Photos courtesy of Glenn Davis. Text by Bill Miller.
On Friday afternoon October 14, 2022, we prepared the 60-foot dish antenna for the weekend’s Moonbounce communications operations in the ARRL EME contest.
Glen Davis updated the tracking software, checked the callibration of the mount and helped as ground crew and photographer. Meanwhile Ray Uberecken and Bill Miller climbed the scaffold and changed the feed from the 437 Mhz antenna to the 1296Mhz antenna. They also installed Ray’s 180 watt amplifier at the antenna feed point and checked the system reception from Ray’s Calhan residence beacon.
On Sunday October 2, 2022 Ray Uberecken, Dan Layne and Gary Agranat climbed on to the 60-foot dish antenna to measure the dish diameter, the distance from the dish center to the feed, and the bore alignment. This verified the original geometry specifications continue to be valid to at least within a quarter of an inch.
The original plan for the day was to also install the 1296 MHz feed at the focus, for the upcoming ARRL EME contest. However, the wind gusts increased, as was anticipated from the forecast. The feed changeout was therefore postponed.
Deep Space Exploration Society will support the Japanese OMOTENASHI Cube Sat Moon lander, by attempting to receive and record its UHF downlink signals enroute to the Moon and after landing. OMOTENASHI is a project created by the Japanese space agency JAXA Amateur Radio Club, and is one of ten Cube Sat satellites on the NASAArtemis 1 lunar mission.
Several hours after Artemis 1 boosts from an Earth parking orbit to a transfer orbit to the Moon, OMOTENASHI should deploy. After 6 days the OMOTENASHI will separate into an orbiter and lander, and the lander will make a hard landing on the Moon. The lander is designed to survive and then transmit signals.
Lewis Putnam and Glenn Davis worked at the Plishner antenna site on Monday November 1. Lewis wrote this trip report to describe what they accomplished. The major reason for the work trip was to evaluate the mount pointing errors after the replacement of 1420 feed.
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.
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.
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.
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.
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.
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:
Myron’s Treasure’s Report Checking $1774.28. Savings $5742.15. We have 49 paid members.
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.”
Bill will write an endorsement letter and have the DSES Board modify and approve for Planet Walk Colorado Springs. See https://www.planetwalkcs.org/
See Bob Haggard’s repost on the Arecibo Radio Telescope status.
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.
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
Glenn says that Phil is working on an elevation tracking update that will need some onsite testing when ready.
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.
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.
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.
Bob Haggart (N0CTV) has been steadily improving the workspace of the science trailer at the Plishner radio telescope site. During the pulsar observation work on May 2, 2020, he completed building his latest enhancement: a partitioned work space at the east side of the science trailer. There is desktop space, which can be used for electronics building and testing. And there is additional shelf space, for better organization and storage.