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Posted: Wed Nov 30, 2016 6:20 pm
by g4rqi

I wasn't sure which forum to post this in

I am using my SDRplay to monitor the noise floor for interference... basically I want to know at what time(s) of day the noise floor on 70Mhz increases here by 15db or so. It doesn't have to be the whole band in fact just a bandwidth of 10Khz would do.

Is there a way of checking the noise floor every minute and outputing the noise floor level to a text file or csv with a time stamp or a method whereby I can get/fetch the noise floor in dbm?

This wouldn't help me but a means of starting and stopping a recording once the squelch opened and closed would be a nice feature



Posted: Thu Dec 01, 2016 6:15 pm
by 13dka
Not knowing why exactly you want to do that (sounds like you're fighting with local interference):

You could use HDSDR's ultra-slow waterfall feature to get the approximate time (within the limits of the timestamps at low speeds). If you click on "Speed" under the main waterfall, you can enter a time in minutes that a whole waterfall window content is covering, e.g. 1440 for an entire day.

Apart from external recording programs, I'm afraid the only "internal" way of squelch-triggered recording is Vasili's awesome "Audio Recorder" plug-in for SDR#. You'd need to use SDR# v1361 (link is somewhere here in the forum) and an old version of the plug-in (both can be found via this forum viewtopic.php?t=248), because newer versions won't run plug-ins with the RSP1.


Posted: Thu Dec 01, 2016 10:08 pm
by g4rqi
Basically I want to know at what time of day my noise floor rises when I'm out at work so that when I do get the chance to try and find the source I know when to expect the QRM to come and go. To be able to output the level of the noise floor into a spreadsheet plotted against time would be quite useful to me.



Posted: Fri Dec 02, 2016 11:59 am
by 13dka
In that case HDSDR's slow waterfall should be helpful. When you come back home, you can stop the radio (hit F2) and just let the mouse cursor hover over the beginning (and end, if any) of the visible traces of the noise to get the times pretty accurately. I'm not sure how a table with absolute levels would help you, the waterfall can give you an impression on when it gets louder or softer only, but may that would suffice?

BTW, this is also very helpful when experimenting with antennas outsides - estimate how long it will take you to fumble around with your antenna, add 15 minutes safety margin for unexpectedly disappearing tools, set your waterfall speed accordingly, go outside, make a change, note the time, make another change, note the time again, go back in and check what the changes did to a chunk of spectrum or a single frequency in question.


Posted: Fri Dec 02, 2016 9:06 pm
by DaveB
SDR-Console v2 has a separate application called SDR Data File Analyser. Once you have recorded a file (or series of files) - from SDR Console v2, or HDSDR (SDR-Uno not tried) you can then load the recording into the program - select signal history and it will display the signal strength of the selected frequency for the whole recording.

The photos linked below show you a 10+ minute recording from HDSDR which consisted of three consecutive files with a 2 Gbyte file size limit. The bandwidth of the recording was 1.536MHz with 2 mbps sampling rate to cover the whole of the medium wave band.

When loading the file into the Data Analyser I selected a 200 kHz bandwidth centred on 1500 kHz which gives a nicely expanded view.

Note that the file analyser has no problem with reading the embedded time stamp in the HDSDR wav file

The signal history shows the variation in the signal on 1521 kHz - which happens to be a Spanish station at that point in time. There doesn't appear to be a method of snapping the mouse to a selected step eg 1 KHz.

I'm starting to use the SDR-Console v2 / Data File Analyser combination for MW DX-ing.

PDF manuals come embedded in the SDR-Console software download.



Posted: Sat Dec 03, 2016 11:29 am
by g4rqi
Thanks for the reply I will take a look and see what I can do

73 David


Posted: Mon Mar 27, 2017 3:29 am
by radiosky
I have a program with a free version on my website that might be of interest. It records a strip chart of the sound card (or adc) output. It runs on Windows, and is called Radio-SkyPipe. So you can run HDSDR or whatever program demodulates to audio, and set Radio-SkyPipe to record the audio envelope. You can set it save automatically every X hours.

The down side is that this only works if the interference is evident at the demod frequency so you need a broadbanded source of RFI or one that always emits at the demod frequency.

I also have a way to record the power in each of 50 to 512 bins at about 10 sweeps per second and it has a interface for the SDRPlay1. ... o-sky.html