Work Trip Report, December 8, 2020

Text & pictures by Bill Miller.

On Tuesday 12/08 Ray Uberecken and Bill Miller traveled to the Plishner site.  We found that the gate chain lock was not properly attached to the post and could be removed without unlocking it

We replaced two of the coaxial cables running from the dish pedestal control deck to the upper deck just below the dish.  These cables had stretched from their own weight and from the elevation rotation of the dish. As a consequence the center pin pulled out from the mating connector, losing the conductivity. We added to the cable a loop over the elevation axis. Ray added a feedthrough connector attachment on the ceramic slip ring collar, in order to remove the rest of the hanging stress on the wires, and he re-added the swivel joints below that.  This arrangement completely eliminates the cables traveling up and down thru the collar as the elevation is changed, and this also virtually eliminates the coaxial cable wrap in the control deck area.  We redressed all of the cables there with tie wraps and tape to get them out of the way of personnel in the deck and to remove the mechanical strain on all the cables. 

At the top deck we removed the AC extension cord, which had been temporarily installed to a power amplifier at the feed for EME.  Its cord insulation might not have survived the winter, and the uninsulated cord could potentially short out to the structure.  A more permanent and reliable 120 volt power distribution is needed to the feed point. 

We also re-dressed all the wires and coax cable in the upper deck. We reused the pipe grommets as a weather shield for the cables going down thru the azimuth axes collar to the control deck level.

We then placed a ladder on the mount and proceeded up to the dish surface. There we continued to remove the  120 volt extension cord, and we inspected the surface and the support. This is a wide angle shot of the scene in the dish. It does give a sense of the surreal feeling of the view from there. 

Wide angle view from atop the dish.

We inspected the attachments and connections.  We discovered that the grounding cable connection on one of the legs leading to the focal box had been cut off.  Furthermore, the wave guide that is attached at the dish structure is not electrically attached to the focal point box. Therefore the only ground to protect from RF, lightning, or static is the coax shield and the low voltage control cable ground wire. This may be one of the causes of failures in the electronics. We should retrofit to provide a good DC ground connection between the feed box at the focal point to the pedestal. 

The ground cable cut, near the dish end of the support arm.

We also wanted to know how the fiber glass supports for the feed are adjusted.

The fiber glass supports are badly weathered after 60 years in the open.  We should derive a plan to rework the fiberglass surface, for the next time we rent a bucket lift to work on them.

Full view of one of the dish’s support arms that supports the feed.

Once we had inspected the dish, we tipped the dish down to the service elevation, donned climbing harnesses, and climbed the scaffold tower.  We removed the 1296 MHz feed and installed the 408MHz antenna using Ray’s quick-change mount.  This only took about an hour where before the process could take as much as half a day.

Lowering the 1296 MHz feed antenna from the dish focus.

We also reworked the connector attachments in the electronics box. Ray then reattached the additional 20db amplifier, and checked everything out with the TDR and Spectrum analyzer.  He reattached the cables in the pedestal to connect the correct coax lines to the Comm. Trailer.

Bill replaced the broken window in the back of the comm. trailer with the new one he purchased from Kent Glass and sealed it with RTV.  This provides a much clearer view of the dish from the trailer.

We parked the dish, turned off all the equipment, locked the site and left for the day.

DSES Succeeds in our 2nd EME Moonbounce Communications Competition

Text and photos by Gary Agranat.

On the weekend following this past Thanksgiving we participated in the second round of the ARRL EME Contest, which ran for 48 hours, on November 28 & 29, 2020, GMT hours. This time it was a cliff-hanger in that we almost didn’t get on the air. But with some dedicated effort we succeeded again. This time we contacted some new places. And we added JT65C digital mode.

Team members for this operation were Ray Uberecken AA0L, Gary Agranat WA2JQZ, Myron Babcock KL7YY, and Bill Miller KC0FHN. Floyd Glick WD0CUJ came out also for one evening, accompanied by our new member Michael Nameika.

For this weekend the Moon was at almost full phase. That meant that it would be up mostly during our nighttime, which therefore was when we would have to do our operations. The contest would start at 0000 Hours GMT, which for us was 5 PM on Friday evening November 27. The Moon was already rising at 3:19 PM, so it would be up high enough to begin operating right away, once the contest started.

The Moon above our horizon already at about 4 PM Friday.

Ray and Bill arrived Friday afternoon by 3 PM to set up and do last minute testing. I (Gary) arrived soon after.

In our testing, we found we could receive the 1296 MHz beacon Ray set up at his home in Peyton. But we couldn’t properly transmit.

We quickly slew the antenna to the service tower, and Ray retrieved the amplifier at the feed. The thinking was the problem might be there.

The 60 foot dish antenna lowered to the service tower, as the sun set.
Ray climbed the service tower and retrieved the amplifier at the feed.
Ray retrieving the amplifier.

Ray did some quick testing of the amplifier. But an initial check didn’t find anything wrong.

Ray quickly tested the amplifier in the operations trailer, but didn’t find a problem. Outside, the Moon was rising, and the contest was starting. But were were not operational.

Ray then climbed back up the tower to return the amplifier to the feed point. We thought about what else could be wrong.

We then checked how much power was being drawn by the amplifier in the pedestal. The power meter was reading about 30 Watts when we tried to transmit, when it should have been reading about 200 Watts. At that point the sky was getting dark. It would not have been safe to do any more climbing. And so for the first night of the contest we couldn’t operate.

Bill returned home, but was available the next day for coordination in Colorado Springs. Ray and I spent overnight at the site, to continue troubleshooting on Saturday. We would have the whole day in sunlight, until the Moon rose for the second pass at 3:47 PM.

Ray replacing the amplifier at the feed, as the sun set.

Pikes Peak was visible on the northwest horizon, as the sun set.
The frost on Gary’s car the next morning.
The bunker Saturday morning.

Before going to sleep I (Gary) made some HF ham radio contacts. So we got on the air still, but on HF. This weekend there was also another contest, the CQ World Wide CW (Morse Code) Contest. On 160 and 80 meters I made three contacts with Canadian stations. There were lots of US stations on, but for the rules of this contest, you have to contact stations outside of your country (or more precisely outside of your DX area, which for us is the CONUS). I afterwards made some HF FT8 digital contacts for the club, on 80 and 40 meters. On 40 meters we made our first DX contact with New Caledonia in the southwest Pacific, with station FK8HM. This was with our recently repaired vertical antenna, so this showed our vertical was working OK.

Early the next morning I made some more CW contacts for the contest, this time on 40 meters using the vertical, and on 15 meters, using both the vertical and Yagi antennas. On 40 meters, while it was still dark across the Pacific, stations in China, Hong Kong, and South Korea were heard, but I didn’t succeed in making contacts. I did succeed though in contacting two Japanese stations. Then on 15 meters, with daylight across the Atlantic, the band was wide open to Europe. For a few minutes while on the air, we made contacts with France, Spain, and Slovenia, and also one contact to the south with Brazil.

Earlier during the year, the 3-band Yagi antenna bank angle slightly tilted. The 5-band vertical antenna also was damaged, probably both from storms. Earlier in the fall we repaired a bent piece of the vertical antenna, and reconnected the radial wires that had been severed. The HF operating showed these were at least working OK again. The 160 and 80 meter contacts were made with dedicated diploe antennas, also lightly visible in the picture. The Yagi antenna on the tower is aimed towards the northeast, towards Europe.
This is an eQSL confirmation we received from VE7JH in British Columbia, Canada, for our 80 meter Morse Code (CW) contact on Friday night. The card came with this caption information: 08 Aug 2009 Frobisher Bay, Baffin Island HMCS Toronto navigates an iceberg HMCS Toronto navigates past an iceberg near Frobisher Bay off the coast of Baffin Island while conducting sovereignty patrols as part of Operation NANOOK 09. Operation NANOOK 09 is a Canada Command sovereignty operation conducted with the participation of personnel, ships and aircraft from the Navy, Army and Air Force, working under the command of Joint Task Force (North) (JTFN). The operation runs from 06 to 28 August 2009, in Canada’s eastern Arctic. Photo by: Corporal Dany Veillette, Canadian Forces Joint Imagery Centre, Ottawa, Ontario.
An eQSL confirmation we received from F6HKA in France, for a Morse Code (CW contact) Saturday morning on the 15 meter band. His card shows several Morse Code keys.

Ray and I had breakfast and resumed troubleshooting work at 9 AM. We retrieved the amplifier again, and this time did a much more thorough test. Ray found one diode was leaking current. But this was a circuit safety issue and not a showstopper for transmitting. Ray replaced the diode, and returned the amplifier to the feed.

Ray retrieved the amplifier again Saturday morning.
Ray doing a thorough test of the amplifier. Nominally it should boost our signal to about 200 Watts at the feed.
Ray tested the output of the amplifier by sending the signal through the disc cone antenna on top of the operations trailer.

We then considered what else could cause our problem. Ray tested the conductivity of our feed lines. We have two coax cables running from the operations trailer to the feed. Ray climbed to the feed, and connected the two cables there. Then we measured the conductivity going out and coming back, together at the same time. His software analyzer showed Coax cable #1 had a fault at 135 feet down the line, and Coax cable #2 had a fault 185 feet down the line. This corresponded with where there are swivel joints for the cables, where the fixed pedestal interfaces with the moving dish antenna structure. A signal test also showed there was more loss on the lines then expected.

The oscilloscope showed we didn’t have as strong as signal as we expected along the feed lines.

At first Ray wondered that the swivel joints might be the problem. However, on visual inspection those were seen to be OK. The problem was eventually traced instead to the weight of the cables at that location pulling on the centers of the feeds, causing those to slip out. 

Ray was able to repair Feed Line #1.  We then did more testing, with Ray’s beacon and the W0TTT beacon in Como, CO, and with an SSB tropospheric scatter contact with Myron in the Springs, and found we were working well. We were back in business.

Saturday, troubleshooting. The disc cone antenna is on the short tower on the left side of the trailer.

Myron drove out to the site, and operated with us the second night. While Myron was on his way, I slew the antenna for Moonrise, getting more practice with the System 1 automatic tracking.

As soon as the Moon rose we heard CW and digital signals. We again had to figure out the Doppler shift correction, using the WSJT 10 software. At the start we made several CW contacts with Europe: to Germany, England, Croatia, France, Poland, and Austria.

Eventually we also tried digital JT65C –for the first time. That was a learning curve, but we finally got it. One of the tricks for that was that the waterfall window on the JT65C has a bar at top designating where the sync pulse of the signal has to be, in order for the software to decode it. Another challenge was that operators were heard with JT65 weren’t using a consistent contact exchange format. And so I had to manually edit the exchange fields quickly, in the 10 seconds between decoding and transmitting.

We made 19 contacts altogether. 16 were with CW (Morse Code) and 3 were digital JT65C. Myron tried several times to make SSB contacts. But there were no takers to respond back to us.

Over the night, I generally made the CW and digital contacts, while Ray operated the radio, including keeping up with the Doppler shift offsets. I offered to let others make contacts too. But we were comfortable doing it this way.

Floyd came during the evening with his astronomy student Michael Namieka. Floyd showed Michael around the site, and I believe also made some HF contacts in the bunker. They watched our EME operation. They got into a good technical discussion about the component causes of the Doppler shifts. Myron had Michael send a voice CQ and test moon bounce signal, and Michael heard his voice come back about 2 seconds later.

Our CW contacts included our DSES member Skip, VE6BGT — he said we sounded much stronger this time. And we found several other stations we had contacted last month too. 

On JT65 we had QSOs with AL Katz K2UYH, W6YX Stanford University, and AA4MD in Florida (who last month we got on CW). 

New countries to Europe this time were France and Croatia. We got KL6M in Alaska, who built our feed. We got one Japanese contact JH1KRC, who we contacted last month. And this time we had one contact with Australia, VK5MC, probably our contact furthest away from us.  I am happy to report we had pileups on us.  At least some of our contacts already knew something about us and our capability.

This is a record of our contacts, from the Cabrillo formatted file we submitted to the ARRL for the contest. CW is Morse Code. DG is JT65C digital. 1.2 G is the 1.2 GHz frequency band. You see the date and times in GMT, our station with the signal report we sent, and the station we contacted with their signal report to us.
QSO: 1.2G CW 2020-11-28 2312 K0PRT 599 DG5CST 599 Germany
QSO: 1.2G CW 2020-11-28 2317 K0PRT 559 SP7DCS 589 Poland
QSO: 1.2G CW 2020-11-28 2324 K0PRT 559 G4CCH 599 England
QSO: 1.2G CW 2020-11-29 0007 K0PRT 559 9A5AA 579 Croatia
QSO: 1.2G CW 2020-11-29 0020 K0PRT 569 DL6SH 579 Germany
QSO: 1.2G CW 2020-11-29 0040 K0PRT 569 VE6BGT 589 Canada
QSO: 1.2G CW 2020-11-29 0057 K0PRT 579 OE5JFL 579 Austria
QSO: 1.2G CW 2020-11-29 0216 K0PRT 569 WA9FWD 579 Wisconsin, USA
QSO: 1.2G CW 2020-11-29 0350 K0PRT 559 F2CT 569 France
QSO: 1.2G CW 2020-11-29 0403 K0PRT 559 KL6M 579 Anchorage, Alaska, USA
QSO: 1.2G CW 2020-11-29 0407 K0PRT 559 OK1KIR 569 Czech Republic
QSO: 1.2G CW 2020-11-29 0413 K0PRT 559 I5MPK 599 Italy
QSO: 1.2G CW 2020-11-29 0420 K0PRT 559 K7CA 559 Nevada, USA
QSO: 1.2G CW 2020-11-29 0430 K0PRT 549 KA1GT 559 Maine, USA
QSO: 1.2G DG 2020-11-29 0629 K0PRT -06 K2UYH -01 New Jersey, USA
QSO: 1.2G CW 2020-11-29 0750 K0PRT 569 JH1KRC 589 Japan
QSO: 1.2G DG 2020-11-29 0811 K0PRT -08 W6YX -08 California, USA
QSO: 1.2G CW 2020-11-29 0920 K0PRT 439 VK5MC 449 Australia
QSO: 1.2G CW 2020-11-29 0946 K0PRT 599 N4PZ 599 Chicago, Illinois, USA
QSO: 1.2G DG 2020-11-29 1006 K0PRT -09 AA4MD -07 Florida, USA

The automatic tracking system display, showing us tracking the Moon.
The WSJT JT65 display on my computer. The upper left shows a spectrum waterfall, where we had to position the signal for the software to decode. We also at times had to adjust the audio gain, to not overwhelm the display. The upper right shows the message exchange, in this case with W6YX in California. The lower window is our logbook.

We decided to stop operating at around 3:30 AM Sunday morning. We were hearing much fewer new contacts. But also the outside wind was picking up immensely. Forecasts for the region were for gusts up to 50 knots. We stowed the antenna back to the safe position. Ray, Myron and I then got sleep in the operations trailer. Outside the temperature dropped to the low 20s, but we kept warm inside with the heaters. Myron left early in the morning. Ray and I closed the site by 11 AM Sunday, and headed back to the Springs.

* * *

Some technical feedback: System 1 was working almost perfectly.  The one glitch again was that there was a discontinuity in elevation reading on Friday night as the elevation was brought close to zero (seen by Bill).  I didn’t experience that on Saturday or Sunday.  Otherwise, the System 1 is an immense help.  It makes the slewing and tracking easy and seamless.  

We had a learning curve figuring out all of the nuances and details (or the sufficient and necessary details) for running JT65.  We did eventually get JT65 working well. You do need to pay attention to its peculiarities.  It probably could use some guidance documents, like we have for System 1. 

I will note I did try to make a number of contacts but didn’t get responses. I don’t know why that was.  I am suspecting part of the reason might be due to not getting the Doppler shift offsets quite right at times. But we did get a number of good signal reports and explicit comments that we had good signals.

Later I did some research. One of our contacts KA1GT has some articles on the Doppler shift math and corrections. These might be helpful:

Bob Atkins – KA1GT – EME Doppler shift 101

CFOM Constant Frequency On Moon Doppler Mode – Bob Atkins – KA1GT

It was a somewhat intense weekend for the team — with not being able to operate Friday evening as it got dark, with the troubleshooting, the cold and windy weather conditions and staying overnight (for some for 2 nights) on site.  But we were very pleased we got our Moon communications back.  We had lots of good signal reports.   We apparently were doing better than in October with our signals. We probably had fewer contacts than last time as we were spending time figuring out the JT65 and Signallink.  And I suspect there might have been fewer hams on for the second night. But I think also we didn’t want to knock ourselves out, especially with all the work we did. We found a good balance that worked.

I think all of us involved were very pleased with what we accomplished this weekend. We spent the effort to troubleshoot, we got ourselves back on the air, and we made a successful second EME Moon bounce operation.

  • 73 Gary WA2JQZ

DSES Science Meeting Nov 23, 2020

Welcome to the DSES Science meeting 11/23/2020

2020-11-23 DSES Science Meeting Notes, by Bill Miller

We had 16 participants in the virtual science meeting today:  Thanks everyone for joining.

Participants: Dr. Rich Russel,  Ray Uberecken, Lewis Putman, Bob Haggart, Don Latham, Floyd Glick, Gary Agranat, Glenn Davis, Jay Wilson, Jon Ayers, Lauren Libby, Myron Babcock, Robert Sayers, Ted Cline. Jerry Espada, Bill Miller

Agenda and notes;

Also see the Zoom Video Recording for more detail:

https://us02web.zoom.us/rec/share/3mwT_OSBrUV6KMi8GTTrcFaiG77Jmuuke72Jk1zmmUDpSrO2nAY3jFx49_muRz5I.7GK8PFSy5Vs-kL4R?startTime=1606177717000

Agenda and notes:

  1. Myron’s Treasure’s Report Checking $1774.28. Savings $5742.15. We have 49 paid members.
  2. Science Fair: 
    • Bill spoke with Carol Bach the coordinator,  she replied, “The Pikes Peak Regional Science and Engineering Fair will be held virtually on February 20, 2021.  We are hoping that the Deep Space Exploration Society will again sponsor a special award or awards at the fair.  In addition, we are hoping you or another member of your group will consider being a special awards judge.  We will send you a code to unlock a showcase with digital displays that you can view.  Virtual judging will take place between February 18-20, 2021.”
    • Bill to send board DSES Special awards criteria for approval.
    • “Please respond by December 2, 2020 to this email and confirm that your organization is planning to participate. Also, please let us know the name and contact email for future communications.”
  3. Planet Walk:
    • Bill will write an endorsement letter and have the DSES Board modify and approve for Planet Walk Colorado Springs. See https://www.planetwalkcs.org/
  4. Arecibo Failure:
    • See Bob Haggard’s repost on the Arecibo Radio Telescope status.
  5. Rich presented the DSES Science part of the Meeting:  See all notes in the DSES Science Meeting Power Point. http://dses.science/wp-content/uploads/2020/11/DSES-Science-Meeting-11-23-20.pdf
  6. Ray
    • Problem with the 1296 feed last trip.  Took down the Feed amplifier and found that the unit was stuck in the transmit configuration again due to a failed FET in the Relay driver.  Fixed this and added more gate protection circuitry to solve the problem. 
    • Also had a bad diode and a bad cable that had to be corrected.
    • The FT-736R Keyer connection failed on last trip but Ray fixed it.
    • Tried CW EME but couldn’t hear the echo.
    • Did receive Rays Home Based beacon bounced off Pikes Peak and verified pointing so the receiver chain is working.
  7. Gary Underground K0PRT  bunker station summary report.
    • FT8,  PSK Reporter website showed our station was received on 40 meters during afternoon in CA and TX.
    • 15M operation was hot
    • Our rare grid square (DM88) attracted many Japanese stations
    • Vertical working well on 15 and 40 meters. 10 meters was tried and at least had good SWR, but band was dead.
    • Yagi was also working well to Japan
    • PSK reporter showed good coverage on 15 meters all around the Pacific Rim.
    • See more in Rich’s slides above
  8. Glenn says that Phil is working on an elevation tracking update that will need some onsite testing when ready.
  9. Much discussion about the SDR receivers, GNU SW and the computer power needed to run them.  See the meeting recording for too much detail to capture here.

Plishner site trip summary of 2020-10-31:

Written summary and photos by Bill Miller.

Ray Uberecken and Bill Miller went to the Plishner site on Sat. October 31.

Ray brought back his EME 200 Watt amplifier box that he had removed on the previous weeks trip.  The unit had blown a relay control FET that kept the unit in the transmit position so it would not connect the feed to the receiver.  Ray and Bill donned climbing harnesses, scaled the scaffold, and installed the amplifier before the wind could start blowing about 11:00 AM at the site. 

Ray also brought back the FT 736 Transceiver after repairing the seized tuning knob.  He brought in a computer and an audio interface with JT-65 HF software loaded.  This will enable digital mode EME on the next contest  EME 50-1296 MHz — November 28-29, 2020.  In addition, he installed  an extra 1296 MHz 18 Watt auxiliary amplifier between the FT736 10W max output  and the Amplifier at the feed point.  This extra amplifier will enable the full power of the linear amp at the feed.  Both the 18 watt amp and the 200 watt feed point amp are enabled with the Key circuit from the FT 736.  

There is an extra power supply on the bench to power the 18 Watt amp and the key circuit to the feed amp is attached with the terminal block on the rack.

Ray also brought back the Electronic Keyer and Paddle for the FT736 moon bounce CW mode.

Once all this equipment was installed, we climbed the tower and replaced the bad swivel joint on the down feed coax with a short segment of very flexible RG8X cable to allow the cable wrap. Because this is the same impedance as the main hard line coax and very short it has insignificant loss to the signal.

We then called Myron Babcock to test the equipment.  We pointed the dish at Colorado Springs and at first did not hear his signal.  He swung his antenna around to point at Pike’s Peak and we did the same and established communication on 1296.1 MHz with clear copy.  This proved the overall system viability.  

Bill set up his phone app and computer program for aiming the Hughes Net dish for internet.  After using the compass to point the dish to the apps specified Azimuth and Elevation and working the dish around for half an hour, we still couldn’t get the modem to lock up and receive the satellite.  More research is needed to make sure we are trying for the correct satellite and have the right coordinates and tools to do the alignment on the next trip. Once we have the Hughes Net system working, we should have high speed internet capability for a number of uses.

Ray has been working on his new radio Astronomy receiver based on a medical signal preconditioner and a stable amplifier/integrator and A/D converter.  The receiver will give a greater bandwidth than current SDRs with  up to 100MHz of bandwidth.

A conversion program is needed to convert the comma delimited tabular output of the A/D to the .Fil file format for radio astronomy.  Ray installed the receiver and checked its operation.

We stowed the dish, shut everything down, removed the trash and locked the site.  Note that the new service  position on the scaffold after the recalibration of the pointing system is 314.5 deg. All old bearings for Beacons and such should be adjusted by -2.5 deg.

You can read a PDF version of this report here: 2020-10-31-Plishner-site-trip-summary-v2-.pdf

DSES Science Meeting October 26, 2020

Welcome to the DSES Science meeting 10-26-2020

2020-10-26 DSES Science Meeting Notes:   by Bill Miller

We had 14 participants in the virtual science meeting today:  Thanks everyone for joining.

Participants: Dr. Rich Russel,  Ray Uberecken, Chad Carter N0ZMG, Don Lewis, Matt Mathews, Bob Haggart, Michael Nameika, Gary Agranat,  Jonathan Ayers,Floyd Glick, Don Latham, Myron Babcock, Ted Cline on Phone, Bill Miller

Also see the Zoom Video Recording for more detail:

https://us02web.zoom.us/rec/share/VGBjHU_8SX1oUIID9rfAETR6FDWU-AiO_jtXLBN5allYy37d8WWxX1-rcsEk_NwV.hIq6Lvmw397kui6R

Agenda and notes:

  1. Myron’s Treasure’s Report Checking $1756 Savings $5742.05  September electric Bill $90
  2. Rich:  See all notes in the DSES Science Meeting Power Point. DSES-Science-Meeting-10-26-20.pdf
  3. Ray
    • Problem with the 1296 MHz feed last weekend.  Took down the Feed amplifier and found the unit was stuck in the transmit configuration due to a failed FET in the Relay driver.  Fixed this and added a gate protection resistor to solve the problem. 
    • A second issue was discovered with one of the coaxial swivel joints that failed on the feed lines.  Will find a new swivel joint or alternate method of coupling the coax while allowing for the cable wrap.
    • See slide 4 of Rich’s slide presentation above.
  4. Gary EME report.
    • Ray has JT65 digital setup ready
      • Use WSJT 10.0 Program for EME.
    • On November 28 and 29th there will be another EME contest under nearly a full moon.
    • Nov 27 – 28 Moon Rise 3:19 PM  set at 5:03 AM
    • Nov 28  – Nov 29th Moon rise 3:47 PM to about 6:03 AM
    • We will benefit by organizing the operation trip, to utilize our time while the moon is overhead with multiple operators.
    • Morse code is simple and effective.  Can be done with the computer keyboard or with a keyer.
    • Simple protocol of multiple repeats on Call sign, signal report and acknowledgement should be followed.
    • Signals experience polarization rotation, we therefore circularly polarize our signal.
    • Operation on JT65C will be added.
    • Operating EME is an experience you won’t forget
  5. Astronomy at Hydrogen Line 1420.406 MHz:  See Rich’s PPT presentation page 6 to end.
  6. SARA “Radio Astronomy in a Box” costs about $250 and is a great platform for a science fair project. Rich has one for evaluation and will lend to a worthy student.
    • 2.4 G dish
    • Stellarium planetarium software
    • Can be used for science fair
    • Don’t download the SW, as it has a virus.
    • Rich has another source of virus free SW.
  7. We have a new student member, Michael Nameika who is a student at UCCS interested in Astrophysics and Radio Astronomy.  He has been working with Professor Floyd Glick at the PPCC observatory and with Steve Plock.  Welcome, Michael.
  8. Myron Babcock, DSES Treasurer, has received a very generous donation of a Yaesu FT-736R from  N6KN, Rocco Lardiere in California.   He also triple boxed the unit and paid the FedEx postage to ensure that it arrived in great shape.  This will make an excellent addition to our radio resources and backup to our high band EME and Tropo communication.  Thank you, Rocco.

Our 1st DSES Earth-Moon-Earth (EME) Moon Bounce Communications

By Gary Agranat, with Myron Babcock and Glenn Davis. Videos by Bill Miller.

Friday evening at sunset as the team prepares for our first EME attempt overnight. Photo by Gary Agranat.

On Saturday October 10, 2020 we succeeded in making our first Earth-Moon-Earth (EME) Moon Bounce communications. We succeeded at our first attempt. This accomplishment was several years in the making, thanks to the work of many members, past and present.

We did this participating in the annual ARRL EME contest held on the weekend of October 10-11, 2020 GMT. (That’s Friday 6 pm to Sunday 6 pm local time.) The frequencies available for this contest were in the ham radio bands from 50 to 1296 MHz. We used our 60-foot dish antenna at Haswell, CO, with a 1296 MHz feed with dual circular polarization, installed 2 weekends earlier.

[ Installing the 1296 MHz feed for Autumn Moon Bounce Communications, Sept 27 ]

EME Moon Bounce communications is directing a signal to the Moon. The Moon’s surface simply reflects the signal back to Earth. If the Moon is above your horizon, if you have suitable equipment, and if you know enough about what to do, it would be possible for you to receive the signal and communicate back. You could communicate to your neighbor or across continents. The signals, however, are extremely weak, having to travel back and forth the Earth-Moon distance, over 238,000 miles. EME generally requires efficient directional antennas to sufficiently increase the signal gain. Amplifiers can be used too. And the antennas have to point to the Moon. Also, radio signals sent through the ionosphere experience a rotation in their polarization. And there is some effective rotation from other causes, including from the changes in orientation from the Moon and from operating on different points of the Earth’s globe. Our solution is to circularly polarize our signals. And also, there is a Doppler shift between transmitted and received signal, mostly due to the Earth’s rotation, causing a difference in velocity between the Moon and our location on Earth. All of these are challenges to deal with.

Our 60-foot dish antenna at sunset as we started preparations. Photo by Glenn Davis.

Our team for the EME operation were Ray Uberecken AA0L, Myron Babcock KL7YY, Gary Agranat WA2JQZ, and Glenn Davis. Bill Miller KC0FHN also came on Saturday morning.

The team arrived Friday evening October 9, while we still had daylight, to set up and test. Testing included making pre-arranged tropospheric scatter contacts, which were successful. We also attempted to complete set-up of a Hughes Internet antenna, to give us Internet access, but that was not successful. We instead sometimes connected to the Internet using cellphones. Although the contest began at 6 PM local time, we had to wait for the moon to rise above the horizon. Moonrise for us was at about 11:30 PM local time, and the Moon was above our horizon until about 2 PM local time the next day Saturday. We chose to stay for just this one Moon pass, and not continue through Sunday, in order to not knock ourselves out on this first attempt.

After we completed our testing, we relaxed until we were ready to start. Looking outside, we had an exceptionally deep starry sky. We could see the Milky Way clearly arching overhead through Cygnus. Jupiter and Saturn were bright to the south, and Mars was very bright, rising in the east. Glenn Davis experimented with his camera and took some nice time exposure photos with the dish antenna, the stars, and the Milky Way.

Photo by Glenn Davis. (Click to enlarge.)
Our 60-foot dish antenna with the Milky Way. Jupiter and Saturn are brightly visible to the left of the antenna. Photo by Glenn Davis. (Click to enlarge.)

I (Gary) meanwhile got some rest. This enabled the others to get some rest later in the morning while I continued.

Myron KL7YY wrote and emailed an update about our operations to the DSES membership on Saturday morning at around 4 AM. It provides a good narrative of how we were doing until that point, and his update follows next:

* * * * * * * * * * *

Summary of DSES first attempt at EME, Earth Moon Earth, contacts using the 60 foot dish:

On Friday evening, October 9 we started with a few nearby Tropospheric Scatter contacts around 7 PM with DSES member KL7IZW, Steve in Monument, CO, and W6OAL Dave in Parker.  Around 9 PM we talked to N0YK in Scott City KS, These contacts ranged from 110 to 130 miles and confirmed that our system was working.

 When the moon came over the horizon at midnight we tried to listen to the ON0EME moon beacon in Belgium but couldn’t hear it.  About 45 minutes after moon rise we started to hear JT-65 digital signals. 10-15 minutes we started to hear CW signals.  Glenn Davis made a few corrections to the tracking program and signals increased in strength.  At times it sounded like a 20 meter CW contest pileup with all the loud signals bouncing off the moon all across 100 KHz of band (1296.0 to 1296.1 MHz).  After about 90 minutes without hearing our own signal we rechecked the power to the amplifier at the feed horn and everything appeared to be normal.  A few moments later we finally heard our own signal 2.5 seconds later on CW off the moon and the Belgium Moon Beacon.  I made several calls on SSB and heard our echo really loud.  We went back to CW and Gary proceeded to start making CW contacts. The first almost contact, a German station, abruptly dropped out so no official contact was completed.  Our first official station worked on CW was with OH2DG in Finland.  England was next followed by Italy, Poland, Denmark, Sweden and with DSES member Skip Macaulay, VE6BGT, in Alberta Canada.. Also made our first voice SSB contact with him as well.  Seems that with every new contact we make it is with a new European country.  In order to correct for Doppler shift and with no RIT we are changing VFO’s from Receive to Transmit by several KHz or more.  Lots of CW signals being heard and we still have 12 more hours of moon to bounce signals off of… We are hearing our own echo and we have lots of hours to go. We plan on Digital mode later in the day but for now there are more than enough signals to hear on CW. 

Our Moon bounce station consist of an older Yaesu FT-736R with 10 watts feeding almost 180 feet of half inch hardline into a 200 watt amplifier at the antenna feed horn.  The receiver pre amplifier is a 30+db gain with a noise figure of minus .35.  Our Effective Radiated Power (ERP) is over 6 million watts. 

* * * * * * * * * * *

We operated with our club call sign K0PRT.

A short video of Myron KL7YY calling CQ. You can hear the echo of his signal coming back from the Moon a couple of seconds later. (Video length 35 seconds)

K0PRT-2020-10-10%2010.24.25.mp4

Because the signals are extremely weak, and there can be fading, there is a standard protocol for exchanging messages for EME contacts. This is intended to ensure as much of the message as possible can be copied and acknowledged on both sides. The basic format is simple, and one repeats a lot. One first exchanges call signs, then the signal reports, and then finally if that worked, an acknowledgement all that was copied correctly. If one only completes part of the contact, one should still log that, as that is an accomplishment. If using Morse Code, the standard is to send at 15 words per minute, but spacing out the characters longer than usual. The faster sending and spacing is to help one copy complete characters if there is fading. If one misses a character, one still has a high chance to get the character with the many repeats.

In order to have the proper frequency offset for the Doppler shift, we referenced the WSJT 10.0 software, at the suggestion of Steve KL7IZW. The software has an astronomical data section that calculates and displays the frequency offset. The higher the frequency, the more significant the offset. At 1296 MHz we had a difference of as much as 3 KHz between transmit and receive frequencies. The software also displays other useful data like local Moon rise and set times (based on Grid Square location).

The WSJT 10.0 software also can be used for JT65C digital EME communication. However, we didn’t figure out how to configure that in time with our setup, and so we didn’t do any digital contacts this time. We could tell we were hearing JT65 signals. They were present from 1296.05 to 1296.1 MHz, and we almost always could hear those signals while the Moon was up.

Glenn stayed up until about 3 AM, when we were sure our antenna azimuth alignment was correct and would continue to point accurately to the Moon. His work was invaluable in troubleshooting the azimuth offset, which turned out to be about 1.5 degrees, and honing in on the Moon once we heard CW signals.

Glenn Davis working with the antenna pointing. Photo by Gary Agranat.
The 60-foot antenna pointing east, for the tropospheric scatter test to N0YC in Kansas. Later we would point east again, to prepare for where the Moon would rise. Photo by Gary Agranat.
Myron making a tropospheric scatter SSB phone contact during testing, with Glenn Davis setting the antenna pointing. The scene was similar when me made SSB phone contacts during the EME contest. Photo by Gary Agranat.
Myron, Glenn, and Ray. Ray was looking for the ON0EME beacon after the Moon rose. Photo by Gary Agranat.

Since the Moon rises in the east, our signal paths at first are to the east. That is to Europe and the North American east coast. As Myron mentions, once we started receiving the signals, we were hearing many European stations, and we were busy. Through the morning we made 14 contacts to Europe, to 8 European countries. We also made the contact to our DSES member Skip Macaulay VE6BGT in Alberta, Canada, on CW and then phone. W4OP in North Carolina, hearing us on SSB, then gave us a call on SSB too.

Ray AAOL brought a CW keyer that can send Morse Code with either a keyer paddle or a keyboard. It can store pre-programmed messages, like a CQ call. I (Gary) decided to use the keyer paddle, as that gave me more flexibility — I could quickly adjust for conditions — and I felt more comfortable as I am used to the key.  Meanwhile, it seemed to me also that some of the CW contacts we made used software to send their messages.  Those didn’t have good spacing between words or call signs.  And that made copying slightly more challenging. A keyboard though can enable any of us to send, even if we don’t have practice sending Morse Code. Most of the contacts we made were with CW Morse Code.

This short video shows part of a Morse Code CW contact by Gary WA2JQZ. XE1XA in Mexico called CQ. We responded by sending our call sign K0PRT several times. Then K (the invitation to respond) several times. When we switch the VFO from the transmit to the receive frequency, you can hear the last part of our signal coming back, reflecting from the Moon, several seconds later. You then here the signal from XE1XA, also coming back reflecting from the Moon. He transmitted back our call sign as K0PRN, instead of K0PRT. We afterwards replied sending our callsign again, only, to give him the correction. That’s why we repeat a lot, and send sections of the message just one at a time. We completed the contact successfully. If you look carefully on the transceiver, you will see we switched about 2 KHz down from the transmit to receive frequency. (Video length 1:16)

K0PRT-2020-10-10%2011.07.09.mp4

At around 6 AM, when the Moon was high enough so that we no longer had a path to Europe, we took a break for breakfast and to rest.

Just before sunrise. Photo by Gary Agranat.
Tracking the Moon during early morning. Photo by Gary Agranat.

In earlier discussions we thought we might have many more contacts across the Pacific and to the North American west coast, when the Moon was sufficiently to the west. But it turned out we had very few contacts that way. We made just two contacts to Japan. Our first was at about 9 AM local time, to JH1KRC. Our second was three hours later to JA6AHB. Instead we made a few more contacts to the US, a few to Canada, and one to Mexico. These other stations we heard were searching around too. That led me to believe that if there were any other signals out there, we likely would have heard them.

Our contacts included: 

  • K2YUH Alan Katz in NJ, who runs the 432 MHz and Above newsletter: http://www.nitehawk.com/rasmit/em70cm.html
  • W5LUA Albert Ward in TX, who some in our group know for EME.  (He at first thought I was Ray, when I contacted him on CW.  Myron then contacted him on SSB.)
  • W6YX, the Stanford University radio club, which was using a 28 foot dish.  We contacted them first on CW.  Then later when Bill was looking to record a phone QSO, which would illustrate the signal delay from the transit time to the Moon and back, W6YX just happened to call CQ on SSB on the frequency we were tuned to.  We then had about a 4 minute QSO on SSB with them, which Bill recorded.

A video of Gary WA2JQZ responding to W6YX at Stanford University and having a 4 minute SSB QSO. (Video length 4:38)

K0PRT-2020-10-10%2012.30.38.mp4

We operated until about noon. We made 30 contacts in all.  25 contacts were CW (Morse Code) and 5 were SSB phone.  4 of the 5 phone contacts were with stations we also had CW QSOs with.

We submitted our contest log to ARRL the next day.

In the judgement of all of us, we had a very good EME operation. We are very pleased it worked so well on the first attempt. We clearly have a capable EME station.

Glenn and his team are continuing to follow up to investigate why we had a 1.5 degree azimuth offset.

It still takes my breath away to hear the echo of our signal coming back from the Moon, a couple of seconds later. The speed of light isn’t just a value in the books, it is something you experience viscerally first hand. It is real. EME is the longest signal path we have for communicating with others. This is fun.

These are the contacts we made. (CW = Morse Code, PH = SSB phone. Given also are the date and GMT times, the signal reports, and the other stations and their locations):

CW 10/10/2020 750 K0PRT 559 DL0SHF 559 Germany
CW 10/10/2020 756 K0PRT 559 OH2DG 579 Finland
CW 10/10/2020 805 K0PRT 559 G3LTF 579 England
CW 10/10/2020 814 K0PRT 549 I5MPK 569 Italy
CW 10/10/2020 846 K0PRT 569 SP6JLW 589 Poland
CW 10/10/2020 900 K0PRT 559 DL4DTU 559 Germany
CW 10/10/2020 912 K0PRT 579 SM4IVE 589 Sweden
CW 10/10/2020 919 K0PRT 549 DG5CST 569 Germany
CW 10/10/2020 934 K0PRT 559 VE6BGT 579 Alberta, Canada
PH 10/10/2020 947 K0PRT 57 VE6BGT 56 Alberta, Canada
PH 10/10/2020 947 K0PRT 55 W4OP 57 North Carolina, USA
CW 10/10/2020 1034 K0PRT 549 OK1KKD 569 Czech Republic
CW 10/10/2020 1043 K0PRT 599 OE5JFL 599 Austria
CW 10/10/2020 1049 K0PRT 579 W6YX 589 California, USA
CW 10/10/2020 1103 K0PRT 569 IK2MMB 569 Italy
CW 10/10/2020 1111 K0PRT 579 OZ4MM 599 Denmark
CW 10/10/2020 1149 K0PRT 549 OK1CS 579 Czech Republic
CW 10/10/2020 1153 K0PRT 569 OK2DL 479 Czech Republic
CW 10/10/2020 1201 K0PRT 559 VE6TA 579 Alberta, Canada
CW 10/10/2020 1503 K0PRT 559 JH1KRC 569 Japan
CW 10/10/2020 1526 K0PRT 549 AA4MD 559 Florida, USA
CW 10/10/2020 1533 K0PRT 569 WA9FWD 559 Wisconsin, USA
CW 10/10/2020 1540 K0PRT 569 W5LUA 579 Texas, USA
PH 10/10/2020 1547 K0PRT 569 W5LUA 579 Texas, USA
CW 10/10/2020 1652 K0PRT 539 VA7MM 559 British Columbia, Canada
CW 10/10/2020 1703 K0PRT 559 XE1XA 559 Mexico
PH 10/10/2020 1731 K0PRT 55 VE6TA 55 Alberta, Canada
CW 10/10/2020 1740 K0PRT 569 K2UYH 559 New Jersey, USA
CW 10/10/2020 1806 K0PRT 549 JA6AHB 569 Japan
PH 10/10/2020 1826 K0PRT 54 W6YX 55 California, USA

And these are summaries of our contacts from the logging program:

K0PRT’s Contest Summary Report

 Total Contacts = 30

 Operating Period: 2020/10/10 07:50 – 2020/10/10 18:26

 Total Contacts by State \ Province: AB 4, CA 2, TX 2, BC 1, FL 1, NC 1, NJ 1, WI 1. 8 total.

Total Contacts by Country: USA 8, Canada 5, Czech Republic 3, Federal Republic of Germany 3, Italy 2, Japan, 2, Austria 1, Denmark 1, England 1, Finland 1, Mexico 1, Poland 1, Sweden 1. Total countries 13.

 Total Contacts by Continent: Europe 14, North America 14, Asia 2. Total continents 3.

Photo by Bill Miller.

-72/73 Gary WA2JQZ

Addendum: QSL confirmations we received:

Colorado Springs Cool Science Festival

Cool Science Festival Presentation on Saturday October 11, 2020

Rich Russel made an online presentation at the Cool Science Festival. The presentation covered the science of radio astronomy and the accomplishments of the Deep Space Exploration Society. The presentation was streamed live on Facebook and Youtube. You can watch the presentation here:

Carnival Day 2020: DSES – Finding Pulsars Using Radio Astronomy (3:50 pm)

Astronomer Rich Russel from the Deep Space Exploration Society describes how he uses the 60-foot Plishner radio astronomy dish antenna 90 miles southwest of Colorado Springs to detect pulsars in deep space.This live-stream presentation was part of our virtual Cool Science Carnival Day for kids, the main event of the 2020 Colorado Springs Cool Science Festival. You can find more information at:https://www.coolscience.org/carnivalday.html

Posted by Colorado Springs Cool Science Festival on Saturday, October 10, 2020

This 8-day regional event, designed to ignite wonder and inspire curiosity about the world around us, attracts between 10,000 and 20,000 attendees each year. For more information about the Cool Science Festival go to:

http://www.coolscience.org

Installing the 1296 MHz feed for Autumn Moon Bounce Communications

Text and photos by Gary Agranat.

A DSES team worked at the Plishner Radio Telescope site in Haswell on Sunday September 27, 2o2o. Team members were Ray Uberecken, Floyd Glick, and Gary Agranat. We accomplished the main objective, to install a new 1296 MHz feed at the focus of the 60 dish antenna. We also installed a mast in the ground, on which will later be added a Hughes Internet satellite antenna. Two friends of Ray’s came out and did an immense service by using metal detectors and magnetic rollers to clear nails and other metallic debris on the site. We changed out two of the locks. And we inspected the bunker.

Mast for Hughes Internet antenna

Ray and I met at the Plishner site at 0930 in the morning. 

We first installed a sturdy pipe mast behind the operations trailer, on which will be mounted a small satellite antenna to access the Hughes network geosynchronous satellite for Internet access.  Ray chose a spot that will not be blocked by the trailer or the 60-foot antenna.  We mixed cement and set the pole in its hole with the cement, using a level to check that the mast is vertical.

Moon Bounce (EME) Preparation

After that we manually rotated the 60-foot dish antenna to the service platform. I figured out, with Ray’s help and the checklists, how to use the software to monitor the antenna pointing. (Note: we might want to add a checklist just for this type of procedure, for using the software for just manual antenna pointing, as when we service the antenna.)

Floyd came out to the site by 1030. Ray and Floyd climbed the service platform. I worked on the ground to move feeds and tools up and down to them. We replaced the 408 MHz feed at the antenna focus with the newly built 1296 MHz feed. The 1296 MHz feed was built by KL6M, to specifications provided by Steve Plock (KL7IZW). The feed mount at the dish focus was designed by Ray, to enable the feed to more easily rotate out and be changed.

Conditions were somewhat windy, with a cold front coming, but still manageable. By the afternoon the winds had picked up enough that we postponed any further work at the feed. Work that still needs completion is installation of a 200 Watt amplifier at the feed. Since we are planning to operate at 1296 MHz from the Operations Trailer, which has a long coax hard line path to the pedestal and antenna feed, we expect significant power loss from the long path. We therefore need to boost the power again at the feed. We plan to install the amplifier the next weekend. We then also intend to test our setup by trying tropospheric scatter communications to the north.

We are planning to use this configuration to operate EME (Earth Moon Earth) Moon Bounce communications. And specifically we plan to participate in the ARRL EME contests on October 10-11, 2020 and on November 28-29, 2020 (UTC).

We discussed our plans for the upcoming contest in 2 weekends. The Moon then will be at last quarter phase. What that means is that it will rise on Friday night a little before midnight (about 1130 PM), and set Saturday a little after 2 PM. That means we will prepare to do overnight and morning operations. After the Moon rises we will try to pick up the ON0EME beacon in Belgium. We can try to contact across the Atlantic Ocean. The US East Coast will be in night time conditions, and so we anticipate less contacts to there. Daytime conditions, when more hams would be awake, are more favorable for the US West Coast, and across the Pacific Ocean to Oceana, Asia, and Australia.

Note that the 60-foot antenna will be configured with the 1296 MHz feed through the end of November. This will be an opportunity to try using it for other 1296 MHz communications, including troposphere scatter.  

Metal souring of the site

A friend of Ray’s who works at Planet Granite Ryan, and his brother, Rob, came out to the site also.  They have ground metal detectors and magnets on rollers, and systematically paced across the site to pick up nails and other small metallic debris.  They did pick up lots of nails, including along the roadway. They spent a few hours with us, and left after lunch. They did us a great service by helping remove a lot of this debris.

Combination Lock and Bunker Inspection

We attempted to open the combination locks at the gate, the bunker, and the generator shack. After still having difficulty, we replaced the locks at the gate and bunker, with the locks Myron Babcock obtained for us. These are similar model locks, and the combinations were kept the same.

We had a report that the bunker had been flooded by two successive rain storms in July. We opened and inspected the bunker. The bunker was dry, though the floor had more-than-normal dust and dirt, and some tiny debris was spread here and there. It will require a fresh cleanup before normal use. We saw no indication of mold from dampness.

Tumbleweeds were accumulated again at the ramp entrance.

We completed our activities by early afternoon, about 3 PM.

For the team, – Gary

We kept the antenna steering in manual configuration. We opened the System 1 steering software to monitor the position angles as we manually steered the antenna to the service platform.
We noted this radio interference at the site on our scope. This scan is from 0 to 1.8 GHz. The higher floor noise level at the left is from the sensitivity of our 408 MHz feed, which was still on the dish antenna, before we changed it out.
The 60-foot antenna is positioned for service.
Ray brought two feeds for the 60-foot antenna. This is Ray showing Floyd the 4 GHz feed, which we will use in the future, to calibrate the pointing position with geosynchronous satellites.
Floyd carrying the 1296 MHz feed to the antenna for installation.
The inside of the 1296 MHz feed. It is designed as a septum feed, with separate channels on each side for left and right circular polarization.
Rob with a metal detector, crisscrossing the site, picking up small metal debris.
Ray and Floyd on the 60-foot antenna service platform, starting work.
Removing the cover.
Ray is disconnecting the 408 MHz feed, so that it can rotate down and out for changeout.
The 408 MHz feed is now rotated down. It is connected simply by the shaft to the mount, for easier changeout.
Installing now the 1296 MHz feed. Its design doesn’t use a shaft, but instead will be securely fastened to the mounting frame.
Ryan using a metal detector on the west side of the site.
Our view towards the west. High clouds in the distance are an indication of a cold front gradually coming this way. We experienced steady windy conditions as the front approached..
Closing up.
Our view of Haswell in the distance. The clouds from the front were getting closer. By the time we left in mid-afternoon, the clouds were over us, but we had no precipitation.
The 1296 MHz feed installed.
We installed this ground mast. It will mount a small satellite antenna, to connect to the Hughes Internet network.

DSES Pulsar Observing on September 12, 2020

Text and photos by Gary Agranat. Analysis pdf by Rich Russel.

On Saturday September 12, 2020 an observing team of Rich Russel, Bob Haggart, Bill Miller, and Gary Agranat spent the day observing pulsars. This is the first observing session since we recalibrated the 60-foot antenna azimuth pointing the weekend before. The team observed 3 pulsars we had not seen before. Plus several other pulsars were attempted. The team spent the whole day at the site, from about 9 AM to 7 PM.

The pulsar signals are so faint that we cannot detect them directly. To observe them, we have to point to the correct celestial coordinates and then track that point as the Earth rotates. While we are pointed, our computer accumulates the signal data. We need at least a half hour continuously tracking the position. At this session some of our observing runs lasted 2 hours, for the fainter objects. At previous sessions we have tracked for as long as 4 hours.

After the observing track, we have our software process the data. The random background noise should cancel itself out. But the pulse signals should build up with time. If we have the correct timing interval of the pulses, and if everything else is working, the computer display will show the pulses, and several other parameters.

Pulsars are very unusual objects. These are what remain of massive stars (greater than 5 solar masses) after they use up all their fuel for nuclear burning. These more massive stars fuse heavier and heavier elements at their cores until they start to fuse iron from silicon. Unlike the fusion of other elements, iron requires energy to fuse, rather than produce energy. The sudden reduction of energy at the core drops the temperature and pressure there. The pressure at the core is no longer enough to counter the weight of the star’s material above it. Gravity is now the stronger force, and the material above collapses in on the center. The pressure and temperature at the core then becomes even higher, which starts new reactions that fuse the matter at the center to neutrons, and and which also generates neutrinos. The outer layers falling in at great speed bounces back out. The result is a supernova explosion. What remains is the neutron star at the center. It is extremely massive and compact. And like an ice skater rotating faster as the arms are brought in, the star’s rotation speeds up immensely. The star’s magnetic field also has become compressed and much more intense. Charged particles will rotate around the magnetic field lines, with very high energy. Whenever charged particles are forced to deviate their paths from a straight line they emit electromagnetic energy, like visible light and radio. At the neutron star’s poles, this energy is channeled out, with immense energy. Because the magnetic poles are generally not at the same spots as the rotational poles, the beam of this light and radio is spun around like a light house. If Earth happens to be in the path of such a beam, we detect that as a pulsar. So that’s what we’re observing.  These neutron stars are hundreds and thousands of light years away.

Pulsars were first discovered by accident in 1967, by Jocelyn Bell (now Jocelyn Bell Burnell) who was then a graduate student at Cambridge University. Bob contributed a recent photograph of her, posed by some radio telescopes. We now proudly have that displayed on the wall above our computer displays.

Because the observing runs take a while, for this session we decided to try watching some videos. Bob brought a DVD player and a large monitor. Gary brought some educational videos, including one about the Crab Nebula and pulsars. Rich brought some movies.

This is a summary of our observing results: http://dses.science/wp-content/uploads/2020/09/11-Pulsars-Observed-so-Far-9-12-20.pdf.

On this work trip the team also inspected damage to our ham radio antennas, damage probably from the storm weather over the past months. 7 radials at the base of the vertical antenna were damaged. And the 3 element Yagi antenna on tower was slightly tilted along its longitudinal boom.

Tumbleweeds also had accumulated again at the bunker ramp. Some of the surrounding fence had also been damaged from the weather. Rich Russel brought some fencing to use in the future, to place over the immediate entrance path to the bunker door.

Repair of the ham antennas and ramp clearing will be planned for a future work trip.

Below is a photo narrative of the day’s work.

It was an excellent day’s work.

At the start of observations, we point to and observe a pulsar with a strong signal that we know we should be able to reliably receive and analyze. If we cannot detect it, that indicates something is wrong with our system. We would then troubleshoot rather than waste our time trying to observe. Here the antenna is pointing to a pulsar we use as a reference source, B0329+54. It is located in the circumpolar sky to our north, so it is always visible above the horizon for us.
Bill Miller, Rich Russel, and Bob Haggart starting observations in the Operations Trailer.
After we checked our equipment and processes, we tried looking for some pulsars that were relatively low on the horizon to our south. Objects that appear to the south are above the horizon only briefly. They rise in the southeast, as the Earth turns they continue to rise in a shallow arc above the southern horizon, then soon set in the south west. If we want to try to observe them, we have just a short window of time to find and track them. Being low on the horizon adds some bias errors and attenuation to the observations. At this session we didn’t succeed in observing any pulsars that were close to the southern horizon.
On this run, the display shows we did not get good data. The software is attempting to synchronize our data with an expected pulse period. In the top window display that is open, for good data we would expect to see clearly spiked peaks rising from a lower noise floor. And in the white rectangular box below that, we would expect to see a signal at that timing accumulate under such spikes. There is no pattern of periodic data. The white box to the right shows timing at the bottom with radio frequency at the side (going up). Because the pulsar signal is broad band (it is spread broadly over a wide range of frequencies), we would expect to see a continuous line of signal from bottom to top, across the frequencies. But we do not see that. (You can click this image to enlarge it.)

The two graphs in the center right tell us we don’t have a definitive measure of a pulse rate, and a steady change in pulse rate. The pulsars are generally slowing down with time, at a very slow but measurable pace. The display is showing the algorithms cannot fit a pattern. If it could, the two peaks would both be centered.
Our Operations Trailer
Our antenna site is surrounded by farm fields.
Rich and Bob are checking data for each next pulsar we attempt to observe. Besides the celestial coordinates, we need to know the expected energy flux. If the signal is weaker, we need to observe and track on the object for a longer period of time. We also need to know the expected pulse timing and several other parameters.
We have up in our control room a framed photo of Jocelyn Bell Burnell, contributed by Bob Haggart. She discovered pulsars serendipitously while she was a graduate student at Cambridge University in 1967.
Rich is assessing a good data set we just got. Here you can see the distinctive pulse timing spikes in the upper left. In the center white plot, you see two straight lines, representing the pulsed signal, across the spectrum of frequencies we observed (we observe across a bandwidth of 10 MHz). At the right, the software found a good analysis for the rate and change of rate of the pulses. The bottom plot slopes downward slightly to the right. That is showing us the dispersion of the signal, something we expect to see. As the pulsar radio signal travels through interstellar space, it has to go through dust and magnetic fields. The effect is that the longer the radio wavelength, the slower the signal will propagate through space. Therefore the longer wavelength signal will arrive slightly later than the shorter. This is an indirect measure of the distance to the pulsar. If the algorithm was just trying to make sense of random noise, we would not see this result in our data. (You can click this image to enlarge it.)
This is a close-up of our SYSTEM 1 software display for pointing our dish antenna. The antenna now can be pointed manually or with several levels of automation.

The first accomplishment was to translate the actual azimuth and elevation pointing angles of the antenna through encoders with digital readouts. That azimuth and elevation angles were then correlated with the celestial coordinates at the given time. That required a good timing reference, as well as an accurate fix on our longitude and latitude. We now take care of that timing and position fix with GPS.

The upper part of the screen shows the direction the antenna is aimed at, in both azimuth and elevation angles, and the celestial coordinates of Right Ascension (RA) and Declination. There is more on the right side that was added later which I will discuss shortly.

The next development was to have a visual reference of the celestial sky, with its coordinate grid system and celestial objects we are interested, displayed on the computer, together with where the antenna is pointing. You see that display in the lower half of the screen. How wide a beam angle our antenna can see (like the field of view you see in an optical telescope) depends on the wavelength of the radio waves we are using. At a wavelength of 70 centimeters (about 400 MHz frequency), the beam width is about 2 degrees for our dish antenna. At wavelength of 21 centimeters (about 1420 MHz where the spectral line of neutral hydrogen is), the beam width is about 0.8 degrees. The software calculates the appropriate beam width and shows that as a circle on the display.

Within the last three months, our software team succeeded in creating a system that will now automatically point and keep tracking a celestial object or any other sky position. As part of this package, the software has a database of celestial objects we may be interested to look at, with their celestial coordinates. The database is updatable. If an object we want is in our database, it will appear on our sky coordinates display, we can point to it with our cursor, and the antenna will slew to point to it and then track it. We can also enter data manually. The software and hardware have safety stops, so that the antenna cannot be pointed below a certain limit above the horizon. And the antenna has azimuth limits, so that our cables to the antenna feed in the pedestal don’t wrap around with too many turns. The software also is programmed to avoid direct pointing towards the sun.

Because it makes the display much more user friendly, the display shows the visible stars and constellations as well. (You can click the image to enlarge it.)
This screen is how we set our data parameters. And the display at lower left shows the signal coming in. The blue line is the data signal, across the bandwidth of 10 MHz, here centered at 420 MHz.

The green line shows the peak maximum of the signal over the course of the run. Earlier in the day we were seeing persistent radio signals, for us interference, at around 390, 406, 408, 410, and 432 MHz.
We were concerned that one possible cause of problems with some of our data was the sun being close in angle to our pointing. We were never closer than 25 degrees from the sun. But we are wondering if the sun still might heat our preamplifiers at the feed focus of the antenna.
The next set of photos are close-ups of the damage seen on the ham radio HF antennas. This is the tower with the 3-band Yagi. There is a slight tilt along the main boom.
7 radials at the multi-band vertical antenna were also damaged. 5 severed at the lugs, which suggests metal fatigue from repeated moving in the wind. 2 were severed in their middles, which suggests some debris may have impacted those from the winds.
Some of the fence damage by the bunker.
The bunker ramp filled with tumbleweed again.
Closeup of the 408 MHz feed and the feed mount at the focus of the 60 foot dish antenna.
A closeup of the display we now use for pointing the dish antenna for astronomical observing. At the upper right, we can acquire the celestial coordinates from our database, or we can manually type in the needed data. The lower part of that window shows the actions the control system is executing, that is if it is slewing to an object, tracking, holding steady, or something else. The lower display shows the celestial sky, the coordinates, our antenna beam, as well as naked eye objects and constellations.
The grain elevator in Haswell in the distance.

DSES Sept 19, 2020 Pulsar Observing Trip Observes 2 More Pulsars

Bob Haggart and Rich Russel did an observation all nighter on Friday/Saturday (September 19, 2020, GMT) and observed 2 pulsars.
VELA (B0833-45) is one of the strongest pulsars at 5 JY while B1946+35 is at 0.145 JY.
DSES is one of the most northern amateur stations to detect VELA. We detected it in 15 minutes at 5 to 6 degrees elevation.
This make 13 pulsars and puts us 5th on the international amateur pulsar hunter list. http://www.neutronstar.joataman.net/