Read this bottom to top, of course.
From : webmaster <webmaster@haarp.alaska.edu> To : "Dave McAllister" <davemcallister@hotmail.com> CC : webmaster@maestro.haarp.alaska.edu Subject : Re: Signal on 5.8 MHz Date : Thu, 25 Oct 2001 15:03:52 +0000 Dave, Thanks for writing again. I will get a HAARP QSL card off to the address you sent. >I monitored the signal nightly between 11 and 23 October 2001. The campaign began 11 OCT at 0400UTC and ended 24 OCT at 1400 UTC. You obviously covered it very well. >Some nights, like 11-12 and 12-13 October, the signal was at >least 40 dB over S9. The night of 21-22 October the signal >was extremely weak and almost undetectable. There was a geomagnetic storm during the period 21 OCT 1700 UTC to about 22 OCT 1900 UTC. That would account for the poor HF propagation. >I made .wav recordings of the signal at various times, in >various modes, and on both receivers. If they would be of >any use to you I would be happy to send them on. I would be happy to receive them if it is no trouble. Another listener (perhaps one of your group?) did send me a ".wav" recording he made. It sounds like the modulation that we were using. >Last night I listened for the VLF signal at my QTH using my >computer soundcard connected to the dipole, and at a quieter >remote location using a homebrew McGreevy BBB-4 receiver. >No joy on either. I have asked for input from VLF monitors >around the world to see if they noticed the signal and I'll >pass that on if you would like. I don't mean to discourage you, but we employ very complex receivers in very quiet locations to listen to the weak ELF signals that are produced by this method. So far, VLF/ELF has not been detected at ranges greater than about 900 km from the facility and, even then, only by using quite long integration times to pull the signal out of the background noise. >1. Your spectrum monitor display shows what appears to be >two ~3.1 MHz signals that alternate with the 5.8 MHz signal. >What were the frequencies of those signals? We also used 3.2 and 3.3 MHz at various times during the research. >I did search for them but had no luck. Being lower in frequency, they would have suffered greater attenuation and would have been weaker than the 5.8 MHz signal. Also, there is less ERP at those frequencies. In addition, there are no sidelobes in the antenna pattern for signals in the 3 MHz range. >Were they modulated in the same manner? The 3.3 MHz signal was used for brief periods at the beginning of each half hour as a diagnostic. The 3.2 MHz signal had the same modulation as the 5.8 MHz signal. >Other frequencies were visible on the diagram, such as ~29 MHz; >were these harmonics? Yes. The source of the harmonics was in the spectrum moitor or in its preamp and not in the transmitter itself which employs strong low pass filtering to keep the HF signal pure. >2. What was the rationale behind the modulation you chose? >Was it simply to provide a recognizable signal in VLF, or did >you expect different VLF behaviour from the different >frequencies? Both. The tones were chosen so that they and their harmonics would not be multiples of each other. Several receivers were used to listen to the direct signal (E-layer downward) and for the magnetospherically propagated signal whoch would arrive after a delay. Timing and tone frequency selection were done to avoid having a new tone (or the harmonic of some other tone) overlap the arrival of the delayed tone from the previous transmission. Tones over a wide range of frequencies gave the experiment the potential to see a variety of possible propagation effects which are likely to be frequency dependent. >3. When I first monitored the signal on 11 October, it was >quite different from what it has become now. The rising/falling >tones rose and fell extremely rapidly indeed; in fact on a >waterfall display I counted dozens. They looked and sounded >broadly similar to the 'whistlers' that are sometimes audible on >VLF. There was also what sounded like brief data bursts. >Was this simply the rising/falling tones coming in very quick >succession? The general waveform structure was the same during the experiment. Experimental parameters are often adjusted after looking at preliminary data so that the chances for success are improved. The "data bursts" you heard could have been part of the diagnostic or calibration signal that was transmitted periodically. >4. During this experiment was your antenna array 'pointed' >directly upward, or did you steer it to various places to >study the effect? It was pointed upward for the duration of the research. >5. What altitude or region of the ionosphere produces the effect >(VLF propagation) you desire? Are you succeeding in 'modulating' >the magnetosphere to produce this result? VLF/ELF is generated through interaction with the auroral electrojet which occurs at E-layer altitudes (about 100 km). VLF/ELF signals produced within the E-layer can propagate upward into the magnetosphere and it was the study of that propagation mechansim that was of interest in this research. >6. Will you be repeating this experiment in the future? Possibly. No one has had the chance yet to look at all the data that was collected. >7. Would you mind if I shared any information you gave me >with other radio hobbyists? Go ahead. We're glad to satisfy any interest. >I fully understand if you are too busy to answer, or for >obvious reasons simply are not willing to discuss the matter. >Thank you very much in advance for your consideration. Thanks for the intelligent and perceptive questions! Thanks also for the detailed HF reception report. >Hope it's not too cold up there, It was -13 this morning. Regards, Webmaster -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= e-mail: webmaster@haarp.alaska.edu HAARP Home Page: http://www.haarp.alaska.edu/ -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= From : webmaster <webmaster@haarp.alaska.edu> To : "Dave McAllister" <davemcallister@hotmail.com> CC : webmaster@maestro.haarp.alaska.edu Subject : Re: Signal on 5.8 MHz Date : Tue, 23 Oct 2001 07:29:05 -0400 Dave, Thanks for your inquiry. There is a current research effort underway at the HAARP Observatory and 5.8 MHz is one of the frequencies being used by the HF transmitter. The research campaign, which is scheduled to end after today, is studying propagation of ELF signals in the magnetosphere, the region above the ionosphere. You are probably hearing the modulation on the 5.8 MHz carrier signal. These tones are converted into independent ELF signals at the same frequency (approximately 1 - 3 kHz). Although the primary purpose of the test is study of ELF propagation mechanisms, we are certainly interested in any technical details you can provide on the HF signal. Also, we would be happy to send you a QSL card to confirm your reception report if you like. I assume we can find your address in the callbook. Best wishes, Webmaster >To whom it may concern, >For a number of days now I have been monitoring a strange signal on >5.8 MHz. I note that your spectrum monitor chart shows it clearly, >as well as a number of other intermittent signals in the HF >spectrum. Can you tell me if this signal is an ionosonde or other >HAARP signal? And if so, are you willing to provide me with any >technical details about this experiment? > >I am a radio amateur who is interested in unusual HF signals, and I >am in contact with a large number of like-minded individuals >worldwide. If you are interested, I can probably arrange for you to >receive reception reports. The signal has been quite strong in >western North America and around the Pacific Rim, but monitors in >Europe have had little success receiving it. > >Thank you very much in advance for your consideration. > >Dave McAllister >VE7HUN >Squamish, BC, Canada |
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