[Discuss-gnuradio] Magnitude dips in transmission

[Usman Haider]

Hi,

I am using Gnu Radio 3.7.8 with uhd 003.008.005 and umtrx v2.2. When I use the attached GRC flowgraph I see random drops in the magnitude of the transmission and also a carrier wave. Please see the link below for the output. I searched on the internet but could not find anything. I used a different umtrx but the result is same. I used uhd.tune_request() as well but no luck. Any thoughts what could be the issue here? Sorry the question is not directly related to Gnu Radio but asking here after find nothing on internet. 

http://imgur.com/a/4P7qP

GRC output:

linux; GNU C++ version 4.8.4; Boost_105400; UHD_003.008.005-0-g7efbd15b

 

Using Volk machine: avx_64_mmx_orc

-- UmTRX driver version: 1.0.3-80-d0a7463

-- Opening a UmTRX device... 192.168.10.2

-- user_mtu.recv_mtu = 1472

-- user_mtu.send_mtu = 1472

-- fifo_ctrl.window_size = 15

-- TempA: 34.500000 C

-- TempB: 30.500000 C

-- Detected UmTRX 2.2

-- Diversity switch for channel 1: false

-- Diversity switch for channel 2: false

-- Known PA types: NONE EPA881F40A EPA942H40A EPA1800F37A

-- Installed PA for sideA: NONE

-- Installed PA for sideB: NONE

-- Time register self-test... pass

-- Looking for FE correction at: /home/man/.uhd/cal/rx_iq_cal_v0.2_4095.A.csv...  Not found

-- Tune Request: 901.000000 MHz

--   The RF LO does not support the requested frequency:

--     Requested LO Frequency: 901.000000 MHz

--     RF LO Result: 901.000000 MHz

--   Attempted to use the DSP to reach the requested frequency:

--     Desired DSP Frequency: -0.000000 MHz

--     DSP Result: -0.000000 MHz

--   Successfully tuned to 901.000000 MHz

--

-- Looking for FE correction at: /home/man/.uhd/cal/tx_iq_cal_v0.2_4095.A.csv...  Not found

-- Looking for FE correction at: /home/man/.uhd/cal/tx_dc_cal_v0.2_4095.A.csv...  Not found

-- Tune Request: 901.000000 MHz

--   The RF LO does not support the requested frequency:

--     Requested LO Frequency: 901.000000 MHz

--     RF LO Result: 901.000000 MHz

--   Attempted to use the DSP to reach the requested frequency:

--     Desired DSP Frequency: 0.000000 MHz

--     DSP Result: 0.000000 MHz

--   Successfully tuned to 901.000000 MHz

Regards,

Usman

umtrx_test.grc
Description: Binary data