(Note: This page starts at the bottom with construction start in ~June 2000. The most recent news is on top).
AL7OB DISH PROJECT STATUSJune 9, 2001
May 2001 EME activites:
May 27: It was a beautiful calm evening and total degradation was VERY low, and 1/2 hour before sked time we got 5 minutes of pounding hail. 300 Watts reflected! Busted! Murphey strikes again!
I was off the air. I tried to restore before moonrise, without luck. I had no more skeds so no big deal. Here are the gruesome details from the day before (conditions were just not too great):
RA3LE Nil ???
OE3JPC Copied him "O" no completion
IN3AGI Copied him "O" no completion
G3LQR O/O (polarity = 72 CCW - perfect, no Faraday) Initial# 85
SM3BYA Nil ???
DL5LF 3 separate skeds copied him each time, no completion (single yagi)
CT1DMK Cancelled (advance email very much appreciated)
W7MEM Cancelled (advance email very much appreciated)
RW3PF Very sorry, the hail storm cancelled this one.
UA6LGH Nil ???
UT3LL O/O Initial# 86
7M2PDT Nil ???
JA8IAD 3 tries. Last one he sent Os I sent ROs but never got R. No QSO.
JHØWJF O/O (perfect case of about 30 degrees of Faraday) Initial# 87
WB5APD Cancelled (advance email very much appreciated)
JH1XUJ Nil ???
Percentages stink but the bottom line is, I had a GREAT time!!!
The icing on the cake: some great QSOs with some of the veterans:
HB9Q 549/549 What a great beacon!
VK4AFL 559/559 Trevor was having fun with SSB. I taped him and HB9Q.
DL9KR 569/569 Unbelieveable
SM2CEW 559/559 Great signal (consistantly)
DL9NDD 569/569 Another unbelieveable
KU4F 569/569 Les seemed to be having fun too - strong!
JA5OVU 549/559 Tom has been QRT w/ 1.6:1 (running 300w today) Visiting Alaska next month
WA4NJP 559/559 Great signal, perfect case of 45 degrees of Faraday
So I was off the air for most of the weekend and cancelled most of the skeds.
Here are the latest new pictures:PICTURE13
March/April 2001 EME activites:
Again I set up a large number of schedules for the March 3-4 weekend. I managed to work ON5OF (559/559), DJ3FI (549/449), KU4F (559/559), KAØRYT (449/559), JA6AHB (549/549), HB9Q (549/549), DL9NDD (569/569), and VK4AFL (449/549), all random. None of the skeds worked out, except for ON5OF and DJ3FI who were worked random before sked time. Friday night I stayed up very late to catch the European moonrise, but I had my (temporary) azimuth drive blow up for the last time. I tried to fix it, but no luck. So I was off the air for most of the weekend and cancelled most of the skeds.
In this update I have included my log from the DUBUS World-wide EME contest (31Mar-1Apr) and have quite a few pictures of the new drive system. The new drive is installed and works just as good as I thought it would. Now I just need a better position indication system, which I am currently working on. The contest went well the first day, I worked 30 stations. Then the wave from the intense solar activity hit the earth and shut the conditions down like a big switch. I only worked 4 more stations next next day for a total of 34. 7 new initials, plus one after the contest bringing my count to 77.
My goals for 1296 have all been set aside. I had too many interruptions, including a sudden trip home to SD to visit my mother. I am heavily considering building a feed for 144 MHz for the 2nd leg of DUBUS on 28-29 April. I have a design for the feed in the works, and should have it fabricated by 16 April.
Pictures and wav files for March/April:PICTURE12
February 2001 EME activites:
I set up a large number of schedules for the February 3-4 weekend. Again, Murphey hit hard. Numerous mechanical problems prevented me from completing the majority of the schedules. I was finally able to operate on the afternoon of the 4th. From that point on, things were looking up. A copy of my log is included in Picture11 below.
The big news this month is that I have finally broken down and ordered the fabrication of the pinion for my azimuth drive. $350 from Circle Gear in Chicago. Best deal I could find anywhere. More on that next month.
Not much for pictures this month, but I included one of the old drive shaft thrown together out of various pipes and reducers, welded at the juctions. It is holding together fairly well now, if I operate strictly with no wind whatsoever. Also a shot of the dish viewed through my old 432 array and a bunch of trees.
Pictures and wav files:PICTURE11
Next month I should have pictures of the new pinion and drive modifications. Also, I have embarked on my 1296 MHz project. I have the following tasks ahead of me:
Target date, April 28 in time for EME contest. I will post my progess here next month.
January 2001 EME activites:January 30, 2001
When I returned home from Georgia on 12 Jan., I found that my tie-down chains had slipped due to high winds, and that my azimuth drive sprocket had broken off. That was the last straw. I installed a "park lock" so chains are no longer needed. I still need to replace the chain and sprocket with a real drive pinion someday.
I have been working hard to get ready for the next prime EME weekend, 3-4 February. Based on strong recommendations from Ray, WA4NJP, I decided to put my preamp and relays right on the back of the 432 feed assembly. My goal was to be finished with it by 28 Jan, but Murphey got the best of me as usual. I am still working on it. I have very little left to do and plan to have everything installed early Friday, 2 Feb. in time for a 2230z sked.
I have almost 2 dozen EME schedules set up with stations world-wide. My biggest concern now is the weather. It has been so terrible all winter, but now it seems to have settled down and the forcast may give me a chance. I have only been on the air with the new dish for less than 4 hours since it became operational back in October. Most of the mechanical problems have been related to weather in some way.
Hopefully my next update will have some new contacts to report from the week of February 3-10. I plan to be operational as much as possible during this time.
TRIP TO GEORGIA December 31, 2000 through January 12.
JANUARY HOME SCENES A couple fotos around the house
PARK LOCK A couple fotos of the new "park lock" so I don't have to use the chains anymore
432 FEED Pictures of the new relay/preamp box attached to the 432 feed
That's it for this month. 73 from AL7OB
Latest Status as of 12/23: .
As of about December 16, all systems are operational, still 432 MHz only..
Azimuth Drive - On December 15, I struggled to finish installation of the azimuth drive. Since I still have no drive pinion, I am still using the temporary chain and sprocket. I made the mistake of using the old pipe driveshaft without reinforcing it with welds. About 15 minutes into the operation, the shaft unscrewed itself. I spent the next 3-4 hours repairing it and missed the European window. I echo tested and called CQ for a couple hours after that with no takers. Echoes were very strong, still not what I think they should be.
Elevation Drive - I finally figured out the cause of my intermittent elevation drive. The 1.5 hp motor itself has an internal centrifugal switch which occasionally hangs up. This switch normally causes the starting capacitor to be switched out of the circuit after the motor reaches a certain speed. I believe it is not disengaging when the motor stops so the starting capacitor is not in the circuit for the next startup. A good whack solves the problem.
Feed focus – I installed a TVRO actuator to provide remote adjustment of the focus while receiving the sun or a small constant signal like Cygnus. This adjustment produced a very broad peak. The calculated focal length and the measured length turned out to be very close.
I am not satisfied with the feed performance and plan to do in-depth checks later in January. I will be in Atlanta during the next schedule weekend, January 6-7. I plan to operate during the following weekend, January 13-14, and will be available for any schedules starting at 13 JAN 0730z. I plan to take the feed down for some bench testing later in January.
Latest pictures and other neat stuff can be seen herePICTURE10
Latest Status as of 11/20:.I finally got on the air! Nothing spectacular, but I made a few contacts before moonset on the last day of the second contest weekend. During the week prior, I managed to accomplish reworking the azimuth drive, and I checked the 7/8" bolts that fasten the bearing to the tower. I have not been able to torque these to spec due to lack of a wrench (and a pair of biceps) that will deliver 480 ft-lbs. So I periodically check them to make sure they aren't vibrating loose. I installed my new brake system....works GREAT! I now have full elevation control. I was unable to find time to do any performance checks before the contest other than essential basics like VSWR. Not even sun checks for alignment. I was pretty sure I was within 10 degrees AZ and 5 degrees EL. Turns out I was right. I finally made my first QSOs with it on 432 on Sunday. It badly needs optimizing before I can be a serious "big gun." I have done no fine adjustments at all but still got 569 from K5GW, 559 from KAØY, 549 from K1FO and 549 from KØRZ. S/N is far superior to the 16 yagis, but for some unknown reason the signals are not reading as high on my s-meter. My echoes were significantly better than I have ever heard from this QTH. The whole experience was short of the huge improvement I expected, but it added dozens of items for improvement to my already lengthy list of things to do.
Latest Status as of 10/29:.I was not quite ready for opening day of the ARRL contest. By midnight I was ready for 2:00AM (local) moonrise for the second day, but I had no opportunity to check alignment or performance since the sun was long gone. A gust of wind moved the azimuth drive against the set screws in the drive sprocket and from that point on I could not keep them tightened enough for reasonable azimuth control. Also I discovered that the highest elevation I could use without a brake system was about 40 degrees. At that point gravity takes over and the dish slowly winds the drive motor in reverse until it comes to rest on the stop. Finally by about 10:00 AM I aborted the attempt to be operational that day. I had to go pack for a trip to Minneapolis.
My new goal is to rework the azimuth drive, system performance checks, full structural inspection, bolt tightening, installation of the elevation brake system prior to the second weekend of the ARRL contest.
The latest pictures are viewable here: PICTURE8
Latest Status as of 10/11:On 10/9 the crane arrived at 10:30 AM. The AZ/EL mount and the dish were in place a little over two hours later.
The crane pictures are viewable here:PICTURE7
The center of gravity of the array is about 6 feet from the center of the bearing. Even with this resultant amount of torque on the bearing, it moves very freely. Azimuth rotation should be no problem at all even with a very small motor. Initially I plan to use a #40 chain around the 30 inch diameter bearing gear and 10 tooth sprocket driven by an Alliance HD-73 rotor. The elevation drive will be a 1.5 hp ac motor with a 4.75:1 sprocket ratio to drive the jackscrew. My goal is full moon arc capability by the end of the weekend.
The ARRL contest on October 21, is well within the realm of possibility!
Latest Status as of 10/7:On 10/2 through 10/4 I took afternoons off from work to take advantage of the nice days, 40+ degrees, calm and broken, (and daylight) to get some final work done. I tipped the AZ/EL mount back onto its bottom and started assembly of the angle iron dish support.
I failed to mention in the 10/3 status that I, of course, missed my deadline for the Italian contest. I now have a new deadline to be operational for the ARRL EME contest on October 21-22 and November 18-19. It looks very likely that I will make this one.
I have the entire framework assembled and plan to finish with the torque wrench on 10/7. I have about a third of the 250+ nuts and bolts torqued to specs. I have acquired the chain and sprocket for the EL drive system and hope to get it tested on 10/7 also. I hope to do some painting on 10/8. I have a crane reserved for 10:00AM Monday, 10/9.
The latest pictures of the above are viewable here:PICTURE6
Latest Status as of 10/3:On 9/23, Del, Kenny and I spent about 6 hours doing the final welding on the tower and on the AZ/EL mount. Prior to their arrival I mounted the bearing and tightened it to pull all the pieces into position for welding.
The latest pictures of the above are viewable here:PICTURE5
Latest Status as of 9/12:On 9/7, Del, Kenny and I brought the tower top and a fork lift up to my place and we raised the assembly into place on top of the pilings. Everything fit perfectly. On 9/9 I prepared the bearing plates which will attach to the AZ/EL mount. I assembled the two upper plates to the lower 36" X 36" plate and bolted the whole thing together on the bearing just to make sure everything fits OK. I plan to install these plates and bolt the bearing onto the AZ/EL mount before the weekend of 9/16-17. When it rains too hard (we have been getting more than our share), I stay in and work on the motors and drive system. The crane will need to be here by 9/20 if I am going to be ready for the Italian EME contest. Its going to be VERY CLOSE!!!
The latest pictures of the above are viewable here: PICTURE4
Latest Status as of 9/6:Assembly of the dish (minus a few petals for lifting) was completed on September 4, thanks to the efforts of my friends Richard Pellessier, Bill Buttrum, and all the way from New Hampshire, Paul Toomey. It went together very smoothly. All parts were number matched and holes aligned well. The crew worked relentlessly until finished. Bravo!
I received my remaining steel parts, 3/4" plate, 1/2" plate and 4 X 8 X 1/4" rectangular tubing on August 31. On September 1, thanks to Del Sandvik, from B&B Welding in Anchorage, the bolt holes were punched in the plates for the big bearing. After that, Del and I began the construction of the tower top. Del's final welds were in place on September 6 and the unit is ready to lift in place on top of the pilings, hopefully before the weekend. I had intended to have a crane on the weekend, but the AZ/EL mount is a few days behind schedule.
Pictures of the dish and tower top plate are viewable here: PICTURE3
Still planning to be on the air for the Italian contest, 9/23, but the challenge is growing.
NEW PICTURES!! Check outhere PICTURE2
Latest Status as of 8/26:The tower is ready and waiting for the top platform to be installed. The materials for the top platform are being acquired right now by a friend who works at a local steel supplier. I hope to have all remaining steel by next Thursday, Aug. 31.
Assembly of the trusses continues today since the weather is excellent. I also will work on the feed mount today.
Be sure you have seen the AZ/EL mount and pile driving pictures too, check here:PICTURE1
I have revised the tower top design as shown below:
Instead of a solid plate which was determined to be very difficult, the tower top is primarily made up of 4 X 8 inch rectangular steel of 1/4 inch wall thickness connected to a rolled 1/2 inch steel cylinder in the center. Total weight of this structure is about 700 pounds. The bearing plate will still be of 3/4 inch steel. The bearing will attach via 29 grade 8, 7/8 inch bolts.
More status later. Still shooting to be ready for the Sept 23-24, Italian EME contest.
Array Location and Neighbor Negotiations:My neighbors issued great concern about the location of my dish. I gave them notice of my intentions about a week before this. I raised a 40 foot push-up mast with red tape marking various heights such as the highest point when the dish is pointed at the horizon, and also the height of the array when parked. They invited me into their living room to see for myself. They have a truly pristine view of the city of Anchorage, Cook Inlet, and the Alaskan Range. The dish would not block any of this view, but it would surely be in full view, just below their horizon.
I have consulted a friend in the city attorney's office as well as my own attorney and they have told me that there is really nothing my neighbors can do since my construction is well within my own property and is not outside of any codes, covenants or restrictions.
Nevertheless, I have chosen to relocate to a position closer to the front of my lot. This will allow the dish to be seen from the street, and will be closer to the property line. The neighbors have said they will not object to even locating on their property, as long as I don't put it in front of their view. The new location will reduce my coax run from 120 to 90 feet.
Foundation Status:I have decided to drastically change my foundation and tower structure design. Instead of digging a 9X9X6 foot hole, and pouring concrete around an 18 foot pipe rack with 4 foot face, I have decided to use pilings instead. I will use three 30 foot X 8.625 inch O.D. casings driven to a depth of about 18 feet leaving 12 feet protruding out of the ground. I will space these 5 feet apart in an equilateral triangle and weld interconnecting braces. A plate will be welded to the top of the pilings on which the azimuth bearing will be bolted.
The pile driving was completed on July 30. Two of the three pilings were successfully driven to 18 feet. The third finally reached refusal at about 16 feet.
Dish mount cutting and welding work:As of July 15, we have completed the major cutting and welding of the dish AZ/EL mount.
The tower top plate will be fabricated an welded in place the week of August 6. The AZ/EL mount will be placed next to the tower on its side for attachment of the bearing during this week also. It will then be pushed over and moved into position for final assembly of the angle iron structure during the week of August 14.
The trailer will be moved into position to the other side of the tower. The dish trusses and petals will be assembled on top of the trailer during the week of August 21.
I plan on renting the crane and setting both the AZ/EL mount and dish around August 26.
Stay tuned for future updates. I should have some new pictures by the middle of August.