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Messages - SW-J

Pages: 1 2 [3] 4 5 6 7 8 9 10 11 ... 37
31
Equipment / Re: RFI pickup problem with an interesting solution
« on: March 17, 2013, 0310 UTC »
Next I tried putting lots of ferrite on the incoming coax. At first I thought I was getting somewhere, after putting about 20 clamp on ferrites on the coax, the RFI was pretty much eliminated. Unfortunately, so were all signals on this part of the spectrum.


This part, just above, is downright scary; sounds like ALL your pickup is via induction between coax, the BALUN and some wire in the 'loop' (and not exclusively due to a "propagating" RF wave creating/inducing currents flowing only in the loop!)

Obviously, speaking RF ex cathedra the majority of the signal was not via differential 'signals' (RF energy) appearing at the input to the BALUN from the loop, but rather something much more involved and un-intended (i.e. not per the intended design!)

One or two 'isolation' ferrite transformers in series with the coax cable might have been tried as well, but with probably the same results as the clamp ferrites.

(Of course, I assume we all understand that the 'differential' currents flowing on the inside shield and outside center conductor of the coax (in what is called "TEM", TEM00 for "Transverse ElectroMagnetic" mode) are not in anyway affected by application of ferrites around the outside *shield* of the coax!)

my $1.25 on the subj anyway.


32
Per wikipedia, area code 938:

http://en.wikipedia.org/wiki/Area_codes_256_and_938

Area codes 256 and 938 are telephone numbering plan codes in the northern portion of the state of Alabama.

...

In March 2009, the Alabama Public Service Commission announced that the state's first overlay area code, 938, would be added on top of the current 256 area code "sometime in 2011"

33
I'll add Capt Morgan to the title; I just heard an op/voice, but too much QRN to make out specifics ... TNX

34
Freq is about 6924.9 kHz ... not terribly strong ...

Local WSPR xmtr is desensing 6925 kHz rcvr too when it comes on ....

Pretty good sounding signal, but sometimes buried in QRN at this locale ...

02:59z Freq closer to 6924.8 kHz now ...

35
" The pulses were variable, that is why I said “about 70 millisec”. "

Due, I contend, to more than one 'spatial source' (with the result being temporal variation; some arriving earlier and some arriving later).

Perform the PW measurements taking into consideration where the individual 'sinusoidal sources' are seen to overlap/interfere and your 'pulse width' starts to converge on more like a uniform 64 ms value ...

Hint: Use either a virtual 'ruler' or something actual and measure zero-zero crossings or peak-peak crossings of the 'signal' ... you will see where the apparent 'phase' changes in an otherwise contiguous series of zero-crossings or sinusoidal peaks near the beginnings and near the ends of the 'pulse' ... 

Performing a coast-coast 'test' using a set of xmtrs synchronized using GPS 1 PPS (pulse per second) signals would be trivial, as would feeding a single WB antenna with a single WB xmtr whose output was a 'driver' containing a 14 bit DAC clocked at something like 100 MHz and synthesizing 20 to 30 carriers simultaneously ... WiMAX does this and more (a series of OFDM carriers), in a six MHz wide 'channel' (in a little different format) for instance ...

http://www.conniq.com/WiMAX/fdm-ofdm-ofdma-sofdma-03.htm

WiMAX even relies upon GPS 1 PPS for BS (base station) synchronization, since WiMAX uses TDD (time division duplex) the BS's must not 'clobber' the band when weaker subscriber units are scheduled to transmit ...


.

36
"Don’t place too much on the video from YouTube for measurement, the compression and multiple handling in my making the video ..."

Sorry, but, you can't 'artifact' the kind of 'shifts' (lucky we are playing with elementary sine waves here and not something more complex!) I am seeing in the video. These (coding aberrations) would result in MAJOR distortions of sound (and we are talking a 'tone' here, pretty easy to detect/observe artifacts) ... try for instance looping (continually replaying) a segment that is continuous vs one of the segments that have the 'shift' and there is noticeable sound difference as well. Be sure to join ends of each segment as the sinusoid goes through zero in the same direction (otherwise MAJOR clicks are introduced; 180 degree phase changes make for a pronounced audible artifact).

You might also make use of your choice of 'phase comparator' and view each segment chosen for looping compared with a steady tone; you will 'see' the phase discontinuity (besides just visually viewing the waveform in a good sound editor) that I'm talking about. SpectrumLab plus a tone generator and the use of a VAC can get you there (or use an external O-scope in X-Y Lissajous mode and an HP 8904A to generate the 2nd reference 'tone').

(Signal process much? ... I'm thinking maybe "no" ... please don't impose your limitations on others if your ability in an area might be a bit 'short'.)


37
North American Shortwave Pirate / Re: Red Mercury Labs 6925
« on: April 20, 2012, 0112 UTC »
Good copy here into DFW area on a 4' loop into an ALinco DX-70 .... 0111z

38
... appears to be a 64 ms pulse width (at about the -10 db point)  at least for the 20 pulses shown on the YouTube video ...

Some of the bursts appear longer, but, that may also be due to more than one simultaneous sources and the delay between them. Upon close inspection of the leading and trailing edges of the waveform there is some non-homogeneousness to the sinusoid series: a change in 'phase' due to co-channel (same channel) signal 'interference' can be definitely noticed as either one signal or the other ramps up or trails off.

Conclusion: More than one source, and the temporal difference translates into a spatial difference (i.e. the spacing of the two sites is calculable).

.


39
Also heard here north of DFW on my Degen portable using whip ant.  

Noted it was absent about the 6:50 AM CST time frame in the morning ... maybe more distant than TX or LA or AR?


Should also add: heard several brief 'carriers' maybe a 1 kHz tone modulating a SSB transmitter, in that same range while listening to this 'service' ... kind of unusual for a service, indicates that maybe radio engineering personnel or technicians are on-site performing some testing, maybe an antenna testing, so, maybe this is something under development or newly installed?

Began working some 160 Meters starting mid-summer this year on the high end and this has been the first time I really noticed this 'service' ... anybody have more info chime in!

There is this regards Part 80 Maritime Services from the FCC:

http://frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=80&SECTION=373&TYPE=TEXT


.

40
Utility / 2.000 MHz, USB, digital data, in the TX maybe AR and LA area
« on: December 13, 2011, 0344 UTC »
Just noticed it tonight ... strong signals into DFW area ...

No idea what system or service these transmissions are associated with, but, the spectrum is normally marine.

Also, using Spectran, the following characteristics were noted:

Occupied BW: 650 Hz .. 2850 Hz  (Rcvr IF BW set for 3 kHz, Rcv freq = 2.000 MHz)

Startup (training sequence) carriers:

790 1090 1160 1460 1760 1840 2130 2430 2510 2810

OFDM data carriers every 60 Hz (yeah, I know: line rate) or so ...



41
Met police using surveillance system to monitor mobile phones


** Newsflash **

Anybody (like cellular personnel e.g. cell engineers, traffic analysts or FBI agents with a warrant or other so-called 'authority') sitting at a console and logged into the HLR (Home Location Register) can obtain your location with the new phones that provide location using assisted GPS -or- at the very least get the cell site number and sector which your phone is 'registering' through ...

And monitoring the SMS messages? Same thing ... easy as pie.


In the US anyway, see: CALEA.

Wiki is a good place to start:

http://en.wikipedia.org/wiki/Communications_Assistance_for_Law_Enforcement_Act


Quote
CALEA's purpose is to enhance the ability of law enforcement and intelligence agencies to conduct electronic surveillance by requiring that telecommunications carriers and manufacturers of telecommunications equipment modify and design their equipment, facilities, and services to ensure that they have built-in surveillance capabilities,

42
North American Shortwave Pirate / 6925 am 0215z unk
« on: October 08, 2011, 0217 UTC »
Some grunge guitar licks coming thru the ether!


0217z ... something 'radio' but QRN is a killer here tonight ... now more guitar.

0225z  Pgm continues ...
 
0232z Pgm continues, QRN abating some, signal stronger at times too.

43
North American Shortwave Pirate / unk AM 6925 as of 0114z 10-08-2011
« on: October 08, 2011, 0115 UTC »
Hear something, unable to make out; lotsa QRN tonight!

0120z
There were two station in there, now one ... and sounds like recorded material, like a regular program of some sort ...

0130z
Program continues ... sounds like cartoonish character. Signal picking up some as night progresses.

0144z
Signal off briefly. Not strong enough to make much out with the QRN here ..

44
HF Beacons / Re: What's up with the sunspots?
« on: June 19, 2011, 0313 UTC »
We should petition the HAARP people to light up the ionosphere for us SWL'ers ;D

Peace!

Or, petition Japan/TEPCO to release more radioactive materials ... "ionizing radiation" - that will excite the ionosphere too ...

My thinking is that some of our enhanced propagation was due to prior releases at the Fukushima Daiichi facility.

Open air nuclear testing in the 50's - 60's contributed to enhanced propagation (long term effects; in the short term propagation from a nuclear detonation can degrade propagation) back too, a facet little discussed in most circles.

Various materials released have a variety of half lives, from weeks to months to years to centuries ... as these decay, they too can 'ionize' air molecules in the ionosphere much like solar effects can.


Fukushima Daiichi disaster:
http://en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disaster

Effects by High-Altitude Nuclear Tests on HF Communications (The last page briefly mentions "long term effects".)
http://blockyourid.com/~gbpprorg/mil/herf/CQ-Nuclear_Explosions_On_HF_Comms.pdf

Other documented effects by open-air nuclear tests:
http://www.geophysica.fi/pdf/geophysica_1965_9_2_119_oksman.pdf



45
The FACT is weather modification using radio IS going on.
...

Maybe you can cite for us the 'first principles' (scientific principles*) involved in doing this?


We anxiously await an answer ... (it may take a few courses on meteorology, physics, chemistry, etc. to do this ... meanwhile first understand that HAARP affects the ionosphere and not the troposphere where actual weather takes place. Weather involves airmasses with or without various percentages of water vapor which are transparent to 'radio waves' ... try an experiment w/microwave oven; first put some 'air' in and see if ... never mind, that experiment is done every day with the same results.)


You *do* realize that HAARP, located in Alaska is basically planar array of 15 x 12 sets of crossed dipoles, and by this configuration can achieve no more than about +- 30 to 40 degrees angle from straight up (ie no horizon shot)?



A good discussion debunking a few misconceptions ensues after the article:
  "First Artificial Neon Sky Show Created (HAARP)"
http://www.freerepublic.com/focus/f-news/1337056/posts



And REMEMBER this principle: If it emits, IT CAN BE LOCATED.

 Re: finding firedrake transmitter(s) - (or HAARP in this case and *prove* it is them - or the Chinese!)
 "Suggestions on how to find this transmitter site would be appreciated."
 Ans: Long baseline time-of-arrival/interferometry, like the chirper/Ionosonde-locating guys do it.

See discussion in the thread linked below for links to sources:
http://www.hfunderground.com/board/index.php/topic,1476.msg7003.html#msg7003



"HAARP -- 'cargo cult science' of 21st Century"
http://www.hfunderground.com/board/index.php/topic,513.msg7065.html#msg7065

Quote
Cargo Cult Science is based on a concept in anthropology, the cargo cult, which describes how some pre-scientific cultures interpreted technologically advanced visitors (e.g. flying airplanes filled with supplies to S. Pacific island outposts) as religious or supernatural figures who brought boons of cargo and food.

Later, in an effort to call for a second visit the natives would develop and engage in complex religious rituals, mirroring the previously observed behavior of the visitors manipulating their machines (by building airports with thatched runways and control towers and RADAR installations made of bamboo) but without understanding the true nature of those tasks (the science, the technology), with the cargo cultists creating mock airports that failed to produce airplanes ...


* Anything Alex Jones, Jeff Rense et al (conspiracy theorist) inspired or produced is not SCIENTIFIC, it's scare mongering (usually for the purpose of making money).


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