix »
Minneapolis, MN

Offline Pigmeat

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Re: New version of RTL-SDR.com dongle now available
« Reply #12 on: August 29, 2016, 0259 UTC »
COBOL is the language of the Gods. Now get to work learning how that card machine works!

You could have simply added a potentiometer with a nice knob between the antenna and the box they claim is a radio to reduce images. That's why knobs are the epitome of radio technology.

Skeez, tell your Dad I know where there are bunch of surplus decollaters and bursters in case the ones he uses for his printers ever go "phht". These new fangled laser printers for your main frame create too much static and wear bursters out. Dot matrix was and is state of the art.

Stay tuned for more tales of "I Was A Teenage Tape Librarian."

Offline corq

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Re: New version of RTL-SDR.com dongle now available
« Reply #13 on: August 30, 2016, 0133 UTC »
I just received one but haven't hooked up. I'm a linux-only nerd, so will have to see how GQRX handles it.
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Offline Kilokat7

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Re: New version of RTL-SDR.com dongle now available
« Reply #14 on: September 06, 2016, 2340 UTC »
Speaking of SDRs, I just got my shiny new AFE822x dual input yesterday. I am planning on writing some custom software for it that will do phasing entirely in software.

Imagine a MW spectrum recording generated by a dual channel SDR where you could perform phase-nulling from within the SDR recording.  At least it seems possible?  Please keep us posted!
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