RTL+R820T2 direct sampling DLL

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m_a_x
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RTL+R820T2 direct sampling DLL

Post by m_a_x » Sun Sep 14, 2014 1:49 pm

Hi all,
i have just purchased a tv stick HERE, i have re3ceived a Terratec Cinergy TStick+, the new version with R820T2. I have installed the software SDRsharp, run Zadig and tested. I can receive FM broadcast and VHF-UHF but nothing below the FM broadcast band, just FM armonics on 27-28 mhz. My insterest is mainly for HF so i downloaded and installed the rtlsdr.dll for direct sampling without hardware modification but it did not make any change, not even a single station on HF from 0 to 14 Mhz. The antenna is the one supplied with the stick, i know... but if it worked i should have received something, at least the local AM radio.
I wonder if the rtlsdr.dll could be not incompatible for the R802T2
Any idea?

P-40 Warhawk
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Re: RTL+R820T2 direct samplingDLL

Post by P-40 Warhawk » Sun Sep 14, 2014 3:26 pm

Hi .
I live in Pensacola Florida . Were do you live ????????
Now here some things that I hope you find helpful . To get the HF - 500khz to 30mhz you will need to bypass the R820T2 chip with T37-43 toroid with 15 turns on the primary and 39 turns on the secondary , use number 30 wire or use T16-6t-kk81 RF transformer from Mini Circuits works the best of anything that you have tried . This way of doing it is called direct sampling . Okay the antenna , the lower you go in frequency the longer of a antenna your going to need . Here is how I am going about , I am getting very good performance from the R820T dongle ever since I used the mini circuits T16-6T-kk81 rf transformer , I am getting about 18db higher signal level than the T37-43 toroid with 200 ohm on the secondary . I live in Pensacola Florida and use a MFJ-1020C active antenna , I am able to pick up hams well into Europe and to the west , Hawaii . My antenna is the aluminum flashing on the eves of my house . This gives me a 246 foot horizontal loop antenna . I also have a inverted ( W ) under the roof of my house , they are tided together . It would be nice to know if anybody has found a RF transformer better than I am using . Also I would like to hear how well other people are doing with their dongles .

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m_a_x
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Re: RTL+R820T2 direct sampling DLL

Post by m_a_x » Sun Sep 14, 2014 6:40 pm

Hi P-40,
i am in Italy; thank you very much for the technical details about hardware mod for direct sampling, they will be helpful when comes time for the mod, for the moment i would like to go by steps and start with the DLL to bypass the tuner via software.
My concern is about compatibility of the dll mod with the tuner R802T2; i have to understand if this is the reason why it is not working or if there is something else

P-40 Warhawk
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Re: RTL+R820T2 direct sampling DLL

Post by P-40 Warhawk » Sun Sep 14, 2014 7:39 pm

Hi Max .
With out any mod's to the dongle you can get 12 , 10 , 6 , and 2 meters ham bands . Now to get anything with sdr dongle you will need a bigger antenna than you got with the kit . That antenna is only good for frequencies higher than 600mhz
A disk cone antenna is something you should get . With any antenna the one thing you should remember is the higher up it is the better it works .

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m_a_x
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Re: RTL+R820T2 direct sampling DLL

Post by m_a_x » Sun Sep 14, 2014 8:45 pm

Hi P-40,
i am talking about the software mod that you read here: http://www.rtl-sdr.com/direct-sampling- ... ifcations/
It has been tested by others and it works even if with lower performance than with the hardware mod
In my case it doesn't work at all because i cannot receive any signal and the cause could be the R802T2 not supported (not bypassed)
I understand that i need a good antenna, i have been active amateur radio untill i moved to a new house after marriage many years ago, however the little antenna with an extension wire to make it longer is enough to say that the dll mod doesn't work, i cannot even receive local AM station, so i am not going to install an antenna before having the receiver working

P-40 Warhawk
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Re: RTL+R820T2 direct sampling DLL

Post by P-40 Warhawk » Sun Sep 14, 2014 11:45 pm

Hi Max .
I have no idea what your local AM station frequencies are , here in the U.S. our local AM stations broadcast from 500khz to 1.700mhz . If you AM stations are below 14mhz you won't pick them up , because the software dill doesn't go below 14mhz . Now if you local stations are above 14mhz than you may have a EMI ( electro magnetic interference ) problem . It comes from dvd players , cable box , TV and satellite receivers , so unplug them when you want to use the dongle . If none of this is the problem than get a long , wire and I mean ten to twenty feet long and see if that does any good . Are you like me , I have dyslexia and you have stated the receiver chip is a R802T2 , or did you mean R820t2 , by the way it's pose to be the same as the R820t just more sensitive .

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Re: RTL+R820T2 direct sampling DLL

Post by rtlsdrblog » Mon Sep 15, 2014 12:37 am

Try this newer modified driver, seems to work better than the direct sampling no-hw-mod dll.

http://www.rtl-sdr.com/new-experimental ... mhz-lower/.

See the comments on that post for some dll downloads.

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