RTL-820T2 IF filters / ISR reception

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JDAK907
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Joined: Sun Feb 10, 2019 10:26 pm

RTL-820T2 IF filters / ISR reception

Post by JDAK907 » Mon Feb 11, 2019 6:10 am

Hello,

I have been looking for specifications on the IF filter stage of the RTL-R820T2, but don't see it listed specifically with that description. I have read that the IF filter can be set as low as 300kHz but the standard setting is around 7MHz for DVB-T signals. I am looking to receive an incoherent scatter radar with a 2μs pulse and need the IF to be around 500MHz. Also a 440μs pulse/2.27kHz IF mode will be a target. I don't necessarily want to decode, just detect. Can anyone tell me if I am on the right track? I haven't purchased an RTL yet, pending confirmation of the specifications.

Thanks!
JD

alanzfq
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Joined: Thu Oct 04, 2018 11:18 am

Re: RTL-820T2 IF filters / ISR reception

Post by alanzfq » Mon Feb 11, 2019 10:25 am

If you use the right DLL
I've no more details except it is associated with this author https://github.com/ms-jdow/rtlsdr-Cplusplus-VS2010
Alan

rtlsdrblog
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Re: RTL-820T2 IF filters / ISR reception

Post by rtlsdrblog » Mon Feb 11, 2019 12:04 pm

Why do you want to change the hardware IF?

You can just tune to 500 MHz in any receiver software like SDR#, and detect it there.

alanzfq
Posts: 14
Joined: Thu Oct 04, 2018 11:18 am

Re: RTL-820T2 IF filters / ISR reception

Post by alanzfq » Tue Feb 12, 2019 9:19 am

Having looked a bit further I find https://www.rtl-sdr.com/new-rtl-sdr-dri ... r-console/ which appears to suggest that in the presence of strong out-of-band signals performance may be improved.
Alan

rtlsdrblog
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Re: RTL-820T2 IF filters / ISR reception

Post by rtlsdrblog » Tue Feb 12, 2019 9:48 am

Tweaking the IF filters can help a bit in borderline cases, but if you're experiencing overload issues the real fix is to use an external filter.

alanzfq
Posts: 14
Joined: Thu Oct 04, 2018 11:18 am

Re: RTL-820T2 IF filters / ISR reception

Post by alanzfq » Tue Feb 12, 2019 10:03 am

Yes, that is the first thing to do.
Front end filtering can improve even the best receivers.
Alan

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