Архив за 28.01.2018

Comment on TETRA Decoder Plugin for SDR# Now Available by Alex

@kikosgc: Yes it plays clear voice if the channel is not encrypted.

Comment on TETRA Decoder Plugin for SDR# Now Available by Alex

Works like charm on Win 10 64bit.

Comment on TETRA Decoder Plugin for SDR# Now Available by Jerzy Szymkiewicz

I tried all the ways. The same problem every time. At the end I installed the latest SDR # and everything started working!

Comment on TETRA Decoder Plugin for SDR# Now Available by Shehzad

brute force,
Thanks for explaining in detail. Very good information is explained in easy to understand manner for people like me who are not engineers .

На 1510 Кгц работа с ЧМ модуляцией. Кто знает, это «свободные вещатели» или военная станция какая то?…

На 1510 Кгц работа с ЧМ модуляцией. Кто знает, это "свободные вещатели" или военная станция какая то?

Comment on TETRA Decoder Plugin for SDR# Now Available by brute force

6> Totally, the encryption used is TEA1, TEA2, TEA3 or possibly even TEA4 which uses a 128 bit key, but probably only 80-bits of which are used actually protect the data. So all you need to do is to brute force roughly an 80-bit key (1208925819614629174706176 possible keys). So if you cycle through each one and validate that the audio is correct, say at the rate of one key per second, it will only take 38308 trillion years to find the right key. And if it actually is using all 128 bits then add an extra 15 zeros to the time required.

But if you feel that you can find a weakness in the algorithm have a look at the original papers documenting the algorithm. I am not saying that there is not a weakness with TEA, just that no one has found one and made that information public.in last quarter of a century.

(TEA1) http://www.movable-type.co.uk/scripts/tea.pdf
(TEA2) http://www.movable-type.co.uk/scripts/xtea.pdf
(TEA3 and TEA4) http://www.movable-type.co.uk/scripts/xxtea.pdf

Comment on TETRA Decoder Plugin for SDR# Now Available by atmel

If the channel is encrypted you can’t listen to the channel. Try to find another channel. (TETRA channels have a charecteristic shape and sound when listening it without the plugin). Also try to set the bandwidth to about the width of the channel like you can see in the capture I linked in another post.

Comment on TETRA Decoder Plugin for SDR# Now Available by Shehzad

I can see Channel is encrypted. In can see see “Air encryption: 1” in the Msys window
RTLSDR is set at 2.048 Msps I
3)Freq is well centered on the channel and set the bandwidth to about 48KHz
4.) Mode is WFM
5) Tetra plug in doesnt accept NFM
6.) Is there any software to hear encrypted transmission ?

Comment on TETRA Decoder Plugin for SDR# Now Available by atmel

There may be two reasons if the sound is not good:
1)Channel is encrypted. In this case you will see “Air encryption: 1” in the Msys window
2)RTLSDR might be instable at 3.2Msps I/Q ADC samplerate. Try to reduce the ADC samplerate to 2.4Mspsbor lower and see if it works better
3)You have to be very well centered on the channel and set the bandwidth to about 18KHz

Comment on TETRA Decoder Plugin for SDR# Now Available by Shehzad

Thank you very much , i reinstalled vcredist 32 AND 64 bit and it worked .
Now I can hear garbled voices

Перевод
Рубрики
Архивы
Январь 2018
Пн Вт Ср Чт Пт Сб Вс
« Дек   Фев »
1234567
891011121314
15161718192021
22232425262728
293031