Hi Lenny I don't see any reason not to.  This was literally a spur of the moment thing, but I hope to eventually put these pictures and more into a presentation. Maybe with enough prodding I'll actually get it done. Daun Daun E. Yeagley II, N8ASB On 6/28/2020 1:55 AM, Lenny via mvus-list wrote: > Hi Daun > > Just wondering if I can use the pictures and description in the Mt > Airy VHF Radio Club ("The Packrats") newsletter. I'm sure the members > would be interested. > > Please let me know either way. > > Tnx, 73 & stay safe, > > --Lenny W2BVH (newsletter editor) > > > > On 6/27/2020 4:28 PM, Daun Yeagley via mvus-list wrote: >> It's "fun" trying to sort through all my pictures from Arecibo, as >> they are stored by date, and who knows what I was doing on a >> particular day! >> >> Anyway, here are some pictures of the HF transmitters, and the >> antennas in the bottom of the dish.   For scale, look for the guys >> that are standing in the opening in the middle. (that's where they >> hoist stuff up to the platform).  Also, on the last one, if you look >> carefully you can see the cables that make up the secondary reflector. >> >> Daun >> >> >> _______________________________________________ >> mvus-list mailing list >> mvus-list@lists.febo.com >> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com

Ethan, I've seen a video from Culebra showing the light emission resulting from bombardment by the Arecibo HF system, and would like to obtain a copy. Do you think that might be possible? Everybody I talk to says that the emission is too dim to see with the unaided eye. I know just enough optics to be dangerous, and have a line of argument that says that it ought to be faintly visible under benign conditions. I've never set foot on Culebra, much less spent a night there. Are the night skies really really dark, like at a high desert site well away from cities, or just so-so? While I was in PR I wanted to visit Culebra for a holiday weekend, but never succeeded in finding transportation there. My preference would have been to fly, largely for the sake of experiencing the approach and landing, which I hear is quite a thrill. Dana On Sun, Jun 28, 2020 at 7:07 AM Daun Yeagley via mvus-list < mvus-list@lists.febo.com> wrote: > Hi Lenny > > I don't see any reason not to. This was literally a spur of the moment > thing, but I hope to eventually put these pictures and more into a > presentation. Maybe with enough prodding I'll actually get it done. > > Daun > > Daun E. Yeagley II, N8ASB > On 6/28/2020 1:55 AM, Lenny via mvus-list wrote: > > Hi Daun > > > > Just wondering if I can use the pictures and description in the Mt > > Airy VHF Radio Club ("The Packrats") newsletter. I'm sure the members > > would be interested. > > > > Please let me know either way. > > > > Tnx, 73 & stay safe, > > > > --Lenny W2BVH (newsletter editor) > > > > > > > > On 6/27/2020 4:28 PM, Daun Yeagley via mvus-list wrote: > >> It's "fun" trying to sort through all my pictures from Arecibo, as > >> they are stored by date, and who knows what I was doing on a > >> particular day! > >> > >> Anyway, here are some pictures of the HF transmitters, and the > >> antennas in the bottom of the dish. For scale, look for the guys > >> that are standing in the opening in the middle. (that's where they > >> hoist stuff up to the platform). Also, on the last one, if you look > >> carefully you can see the cables that make up the secondary reflector. > >> > >> Daun > >> > >> > >> _______________________________________________ > >> mvus-list mailing list > >> mvus-list@lists.febo.com > >> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > _______________________________________________ > > mvus-list mailing list > > mvus-list@lists.febo.com > > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >

I just watched a 15 minute video tour of Arecibo given by Angel, WP3R, to two hams. https://youtu.be/IqGnnpwEwug <https://youtu.be/IqGnnpwEwug> You really should watch this. Incredible!!! Joe - WA8OGS

Joe, You might enjoy this one, too: https://www.youtube.com/watch?v=vicxDnn6LEY&t=306s Dana On Mon, Jun 29, 2020 at 10:45 AM Joe via mvus-list <mvus-list@lists.febo.com> wrote: > I just watched a 15 minute video tour of Arecibo given by Angel, WP3R, to > two hams. > https://youtu.be/IqGnnpwEwug <https://youtu.be/IqGnnpwEwug> > > You really should watch this. Incredible!!! > > Joe - WA8OGS > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >

Dana, Yes, very nice…and I recognized you working in the video. How long were you there? Joe - WA8OGS > On Jun 29, 2020, at 12:05 PM, Dana Whitlow via mvus-list <mvus-list@lists.febo.com> wrote: > > Joe, > > You might enjoy this one, too: > https://www.youtube.com/watch?v=vicxDnn6LEY&t=306s > > Dana > > > On Mon, Jun 29, 2020 at 10:45 AM Joe via mvus-list <mvus-list@lists.febo.com> > wrote: > >> I just watched a 15 minute video tour of Arecibo given by Angel, WP3R, to >> two hams. >> https://youtu.be/IqGnnpwEwug <https://youtu.be/IqGnnpwEwug> >> >> You really should watch this. Incredible!!! >> >> Joe - WA8OGS >> _______________________________________________ >> mvus-list mailing list >> mvus-list@lists.febo.com >> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >> > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com

Hi Joe, 4 weeks shy of 10 years. Dana On Mon, Jun 29, 2020 at 12:38 PM Joe via mvus-list <mvus-list@lists.febo.com> wrote: > Dana, > > Yes, very nice…and I recognized you working in the video. > How long were you there? > > Joe - WA8OGS > > > On Jun 29, 2020, at 12:05 PM, Dana Whitlow via mvus-list < > mvus-list@lists.febo.com> wrote: > > > > Joe, > > > > You might enjoy this one, too: > > https://www.youtube.com/watch?v=vicxDnn6LEY&t=306s > > > > Dana > > > > > > On Mon, Jun 29, 2020 at 10:45 AM Joe via mvus-list < > mvus-list@lists.febo.com> > > wrote: > > > >> I just watched a 15 minute video tour of Arecibo given by Angel, WP3R, > to > >> two hams. > >> https://youtu.be/IqGnnpwEwug <https://youtu.be/IqGnnpwEwug> > >> > >> You really should watch this. Incredible!!! > >> > >> Joe - WA8OGS > >> _______________________________________________ > >> mvus-list mailing list > >> mvus-list@lists.febo.com > >> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >> > > _______________________________________________ > > mvus-list mailing list > > mvus-list@lists.febo.com > > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >

Ethan, What got me interested in "seeing" the light emission resulting from operation of Arecibo's HF system was in search of a better, more practical solution to the problem of properly phasing the transmitters' outputs into their respective dipoles in the array. I designed the multi-phase splitter for Arecibo while still employed there, and Daun pretty much built the whole thing hardware-wise. But the problem is that the dipoles talk to each other, and the driving impedance presented to each dipole's feed point is not infinity, so radiation from each dipole affects the amplitudes and phases of the currents in all the other dipoles, ad nauseum. One option is careful system simulation, and I have put some effort into this, but frankly it's not looking like a viable solution to me. Too many imponderables and guesses are involved. BTW, does anybody have a good Spice model for a 4CW150,000E power tetrode? Another is direct measurement of the feed point complex currents with Rogowski coils (or similar sensors), but this is not trivial and would require the expenditure of significant funds in the sensors and in phase-matched cables running back to the TX building. Nevertheless I suspect this is the best way. Another, that is more economical, is to make all the transmission lines an exact integer number of half waves, and make the measurements at the TX end of the cables. I worked out a way of doing the measurements with dual-directional couplers, of which sufficient extras came installed in the transmitters. I used this basic technique for trimming our feedlines to the same "length" (although they could differ in length by integer multiples of a half-wave), and it looked very promising. But using the technique in actual operation requires building a bunch of additional electronics, and nobody has yet had the time or money to do so. So, at present the technique used is to measure amplitude and phase of the *forward* *wave* (only) at the TX end of each line, basically by hand, and iteratively tweak on the transmitters' drive signals until we're happy with the results. This actually *seems* to be working OK, but we don't know for sure, and it's a royal pain to do in any case. The real problem is that this method does not really account for interactions between the dipoles, especially given that the transmitters' output are "power matched", (not impedance matched). BTW, does anybody have a good Spice model for a 4CW150,000E power tetrode? The means for setting phases is via computer control of the stuff that Daun put together, with a Python program written by another engineer (who has also left the observatory). But now, I can get to my other idea for optimizing phasing, which is to view the spot of emitted light in real time and crank on the "knobs" until the spot becomes brightest and most compact. It could even be done with a camera at a very remote location via the internet, thus allowing a camera location where the skies are really dark. Naturally the Culebra site comes to mind for this. Dana On Sun, Jun 28, 2020 at 6:58 AM Ethan Miller K8GU via mvus-list < mvus-list@lists.febo.com> wrote: > Daun/Dana, > > Sorry I missed the MVUS showing of Arecibo photos. I had an HF > receiver and a relatively sensitive all-sky (fisheye) imager (the > imager is still there but operated by someone else now) in Culebra for > a couple of years (for a different experiment) that was occasionally > repurposed for Arecibo HF experiments. It's pretty wild to see some > of the ionospheric structures they created with the HF system, > including airglow structures that were sub-visual magnitude blinking > on and off with the HF transmitter. Of course, at HAARP they've done > visual magnitude airglow, which does nothing to quell the conspiracy > theories! > > I'm not a hard-core plasma physicist, but the stimulated RF emissions > from the Arecibo HF were also always interesting to see...the > high-power HF mode converts into plasma waves which interact with each > other and some of them mode convert back into electromagnetic waves at > different frequencies, shifted by "natural frequencies" (for example > the electron gyrofrequency) of the plasma. These are the types of > things that are theorized to be explanations for long-delayed echoes > (LDEs) and other radio oddities. I'll have to see if I have any data > floating around still that is clear and illustrative to a > technically-literate non-expert audience... > > 73, > > --Ethan, K8GU. > > On Sun, Jun 28, 2020 at 1:56 AM Lenny via mvus-list > <mvus-list@lists.febo.com> wrote: > > > > Hi Daun > > > > Just wondering if I can use the pictures and description in the Mt Airy > > VHF Radio Club ("The Packrats") newsletter. I'm sure the members would > > be interested. > > > > Please let me know either way. > > > > Tnx, 73 & stay safe, > > > > --Lenny W2BVH (newsletter editor) > > > > > > > > On 6/27/2020 4:28 PM, Daun Yeagley via mvus-list wrote: > > > It's "fun" trying to sort through all my pictures from Arecibo, as > > > they are stored by date, and who knows what I was doing on a > > > particular day! > > > > > > Anyway, here are some pictures of the HF transmitters, and the > > > antennas in the bottom of the dish. For scale, look for the guys > > > that are standing in the opening in the middle. (that's where they > > > hoist stuff up to the platform). Also, on the last one, if you look > > > carefully you can see the cables that make up the secondary reflector. > > > > > > Daun > > > > > > > > > _______________________________________________ > > > mvus-list mailing list > > > mvus-list@lists.febo.com > > > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > _______________________________________________ > > mvus-list mailing list > > mvus-list@lists.febo.com > > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > > -- > http://www.k8gu.com/ > Repair. Re-use. Re-purpose. Recycle. > > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >

Dana, Cool. Yes, there's quite a bit of mutual coupling in this system! I'm vaguely familiar with the source of the transmitters (I was involved with putting a newer instrument at the location of the West Coast counterpart), but have not gotten into the details of the feeds, antennas, etc. It's neat to hear the backstory on the role that you and Daun played! Here is a link to a time-lapse movie taken at the Observatory (for whatever reason, I can't lay my hands on data from the Culebra instrument during heating right now). About 24 seconds into the movie, you'll see a white spot in the center of the field of view blinking ON and OFF. That's the HF. http://k8gu.com/webpost/ao151109_6300.avi I believe the Arecibo imager was only looking at the 630-nm emission and my camera was configured for 557.7-nm, 589.3-nm, and OH broadband in the near-IR. Because this is a filterwheel system, each additional wavelength reduces temporal sampling. It becomes burdensome at the four-minute exposures we were doing! In case you wondered, for some reason, this imager is also out of focus. Mine was never that bad! The Culebra site is quite good for the Caribbean, better than Arecibo, but perhaps comparable to Bonaire, which is dry and not too overrun with tourists and hotels. It is nothing like a number of other optical sites where I've operated equipment, for example Cerro Tololo, Chile, and Haleakala, Hawaii. I have not been to the new site that they negotiated after the new management came in a couple of years ago. I'll try to drag out some more heating imagery and see what I have that I've never looked at. Believe it or not, my HF receiving data from Culebra has been more interesting than the imagery so far. We originally installed the imager to study a certain class of traveling ionospheric disturbances that are pretty commonly observed over Puerto Rico. There is a paper on this coming out in J. Geophys. Res. soon, led by Pedrina Santos, of Arecibo. The airport approach into CPX is pretty cool...going through that little pass that's not-quite-aligned with the runway! My coworker and I flew over on a Cape Air BN-2B Islander from SJU and had 4-5 Pelican cases full of gear. The pilot very carefully balanced the plane before we took off and I think we may have bumped another passenger. That was a great trip. 73, --Ethan, K8GU. On Mon, Jun 29, 2020 at 5:42 PM Dana Whitlow via mvus-list <mvus-list@lists.febo.com> wrote: > > Ethan, > > What got me interested in "seeing" the light emission resulting from > operation of > Arecibo's HF system was in search of a better, more practical solution to > the > problem of properly phasing the transmitters' outputs into their respective > dipoles > in the array. I designed the multi-phase splitter for Arecibo while still > employed > there, and Daun pretty much built the whole thing hardware-wise. But the > problem > is that the dipoles talk to each other, and the driving impedance presented > to each > dipole's feed point is not infinity, so radiation from each dipole > affects the amplitudes > and phases of the currents in all the other dipoles, ad nauseum. > > One option is careful system simulation, and I have put some effort into > this, but > frankly it's not looking like a viable solution to me. Too many > imponderables and > guesses are involved. BTW, does anybody have a good Spice model for a > 4CW150,000E power tetrode? > > Another is direct measurement of the feed point complex currents with > Rogowski > coils (or similar sensors), but this is not trivial and would require the > expenditure > of significant funds in the sensors and in phase-matched cables running > back to > the TX building. Nevertheless I suspect this is the best way. > > Another, that is more economical, is to make all the transmission lines an > exact > integer number of half waves, and make the measurements at the TX end of the > cables. I worked out a way of doing the measurements with dual-directional > couplers, > of which sufficient extras came installed in the transmitters. I used this > basic technique > for trimming our feedlines to the same "length" (although they could differ > in length by > integer multiples of a half-wave), and it looked very promising. But using > the technique > in actual operation requires building a bunch of additional electronics, > and nobody has > yet had the time or money to do so. > > So, at present the technique used is to measure amplitude and phase of the > *forward* > *wave* (only) at the TX end of each line, basically by hand, and > iteratively tweak on the > transmitters' drive signals until we're happy with the results. This > actually *seems* to be > working OK, but we don't know for sure, and it's a royal pain to do in any > case. The > real problem is that this method does not really account for interactions > between the > dipoles, especially given that the transmitters' output are "power > matched", (not > impedance matched). BTW, does anybody have a good Spice model for a > 4CW150,000E > power tetrode? > > The means for setting phases is via computer control of the stuff that Daun > put together, > with a Python program written by another engineer (who has also left the > observatory). > > But now, I can get to my other idea for optimizing phasing, which is to > view the spot of > emitted light in real time and crank on the "knobs" until the spot becomes > brightest and > most compact. It could even be done with a camera at a very remote > location via the > internet, thus allowing a camera location where the skies are really dark. > Naturally the > Culebra site comes to mind for this. > > Dana > > > On Sun, Jun 28, 2020 at 6:58 AM Ethan Miller K8GU via mvus-list < > mvus-list@lists.febo.com> wrote: > > > Daun/Dana, > > > > Sorry I missed the MVUS showing of Arecibo photos. I had an HF > > receiver and a relatively sensitive all-sky (fisheye) imager (the > > imager is still there but operated by someone else now) in Culebra for > > a couple of years (for a different experiment) that was occasionally > > repurposed for Arecibo HF experiments. It's pretty wild to see some > > of the ionospheric structures they created with the HF system, > > including airglow structures that were sub-visual magnitude blinking > > on and off with the HF transmitter. Of course, at HAARP they've done > > visual magnitude airglow, which does nothing to quell the conspiracy > > theories! > > > > I'm not a hard-core plasma physicist, but the stimulated RF emissions > > from the Arecibo HF were also always interesting to see...the > > high-power HF mode converts into plasma waves which interact with each > > other and some of them mode convert back into electromagnetic waves at > > different frequencies, shifted by "natural frequencies" (for example > > the electron gyrofrequency) of the plasma. These are the types of > > things that are theorized to be explanations for long-delayed echoes > > (LDEs) and other radio oddities. I'll have to see if I have any data > > floating around still that is clear and illustrative to a > > technically-literate non-expert audience... > > > > 73, > > > > --Ethan, K8GU. > > > > On Sun, Jun 28, 2020 at 1:56 AM Lenny via mvus-list > > <mvus-list@lists.febo.com> wrote: > > > > > > Hi Daun > > > > > > Just wondering if I can use the pictures and description in the Mt Airy > > > VHF Radio Club ("The Packrats") newsletter. I'm sure the members would > > > be interested. > > > > > > Please let me know either way. > > > > > > Tnx, 73 & stay safe, > > > > > > --Lenny W2BVH (newsletter editor) > > > > > > > > > > > > On 6/27/2020 4:28 PM, Daun Yeagley via mvus-list wrote: > > > > It's "fun" trying to sort through all my pictures from Arecibo, as > > > > they are stored by date, and who knows what I was doing on a > > > > particular day! > > > > > > > > Anyway, here are some pictures of the HF transmitters, and the > > > > antennas in the bottom of the dish. For scale, look for the guys > > > > that are standing in the opening in the middle. (that's where they > > > > hoist stuff up to the platform). Also, on the last one, if you look > > > > carefully you can see the cables that make up the secondary reflector. > > > > > > > > Daun > > > > > > > > > > > > _______________________________________________ > > > > mvus-list mailing list > > > > mvus-list@lists.febo.com > > > > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > _______________________________________________ > > > mvus-list mailing list > > > mvus-list@lists.febo.com > > > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > > > > > > -- > > http://www.k8gu.com/ > > Repair. Re-use. Re-purpose. Recycle. > > > > _______________________________________________ > > mvus-list mailing list > > mvus-list@lists.febo.com > > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com -- http://www.k8gu.com/ Repair. Re-use. Re-purpose. Recycle.

Ethan... Cool video, but don’t understand why the UFO's are moving but not the stars 😉. Can you talk more about the hardware you have to do this? Have been to Haleakala a couple of times, but always had family so didn’t make the effort to bluff my way into the observatory. Would have loved to see it. I have been to Kitt's Peak in AZ, and to the VLA, both of which are quite fascinating, each in their own way. Tom Holmes, N8ZM -----Original Message----- From: mvus-list <mvus-list-bounces@lists.febo.com> On Behalf Of Ethan Miller K8GU via mvus-list Sent: Monday, June 29, 2020 6:44 PM To: Midwest VHF/UHF Society Mailing List <mvus-list@lists.febo.com> Cc: Ethan Miller K8GU <ethan@k8gu.com> Subject: Re: [mvus-list] Arecibo HF Dana, Cool. Yes, there's quite a bit of mutual coupling in this system! I'm vaguely familiar with the source of the transmitters (I was involved with putting a newer instrument at the location of the West Coast counterpart), but have not gotten into the details of the feeds, antennas, etc. It's neat to hear the backstory on the role that you and Daun played! Here is a link to a time-lapse movie taken at the Observatory (for whatever reason, I can't lay my hands on data from the Culebra instrument during heating right now). About 24 seconds into the movie, you'll see a white spot in the center of the field of view blinking ON and OFF. That's the HF. <http://k8gu.com/webpost/ao151109_6300.avi> http://k8gu.com/webpost/ao151109_6300.avi I believe the Arecibo imager was only looking at the 630-nm emission and my camera was configured for 557.7-nm, 589.3-nm, and OH broadband in the near-IR. Because this is a filterwheel system, each additional wavelength reduces temporal sampling. It becomes burdensome at the four-minute exposures we were doing! In case you wondered, for some reason, this imager is also out of focus. Mine was never that bad! The Culebra site is quite good for the Caribbean, better than Arecibo, but perhaps comparable to Bonaire, which is dry and not too overrun with tourists and hotels. It is nothing like a number of other optical sites where I've operated equipment, for example Cerro Tololo, Chile, and Haleakala, Hawaii. I have not been to the new site that they negotiated after the new management came in a couple of years ago. I'll try to drag out some more heating imagery and see what I have that I've never looked at. Believe it or not, my HF receiving data from Culebra has been more interesting than the imagery so far. We originally installed the imager to study a certain class of traveling ionospheric disturbances that are pretty commonly observed over Puerto Rico. There is a paper on this coming out in J. Geophys. Res. soon, led by Pedrina Santos, of Arecibo. The airport approach into CPX is pretty cool...going through that little pass that's not-quite-aligned with the runway! My coworker and I flew over on a Cape Air BN-2B Islander from SJU and had 4-5 Pelican cases full of gear. The pilot very carefully balanced the plane before we took off and I think we may have bumped another passenger. That was a great trip. 73, --Ethan, K8GU. On Mon, Jun 29, 2020 at 5:42 PM Dana Whitlow via mvus-list < <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com> wrote: > > Ethan, > > What got me interested in "seeing" the light emission resulting from > operation of > Arecibo's HF system was in search of a better, more practical solution to > the > problem of properly phasing the transmitters' outputs into their respective > dipoles > in the array. I designed the multi-phase splitter for Arecibo while still > employed > there, and Daun pretty much built the whole thing hardware-wise. But the > problem > is that the dipoles talk to each other, and the driving impedance presented > to each > dipole's feed point is not infinity, so radiation from each dipole > affects the amplitudes > and phases of the currents in all the other dipoles, ad nauseum. > > One option is careful system simulation, and I have put some effort into > this, but > frankly it's not looking like a viable solution to me. Too many > imponderables and > guesses are involved. BTW, does anybody have a good Spice model for a > 4CW150,000E power tetrode? > > Another is direct measurement of the feed point complex currents with > Rogowski > coils (or similar sensors), but this is not trivial and would require the > expenditure > of significant funds in the sensors and in phase-matched cables running > back to > the TX building. Nevertheless I suspect this is the best way. > > Another, that is more economical, is to make all the transmission lines an > exact > integer number of half waves, and make the measurements at the TX end of the > cables. I worked out a way of doing the measurements with dual-directional > couplers, > of which sufficient extras came installed in the transmitters. I used this > basic technique > for trimming our feedlines to the same "length" (although they could differ > in length by > integer multiples of a half-wave), and it looked very promising. But using > the technique > in actual operation requires building a bunch of additional electronics, > and nobody has > yet had the time or money to do so. > > So, at present the technique used is to measure amplitude and phase of the > *forward* > *wave* (only) at the TX end of each line, basically by hand, and > iteratively tweak on the > transmitters' drive signals until we're happy with the results. This > actually *seems* to be > working OK, but we don't know for sure, and it's a royal pain to do in any > case. The > real problem is that this method does not really account for interactions > between the > dipoles, especially given that the transmitters' output are "power > matched", (not > impedance matched). BTW, does anybody have a good Spice model for a > 4CW150,000E > power tetrode? > > The means for setting phases is via computer control of the stuff that Daun > put together, > with a Python program written by another engineer (who has also left the > observatory). > > But now, I can get to my other idea for optimizing phasing, which is to > view the spot of > emitted light in real time and crank on the "knobs" until the spot becomes > brightest and > most compact. It could even be done with a camera at a very remote > location via the > internet, thus allowing a camera location where the skies are really dark. > Naturally the > Culebra site comes to mind for this. > > Dana > > > On Sun, Jun 28, 2020 at 6:58 AM Ethan Miller K8GU via mvus-list < > <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com> wrote: > > > Daun/Dana, > > > > Sorry I missed the MVUS showing of Arecibo photos. I had an HF > > receiver and a relatively sensitive all-sky (fisheye) imager (the > > imager is still there but operated by someone else now) in Culebra for > > a couple of years (for a different experiment) that was occasionally > > repurposed for Arecibo HF experiments. It's pretty wild to see some > > of the ionospheric structures they created with the HF system, > > including airglow structures that were sub-visual magnitude blinking > > on and off with the HF transmitter. Of course, at HAARP they've done > > visual magnitude airglow, which does nothing to quell the conspiracy > > theories! > > > > I'm not a hard-core plasma physicist, but the stimulated RF emissions > > from the Arecibo HF were also always interesting to see...the > > high-power HF mode converts into plasma waves which interact with each > > other and some of them mode convert back into electromagnetic waves at > > different frequencies, shifted by "natural frequencies" (for example > > the electron gyrofrequency) of the plasma. These are the types of > > things that are theorized to be explanations for long-delayed echoes > > (LDEs) and other radio oddities. I'll have to see if I have any data > > floating around still that is clear and illustrative to a > > technically-literate non-expert audience... > > > > 73, > > > > --Ethan, K8GU. > > > > On Sun, Jun 28, 2020 at 1:56 AM Lenny via mvus-list > > < <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com> wrote: > > > > > > Hi Daun > > > > > > Just wondering if I can use the pictures and description in the Mt Airy > > > VHF Radio Club ("The Packrats") newsletter. I'm sure the members would > > > be interested. > > > > > > Please let me know either way. > > > > > > Tnx, 73 & stay safe, > > > > > > --Lenny W2BVH (newsletter editor) > > > > > > > > > > > > On 6/27/2020 4:28 PM, Daun Yeagley via mvus-list wrote: > > > > It's "fun" trying to sort through all my pictures from Arecibo, as > > > > they are stored by date, and who knows what I was doing on a > > > > particular day! > > > > > > > > Anyway, here are some pictures of the HF transmitters, and the > > > > antennas in the bottom of the dish. For scale, look for the guys > > > > that are standing in the opening in the middle. (that's where they > > > > hoist stuff up to the platform). Also, on the last one, if you look > > > > carefully you can see the cables that make up the secondary reflector. > > > > > > > > Daun > > > > > > > > > > > > _______________________________________________ > > > > mvus-list mailing list > > > > <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com > > > > <http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > _______________________________________________ > > > mvus-list mailing list > > > <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com > > > <http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > > > > > > -- > > <http://www.k8gu.com/> http://www.k8gu.com/ > > Repair. Re-use. Re-purpose. Recycle. > > > > _______________________________________________ > > mvus-list mailing list > > <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com > > <http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > _______________________________________________ > mvus-list mailing list > <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com > <http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com -- <http://www.k8gu.com/> http://www.k8gu.com/ Repair. Re-use. Re-purpose. Recycle. _______________________________________________ mvus-list mailing list <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com <http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com

Tom, Like "Fight Club," the first rule of UFOs is "don't talk about the UFOs." I don't currently have any equipment to do all-sky imaging. There are several commercial sources and the pricing is from ~$10K to ~$100K. The basic design is a fast off-the-shelf (f/2.8 or better) fisheye lens combined with some carefully-designed fixed lenses to produce telecentric rays through a bank of high-quality narrow-band interference filters (e.g., 2-nm bandwidth at half-max, OD5 in the stop-band, usually with other requirements on film quality, etc; very custom). The filters are between 2 and 4 inches in diameter, so the telecentric requirement is pretty stringent for many designs to keep the filter wavelength from shifting across the image. The filters are often selectable by a motorized filterwheel. Then, there are some more custom fixed optics that focus the telecentric rays back onto the imaging detector. The precise choice of detector depends a lot on the science you're trying to do. My experience has been predominantly with consumer astronomical CCDs and CMOS detectors from Atik, SBIG, and Andor (a little better than "consumer-grade"). I'll see if I can find pictures of some of the instrumentation for you if you'd like to geek out on it. The emissions we're looking at usually pretty faint and require long integration (exposure) times to overcome measurement noise. The 630-nm "red line" emission comes from an excited state of oxygen that's observed in both the aurora and the airglow. Airglow is a by-product of the plasma process of recombination, which is the reverse of production (ionization), which is what the Sun does to create the ionosphere in the first place. Red airglow comes from just below the peak plasma density of the F2 region, about 250 km up. Green airglow (557.7 nm) is a brighter oxygen emission and comes from the E region, about 97 km altitude. If you've seen astronomical photos of waves in the night sky, these are probably green airglow. This is also the photochemistry as the green aurora, although the driving process is the magnetosphere, not diurnal recombination. I've been "inside the fence" at Haleakala. I was a grad student at the time and my advisor dropped into my office one day and said, "How do you feel about going to Hawaii?" I responded affirmatively. The following day, he came in and said, "How's Monday?" My host/minder was an USAF contractor who had been an MP in Bosnia. The instrumentation (two separate cameras) resided in several "huts" that could only be accessed by passing through secure areas. The big dial locks on the doors made an impression for sure. I don't think there would have been much "talking your way in," at least on the Air Force side. Their telescope can do things that the one on the astronomy side can't. It moved really fast when they demo'ed it for me. Of course, the night sky was amazing, too, with the clouds below you. Did that scratch the itch? Now I'm getting wanderlust... 73, --Ethan, K8GU. On Mon, Jun 29, 2020 at 7:00 PM Tom Holmes via mvus-list < mvus-list@lists.febo.com> wrote: > Ethan... > > > > Cool video, but don’t understand why the UFO's are moving but not the > stars 😉. > > > > Can you talk more about the hardware you have to do this? > > > > Have been to Haleakala a couple of times, but always had family so didn’t > make the effort to bluff my way into the observatory. Would have loved to > see it. I have been to Kitt's Peak in AZ, and to the VLA, both of which are > quite fascinating, each in their own way. > > > > Tom Holmes, N8ZM > > > > -----Original Message----- > From: mvus-list <mvus-list-bounces@lists.febo.com> On Behalf Of Ethan > Miller K8GU via mvus-list > Sent: Monday, June 29, 2020 6:44 PM > To: Midwest VHF/UHF Society Mailing List <mvus-list@lists.febo.com> > Cc: Ethan Miller K8GU <ethan@k8gu.com> > Subject: Re: [mvus-list] Arecibo HF > > > > Dana, > > > > Cool. Yes, there's quite a bit of mutual coupling in this system! > > I'm vaguely familiar with the source of the transmitters (I was > > involved with putting a newer instrument at the location of the West > > Coast counterpart), but have not gotten into the details of the feeds, > > antennas, etc. It's neat to hear the backstory on the role that you > > and Daun played! > > > > Here is a link to a time-lapse movie taken at the Observatory (for > > whatever reason, I can't lay my hands on data from the Culebra > > instrument during heating right now). About 24 seconds into the > > movie, you'll see a white spot in the center of the field of view > > blinking ON and OFF. That's the HF. > > > > <http://k8gu.com/webpost/ao151109_6300.avi> > http://k8gu.com/webpost/ao151109_6300.avi > > > > I believe the Arecibo imager was only looking at the 630-nm emission > > and my camera was configured for 557.7-nm, 589.3-nm, and OH broadband > > in the near-IR. Because this is a filterwheel system, each additional > > wavelength reduces temporal sampling. It becomes burdensome at the > > four-minute exposures we were doing! In case you wondered, for some > > reason, this imager is also out of focus. Mine was never that bad! > > > > The Culebra site is quite good for the Caribbean, better than Arecibo, > > but perhaps comparable to Bonaire, which is dry and not too overrun > > with tourists and hotels. It is nothing like a number of other > > optical sites where I've operated equipment, for example Cerro Tololo, > > Chile, and Haleakala, Hawaii. I have not been to the new site that > > they negotiated after the new management came in a couple of years > > ago. I'll try to drag out some more heating imagery and see what I > > have that I've never looked at. Believe it or not, my HF receiving > > data from Culebra has been more interesting than the imagery so far. > > > > We originally installed the imager to study a certain class of > > traveling ionospheric disturbances that are pretty commonly observed > > over Puerto Rico. There is a paper on this coming out in J. Geophys. > > Res. soon, led by Pedrina Santos, of Arecibo. > > > > The airport approach into CPX is pretty cool...going through that > > little pass that's not-quite-aligned with the runway! My coworker and > > I flew over on a Cape Air BN-2B Islander from SJU and had 4-5 Pelican > > cases full of gear. The pilot very carefully balanced the plane > > before we took off and I think we may have bumped another passenger. > > That was a great trip. > > > > 73, > > > > --Ethan, K8GU. > > > > > > > > On Mon, Jun 29, 2020 at 5:42 PM Dana Whitlow via mvus-list > > < <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com> wrote: > > > > > > Ethan, > > > > > > What got me interested in "seeing" the light emission resulting from > > > operation of > > > Arecibo's HF system was in search of a better, more practical solution to > > > the > > > problem of properly phasing the transmitters' outputs into their > respective > > > dipoles > > > in the array. I designed the multi-phase splitter for Arecibo while > still > > > employed > > > there, and Daun pretty much built the whole thing hardware-wise. But > the > > > problem > > > is that the dipoles talk to each other, and the driving impedance > presented > > > to each > > > dipole's feed point is not infinity, so radiation from each dipole > > > affects the amplitudes > > > and phases of the currents in all the other dipoles, ad nauseum. > > > > > > One option is careful system simulation, and I have put some effort into > > > this, but > > > frankly it's not looking like a viable solution to me. Too many > > > imponderables and > > > guesses are involved. BTW, does anybody have a good Spice model for a > > > 4CW150,000E power tetrode? > > > > > > Another is direct measurement of the feed point complex currents with > > > Rogowski > > > coils (or similar sensors), but this is not trivial and would require the > > > expenditure > > > of significant funds in the sensors and in phase-matched cables running > > > back to > > > the TX building. Nevertheless I suspect this is the best way. > > > > > > Another, that is more economical, is to make all the transmission lines > an > > > exact > > > integer number of half waves, and make the measurements at the TX end of > the > > > cables. I worked out a way of doing the measurements with > dual-directional > > > couplers, > > > of which sufficient extras came installed in the transmitters. I used > this > > > basic technique > > > for trimming our feedlines to the same "length" (although they could > differ > > > in length by > > > integer multiples of a half-wave), and it looked very promising. But > using > > > the technique > > > in actual operation requires building a bunch of additional electronics, > > > and nobody has > > > yet had the time or money to do so. > > > > > > So, at present the technique used is to measure amplitude and phase of > the > > > *forward* > > > *wave* (only) at the TX end of each line, basically by hand, and > > > iteratively tweak on the > > > transmitters' drive signals until we're happy with the results. This > > > actually *seems* to be > > > working OK, but we don't know for sure, and it's a royal pain to do in > any > > > case. The > > > real problem is that this method does not really account for interactions > > > between the > > > dipoles, especially given that the transmitters' output are "power > > > matched", (not > > > impedance matched). BTW, does anybody have a good Spice model for a > > > 4CW150,000E > > > power tetrode? > > > > > > The means for setting phases is via computer control of the stuff that > Daun > > > put together, > > > with a Python program written by another engineer (who has also left the > > > observatory). > > > > > > But now, I can get to my other idea for optimizing phasing, which is to > > > view the spot of > > > emitted light in real time and crank on the "knobs" until the spot > becomes > > > brightest and > > > most compact. It could even be done with a camera at a very remote > > > location via the > > > internet, thus allowing a camera location where the skies are really > dark. > > > Naturally the > > > Culebra site comes to mind for this. > > > > > > Dana > > > > > > > > > On Sun, Jun 28, 2020 at 6:58 AM Ethan Miller K8GU via mvus-list < > > > <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com> wrote: > > > > > > > Daun/Dana, > > > > > > > > Sorry I missed the MVUS showing of Arecibo photos. I had an HF > > > > receiver and a relatively sensitive all-sky (fisheye) imager (the > > > > imager is still there but operated by someone else now) in Culebra for > > > > a couple of years (for a different experiment) that was occasionally > > > > repurposed for Arecibo HF experiments. It's pretty wild to see some > > > > of the ionospheric structures they created with the HF system, > > > > including airglow structures that were sub-visual magnitude blinking > > > > on and off with the HF transmitter. Of course, at HAARP they've done > > > > visual magnitude airglow, which does nothing to quell the conspiracy > > > > theories! > > > > > > > > I'm not a hard-core plasma physicist, but the stimulated RF emissions > > > > from the Arecibo HF were also always interesting to see...the > > > > high-power HF mode converts into plasma waves which interact with each > > > > other and some of them mode convert back into electromagnetic waves at > > > > different frequencies, shifted by "natural frequencies" (for example > > > > the electron gyrofrequency) of the plasma. These are the types of > > > > things that are theorized to be explanations for long-delayed echoes > > > > (LDEs) and other radio oddities. I'll have to see if I have any data > > > > floating around still that is clear and illustrative to a > > > > technically-literate non-expert audience... > > > > > > > > 73, > > > > > > > > --Ethan, K8GU. > > > > > > > > On Sun, Jun 28, 2020 at 1:56 AM Lenny via mvus-list > > > > < <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com> wrote: > > > > > > > > > > Hi Daun > > > > > > > > > > Just wondering if I can use the pictures and description in the Mt > Airy > > > > > VHF Radio Club ("The Packrats") newsletter. I'm sure the members > would > > > > > be interested. > > > > > > > > > > Please let me know either way. > > > > > > > > > > Tnx, 73 & stay safe, > > > > > > > > > > --Lenny W2BVH (newsletter editor) > > > > > > > > > > > > > > > > > > > > On 6/27/2020 4:28 PM, Daun Yeagley via mvus-list wrote: > > > > > > It's "fun" trying to sort through all my pictures from Arecibo, as > > > > > > they are stored by date, and who knows what I was doing on a > > > > > > particular day! > > > > > > > > > > > > Anyway, here are some pictures of the HF transmitters, and the > > > > > > antennas in the bottom of the dish. For scale, look for the guys > > > > > > that are standing in the opening in the middle. (that's where they > > > > > > hoist stuff up to the platform). Also, on the last one, if you > look > > > > > > carefully you can see the cables that make up the secondary > reflector. > > > > > > > > > > > > Daun > > > > > > > > > > > > > > > > > > _______________________________________________ > > > > > > mvus-list mailing list > > > > > > <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com > > > > > > <http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com> > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > > > _______________________________________________ > > > > > mvus-list mailing list > > > > > <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com > > > > > <http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com> > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > > > > > > > > > > > > > > -- > > > > <http://www.k8gu.com/> http://www.k8gu.com/ > > > > Repair. Re-use. Re-purpose. Recycle. > > > > > > > > _______________________________________________ > > > > mvus-list mailing list > > > > <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com > > > > <http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com> > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > > > > > _______________________________________________ > > > mvus-list mailing list > > > <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com > > > <http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com> > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > > > > > > -- > > <http://www.k8gu.com/> http://www.k8gu.com/ > > Repair. Re-use. Re-purpose. Recycle. > > > > _______________________________________________ > > mvus-list mailing list > > <mailto:mvus-list@lists.febo.com> mvus-list@lists.febo.com > > <http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com> > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > -- http://www.k8gu.com/ Repair. Re-use. Re-purpose. Recycle.