Messages

1786

SDR - Software Defined Radio / Re: SDR# Waterfall

« on: March 15, 2013, 0456 UTC »

A couple of suggestions.

First select “Correct IQ” in the “Radio” pane (upper left).  This will not do anything for your noise issue but it will reduce the DC bias or LO spike in the middle of your display

Then try adjusting the Spectrum “Offset” and “Range” slider under the “FFT Display” pane (lower left).  I would try the Range slider first, pushing it to the left a bit from where you have it.

Another suggestion, crank up the FFT Resolution (you have it at 2048 in that image, try 8k or 16k and see how that looks).  This will result in a smoother waterfall, with the data less blocky.

It also looks like the switch in resolution when you went full screen messed with the display, there may not be anything you can do about that excpet to not switch resolutions.

T!

1787

General Radio Discussion / Re: Waterfall Display

« on: March 14, 2013, 0243 UTC »

The last example for this evening will be CW, Morse Code.  More correctly this is actually ICW, Interrupted Carrier Wave, as pure CW would carry no data.  In the Hobby Morse on a keyed carrier is just called CW by most people.

Notice that there is just the carrier, and it is interrupted, turned on and off.  This makes the Dihs and Dahs of the Morse code.  Depending on the flow rate of your waterfall and the speed of the CW sent you might be able to make out each character as it is sent.

In the case of this picture there are 3 CW signals near the center of the waterfall.  Theya re unrelated.  Using the frequency scale across the top you can tell these 3 CW transmissions fall on 7042 kHz, 7045 kHz, and 7047.5 kHz.



I will grab some other examples and post them later if I remember, maybe some digital signals, FSK, FAX, radars, etc.

T!

1788

General Radio Discussion / Re: Waterfall Display

« on: March 14, 2013, 0234 UTC »

This next example will be SSB, Single Sideband, an image for each, USB (upper side band) and LSB (lower side band).

With SSB you notice that there is no carrier present.  SSB is realistically an AM signal with an unwanted sideband and the carrier stripped away.  In the case of USB you strip away the carrier and the lower sideband, for LSB you strip away the carrier and upper sideband.

The first picture is USB.  Note that the data (voice) seems to bunch up at the left side of the signal with a more even line to the left and a more ragged line to the right.  Left in this case is the lower frequency side.  If your waterfall reverses this, low frequency to the right, then the data would appear reversed.

The second image is LSB.  Now the data is reversed.  The information seems more bunched on the right side of the signal.  The right side is more “even” and the left side more ragged.

This right/left smoothing ONLY works for voice, and female voices can be less clear on the waterfall, as they often have a lot of high frequency components.  When digital signals are sent via SSB it is sometimes difficult to tell, visually, which mode they use.  If the mode is symmetrical, having no dominant data tones or lines, it might be impossible to tell visually which mode is being used.

USB signal:



LSB signal:


T!

1789

General Radio Discussion / Re: Waterfall Display

« on: March 14, 2013, 0222 UTC »

OK, I grabbed some basic examples.  I have been meaning to add some to my pictures online anyway, so this is a good time.  Will start with the basics and maybe move on from there.

Keep in mind that your specific settings of waterfall rate, displayed bandwidth, palette selection, intensity and amplitude scale, etc, will all change the look of the signal.  This is just a general example of how the signal looks, but with some setting you can make it look very different.

First will be AM (Amplitude Modulation), full double sideband plus carrier, this is the most common type of signal called "AM" but that term can actually be applied to several different common modes.  In this case the first picture is an AM broadcast station.  The second picture is WWV on 10000 kHz.

With AM the first thing you see is the carrier in the middle of the data.  The next thing to notice is that the data is presented twice actually.  On the left and right of the carrier is the data/information/audio, and they will be mirror images of each other.  These are called the sidebands of the signal (not to be confused with SSB, Single Side Band).  And yes, they each should contain the exact same data.





T!

1790

General Radio Discussion / Re: Waterfall Display

« on: March 12, 2013, 2206 UTC »

A waterfall display in what application?  Are we talking an audio based waterfall of the detected signal or are we talking something wider banded, such as on the IF of a traditional receiver or as is commonly found with many hobby SDRs?

Assuming the waterfall flows down the page (shouldn’t all waterfalls?  But, all do not, some are sideways or even flow up the page) then down the page is a history.  The newest data/information/signals are at the top of the display and the oldest are at the bottom.  How old depends on the flow rate.

Most commonly lower frequencies are to the left and higher to the right.

Intensity or signal strength is often in the Z axis.

Assuming the waterfall flows down, the lower freqs are to the left, and the intensity is in the Z-axis:

At a glance then you can tell several things about any signal on the display.  First you can tell when it happened, several seconds ago, now, etc.   This is seen in the vertical axis.  You can also tell if signals across the bandwidth displayed are synchronized or related in time.

Next you can tell frequency of the signal (or many signals at one time), because of the left to right (horizontal) relationship of the bandwidth displayed.  Remaining in the horizontal axis you can also tell the bandwidth of the signal.

And finally you can tell the strength of the signal.  Quite often “brighter” is stronger, but the color palette can be set up almost any way you want, you could have dark be strong if you so desire.

With relatively little exposure you can tell signal mode at a glance also.  AM signals can be easily differentiated form SSB.  USB and LSB can each be visually identified.  CW signals are clearly identifiable.  More complex signals, such as various digital modes, can often be visually identified to specifics of the signal, such as the shift of an FSK signal.  On much more complex signals, like radars, the modulation techniques used and basic performance capabilities can sometimes be quickly approximated by the visual representation.

Waterfalls are a completely different way to deal with signals.  If you have never used one it is like opening your eyes for the first time (in my opinion) and if you have used one going to a situation without a waterfall is like losing a dimension or a sense.

Then again, I have been using waterfalls for over 35 years, so I might be a little biased or jaded.  It is, and has been for a long time, second nature now.

T!

1791

General Radio Discussion / Re: Ham Radio in Hollywood: Last Man Standing to Feature Amateur Radio Storyline

« on: March 12, 2013, 1415 UTC »

Well at least she is on 14272, and not 275 or 313

T!

1792

General Radio Discussion / Re: Question about Logging Receptions

« on: March 11, 2013, 2040 UTC »

For reception stuff I have a custom logging DB that I built in FileMaker Pro.  It has specific input formats depending on the type of reception, selectable with the click of a button.  Examples of formats: numbers station input, military input, maritime input, aviation input, general utility input, BC SWL input, MW BCB input, RADAR/Sounder input, etc.  All the info is in the same DB, but each input page is tailored to the service.  Although it sounds elaborate the process is very simple, for example if I hear an SWL station and want to log it I click the SWL button and SWL specific input fields show up on the form.  Been using it for years.  However, because digital is fragile, and in addition to digital backups, I also print reports generated using the DB from time to time and put them in a 3 ring binder.

Yes, my ham stuff goes in a separate log.  For ham use I have an off the shelf logging program, I think it is from N3FJP.  Again, I periodically prit reports from the information in the log, so that if it ever dies I have a paper backup.

T!

1793

Other / Re: 43 meter band wide noise 2105 UTC 10 Mar 2013

« on: March 11, 2013, 2019 UTC »

Chris, how long does the noise last?  There is a 400 kHz wide sounder that wacks that portion of the band from time to time that presents a pattern like that on the waterfall, but it is on for aobut 2 minutes and off for 15 or so.

T!

1794

North American Shortwave Pirate / Re: 6925U 01:42 UNID

« on: March 11, 2013, 0145 UTC »

This station was in AM, not USB.  Part of a single song (Beethoven's 5th) and then off.

T!

1795

North American Shortwave Pirate / Re: BOR 13875 KHz USB 3/10/2013 1626 UTC+

« on: March 10, 2013, 1726 UTC »

Signal peaked here for a while at about 15 or 20 over S9, but most of the time has been right about S9 or jsut atad over.  Signal is strongest on my China oriented Rhombic, stronger even than either of the beams.

T!

1796

North American Shortwave Pirate / KMUD, 6930 USB, 03/09/2013, 0225 UTC

« on: March 09, 2013, 0244 UTC »

KMUD on 6930 USB, 03/09/2013, started about 0225 UTC.

Several IDs sent at various times, both voice and CW.  Voice was sent "Kilo Mike Uniform Delta" and "K - mud".  Announced "an eclectic mix of music for the discriminating shortwave listener".  Very nice signal, but that is to be expected since their announced location and mine are about the same.

Nice!

T!

1797

Utility / Re: HAARP 8605 & 9305 3:00z 3/6/3

« on: March 08, 2013, 0320 UTC »

glimmer, when looking at these kinds of signals it is conventional to list the center frequency.  In this case the center freqs for the 2 transmissions (simultaneous) were 8630 and 9330 kHz.

HAARP has been using these freqs (and others) for this FMCW signal for the last 5 or 6 nights. 

T!

1798

Utility / Re: UNID 6900AM 0132UTC 5Mar13

« on: March 08, 2013, 0244 UTC »

HAARP.

The 6900 kHz carrier is associated with the 100 kHz wide FMCW HAARP transmission on 7700 kHz.  The last few nights I have noted this 800 kHz offset carrier with the HAARP FMCW.  Note that the carrier happens twice as often as the FMCW waveform.

Image here (would embed, but it is a bit over 1 MB in size, will just post a link instead):
http://www.pbase.com/token/image/149104580/original.jpg

After HAARP vacated the 7700 / 6900 kHz pair it moved the FMCW to 6900 kHz and the carrier was on 6100 kHz.

T!

1799

SDR - Software Defined Radio / Re: NooElec brand RTL-SDR dongle

« on: March 04, 2013, 1512 UTC »

The lower frequency cutoff on the dongles is usually around 60MHz or so.  However....lookee what I found:

http://george-smart.co.uk/wiki/FunCube_Upconverter

And it even looks achievable by my (questionable) soldiering skills.

The E4000 dongle cuts off just below 60 MHz, the R820T cuts off just below 25 MHz.  The R820T is also more stable and has tighter phase tracking across the two I/Q channels.

T!

1800

SDR - Software Defined Radio / Re: New to SDR

« on: February 04, 2013, 2319 UTC »

While the SoftRock Ensemble II has performance issues (as do all sound card based SDRs) it is probably, dollar for dollar, the best HF SDR on the market.  For less than the cost of a low end portable you get really decent performance.

The problem I have with the Ensemble, and similar, SDRs is that they are often not plug and play, it sometimes takes a little tinkering to get them working optimally.  I seldom recommend them as a “first” SDR unless the person using is fairly techy.  Particularly a while back, before SDR-Radio and some of the later software, I saw a few people run off of the hobby in frustration.  Today it is a little more straight forward.

I have a couple of them here, and often loan them out to local newbies.  I help them get the SDR set up on their machine and also get them introduced to HF monitoring, they use the Ensemble II for a while and then decide if they want to invest time/money into the hobby.  I think my 2 radios have been through 5 or 6 people so far, and I gave my first one away to a severely budget limited newb a couple years ago, he still uses it as his primary listening rig today.

T!