Архив за 23.05.2019

[NOAA 18] Constance lake this evening. We still have snow on the Alpes!

[NOAA 18] Constance lake this evening. We still have snow on the Alpes! submitted by /u/Florentin314
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Comment on Stratux 1090 MHz + 978 MHz Diplexer Now Available by snn47

Thank you for the curves. Imho the insertion loss representation at amazon is quite misleading to potential buyers, since it does not clearly identify the total insertion loss
– 978 MHz insertion loss (above 3 dB): 2.73 dB @amazon vs. total insertion loss of 5.78 dB @978 MHz
– 1090 MHz insertion loss (above 3 dB): 2.88 dB @amazon vs. total insertion loss of 5.88 dB @1090 MHz

Can you confirm if I identified the logo correctly for 1090 MHz as Tai-Saw Filter, possibly TA1090EC (insertion loss 2.3 dB typ. 3.0 dB max) and the 978 MHz saw filter could be a TA0395a (insertion loss 2.2 dB typ. 3.5 dB max) since there don’t seem to be to many manufacteres for 978 MHz.

If you check the filter curves they are quite wide and provide not much more attenuation than 10 dB 20 to 30 MHz above and below the center frequency.
Depending the frequencies in use on your location signals can exceed -40 dBm (meassured) on multiple/many channel from e.g. :
– cell phone base stations below 960 MHz
– ground and aircraft transmitter
– L-Band PSR between 1215 MHz and 1400 MHz

KerberosSDR • Re: Problem with direction

rtlsdrblog wrote:
Thu May 23, 2019 10:26 pm
Could you post some screenshots? Also what model phone and Android version do you have? I'll get the Android dev to look into it.

The manual mode is a bit tricky at the moment. You need to rotate the map, and that sets the manual heading. In a future version i'm going to have him change it to simply entering a heading manually.
Oneplus 6 android version 9. Also briefly tried with Nokia 6 and it seemed to have same problem.

Here's screenshot from logfile

Thanks again for quick reply!
Screenshot_20190524-012833.jpg

Statistics: Posted by Duppo — Thu May 23, 2019 10:31 pm


KerberosSDR • Re: Problem with direction

Could you post some screenshots? Also what model phone and Android version do you have? I'll get the Android dev to look into it.

The manual mode is a bit tricky at the moment. You need to rotate the map, and that sets the manual heading. In a future version i'm going to have him change it to simply entering a heading manually.

Statistics: Posted by rtlsdrblog — Thu May 23, 2019 10:26 pm


KerberosSDR • Problem with direction

Is anyone else having problems with GPS heading? As far as I understand red line is supposed to be the gps heading, but for me it usually points 20-25 degrees to the right from where I'm actually heading. The regular blue arrow points correct.
Also how exactly manual heading mode works?

Thank you :)

Statistics: Posted by Duppo — Thu May 23, 2019 10:19 pm


KerberosSDR • GPR/WPR

Assuming "1000V" is a peak voltage (plus and minus), that is 354 Vrms and into a 50 ohm load would be 2.5 kW.

According to http://www.radartutorial.eu/02.basics/G ... ar.en.html, a page I found to be correct on PSR and SSR RADAR so far, Ground Probing RADAR that use a short pulse with peak voltages is between 20 to 200 V. I have not seen details of antenna designs and how they are fed by the pulsegenerator, but I do not assume that they are anywhere near to 50 Ohm due to the high bandwidth and very low frequencies involved.

There are also Wall Probling RADAR operating above 1 GHz using UWB signals, which have much lower EIRP.

Problem for all types of such wideband sensors is as always Electro Magnetic Compatibility and Radio Frequency Interference to existing primary services.

Statistics: Posted by snn47 — Thu May 23, 2019 9:38 pm


Comment on Assembling the Chinese RTL-SDR Direct Sampling Kit by Eric Carter

I am at the assembly stage of making the RF Impedance transformer. The Amazon.de seller included wire, but without differing colors. I am so glad I found this website.

Разъясните, пожалуйста, вопрос в отношении необходимости применения…


Разъясните, пожалуйста, вопрос в отношении необходимости применения сепаратора (разделителя) питания при работе связки LNA от RTL-SDR Blog и RTL-SDR V3.
В описании к МШУ указано: "...Requires bias tee power, but there is an internal header which can be used to switch to external power, although for external power wires you'll need to drill a hole into the enclosure.
Please note again: Requires 3 - 5v bias tee power. The RTL-SDR V3 provides 4.5v so is suitable..."
Судя по фото, можно припаять провода питания на плату МШУ и использовать переключатель (BT OFF BT ON) и тогда сепаратор уже не нужен ?

Comment on Submit a Story/Contact by qrp

I opened topic on the forum for discussion about it: https://www.rtl-sdr.com/forum/viewtopic.php?f=1&t=4710

Other SDR Devices • Airspy HF+ Discovery

This morning when I opened my email I saw this letter from Airspy ( Dear Airspy fans,

Thank you for your patience and your encouragement during all these years! We are pleased to announce the availability of the Airspy HF+ Discovery on pre-order. We got everything ready for delivery in about one month.

How did we come to this? Do you remember the high performance HF Pre-selector project we started a few months ago? It was an opportunity for us to Discover the full potential of the Harmonic Rejection Mixer design when used in certain conditions. With the help of our partners Itead Studio, ST Micro and friends, most notably Leif Asbrink SM5BSZ, we could squeeze a new and improved front-end with a lot of pre-selectors along with a new firmware into a state of the art radio with unprecedented performance and form factor.

We created a coupon code for you, Airspy Fans, so you can get $50 off at Itead and Airspy.US when you pre-order this unit. The coupon is limited to 100 units at each reseller, then the regular price applies. First come, first served!

Coupon: AIRSPY2019 )
Now I think it's grate that they have a improved HF+ and I ordered one . The only complaint that I have is that the Dam collage kid's couldn't leave well enough alone and keep the two RF connectors , No they had to take one way . Dam Collage Kid's

Statistics: Posted by P-40 Warhawk — Thu May 23, 2019 1:36 pm


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