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From: | Derek Kozel |
Subject: | Re: This flow graph is radiating negative Tx power |
Date: | Tue, 16 Mar 2021 19:33:46 +0000 |
User-agent: | Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 |
connected the antenna to the good channel Rx/TxThanks, I have been checking out your suggestions.
What i meant by "negative Tx power" is that the Tx power is giving negative value (-30dbm)
1. I have upgraded to GNURadio >=3.8 but it is giving this warning message after trying to import QT GUI sinkBlock paths:
/home/elect/gnuradio/share/gnuradio/grc/blocks
Warning: restarting the docstring loader (crashed while loading 'qtgui_bercurve_sink')
Warning: restarting the docstring loader (crashed while loading 'qtgui_const_sink_x')
Warning: restarting the docstring loader (crashed while loading 'qtgui_edit_box_msg')
Warning: restarting the docstring loader (crashed while loading 'qtgui_freq_sink_x')
Warning: restarting the docstring loader (crashed while loading 'qtgui_histogram_sink_x')
Warning: docstring loader crashed too oftenPls, can you help to solve this problem?2. For QT GUI Sink bandwidth, I will do that when the above problem is solved.
3. Yes I measured the signal power using a spectrum analyzer.4. Did you check your signal amplitude at USRP bloc input? i don't know how to do this but check it when i solve the problem5. yes, i connected the antenna to the good channel Rx/Tx.
On Fri, Mar 12, 2021 at 3:30 PM Christophe Seguinot <christophe.seguinot@orange.fr> wrote:
Hi
- What does "negative Tx power" means ?
A few suggestions:
- move to GNURadio >=3.8 (most of us uses GR 3.8 or 3.9 so it's difficult to help for outdated GR 3.7)
- QT GUI Sink : Bandwith should be equal to sample rate of the block incoming signal, i.e. samp_rate at the RRC Filter output (the FFT Sink does not work as a real spectrum analyzer)
- Did you measure the signal power using a spectrum analyzer ? When do so, the receiving antennna being close to the emitter antenna, you should get the -20 to -30 dB as compared to the emitted power (frequency close to 1GHz and 6dBi antennas (Indoor panel), this is depending on frequency and antenna gain). If your emitted power is +20 dBm, you should measure something in the range 0 dBm to -20 dBm. If not, there is something wrong in the transmission chain.
- Did you check your signal amplitude at USRP bloc input (The maximum value should be 1 Volt to get maximum RF power which also depend on USRP settings
- Did you connected the antenna to the good channel Rx/Tx ?
Sincerely, Christophe
On 12/03/2021 15:08, AKINYELE ITAMAKINDE wrote:
Good day to all community members.Please, I need you to help correct this flow graph configuration. The Tx power radiating is too minimal. I have adjusted and also added some other blocks to boost the signal but all to no avail. The flow graph is been used for propagation channel measurement. I will like someone to take me through or send video and other link on how to solve this problem. The flow graph is attached.Thank you.Akinyele.
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