Saturday, April 29, 2017

Elevation Rotor Adventure

My original plans for my 2-M EME station were to use things that I already had on-hand.  Well, that was a good "plan" but sometimes those plans don't always work out.  I had a TailTwister rotor which I had planned to use as an azimuth rotor.  However, the Hazer which I bought did not come with a rotor plate to accommodate a TailTwister.  It would have cost an additional $69.00 to purchase that mounting plate.  But before I purchased it, I became aware that the tailtwister was not a good rotor for EME use because of its braking system.  When the rotor stops rotating, the wedge brake seats into one of 60 segments spaced 6° apart.  That severely limits the pointing accuracy of the rotor.  Depending on exactly when the brake is engaged, I could be as much as 9° off the exact angle I needed to be pointed directly at the moon.  Since I was only planning a 2 antenna system, I did not feel I could give up that accuracy.  I need everything in my system to work as well as it possibly can.  So, I scrapped the idea of using the Hy-Gain TailTwister (T2X) and bought a new Yaesu G800-DXA for the azimuth rotor. 

Interconnects to EA4TX ARS-USB
Wiring Diagram for G-550
Still, from my prior days on EME and satellites, I had an abundance of elevation rotors.  I actually had THREE KenPro KR-500 elevation rotors so I felt I had that base covered.  But, Mr. Murphy reared his ugly head and the first two (and best of the three) elevation rotors failed to rotate on the bench!

Bummer!  But in looking at the facts, these rotors were 35-40 years old so it was not unreasonable that they failed to work.  And, considering their age, did I want to hinge the success of this project on that old a piece of equipment?

Still, I did not really want to put more money into this project than necessary.  In looking at all the usual websites, I found none used but I did discover that I could save $125 by buying only the motor and not the control box for a new Yaesu G-550 elevation rotor from R&L Electronics.  As they are located in Hamilton, OH, I had the new rotor the next day and it was quickly on the bench and ready to be tested with one of the control boxes I had from the KenPro rotors.

Of course, I then ran into a snag.  The KenPro motors had an 8-screw terminal block for connecting the wires to the motor and the new Yaesu had a nice 7-pin round connector.  That connector did NOT come with the motor I had purchased.  But, now Mr. Murphy threw me a bone in the fact that Yaesu uses the same connector on both the G800-DXA and the G-550 rotors and I had received just such a connector with the new G800-DXA.  It was surplus to my needs because I had purchased a Jetstream rotor cable which came with that connector already installed!

Modifications to Control Box
In looking at the schematics of the KenPro and Yaesu control boxes I noticed that the KenPro had a 70 uF capacitor wired across the motor windings but the Yaesu had a 100 uF capacitor actually inside the rotor motor housing.  I decided to simply lift the connections off one side of the 70 uF capacitor in my control box to remove it from the circuit since the new rotor motor already had the capacitor inside it.  At the same time, I drilled a hole in the rear of the control box, installed a grommet, and wired a cable that connected to the 29 VAC of the control box and the UP and DOWN connections to the rotor motor.  This will provide the interconnection to the EA4TX ARS-USB control box to allow it to control the elevation rotor.  You can see a photo of my modifications on the right.  Click on any photo to see a larger image. 

Once the rotor cable arrived from The Wireman it was time to connect everything up and see if the system worked.  Yesterday I wired the 7-pin connector (only 6-pins are used) to one end of the rotor cable and tinned the leads on the other end to screw onto the KenPro control box.  SUCCESS - It WORKS!  I now have a working Elevation Rotor and the control box is wired to connect to the EA4TX ARS-USB control system (once I clean the dust off it!)

This is a big step forward in the EME project because now I can mount the Elevaton Rotor on a short mast above the Azimuth Rotor and begin to install the antenna parts.  Just nine days ago I received my fiberglass/aluminum cross-boom, antenna boom supports, Rear Splitter mounting kit with 2.5m long rearward boom, and the cables to run between the antennas and the power divider.  Interestingly these parts were shipped from InnovAntennas in Great Britain just TWO days before!  The box was an 8-foot 4-inch long by 6-1/2-inch diameter round cardboard tube.  It was picked up in Hockley, Great Britain by FedEx on April 18th and delivered to my door at 1:24 p.m. on April 20th!  UNBELIEVABLE!  I simply could not believe the speed of that shipment!

So, with the Elevation Rotor piece of the EME project puzzle now working, the project can move forward - hopefully with some speed now! 

Friday, April 21, 2017

EME Tower Construction Progresses

OH, to be young again!  I can remember doing station construction projects about 40 years ago and today, there is simply no way I can manage to do things at that level.  Surprised?  Not really, but when my 14 and 15 year old grandsons "help" me, Grandpa sure notices his deficiencies!

This week 15 year-old Owen and 14 year-old Grant came to my QTH for three straight days while they were on Spring Break.  They were really eager to help Grandpa with his EME station construction project.  AND, Grandpa was extremely glad to have their help!!!  A lot of what they helped me do were things they had never done before.  Plus, they did things that they had never even SEEN anyone do before!

The boys are now big enough to wear my tower climbing safety gear so they got some very valuable experience in tower construction.  On the right you can see Grant pulling up and placing the Hazer cage at the top of the tower.  (Click on any image to see it larger.)  This was his first time actually working at height and he was a little unsure about whether he could reach up above the top of the tower to place the Hazer cage.  So, he secured the cage to the top of the tower and his brother, Owen, gave it a try.

On the left you can see Owen placing the Hazer cage over the top of the tower.  He then descended the tower allowing the cage to follow him down to the ground.  Since I had purchased the Hazer used, it came already assembled.  Otherwise I suppose I could have built the cage "around" the tower at the bottom and this operation would not have been needed.

Now that the Hazer was in place at the bottom of the tower, we needed to raise the top (and last) tower section into its place.  Grant was eager to get this job so he went up the tower and first pulled up and bolted into place the Gin Pole.  He had never seen this device used before so it was a great learning experience.  Once the Gin Pole was there, Grandpa pulled the top tower section up to Grant.  You can see on the right a photo of when that section reached him.  Even though he had no experience with stacking tower, it took Grant very little time to position the three legs from the top section onto the existing tower and squeeze them together so that they mated with each other.  SUCCESS!  We now had the tower complete.  And, I have completed the basic training of my new "Tower Crew" for all future tower projects!

Before the top section of tower was raised, we needed to construct a Pulley Block for the Hazer winch wire.  This mounts at the top of the tower and provides the point where the Hazer Pulley is attached.  This did not come with my used Hazer so Owen cut and drilled a piece of C-Channel for attachment of the pulley and the U-bolts to attach to the tower legs. (See photo on left.)

We then attached the Pulley Block to the top tower section before it was raised.  On the right you can see a photo of the mounted Pulley Block that I took after the tower was erected.

At this point the boys had to go home sooner than we expected.  Unfortunately, this left Grandpa to climb the tower, pull up the winch cable, thread it through the pulley and drop it to the ground through the center of the tower, put the last three bolts in the leg joints, remove the Gin Pole, wind up the rope, and put everything away.  WHEW!  That was a LONG two hours of work that the grandsons could have done in about 30 minutes.

The next day Owen and Grant arrived here at 6:50 a.m. (they had arrived at 7:00 a.m. the day before) ready and willing to get on with the project.  However, it took Grandpa a couple of hours to shake the sleep out of his eyes and get to the point where I could get started myself.  If anyone can bottle this type of youthful energy - I'll buy it by the case.

To finish up from our Day 1 projects, Owen drilled two holes for a second U-bolt in the new winch bracket for mounting it to the tower.  We then had 100-feet of new winch cable to attach.  Since the tower is only 28-feet tall it turned out we only needed 50-feet.  So, Owen got the Dremel tool and he cut the cable in half.  That leaves me with a spare 50-feet of cable if something happens to the cable that is now in place.  On the left you can see the winch installed on the tower with the Hazer cage above it.

Now we needed to make an excursion under the house.  I have a hole in the wall behind my ham equipment and all my antenna cables enter the hamshack from underneath the house through holes in the sole plate (two 2x4's) inside the wall.  The boys and I packed up all the gear we needed (large power drill, long bits, head lamps, extension cord, drop light, drinks, etc.) and we began a 75-foot crawl under the house.   The grandsons remembered being in there (what they used to call the "cave") when they were younger but they said it was really MUCH smaller now!  Thank goodness Grandpa had knee pads!  The ground under the plastic moisture barrier is NOT soft and smooth!

We had some difficulty as the original holes were drilled from the top down before the wall was dry-walled.  That wall sits on top of a steel I-beam so our options for drilling were limited.  I ended up drilling at a steep angle a half dozen 3/4-inch holes to make a very ragged opening.  I think I managed to do that without damaging any of the cables that were already in place.  We had also carried with us the azimuth rotor control cable, the RX feedline (LMR400-UF) and a 500-foot roll of 4-conductor shielded cable.  We then ran those up through one of the previously drilled holes into the shack.

After crawling back out of the "cave", we installed the azimuth rotor on the Hazer, connected the cable to the rotor and to the control box inside, and ran through the calibration process.  An issue was discovered that I will need to find an answer for before using the rotor.  As the rotor was being rotated clockwise, it reached a point about 120° where it jumped up to a fast speed for about 45° then reversed to the point where it started and repeated that fast back and forth motion a couple of times before resuming the clockwise rotation.

After dinner the grandsons decided they wanted to try climbing the big Rohn 45G tower down over the hill.  Both went up the 85-foot tower and were amazed at how much better the climbing felt on the bigger tower (the EME tower is Rohn 25G.)  The photo at the right shows Owen at about the 50-foot level.

The boys decided to stay the night with us so we had a great time relaxing that evening.  We watched part of a movie until Owen decided he needed to hit the sack.  Grant just feel asleep on the couch!

The next morning we decided to finish the exit method for the cables from under the house.  It was simplest to just bring them through an existing vent hole.  That hole is covered with an automatic vent cover.  Grant and I took it apart and we each worked on one half to cut a hole in the cover to pass a 2-inch (I.D.) piece of PVC.  You can see a photo of the finished vent cover modification on the left.

We then un-spooled the piece of 7/8-inch Andrew Heliax, routed it through the modified vent cover, and Owen pulled it under the house.  He then managed to push it up through the ragged hole I had cut the day before and Grant pulled it through the hole in the wall and brought it out behind the operating table.  Just having these boys to get down on the floor under my desk and fish these cables out through the hole in the wall is worth BIG money!  Grandpa's knees are not what they used to be.

While we were starting to fish the Heliax under the house a very strong storm front moved through unexpectedly.  It caught us off-guard and we had to dry off the tools after quickly moving them to the back porch.  Once the rain passed, Owen helped me measure out two 100-foot lengths of the 4-conductor shielded cable, marking both ends of each with colored tape for identification.  Grant made a speed run through the crawl space and fed those wires up through the wall.  That completed the running of 6 of the 9 cables that must be run under the house.  Only the elevation rotor control cable, a 12 VDC and 28 VDC cable now need to be run to complete the cabling under the house.

Those three days of help from my grandsons has helped me to complete the major parts of the tower construction process.  I can finish most of the rest of the project on my own since the infra-structure is now in place.  Many thanks to Owen and Grant for giving me three days of their Spring Break to get all this work done.  They are the BEST!

Modifying the EA4TX ARS-USB Rotor Controller

The EA4TX ARS-USB Rotor Controller will handle the job of automatically keeping the antennas pointed at the moon.  However, there are times when I will need to manually point them.  For instance, when I need to bring the antennas down (to hide them from the neighbors!) or when I am installing or otherwise working on the antenna system.  It would be difficult to run inside the shack and move the antennas a little then go back outside to see if it was enough.  And, with the tower being right next to the house, the potential for having the antennas hit the roof or a vent pipe is large.

I felt that if I could control the antenna rotors from the base of the tower, I would solve this problem.  That meant a set of switches to control (UP, DOWN, EAST, and WEST) movement of the array which needed to be wired to the EA4TX Rotor Controller.  I found the perfect set of switches on eBay (see my Post Pointing my EME Antennas at the Moon.)

Now I needed to find a way to connect those switches to the EA4TX Rotor Controller.  A short email to Pablo, EA4TX, gave me a quick reply with the points where I could connect the switches.  It seems there was a insulation-displacement contact (IDC) connector on the LCD circuit board that would do the job.  This IDC connector (also known as insulation-piercing contact) was something I had never worked with.  But in looking around the wonderful Internet I learned about them and found a place where I could order a couple (along with a short piece of ribbon cable that could be installed in the IDC.)  Cost was only $0.58 each and $0.32 per foot for the ribbon cable.  Turns out it was from a company where I already had another item I needed to order so shipping was not an issue.  (See the IDC connector in the photo on upper-left. Click on any photo for a larger image.)

To make the installation clean, I needed a 5-conductor connector to mount on the back panel of the EA4TX Controller.  Again, eBay came to the rescue!  I found a set of FIVE SETS of Aviation Plugs (Male and Female) that have 6-conductors (more than I need) for a total cost of $8.30 including shipping.  These are similar to an 8-pin microphone plug and measure 11mm or 0.43 inches in diameter (for the portion that will go through the back panel of the EA4TX Controller.)  (See photo on the right.)

Now all that was required was for me to connect a short piece of ribbon cable to the IDC connector and wire it to the female 6-conductor panel-mount connector.  But, since I had never worked with those connectors before, it was back to the ubiquitous Internet for instructions and I quickly found  a YouTube video that told me everything I needed.  Now that those connections have been made, I can run the 5-conductor cable to the base of the tower and connect it to the fancy Rain Proof Hoist Crane Pendant and I will be able to manually control the antennas from the base of the tower.  Excellent!

Of course, those switches will not function when the EA4TX Rotor Controller is turned off so I have no worries about someone messing with the antennas when I am not here.

On the left you can see the modification I made to the EA4TX Rotor Controller to add the ability to remotely control the antennas from the base of the tower.  The IDC connector is on the top right and I labeled it with the word "Top" as there is no keying to make sure it is connected properly.  It connects to the LCD Circuit Board and passes down and across the bottom of the EA4TX Controller box to the rear panel where it connects to the 6-pin Female chassis mounted connector.  Later the cable from the Remote Switches will plug into this connector.

The bottom portion of the image shows the rear panel with the pass-through grommets for the cables to connect to the Azimuth and Elevation rotors (as well as the cable for the inclinometer.) Also you can see the new 6-pin connector I added for the Remote Switches.

This modification of the EA4TX Rotor Controller took me just a couple of hours and will (in my opinion) greatly enhance my ability to utilize the controller to move my antennas.  I am very happy with how it turned out.

The wires in the ribbon cable between the 6-conductor Female chassis mounted connector and the CN_KBD IDC connector on the LCD Circuit Board are connected in this order:

Pin 1 to CN_KBD-2: +5Vdc (This is VOLTAGE and not a Ground)
Pin 2 to CN_KBD-4: Manual Left/CCW control.
Pin 3 to CN_KBD-6: Manual Right/CW control.
Pin 4 to CN_KBD-8: Manual Down control.
Pin 5 to CN_KBD-10: Manual Up control.

The Remote Switches will have the +5VDC as the "Common" connection across all the switches.  Closing any of the 4 switches, UP, DOWN, LEFT, or RIGHT, will simply apply +5VDC to the appropriate pin in the ARS-USB unit to cause the proper rotor to move in the proper direction.

Friday, April 14, 2017

Pointing my EME Antennas at the Moon

EA4TX ARS-USB Rotor Controller
Once you have the 2-M antennas in the air, you need to figure out how to rotate them to track the moon.  Back in the early 1980's when I was first on 2-M EME, it was a major thing to know where the moon was at any particular point in time.  Remember, there were NO Smartphones and NO Internet at that time - yep, it was the "Dark Ages." 

At first, I had to use the Nautical Almanac to find the Greenwich Hour Angle (GHA) and use that to calculate BY HAND the moon's position.  After a short time I acquired a printed copy of a BASIC computer program from Lance, WA1JXN/7, (now W7GJ), which was written for his Apple II home computer.  I converted that to Commodore BASIC and typed it into my Commodore Pet 2001 home computer.  I could now print out the Azimuth and Elevation headings for the moon.  This was done in increments of 10 minutes.  Then, to track the moon I had to manually turn the two rotors to the headings shown on the printout and then remember to keep incrementing the rotors as the moon moved.  I also needed to watch the clock and manually switch from receive to transmit at the end of each period.  Often I was not sure the antennas were on the moon so I ran out in the yard and eyeballed it.  It was a lot of work!

MoonSked Sked Maker Window
Boy, have things changed now!!  The home computer now will calculate the position of the moon every SECOND.  It will send that information over USB to the EA4TX ARS-USB Rotor Controller (shown at the upper right.  Click on any photo to see it larger.)  That device is connected to the Azimuth Rotor Control Box and the Elevation Rotor Control Box.  As the moon moves, the ARS-USB will turn the rotors automatically.

EA4TX Graphical Interface
The program that I use to track the moon is MoonSked by GM4JJJ. Not only will it track the moon in realtime but it will calculate a suitable date/time for setting schedules with other stations (the Sked Maker window is shown at the left), it will create a sky map showing the moon's location (to help determine when the moon is in a favorable location), it will search a database of EME stations for a partial call, and it will display a World Map with the moon's ground-track shown.  But, one of the coolest things (in my opinion) is that it will ONLY send the tracking information during transmit (TX) periods!  That way any potential noise being generated by the rotors will not affect the receiver.
Remote Ant. Control
The EA4TX Rotor Controller has a small graphical interface for displaying the antenna positions (shown at the right.)  And, with this interface you can control the rotors by using the mouse or by pressing the buttons on the front panel.

All the above will automate the pointing of the antennas and let me concentrate on the actual operation of the MAP65 software to make the EME QSO's.  When you think about operating moon-bounce for hours at a time, the ability to have the antennas continuously track the moon is huge!  Sometimes I think back to the days when I had to actually calculate the moon's position by hand and later from a printout made by my home computer, and compared to that, this is heaven!

One final thing I wanted to have was someway to control the pointing of the antennas from outside the house.  The antennas are mounted on a Hazer tram system and the tower is right next to the house.  When raising and lowering the Hazer, someone needs to manually rotate the antennas (especially the Elevation rotor) to make sure the antennas do not hit the house or the ground as the Hazer is raised or lowered.  I was planning on building a box to mount at the base of the tower with four switches (UP, DOWN, LEFT, and RIGHT) and wire them to the EA4TX Rotor Controller.  While looking on eBay for some suitable small switches, I found the Rain Proof Hoist Crane Pendant shown at the left.  WOW!  Was this exactly what I needed or what?  This item was New and would be shipped to me from Hong Kong.  The price?  Trust me - you will NOT believe it!  Including shipping I paid a whopping $8.15 for this!  WOWZER!

Thursday, April 6, 2017

The EME Tower has been Planted!

Gravel for Drainage
Build the Form
Once my grandsons had finished the digging of the hole for my new tower (see the "O&G Tower Construction Crew" Post), it was time to call Mr. Concrete (aka, Tim, K8RRT) and get the tower firmly planted in the ground.  Working around everyone's schedules and the weather, it turned out that Sunday, April 2, 2017, was THE DAY!

I picked up the grandsons and then we picked up Tim plus his wheelbarrow and concrete finishing tools.  After a brief stop for fuel for the workers (Tudors Biscuit World) we were ready to begin the job.  My grandsons, Owen and Grant, had no real experience working with concrete so this was a learning experience for them.  Mr. Concrete had mucho experience so he was appointed as the Job Boss!

Lay Down the Tarp
Tim was very good about telling the boys everything he was doing and, most importantly, the WHY of what he was doing.  I am sure they leaned quite a bit that day.  Not just about concrete but even some tricks about sawing wood with a hand saw.  Tim was really impressed by how well the boys listened so it was a really great crew all around.

Pour the Concrete
I took on the role of "Stupidvisor" and Chief Gopher!  Anyone needs something and W8TN is your man to go and get it.  We only had one major issue develop and that was my choice of where to locate the tower in the hole.  Tim noticed that if we put it there, the Hazer that would eventually carry the antennas up and down the tower would not be able to clear the gutter on the house.  WHEW!  I am sure glad he spotted that one!
Just Add Water

You can click on any of the images here to see them larger.

We first put a couple of inches of gravel in the hole to allow water (that WILL accumulate in the tower legs) to drain out.  To make sure the tower did not sink in the gravel and get plugged by dirt, we suspended the tower by using a small rake under a couple of rungs to hold it at a particular height.  We tied three light lines to the tower and staked them to make sure the tower did not topple while we were working.  Another 3 inches or so of gravel was added and then it was time to add the concrete.

We had previously purchased eleven 80-pound bags of Quickrete.  When the smoke cleared, we had about 15 pounds left over.  I get credit for measuring the hole and calculating how much concrete would be required (plus, just maybe a little luck?)

Once the concrete job was finished, Evelyn prepared a great hot dog lunch that all enjoyed immensely!  My recollection is that the entire job took about 4 hours including correcting our (my) mistakes.  We then cleaned up our tools and the grandsons asked could they please mow the yard?  WOW!  They are at an age where that stuff is fun for them. 

After I took everyone home, I came back and spent a couple of hours doing the final cleanup work including putting the tools back where they belong.  The next two days were miserable for me!  I was sore in places I did not even know I had!  All I did was "fetch and carry" and that did not include lugging 80-pound bags of Quickrete.  Could I really be that out of shape?  DUH!

"The Crew" is DONE!
The Base is Now Planted
Over the next few days I kept the concrete moist to prevent it from cracking by drying out too fast.  Now all that we need to do is to install the Hazer and add the top section of the tower.  Then, it's time for ANTENNAS!

I am very grateful for the help of ALL the crew (and my wonderful wife!)  Without everyone pulling together this would not have taken place in such a relatively short length of time.