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 -- Daun E. Yeagley II, N8ASB

Daun, Impressive! What are the turnstile/crossed dipole looking structures above the surface of the dish? It’s hard to tell how high these might be above the surface. I see the focal point feed way above that in the top of the picture. And off to the left, part of a structure with some spoke-like pieces. Is lightning much of a problem at the site? Joe - WA8OGS > On Jun 27, 2020, at 4:28 PM, Daun Yeagley via mvus-list <mvus-list@lists.febo.com> 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 > > -- > Daun E. Yeagley II, N8ASB > > <DSC00994.JPG><DSC00293.JPG><DSC00299.JPG>_______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com

Hi Joe Those ARE  crossed dipoles!  You might want to look at the photo at 100% scaling (That's why I sent them at full resolution... The picture gets pretty large at 100%).  Those are resonant dipoles on the top of those poles at the range of 5 to 8 MHz for perspective. Remember too, that the dish itself is nearly a thousand  feet across!  Also, with it at 100% you can also see the workers at the opening in the center of the dish for further perspective. I just realized that I don't think you were on the zoom meeting last night.   I did a bit of an impromptu "tour" of the platform... I couldn't find these particular pictures then, so that's why I sent this email.  Some day I hope to put together a presentation that includes these photos, and perhaps some video as well. I don't know if it is correct to say lightning is a *problem* there, but there is a fair amount of protection included.  I had a photo or two of some of that as well. It was good that Dana was on the teleconference as well, as he has a lot more information than I do about the inner workings. Daun Daun E. Yeagley II, N8ASB On 6/27/2020 5:07 PM, Joe via mvus-list wrote: > Daun, > > Impressive! > > What are the turnstile/crossed dipole looking structures above the surface of the dish? It’s hard to tell how high these might be above the surface. > I see the focal point feed way above that in the top of the picture. And off to the left, part of a structure with some spoke-like pieces. > > Is lightning much of a problem at the site? > > Joe - WA8OGS > >> On Jun 27, 2020, at 4:28 PM, Daun Yeagley via mvus-list <mvus-list@lists.febo.com> 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 >> >> -- >> Daun E. Yeagley II, N8ASB >> >> <DSC00994.JPG><DSC00293.JPG><DSC00299.JPG>_______________________________________________ >> 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 think I just caught Daun in an error. The crossed dipoles themselves are only partway up the poles, not at the tops but maybe 30-50 ft above the dish surface. The funny-looking things at the top of the poles are supports for blocks (as in "block & tackle") that are used for halyards that can be used to pull the dipole elements into a vertical position to make them more wind tolerant during storms. The things are *not* lightning catchers as they might appear to some. I had never seen them used prior to my departure, but assume that they *were* used during Hurricane Maria. The dipole elements are fat- IIRC they're 4" diameter thick-walled aluminum tubing. Note that they also have anti-corona balls at the ends- I believe those are each of 12" diameter. In photo #2 (the one with the people visible in the center opening), if you look closely enough you can also see that there is a man working at the top of the pole straight behind the center opening. Daun has an exquisite sense of timing, I guess. I think you can also see a hint of the HF reflector mesh in photo 2, but it's easier to see in photo 3. Also in photo 3, with all the people not in the way, you can see the platform on which the people of photo 2 had been standing. There is a pole that's ground mounted and which sticks up perhaps 3 feet above that platform floor, and atop that pole there is a survey marker indicating the exact center of the big dish. I never thought to write down the numbers on that marker- now I wish I had. Lightning has not been a major problem at the observatory since almost all of the signal lines from the platform to the downstairs control room were replaced with single-mode fiber optics. There are a lot of fibers going up to the platform! I remember once on the platform seeing a man, who looked rather uncomfortable, sitting at a card table putting connectors on the ends of a whole bunch of fibers. That's a tricky job- since then I've seen one of our own techs doing the same thing and it does not look easy. Dana On Sat, Jun 27, 2020 at 5:58 PM Daun Yeagley via mvus-list < mvus-list@lists.febo.com> wrote: > Hi Joe > > Those ARE crossed dipoles! You might want to look at the photo at 100% > scaling (That's why I sent them at full resolution... The picture gets > pretty large at 100%). Those are resonant dipoles on the top of those > poles at the range of 5 to 8 MHz for perspective. Remember too, that the > dish itself is nearly a thousand feet across! Also, with it at 100% > you can also see the workers at the opening in the center of the dish > for further perspective. > I just realized that I don't think you were on the zoom meeting last > night. I did a bit of an impromptu "tour" of the platform... I > couldn't find these particular pictures then, so that's why I sent this > email. Some day I hope to put together a presentation that includes > these photos, and perhaps some video as well. > I don't know if it is correct to say lightning is a *problem* there, but > there is a fair amount of protection included. I had a photo or two of > some of that as well. > It was good that Dana was on the teleconference as well, as he has a lot > more information than I do about the inner workings. > > Daun > > Daun E. Yeagley II, N8ASB > On 6/27/2020 5:07 PM, Joe via mvus-list wrote: > > Daun, > > > > Impressive! > > > > What are the turnstile/crossed dipole looking structures above the > surface of the dish? It’s hard to tell how high these might be above the > surface. > > I see the focal point feed way above that in the top of the picture. And > off to the left, part of a structure with some spoke-like pieces. > > > > Is lightning much of a problem at the site? > > > > Joe - WA8OGS > > > >> On Jun 27, 2020, at 4:28 PM, Daun Yeagley via mvus-list < > mvus-list@lists.febo.com> 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 > >> > >> -- > >> Daun E. Yeagley II, N8ASB > >> > >> > <DSC00994.JPG><DSC00293.JPG><DSC00299.JPG>_______________________________________________ > >> 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 >

Well, it was unintentional...    They certainly not at the bottom of the poles, and I thought it would be obvious that those big long poles (most of the way up the vertical pole) are the actual dipole elements.  You gotta be very precise with this crowd! Just remember that all this stuff is BIG! Daun Daun E. Yeagley II, N8ASB On 6/27/2020 8:15 PM, Dana Whitlow via mvus-list wrote: > I think I just caught Daun in an error. The crossed dipoles themselves are > only partway > up the poles, not at the tops but maybe 30-50 ft above the dish surface. > The funny-looking > things at the top of the poles are supports for blocks (as in "block & > tackle") that are used > for halyards that can be used to pull the dipole elements into a vertical > position to make > them more wind tolerant during storms. The things are *not* lightning > catchers as they > might appear to some. I had never seen them used prior to my departure, > but assume that > they *were* used during Hurricane Maria. The dipole elements are fat- IIRC > they're > 4" diameter thick-walled aluminum tubing. Note that they also have > anti-corona balls > at the ends- I believe those are each of 12" diameter. > > In photo #2 (the one with the people visible in the center opening), if you > look closely > enough you can also see that there is a man working at the top of the pole > straight > behind the center opening. Daun has an exquisite sense of timing, I > guess. I think > you can also see a hint of the HF reflector mesh in photo 2, but it's > easier to see in > photo 3. Also in photo 3, with all the people not in the way, you can see > the platform > on which the people of photo 2 had been standing. There is a pole that's > ground > mounted and which sticks up perhaps 3 feet above that platform floor, and > atop that > pole there is a survey marker indicating the exact center of the big dish. > I never > thought to write down the numbers on that marker- now I wish I had. > > Lightning has not been a major problem at the observatory since almost all > of the > signal lines from the platform to the downstairs control room were replaced > with > single-mode fiber optics. There are a lot of fibers going up to the > platform! I > remember once on the platform seeing a man, who looked rather uncomfortable, > sitting at a card table putting connectors on the ends of a whole bunch of > fibers. > That's a tricky job- since then I've seen one of our own techs doing the > same thing > and it does not look easy. > > Dana > > > On Sat, Jun 27, 2020 at 5:58 PM Daun Yeagley via mvus-list < > mvus-list@lists.febo.com> wrote: > >> Hi Joe >> >> Those ARE crossed dipoles! You might want to look at the photo at 100% >> scaling (That's why I sent them at full resolution... The picture gets >> pretty large at 100%). Those are resonant dipoles on the top of those >> poles at the range of 5 to 8 MHz for perspective. Remember too, that the >> dish itself is nearly a thousand feet across! Also, with it at 100% >> you can also see the workers at the opening in the center of the dish >> for further perspective. >> I just realized that I don't think you were on the zoom meeting last >> night. I did a bit of an impromptu "tour" of the platform... I >> couldn't find these particular pictures then, so that's why I sent this >> email. Some day I hope to put together a presentation that includes >> these photos, and perhaps some video as well. >> I don't know if it is correct to say lightning is a *problem* there, but >> there is a fair amount of protection included. I had a photo or two of >> some of that as well. >> It was good that Dana was on the teleconference as well, as he has a lot >> more information than I do about the inner workings. >> >> Daun >> >> Daun E. Yeagley II, N8ASB >> On 6/27/2020 5:07 PM, Joe via mvus-list wrote: >>> Daun, >>> >>> Impressive! >>> >>> What are the turnstile/crossed dipole looking structures above the >> surface of the dish? It’s hard to tell how high these might be above the >> surface. >>> I see the focal point feed way above that in the top of the picture. And >> off to the left, part of a structure with some spoke-like pieces. >>> Is lightning much of a problem at the site? >>> >>> Joe - WA8OGS >>> >>>> On Jun 27, 2020, at 4:28 PM, Daun Yeagley via mvus-list < >> mvus-list@lists.febo.com> 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 >>>> >>>> -- >>>> Daun E. Yeagley II, N8ASB >>>> >>>> >> <DSC00994.JPG><DSC00293.JPG><DSC00299.JPG>_______________________________________________ >>>> 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 >> > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com

Daun - Yes, I missed your zoom meeting discussion last evening…was watching grandkids kayaking at a park lake nearby. I re-looked at your pictures with a larger scaling, and now see so much more that I missed with the smaller scaling. There would be big interest if you put together an Arecibo presentation. It would be a great session at either the Microwave Conference, a DXers Conference, one of the VHF/UHF Conferences, or at the Hamvention. And Dana should be there with you (or via zoom) when you give the presentation…and it needs to be recorded and then made available on the DARA TNG site for more to view. Joe - WA8OGS > On Jun 27, 2020, at 8:41 PM, Daun Yeagley via mvus-list <mvus-list@lists.febo.com> wrote: > > Well, it was unintentional... They certainly not at the bottom of the poles, and I thought it would be obvious that those big long poles (most of the way up the vertical pole) are the actual dipole elements. You gotta be very precise with this crowd! > Just remember that all this stuff is BIG! > > Daun > > Daun E. Yeagley II, N8ASB > On 6/27/2020 8:15 PM, Dana Whitlow via mvus-list wrote: >> I think I just caught Daun in an error. The crossed dipoles themselves are >> only partway >> up the poles, not at the tops but maybe 30-50 ft above the dish surface. >> The funny-looking >> things at the top of the poles are supports for blocks (as in "block & >> tackle") that are used >> for halyards that can be used to pull the dipole elements into a vertical >> position to make >> them more wind tolerant during storms. The things are *not* lightning >> catchers as they >> might appear to some. I had never seen them used prior to my departure, >> but assume that >> they *were* used during Hurricane Maria. The dipole elements are fat- IIRC >> they're >> 4" diameter thick-walled aluminum tubing. Note that they also have >> anti-corona balls >> at the ends- I believe those are each of 12" diameter. >> >> In photo #2 (the one with the people visible in the center opening), if you >> look closely >> enough you can also see that there is a man working at the top of the pole >> straight >> behind the center opening. Daun has an exquisite sense of timing, I >> guess. I think >> you can also see a hint of the HF reflector mesh in photo 2, but it's >> easier to see in >> photo 3. Also in photo 3, with all the people not in the way, you can see >> the platform >> on which the people of photo 2 had been standing. There is a pole that's >> ground >> mounted and which sticks up perhaps 3 feet above that platform floor, and >> atop that >> pole there is a survey marker indicating the exact center of the big dish. >> I never >> thought to write down the numbers on that marker- now I wish I had. >> >> Lightning has not been a major problem at the observatory since almost all >> of the >> signal lines from the platform to the downstairs control room were replaced >> with >> single-mode fiber optics. There are a lot of fibers going up to the >> platform! I >> remember once on the platform seeing a man, who looked rather uncomfortable, >> sitting at a card table putting connectors on the ends of a whole bunch of >> fibers. >> That's a tricky job- since then I've seen one of our own techs doing the >> same thing >> and it does not look easy. >> >> Dana >> >> >> On Sat, Jun 27, 2020 at 5:58 PM Daun Yeagley via mvus-list < >> mvus-list@lists.febo.com> wrote: >> >>> Hi Joe >>> >>> Those ARE crossed dipoles! You might want to look at the photo at 100% >>> scaling (That's why I sent them at full resolution... The picture gets >>> pretty large at 100%). Those are resonant dipoles on the top of those >>> poles at the range of 5 to 8 MHz for perspective. Remember too, that the >>> dish itself is nearly a thousand feet across! Also, with it at 100% >>> you can also see the workers at the opening in the center of the dish >>> for further perspective. >>> I just realized that I don't think you were on the zoom meeting last >>> night. I did a bit of an impromptu "tour" of the platform... I >>> couldn't find these particular pictures then, so that's why I sent this >>> email. Some day I hope to put together a presentation that includes >>> these photos, and perhaps some video as well. >>> I don't know if it is correct to say lightning is a *problem* there, but >>> there is a fair amount of protection included. I had a photo or two of >>> some of that as well. >>> It was good that Dana was on the teleconference as well, as he has a lot >>> more information than I do about the inner workings. >>> >>> Daun >>> >>> Daun E. Yeagley II, N8ASB >>> On 6/27/2020 5:07 PM, Joe via mvus-list wrote: >>>> Daun, >>>> >>>> Impressive! >>>> >>>> What are the turnstile/crossed dipole looking structures above the >>> surface of the dish? It’s hard to tell how high these might be above the >>> surface. >>>> I see the focal point feed way above that in the top of the picture. And >>> off to the left, part of a structure with some spoke-like pieces. >>>> Is lightning much of a problem at the site? >>>> >>>> Joe - WA8OGS >>>> >>>>> On Jun 27, 2020, at 4:28 PM, Daun Yeagley via mvus-list < >>> mvus-list@lists.febo.com> 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 >>>>> >>>>> -- >>>>> Daun E. Yeagley II, N8ASB

Joe & Daun, I could contribute a PPT presentation I gave at Dayton back around 2011, at the VHF Low-Noise group dinner on Friday evening. I just checked and found that I seem to have two versions of the presentation, but I have no recollection as to how they differ. Both are large files, something like 40 MB each. I'll try to see if I even have a way to view them here to see which might be better for club Zoom meetings. The general topic is noise and how radio astronomers work to keep it down. The title is "Noise at Arecibo (it's not just the Coqui)". Too late to implement at the Dayton presentation, it occurred to me that I should have arranged to play a lengthy recording of Puerto Rico Coqui peeping sounds at slightly greater than subliminal level throughout the dinner. Dana On Sat, Jun 27, 2020 at 8:18 PM Joe via mvus-list <mvus-list@lists.febo.com> wrote: > Daun - Yes, I missed your zoom meeting discussion last evening…was > watching grandkids kayaking at a park lake nearby. > I re-looked at your pictures with a larger scaling, and now see so much > more that I missed with the smaller scaling. > > There would be big interest if you put together an Arecibo presentation. > It would be a great session at either the Microwave Conference, a DXers > Conference, one of the VHF/UHF Conferences, or at the Hamvention. And Dana > should be there with you (or via zoom) when you give the presentation…and > it needs to be recorded and then made available on the DARA TNG site for > more to view. > > Joe - WA8OGS > > > On Jun 27, 2020, at 8:41 PM, Daun Yeagley via mvus-list < > mvus-list@lists.febo.com> wrote: > > > > Well, it was unintentional... They certainly not at the bottom of the > poles, and I thought it would be obvious that those big long poles (most of > the way up the vertical pole) are the actual dipole elements. You gotta be > very precise with this crowd! > > Just remember that all this stuff is BIG! > > > > Daun > > > > Daun E. Yeagley II, N8ASB > > On 6/27/2020 8:15 PM, Dana Whitlow via mvus-list wrote: > >> I think I just caught Daun in an error. The crossed dipoles themselves > are > >> only partway > >> up the poles, not at the tops but maybe 30-50 ft above the dish surface. > >> The funny-looking > >> things at the top of the poles are supports for blocks (as in "block & > >> tackle") that are used > >> for halyards that can be used to pull the dipole elements into a > vertical > >> position to make > >> them more wind tolerant during storms. The things are *not* lightning > >> catchers as they > >> might appear to some. I had never seen them used prior to my departure, > >> but assume that > >> they *were* used during Hurricane Maria. The dipole elements are fat- > IIRC > >> they're > >> 4" diameter thick-walled aluminum tubing. Note that they also have > >> anti-corona balls > >> at the ends- I believe those are each of 12" diameter. > >> > >> In photo #2 (the one with the people visible in the center opening), if > you > >> look closely > >> enough you can also see that there is a man working at the top of the > pole > >> straight > >> behind the center opening. Daun has an exquisite sense of timing, I > >> guess. I think > >> you can also see a hint of the HF reflector mesh in photo 2, but it's > >> easier to see in > >> photo 3. Also in photo 3, with all the people not in the way, you can > see > >> the platform > >> on which the people of photo 2 had been standing. There is a pole > that's > >> ground > >> mounted and which sticks up perhaps 3 feet above that platform floor, > and > >> atop that > >> pole there is a survey marker indicating the exact center of the big > dish. > >> I never > >> thought to write down the numbers on that marker- now I wish I had. > >> > >> Lightning has not been a major problem at the observatory since almost > all > >> of the > >> signal lines from the platform to the downstairs control room were > replaced > >> with > >> single-mode fiber optics. There are a lot of fibers going up to the > >> platform! I > >> remember once on the platform seeing a man, who looked rather > uncomfortable, > >> sitting at a card table putting connectors on the ends of a whole bunch > of > >> fibers. > >> That's a tricky job- since then I've seen one of our own techs doing the > >> same thing > >> and it does not look easy. > >> > >> Dana > >> > >> > >> On Sat, Jun 27, 2020 at 5:58 PM Daun Yeagley via mvus-list < > >> mvus-list@lists.febo.com> wrote: > >> > >>> Hi Joe > >>> > >>> Those ARE crossed dipoles! You might want to look at the photo at > 100% > >>> scaling (That's why I sent them at full resolution... The picture gets > >>> pretty large at 100%). Those are resonant dipoles on the top of those > >>> poles at the range of 5 to 8 MHz for perspective. Remember too, that > the > >>> dish itself is nearly a thousand feet across! Also, with it at 100% > >>> you can also see the workers at the opening in the center of the dish > >>> for further perspective. > >>> I just realized that I don't think you were on the zoom meeting last > >>> night. I did a bit of an impromptu "tour" of the platform... I > >>> couldn't find these particular pictures then, so that's why I sent this > >>> email. Some day I hope to put together a presentation that includes > >>> these photos, and perhaps some video as well. > >>> I don't know if it is correct to say lightning is a *problem* there, > but > >>> there is a fair amount of protection included. I had a photo or two of > >>> some of that as well. > >>> It was good that Dana was on the teleconference as well, as he has a > lot > >>> more information than I do about the inner workings. > >>> > >>> Daun > >>> > >>> Daun E. Yeagley II, N8ASB > >>> On 6/27/2020 5:07 PM, Joe via mvus-list wrote: > >>>> Daun, > >>>> > >>>> Impressive! > >>>> > >>>> What are the turnstile/crossed dipole looking structures above the > >>> surface of the dish? It’s hard to tell how high these might be above > the > >>> surface. > >>>> I see the focal point feed way above that in the top of the picture. > And > >>> off to the left, part of a structure with some spoke-like pieces. > >>>> Is lightning much of a problem at the site? > >>>> > >>>> Joe - WA8OGS > >>>> > >>>>> On Jun 27, 2020, at 4:28 PM, Daun Yeagley via mvus-list < > >>> mvus-list@lists.febo.com> 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 > >>>>> > >>>>> -- > >>>>> Daun E. Yeagley II, N8ASB > > > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >

Now I know which version of my presentation to send- the other is missing one critical slide. Daun and I can probably discuss how best to do all this tomorrow. Dana On Sat, Jun 27, 2020 at 9:49 PM Dana Whitlow <k8yumdoober@gmail.com> wrote: > Joe & Daun, > > I could contribute a PPT presentation I gave at Dayton back around 2011, > at the > VHF Low-Noise group dinner on Friday evening. I just checked and found > that > I seem to have two versions of the presentation, but I have no > recollection as to > how they differ. Both are large files, something like 40 MB each. I'll > try to see > if I even have a way to view them here to see which might be better for > club > Zoom meetings. > > The general topic is noise and how radio astronomers work to keep it down. > The title is "Noise at Arecibo (it's not just the Coqui)". Too late to > implement > at the Dayton presentation, it occurred to me that I should have arranged > to > play a lengthy recording of Puerto Rico Coqui peeping sounds at slightly > greater than subliminal level throughout the dinner. > > Dana > > > On Sat, Jun 27, 2020 at 8:18 PM Joe via mvus-list < > mvus-list@lists.febo.com> wrote: > >> Daun - Yes, I missed your zoom meeting discussion last evening…was >> watching grandkids kayaking at a park lake nearby. >> I re-looked at your pictures with a larger scaling, and now see so much >> more that I missed with the smaller scaling. >> >> There would be big interest if you put together an Arecibo presentation. >> It would be a great session at either the Microwave Conference, a DXers >> Conference, one of the VHF/UHF Conferences, or at the Hamvention. And Dana >> should be there with you (or via zoom) when you give the presentation…and >> it needs to be recorded and then made available on the DARA TNG site for >> more to view. >> >> Joe - WA8OGS >> >> > On Jun 27, 2020, at 8:41 PM, Daun Yeagley via mvus-list < >> mvus-list@lists.febo.com> wrote: >> > >> > Well, it was unintentional... They certainly not at the bottom of >> the poles, and I thought it would be obvious that those big long poles >> (most of the way up the vertical pole) are the actual dipole elements. You >> gotta be very precise with this crowd! >> > Just remember that all this stuff is BIG! >> > >> > Daun >> > >> > Daun E. Yeagley II, N8ASB >> > On 6/27/2020 8:15 PM, Dana Whitlow via mvus-list wrote: >> >> I think I just caught Daun in an error. The crossed dipoles >> themselves are >> >> only partway >> >> up the poles, not at the tops but maybe 30-50 ft above the dish >> surface. >> >> The funny-looking >> >> things at the top of the poles are supports for blocks (as in "block & >> >> tackle") that are used >> >> for halyards that can be used to pull the dipole elements into a >> vertical >> >> position to make >> >> them more wind tolerant during storms. The things are *not* lightning >> >> catchers as they >> >> might appear to some. I had never seen them used prior to my >> departure, >> >> but assume that >> >> they *were* used during Hurricane Maria. The dipole elements are fat- >> IIRC >> >> they're >> >> 4" diameter thick-walled aluminum tubing. Note that they also have >> >> anti-corona balls >> >> at the ends- I believe those are each of 12" diameter. >> >> >> >> In photo #2 (the one with the people visible in the center opening), >> if you >> >> look closely >> >> enough you can also see that there is a man working at the top of the >> pole >> >> straight >> >> behind the center opening. Daun has an exquisite sense of timing, I >> >> guess. I think >> >> you can also see a hint of the HF reflector mesh in photo 2, but it's >> >> easier to see in >> >> photo 3. Also in photo 3, with all the people not in the way, you can >> see >> >> the platform >> >> on which the people of photo 2 had been standing. There is a pole >> that's >> >> ground >> >> mounted and which sticks up perhaps 3 feet above that platform floor, >> and >> >> atop that >> >> pole there is a survey marker indicating the exact center of the big >> dish. >> >> I never >> >> thought to write down the numbers on that marker- now I wish I had. >> >> >> >> Lightning has not been a major problem at the observatory since almost >> all >> >> of the >> >> signal lines from the platform to the downstairs control room were >> replaced >> >> with >> >> single-mode fiber optics. There are a lot of fibers going up to the >> >> platform! I >> >> remember once on the platform seeing a man, who looked rather >> uncomfortable, >> >> sitting at a card table putting connectors on the ends of a whole >> bunch of >> >> fibers. >> >> That's a tricky job- since then I've seen one of our own techs doing >> the >> >> same thing >> >> and it does not look easy. >> >> >> >> Dana >> >> >> >> >> >> On Sat, Jun 27, 2020 at 5:58 PM Daun Yeagley via mvus-list < >> >> mvus-list@lists.febo.com> wrote: >> >> >> >>> Hi Joe >> >>> >> >>> Those ARE crossed dipoles! You might want to look at the photo at >> 100% >> >>> scaling (That's why I sent them at full resolution... The picture gets >> >>> pretty large at 100%). Those are resonant dipoles on the top of those >> >>> poles at the range of 5 to 8 MHz for perspective. Remember too, that >> the >> >>> dish itself is nearly a thousand feet across! Also, with it at 100% >> >>> you can also see the workers at the opening in the center of the dish >> >>> for further perspective. >> >>> I just realized that I don't think you were on the zoom meeting last >> >>> night. I did a bit of an impromptu "tour" of the platform... I >> >>> couldn't find these particular pictures then, so that's why I sent >> this >> >>> email. Some day I hope to put together a presentation that includes >> >>> these photos, and perhaps some video as well. >> >>> I don't know if it is correct to say lightning is a *problem* there, >> but >> >>> there is a fair amount of protection included. I had a photo or two >> of >> >>> some of that as well. >> >>> It was good that Dana was on the teleconference as well, as he has a >> lot >> >>> more information than I do about the inner workings. >> >>> >> >>> Daun >> >>> >> >>> Daun E. Yeagley II, N8ASB >> >>> On 6/27/2020 5:07 PM, Joe via mvus-list wrote: >> >>>> Daun, >> >>>> >> >>>> Impressive! >> >>>> >> >>>> What are the turnstile/crossed dipole looking structures above the >> >>> surface of the dish? It’s hard to tell how high these might be above >> the >> >>> surface. >> >>>> I see the focal point feed way above that in the top of the picture. >> And >> >>> off to the left, part of a structure with some spoke-like pieces. >> >>>> Is lightning much of a problem at the site? >> >>>> >> >>>> Joe - WA8OGS >> >>>> >> >>>>> On Jun 27, 2020, at 4:28 PM, Daun Yeagley via mvus-list < >> >>> mvus-list@lists.febo.com> 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 >> >>>>> >> >>>>> -- >> >>>>> Daun E. Yeagley II, N8ASB >> >> >> _______________________________________________ >> mvus-list mailing list >> mvus-list@lists.febo.com >> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >> >

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

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.