Radarspotting

Mode-S Receivers => DVB-T Dongles and Self-Assembly Receivers => Topic started by: Bethsalem on November 18, 2014, 05:49:40 PM

Title: R820T2 Dongle - First Impressions
Post by: Bethsalem on November 18, 2014, 05:49:40 PM
The R820T2 dongle arrived today, together with a smart new enclosure. I've connected it to my balcony window pcb antenna and LNA.

My first impressions are very favourable.

The noise threshold has dropped by 3dB according to the RTL1090 software and the signal strength/message rate is stronger/higher. I am using the same pcb antenna and would say that I'm not sure if the range has increased because my view from the window is obstructed in some directions. It certainly isn't worse.

At the moment the R820T2 is about double the price of the R820T dongle, but I think it's a worthwhile improvement on the original and worth buying.

Stephen
Title: Re: R820T2 Dongle - First Impressions
Post by: shakysen on November 18, 2014, 06:13:35 PM
Bethy. Buy another PCB antenna an place side by side 10-11/16ins apart. an see if any improvement
Title: Re: R820T2 Dongle - First Impressions
Post by: Bethsalem on November 18, 2014, 06:22:34 PM
Alas the money well runneth dry, so you're going to have to rely on my great observational skills  :)
Title: Re: R820T2 Dongle - First Impressions
Post by: Bethsalem on November 27, 2014, 07:21:42 PM
Quote from: Bethsalem on November 18, 2014, 05:49:40 PM
The R820T2 dongle arrived today, together with a smart new enclosure. I've connected it to my balcony window pcb antenna and LNA.

My first impressions are very favourable.

The noise threshold has dropped by 3dB according to the RTL1090 software and the signal strength/message rate is stronger/higher. I am using the same pcb antenna and would say that I'm not sure if the range has increased because my view from the window is obstructed in some directions. It certainly isn't worse.

At the moment the R820T2 is about double the price of the R820T dongle, but I think it's a worthwhile improvement on the original and worth buying.

Stephen

A more scientific review over at Ham Radio Science can be found here. The newer dongle seems to be an improvement over the original R820T

http://www.hamradioscience.com/rtl2832u-r820t-vs-rtl2832u-r820t2/2/
Title: Re: R820T2 Dongle - First Impressions
Post by: Radio2.0 on December 18, 2014, 10:43:25 AM
SDR# + RTL1090 say my dongle is a R820T instead of a R820T2.  ::)

So what is true?
Title: Re: R820T2 Dongle - First Impressions
Post by: Bethsalem on December 18, 2014, 11:13:03 AM
The software is telling you that you have an R820T dongle. Your dongle is not an R820T2.
Title: Re: R820T2 Dongle - First Impressions
Post by: Radio2.0 on December 18, 2014, 11:32:25 AM
i order an t2 so?
on that picture is no "2" to:
http://www.hamradioscience.com/wp-content/uploads/2014/11/RTL1090-2.jpg
Title: Re: R820T2 Dongle - First Impressions
Post by: Bethsalem on December 18, 2014, 11:52:17 AM
You need to ask for your money back as you've been sent an R820T dongle and not an R820T2.
Title: Re: R820T2 Dongle - First Impressions
Post by: IanH on December 18, 2014, 12:15:13 PM
Not sure whether the software tells the difference. Anyone confirm or otherwise?

The certain way to check is to take the dongle apart. The case just clicks open. Then look to see what the writing on the small black chip inside says - mine said R820T2 so I was happy,
Title: Re: R820T2 Dongle - First Impressions
Post by: IanH on December 18, 2014, 06:01:17 PM
Just run RTL1090, Dump1090 and ModeSDeco with the R820T2 dongle.

Like I thought, none of these identify the T2 chip - they just refer to R820T tuner.

So don't rely on software to check what version you have. Seems like opening up the plastic dongle case is the only certain way to identify the chip.
Title: Re: R820T2 Dongle - First Impressions
Post by: spotter.ssol on May 21, 2015, 09:17:38 PM
I'm getting better range with old R820T:

(http://i657.photobucket.com/albums/uu298/spotter-ssol/2015-05-20_132306.jpg)

???
Title: Re: R820T2 Dongle - First Impressions
Post by: Radio2.0 on May 21, 2015, 09:29:09 PM
1) where do you get the Dongle from?
2) Do you check the Frequency Correction?
3) Do you use the same Antenna at the same Time? (an reset the counter ?)
Title: Re: R820T2 Dongle - First Impressions
Post by: spotter.ssol on May 22, 2015, 12:58:12 AM
1) Both from China;
2) With kalibrate (http://www.satsignal.eu/raspberry-pi/acars-decoder.html#kalibrate)
3) Same antenna (6-element colinear), different days, but same time interval (20 hours, starting at 20:00 GMT).
Did the same test many times, with different dongles, even with different antennas. R820T aways performs better than T2 regarding range. Very weird!
I've posted this because I couldn't find any comparisson over Internet regarding those two. Have any of you guys have made such comparative?

ps: sorry my English!
Title: Re: R820T2 Dongle - First Impressions
Post by: Radio2.0 on May 22, 2015, 10:17:39 AM
I never compare with each other.  ;D.

But buy your dongle on your pc, laptop and search for the next VPLMET in your Area and use this for the exact frequency shift.
Title: Re: R820T2 Dongle - First Impressions
Post by: ajen on May 22, 2015, 01:04:22 PM
Same here.
In my setup the "old" R820T also performs better with receiving ADS-B.
Title: Re: R820T2 Dongle - First Impressions
Post by: spotter.ssol on May 22, 2015, 02:01:15 PM
Quote from: Radio2.0 on May 22, 2015, 10:17:39 AM
I never compare with each other.  ;D.

But buy your dongle on your pc, laptop and search for the next VPLMET in your Area and use this for the exact frequency shift.

Thanks for the tip! Looks like kalibrate was giving me unpropper ppm correction. Will do some tests and report later.
Title: Re: R820T2 Dongle - First Impressions
Post by: spotter.ssol on May 22, 2015, 02:12:36 PM
Quote from: ajen on May 22, 2015, 01:04:22 PM
Same here.
In my setup the "old" R820T also performs better with receiving ADS-B.
Did you used ppm correction?
Title: Re: R820T2 Dongle - First Impressions
Post by: ajen on May 22, 2015, 08:31:43 PM
Yes, I use the ppm correction.
On 1090 MHz the 820T performs better. On other frequencies (ie. 420-470 MHz) the newer 820T2 is better.
Title: Re: R820T2 Dongle - First Impressions
Post by: spotter.ssol on May 22, 2015, 09:46:00 PM
Quote from: ajen on May 22, 2015, 08:31:43 PM
Yes, I use the ppm correction.
On 1090 MHz the 820T performs better. On other frequencies (ie. 420-470 MHz) the newer 820T2 is better.
I've conducted some tests today with propper frequency correction and still got better range with R820T.
Title: Re: R820T2 Dongle - First Impressions
Post by: Rbethman on June 27, 2015, 12:04:47 AM
I obtained the Keedox DVB dongles.  They only have the R820T.  I'm having fantastic results!  I took off that silly tiny whip.  I rummaged around the old ham shack, and located an old telescoping antenna.  It screwed right on the base.  It is 9+ wavelengths long.  The 1090MHz has a wavelength of 5.+ inches.  So by using a four foot whip, the signal has really come up!  The second one I slipped a four foot piece of brass tubing over the tiny whip, and crimped it fairly tight.

Since I'm directly under the Dulles International Airport Southern approach, I can even track them on the runway.