Greyline_Charts_Using_SpecLab

"Watch and Plot" Look below. This makes charts like mine. There are many free "Screen Capture" programs that can be used to keep records.

http://www.qsl.net/dl4yhf/spectra1.html Any new release should be considered a "beta". Wolf will correct any bugs but best wait a few weeks if you don't want to be a beta tester. See the Yahoo group https://groups.yahoo.com/neo/groups/SpectrumLabUsers/info

As in all I do, I am not an expert. "Spec Lab" is a versatile program that I use to record the signal level from radio stations. It has a comprehensive "Help" file, I include these notes to outline the items relevant to my application.

One can configure it to record two independent signals, fed in as left and right inputs.

With AGC turned off the program will record audio levels representing the received signal strength as long as there is no overloading of the receiver or soundcard. I usually find an attenuator between the radio and soundcard is needed. This can be a preset potentiometer of 5-50KOhms. When signals are expected to be strong an external RF attenuator may be desirable, depending on the radio. Do not set levels too high, raise the soundcard slider so RX noise just increases the noise level on the Spectrum display. Removing the antenna should only lower this level slightly. If signals are expected to be very strong it may be necessary to set levels so antenna noise is not seen.

SpecLab will record the level of the signal by tuning the RX in CW or LSB/USB to produce a beat note with the carrier. The easiest way is to use USB tuned, for example, 1.5KHz below the carrier frequency. A tone of approximately 1.5KHz will be produced depending on the accuracy of the RX display and the computer soundcard. If you know what tone the CW mode produces most radios will produce that tone when the display is set to the carrier frequency. Observe the waterfall or Spectrum Display to make fine adjustments.

SpecLab must be set to record this frequency (Text File Export - Calculated Data). The audio bandwidth that the program responds to can be set to suit the characteristics of the receiver and transmission to be monitored. To avoid false results due to interference the bandwidth needs to be set as narrow as possible consistent with the amount of frequency drift experienced.

Everything is highly configurable, SpecLab has some preset modes, if you make adjustments it will restart using the modified settings but will lose these settings if another mode is selected. You may save your settings, Quick Settings - Load and Create... - Select Menu Nr first - "Menu text" appears in drop down. These settings are saved in the Program Folder (Usually C:\Program Files\Configurations\..) as a .usr file it can be transferred to another computer to duplicate settings.

Take care when changing modes! Each time you select a mode the screen capture number is returned to that set when saving the mode so previous captures may be overwritten. This is not noticed until you begin to wonder why earlier captures cannot be found! To avoid this, and to make the monitoring process automatic "Scheduled Actions" may be used. This requires use of the Command Interpreter. I include a couple of examples below.

The waterfall sensitivity range is affected by the range selected on the spectrum display. Options - Spectrum Display - second tab - Set "Displayed Amplitude Range" to cover the range of signals you are viewing. Then the sliders on "Color Pallette" can be set.

Spec Lab will capture the screen at preset intervals, this is useful to confirm results by examining the waterfall. This is especially useful when signals are weak and the program may be recording interference within the passband. The actual audio frequency recorded can be included in the exported txt file, jumps in frequency can indicate false results due to interference. The frequency trace will show multipath effects, sometimes seen around dawn/dusk and sometimes during the night. This is best seen on the captured waterfall. The system setup can be confirmed later by recording the noise level. Undue interference may show up with increased levels of noise. The the actual noise level can help confirm that signal levels were setup similarly to other recordings. The difference between signal and noise (S/N ratio) will give a measure of the readability of the signal. Especially at the lower frequencies the noise may reduce giving better readability without an actual increase in signal strength.

The exported text file may be displayed as a chart using "Excel" or other program. The freely available "Open Office" has a spreadsheet application similar to Excel. See my notes at the bottom of this page.

SpecLab has a "Watch and Plot" function that will draw charts.

I do not use this feature as I have always used Excel, along with SpecLab's "Scheduled Actions" this makes regular recordings with the minimum of work.

The ini file that configured this plot my be downloaded at the bottom of this page. Note Wolf obviously likes a black background, I had to experiment a bit before I got what I wanted.. Then I read the "Help"!

The plotter is found at "View/Windows" and the ini will need to be loaded at "File" on the plotter window. Basically all that is needed is just one of the free screencapture programs that enable you to select the chart, "Paint" will do the rest. As always, if the capture is saved in PNG format the file size will not be excessive. IrfanView,http://www.irfanview.com/ has screen capture/crop features and will add text. The PNGSAVE included in it's add-ons reduces file size further.

"Watch and Plot" charts may be saved by a "Scheduled Action" eg. plot.capture("C:\SpecLab\Chart-"+str("DD-MM-YY",now)+".jpg") or maually by "File - Capture Plot"

The "Watch and Plot" is highly configurable, like all of SpecLab's features. It may take some time to get it as you wish. Regularly ticking the two "Apply" buttons and restarting the plotter eventually gets you there!

Chart Features:- The top line shows the signal strength as recorded, (equivalent to "S meter") The bottom, black line shows noise level. This will give some measure of the readability of the signal. Especially on lower frequencies the noise level can vary a lot, usually higher at night, sometimes raised by local interference. The green frequency trace shows variations caused by propagation. This is also affected by receiver or transmitter drift. Large jumps usually indicate an interfering signal making readings unreliable. Examination of the waterfall may confirm this but there is always the possibility that another station is present on exactly the same frequency.

Note this chart I show does not use the configuration displayed below but the principle is the same. This chart window can be resized to show just the portion required. My configuration shows about 17 hours, use the past/present slider. This can be increased by adjusting the buffer in the Memory/Misc window. The "Watch List" is configured like the Text Export below.

This is one of mine. The "-4" of the noise expression is an adjustment to bring the signal and noise traces to the same level when there is no signal.

SpecLab:- SETTING UP THE TEXT FILE

File - Text file export - Export of calculated data - File contents tab.

This sets up the text file contents so that it may be imported into Excel/Open Office or similar program.

Column 1. Time format.

Column 2. Signal being observed. Sets frequency range to be recorded. Needs to be as narrow as possible consistent with the drift of the signal and receiver.

Column 3. Noise figure recording. This is useful to give an idea of the signal to noise ratio. Also when displayed on a chart it will indicate that interference may be present, referring to a screen capture may then confirm the readings. This noise figure is compensated, the -4 deducts 4db from the recorded figure. I made this adjustment so the signal and noise figures were the same when no signal is being received. The frequency range is selected to avoid any signals. There are many options to produce this figure, this is what I am using at the moment, the Help files give other techniques that may give better results.

Column 4. Not really needed. Records the frequency of the peak that is recorded. I rarely refer to this, it is more relevant for recording signal drift. If a trace is included on the chart a frequency jump could indicate false readings.

(Column 5. (Not illustrated) It has been suggested the date is included, enter as column 1 Date - time - DD-MM-YY (or your preferred.) OR include in column 1.)

Click the "Test" button to test the results are as expected. The Help files are in the "Program Files" SpecLab folder \html. (In some of my SpecLab installations of I have not found the "Help" button to work)

Sets location where text file is stored. The write interval gives the period that samples are taken, 15 secs gives 4 lines of text each minute. 60 secs is probably more than normally required.

Scheduled Actions. You may make SpecLab do it all automatically - just leave the radios and computer on. This requires use of the Command Interpreter, example below.

At a specified time, eg 04.59, the following.... export.start(#1,"C:\SpecLab\3935-Text\3935-e"+str("DDMMYY",now)+".txt") .... will start a text export file in C drive folder SpecLab\3935-Text , its file name will be 3935-e241206.txt (As specified for the first text file if you need than one text file) The date (English format but put it in whatever you like) and time will make the file unique. Similarly on another line with another time...capture("C:\SpecLab\1-AM"+str("DD-MM-YY-hhmm",now)+".jpg") .... will give a screen capture in that folder, again with a unique filename, 1-AM24-12-06-0935.jpg . . .... export.stop(#1) .... will stop the export to the #1 text file. Do not specify two actions for the same time.

SpecLab will record two separate signals from two different sources. (But NOT in the high resolution "MW-MH" mode). the screenshots above show the parameters. The Flag directs the readings to separate text files, value "3" directs the time to both files. The waterfall is split into two to show the independent traces. My file 23102485.zip may be downloaded at the bottom of this page The .usr files may be imported into SpecLab to show my settings, used or modified as required.

I also use a modified version of the "MW Offsets" SpecLab file MW-WH.usr My file mwmh1701.zip my be downloaded at the bottom of this page. It is altered to suit my radio's frequency (CW, narrow filter mode). I also prefer a coloured waterfall.

I recommend as much experimenting and practice as possible. Although useful results are quickly obtainable it took me a long time to set things to what I consider optimum. A reasonably good receiver is desirable with good frequency stability. It may be possible to use one that does not enable you to turn off the AGC, try reducing RF gain or putting a variable attenuator in the antenna so that AGC does not operate. I have used an AOR 7030 and Yaesu FT840 (With a mod to disable AGC and a Khune Crystal Heater to improve stability). Signals at the antenna socket do not need to be strong, I use at least 15db attenuation. (I was not satisfied by an HF225 but an FT847 will give adequate results with the RF gain turned well down.)

SpecLab has an I/Q function that is ideal for using an SDR for recording signals. Sample rate may be selected as required, I now have a total of five "Softrocks" running on my monitor computer. There are four instances of SpecLab I/Q at 8KHz sample rate. I use Si570s with a "centre frequency" 3KHz below the signal, this gives an audio output of +3KHz. (Because SDR uses phase cancelling you get "negative" frequencies as well!)

The "Lite" version of the Softrock, an early version is shown below.

These are "Software Defined Radios" (SDR) using a small cheap board that converts the antenna signal to a low frequency that the soundcard of a computer can process. These receivers have a limited tuning range but if a crystal is available to give reception near the required frequency (+/- 48 or 96KHz depending on soundcard used) then they are ideal for long term monitoring. A DDS or the Si570 can be used for frequency flexibility. They can even use the computer to power them! https://groups.io/g/softrock40 is the group, the kit designer and supplier is here, dig around or ask for details. They are much cheaper from Tony than at local dealers and postage from USA is only a few days.

More expensive are the "Ensemble" receivers which cover all HF without modification. Kits or ready-made http://fivedash.com/ Other companies also supply similar receivers. 2020;- now not so many available, some others suppliers are still selling soundcard SDRs.

In addition to the RX versions there are RX/TX ones that will enable QRP with a laptop and an antenna. SSB, CW and digital modes can be used over the tuning range. It is surprisingly easy to fit the few surface mount components.

An audio output is possible see Wolf's remarks below!

"Of course the combination SpecLab/Softrock is not display only. It can be used as demodulator with filtered / converted / inverted audio output, i.e. you can use it as USB / LSB / CW receiver. With some more fiddling, you can also use it as an FM / AM demodulator (the "dsp blackboxes" must be used to demodulate the latter).

As a starting point, use the configuration "Image Canceling receivers (I/Q)".."SDR-IQ / 37 kHz / downconverter and adjustable filter". You will get an error message first (because there is no SDR/IQ connected to your PC). So after loading the "SDR" -configuration, select "Options"..:"Audio Settings", set the Audio Input Device to "Soundcard" (instead of SDR-IQ), and set the audio sampling rate to 44.1, 48, or 96 kHz (depending on your soundcard). When you open the Spectrum Lab Components window after this, you'll see both inputs from the (stereo) soundcard go to the digital filter in the middle of the window. The filter actually does the I/Q processing, filtering, and conversion of the complex signal into a real signal which is finally sent to the output. 73, Wolf DL4YHF ."

The Softrock is not over sensitive but may need an attenuator for strong signals.

EXCEL SPREADSHEET FOR MAKING CHARTS. ( SpecLab has a plotter, will make and capture charts similar to these. See my notes above.

Charts may be prepared from the text file using Excel. They give a summary of a recording session at a glance. Always compare the chart with the waterfall screencaptures to ensure they actually DO represent reception! If anyone has Excel I can provide my crude .xls file and some guidance from knowledge I have gained by fumbling around with tips given by others.

I am pretty well a beginner in "Excel" so this is written for beginners!

Data can be used straight from the text file, or, copy and paste from it into a new .txt file. Excel will import a text file. "Data - Get External Data - Import Text File". Direct Excel to the file, Import as Delimited, Tab. Afterwards, "Data - Refresh" will go to that location for another text file.

To make a chart:- "Insert - Chart" This can take a bit of doing! I have various Excel files which will enable you to make a start by just refreshing the text file. (Use "Data - Refresh") Save a copy of my file, then you can do anything and start again. Most likely you will improve on my effort and save that instead! Contact me if you have any questions.

I now use the method of "Including the Chart as an Object on a Sheet". This gives the option of resizing the chart to suit your purpose. A sample Excel file XLsample2.zip may be downloaded at the bottom of this page.

Click on the "Chart" Tab. Right click on grid lines to alter the scale. Right click on the chart background to change title, right click on the plot lines to change colour etc. If the chart is not correct the data may be edited, or, start again with an edited text file. Do not save changes! Keep an unmodified copy of my original .xls My chart contains Text Boxes and marker lines, these can be edited, moved or deleted.

I have found that Excel charts "Saved as a Web Page" do not always place the added objects correctly. I copy the chart (Right click on the outer edge of the Chart area, click "Copy"). Open "Irfan View" (IrfanView (Free image viewer and converter etc). ) - Image - Create New (Empty) Image. Control-V pastes the chart image into Irfan, then "Save As" .png gives a true image. This may be reduced in file size by using the IrfanView PNGsave plug-in.