Wednesday, September 20, 2017

Building Finally Begins on 2-M Antennas

220 VAC Y-Splitter for 6-M & 2-M amps
OK, Sports Fans, today I began building the 2-M antennas for the EME project.  YAY!

Two 13-L 144-MHz Yagis
But first, last night I built a "Y"-Splitter for my 220 VAC circuit.  I have two large 30-amp 220 VAC outlets in the wall of my shack but felt that it would be nice to have the HF amp plugged into one of them and the 2-M and 6-M amps "share" the other.  So, I built the splitter shown on the left.  Not a hard job but one that really needed to be done because the 220 VAC outlets are behind the operating table and very difficult to reach.  I have to pull out a 2-drawer file cabinet (which has the 6-M and 2-M amps on top of it) in order to reach the wall behind the operating desk.  Not fun!

Today I began the building of the 2-M antennas in earnest.  On the right you can see the shipping tube that contained the two 13-L InnovAntenna 144-MHz yagis.  The two 13el LFA2 2-M yagis were tendered to FedEx on June 29th (of 2016) and delivered to me on July 5th.  That's just 6 days and may have been much less if it wasn't for the weekend and the holiday.  I can't believe how fast InnovAntennas can ship antennas from England right to my house in Hurricane, WV. (Click on any photo to see a larger image.)

Elements Named
Element Center Markings
Once everything was un-boxed and inventoried, I was very pleasantly surprised.  Each end of every boom section was VERY plainly marked as "1", "2", "3", "4", "5", and "6."  Even better, since there were two antennas in the package, one set of booms was marked in Black and the other in Red.  NICE!

Next, each element was plainly marked as "RE", "DE", "D1", "D2", "D3", etc.  WOW!  No need to measure each element to find the correct one.  I am suitably impressed now.

Next I noticed that the elements have three marks near the center of each.  The manual indicates that these marks show EXACTLY where the center of the elements are and the two marks on either side, are spaced perfectly so that you can see them on the outside of the insulated element mounting brackets to know you have the element centered.  (This just keeps getting better and better!)

You can see in the photo on the left how those centering marks work.  When the top piece of the element mounting bracket is installed, the marks on the outside show up nicely so you can perfectly center each element.

The one complaint I have is that the actual written instructions for the antenna leave a good bit up to the builder to figure out on his own.  Luckily I had built an InnovAntenna 6-M beam two years ago and had solved some of those problems.  For example, there is a one metal element mounting bracket (all the rest are plastic) and no indication in the manual of where this goes.  From the 6-M antenna build I knew that this was a grounding bracket for the Driven Element loop.  Things like metric measurements, "P" clips, "RivNut inserts", "Jubilee" clips, and so on can cause some confusion but Mr. Google is your friend in these circumstances.  ("Jubilee" clips are "hose clamps.")

Marks Center Elements
The first thing I did was to assemble the first two boom sections.  The boom is square tubing and there are short pieces of round tube that slide inside the square tubing.  Those short pieces are plainly marked with tape that are numbered to match the pieces of the boom where they fit.  During manufacture, they were drilled in those locations so there is no problem in lining them up.  Yes, the short round pieces are also marked in Black and Red to denote the two separate antennas!

Never-Seez on Boom Joints
I coated the round pieces with Never-Seez and they slipped right in place.  Just as I had completed the first joint, Bob, W8OM, stopped by to drop off a contribution to VK9MA.  He noticed (as I had noticed) that the two square boom pieces were not perfectly aligned.  I said I could take one off and turn it around but Bob suggested I just loosen both and see if they would twist into place.  Yep!  That did it!  Bob's 'da Man today!

After the boom pieces were in place and supported on plastic saw horses, I began the process of installing the elements.  Since the elements were labeled and the centers were marked, this process proceeded at light-speed.  I just laid down one of the element clamp halves, placed the element on it, put the other half of the clamp on top, smeared some Never-Seez on the end of the metric Cap Bolts, and screwed the bolts (with an Allen wrench) into the "RivNut" inserts that were already installed in the boom.  Notice there was NO MEASURING to figure out where to mount the elements.  The "RivNut" inserts were already in the boom and I just had to screw in the bolts.  Easy-Peasy! 

 I found that I could pick up the two halves of the element clamp, two cap screws, the next element, smear on the Never-Seez and install the element in about 3-4 minutes.  It went SO fast I was getting dizzy!  I did double (and triple) check the element names to make sure they were in the right order as well as the centering marks.  Before completely tightening down the elements, I placed a large metal square alongside the boom and made sure the elements were square to the boom. 

Antenna #1 Nearly Completed
Never-Seez on Bolts
The driven element loop took a little longer to install as there is a C-shaped piece of tubing that slips into each side of the two DE ends.  This is held in place with "Jubilee" clips (hose clamps.)  And, the measurement from the inside of one "C-end" to the inside of the other is nominally 908mm.  I have a carpenter's rule that is marked in mm so that made this part of the project simple.  Adjusting the length of that loop by sliding that "C-piece" in or out is how the antenna is tuned.  This will need to be done with the antenna in its operating location at a later time.  I also used Never-Seez on mounting these "C-pieces" to insure good conductivity and prevent the metal from seizing over time.

There is also a "Truss" assembly that I need to construct and install to support the 26.26-foot length of the antenna.  Also, the boom-to-mast bracket needs to be installed.  This was not done today because it requires balancing the antenna and I'll leave that for another day.

So, today was a VERY good day on the EME project.  Antenna No. 1 is pretty much complete.  Building Antenna No. 2 should go a little faster now that I have a work flow established and all the necessary tools in place.  I carried the antenna around to the EME tower and just laid it on the roof so that the deer won't trample it in the yard.  Hopefully we get no strong storms before I finish the mounting - Hi!

Monday, September 4, 2017

Serial PTT Circuit

In the spring of 2009 I purchased N8LP's LP-Pan Panadapter and needed a better computer in order to run the SDR programs like NaP3 which could utilize that hardware.  I decided I would build myself a speedy computer to do just that.  I researched and purchased all the parts necessary and then on July 3rd I broke my right leg really bad.  I was in a wheelchair for 4 months after spending about 16 days in the hospital.  During all this the computer parts just got shoved under the bench and left there for about 7 years!  Recently a friend put it all together and I have a nice (essentially new) XP Pro SP3 computer with 4 GB of RAM. Since XP is really not supported anymore, I decided to utilize this computer for my digital operations thus keeping those separate from the computer I use for Internet surfing, email, etc.

Serial PTT Circuit
In setting up that newly-built computer to do this, I find that I need some way to allow that computer to key the PTT of the Elecraft K3S.  My normal station setup has the microKEYER II connected to the K3S and the Windows 7 computer.  So, I purchased a 2-port Serial PCI controller card and installed it in the XP computer.  That gives me two COM ports that I can use for various things - one of which will be to key the Footswitch input of the microKEYER II.  This will cause the K3S to go into transmit when the WSJT software wants it to transmit.

Completed Wiring of the Circuit
A little searching on the Internet found a suitable circuit (shown on the left) and I only needed to acquire a couple of diodes and a transistor to build it.  Luckily there is still a Radio Shack outlet in Kanawha City and they had an MPS2222A transistor and a pair of 1N4001 diodes in stock.  I already had the resistor, the DB-9 plug, and the cable in my junk box.

It did not take much time to wire up the parts and you can see the completed Serial PTT circuit on the right (click on any image to see it larger.)  I chose to use the RTS line but I could have used DTR just as easily.  I only need to tell the WSJT software the COM Port number and click on the RTS button to allow the software to communicate with the microKEYER II.

A quick check of the circuit by telling the WSJT program which COM port to use and plugging the cable into the Footswitch input of the microKEYER II and, VOILA!  I can now key the K3S from the newly-built XP Pro computer - SUCCESS!

Monday, July 3, 2017

Yaesu G800-DXA Azimuth Rotator Adventure

This post is a little late but here we go.  I had originally planned to use a Hy-Gain TailTwister rotor that I already had on-hand as my Azimuth rotor for the EME array.  However, as my project progressed, 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 heading which I needed in order to be directly aimed at the moon.  Since I was only planning a 2 antenna system, I did not feel I could give up that much 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. 

I purchased the Yaesu G-800DXA Antenna Rotator new from GigaParts and received it on March 8, 2017.  Since it was a Brand-New unit in the factory box, I "assumed" that it would work properly out-of-the-box.  WRONG! 

When I first un-boxed this rotor and started going through the setup, I noticed a problem.  When rotating it clockwise, at about 130° it suddenly reverses direction, speeds up, goes back to about 105°, reverses direction again and runs up to about 165° where it goes back to normal speed.  All the time this was going on I kept the Clockwise button pushed.  This is totally repeatable.  It did the same thing every time.  Also, when moving counterclockwise, it does the same "back and forth, speeded up" gyrations but not at the same headings, just in the same quadrant.

It is interesting to note that the rotor itself does NOT change direction.  It continues to rotate in the same direction at the same speed.

Below is a link to a 37 second video of what my G800-DXA was doing:

As I noted above, the rotator motor unit continues to turn normally but the readout behaves erratically as the video above shows.  This erratic display of the azimuth heading is also communicated from the Yaesu control box to the EA4TX ARS-USB rotor controller.  I can only imagine what that controller would try to do to compensate for this crazy display of the beam heading.  So, I called Yaesu Technical Support for help.

I started talking to Yaesu about the problem on May 3rd.  I think I made about FIVE telephone calls to Yaesu (two were voice mails I left) and had three discussions with their Technician and exchanged a couple of emails.  He gave me several things to try in order to diagnose the problem which took up about 10 hours of my time.  Finally, he determined that both the rotator and control box would need to be returned to them for Warranty repair and I shipped it to them on May 10th. 

It cost me $36.40 to return this BRAND-NEW rotator to Yaesu for WARRANTY repair!  But, under the terms of their warranty, they are not responsible for return shipping to them even though the rotator was bad when they supplied it.  At least they repaired it under warranty and paid to ship it back to me but I would have had to pay extra for any insurance on the return shipment.  I guess money is tight everywhere!

I called Yaesu Customer Service after the rotor was returned to find out the problem.  The tech said it was a bad potentiometer.  He agreed that it was a problem during manufacture since I bought it brand-new and just opened it up and checked it out inside the shack when I first found the problem.

The rotor was returned to me on June 2nd so my project was "delayed" by a month over that BRAND-NEW G800-DXA Rotator that arrived DAMAGED from the factory!  Unfortunately that delay was during the time when I should have been able to work more on the EME project.  And by not having the Azimuth rotor in place, I was not able to build the rest of the project that goes on top of it.  

Thus, I have not been making the progress on the EME project that I had hoped to make.  Still, I am moving forward, even though at a slower pace. The Yaesu Azimuth Rotator has now been installed on the Hazer and appears to be completely repaired - at least I can no longer get it to misbehave.

Finishing the Tower Base

Yesterday my friend and concrete master, Tim, K8RRT, came by to remove the form from the base around of the EME tower and do some concrete finishing work.  He had no idea what a nightmare he was facing.  Of course, temperatures were in the low 90's and pretty humid and Tim had just finished a few hours working on Charlie, N8RR's, EME tower!

Tim has done this job hundreds of times but this time, the 2x4 frame would not cooperate.  It seems that during the pouring of concrete, some was spilled on one side of the frame, next to the house steps.  When it set up and expanded, that piece of 2x4 was trapped just as if it were in a vise.

The other sides were easily removed but that one 2x4 would not budge an inch.  Tim tried prying it out, chipping it out with a pry bar and hammer, even beating it to death with a 5-foot spud bar.  But, that wood would not move.

I brought out a reciprocating saw and although it did some serious damage to the 2x4, the blade was not long enough to cut completely through the long dimension of the wood.  So, time to bring out the big gun!  My Stihl chainsaw was pressed into service and made short work of removing (and destroying) the 2x4.  (Click on the image at the left for a larger view.)  Tim then mixed up some concrete and smoothed off the surface and edges of the tower base very professionally.

Now I can get my "crack tower crew" (the grandsons) to replace the landscaping rock.  This will please Evelyn that things are getting back to no longer looking as if we are "Under Construction!"

Thanks So Much, Tim!

Sunday, June 25, 2017

24 VDC Power Supply Modifications

Original Power Supply
The T/R Relay for the EME station requires 20-28 VDC.  Since I did not have that supply voltage available, I was planning on using a Boost Regulator from W6PQL to provide the necessary power for that relay.  However, my friend Steve Gillispie, K8LZ, just happened to offer me a very nice 24/28 VDC power supply that would do the job.  He had no way of knowing I needed just the very thing that he was planning to dispose of while down-sizing his shack.  We had the "Perfect Match" - he needed to get rid of a power supply and I needed that exact power supply!  You can see a photo of the supply Steve gave me on the left.  (Click on any photo to see a larger image.)

Modified Power Supply
The power supply came from Steve in the original box with the manual so I had everything I needed to install and operate it.  It was a "bare bones" device with just a barrier strip for connections and no way to switch on (or off) the AC voltage.  Thus, I needed to make a few minor modifications to it so that it was more efficient for my needs.

I picked up a power switch and fuse holder at the Charleston hamfest for just a couple of bucks and my junk box already had a new AC power cord and an LED.  I used a couple of existing holes in the metal case to mount the AC Power Switch and the LED after drilling them out to the necessary sizes.  I then had to drill a new hole on the side for the fuse holder.  A little heat shrink, a 1.2 k ohm dropping resistor for the LED from the junk box, a strain relief for the AC cord and a couple of hours work turned this "bare bones" 24 VDC power supply into a needed shack accessory.

You can see in the photo at the right the modifications I made to Steve's power supply.  I am now ready to add this to the EME station equipment and move on to the next thing I need to build (like maybe the antennas?)


Monday, May 1, 2017

Final Mods to the EA4TX ARS-USB Controller

Final Mods to EA4TX Box
If you read my previous post about Modifying the EA4TX ARS-USB Rotor Controller you will have seen where I added a connector to the controller box so that I could connect some remote switches for adjusting the rotors while standing at the base of the tower.  In doing that I had acquired FIVE SETS of Aviation Plugs (Male and Female) which have 6-conductors each for a very reasonable price.  I used one set for the Remote Switches.  But, while modifying the Elevation Rotor control box (so it could be controlled by the EA4TX ARS-USB), I decided to go ahead and use another set of those connectors to allow me to easily set up or move the components of the station.  I removed the grommet which was already installed for the J2 cables and quickly placed one of the 6-conductor jacks in its place.  (It fit perfectly!) I also drilled and punched another hole for one more jack that will be used to interconnect the inclinometer cable.

My EA4TX ARS-USB was purchased with a cable to connect to the Yaesu G800-DXA azimuth rotor.  That cable came already installed by EA4TX and it is the white cable that exits the controller at the J1 hole which you can see at the bottom of the image to the left. (Click on any image to see it larger.)

The red/white/green wires at the top right of the circuit board go to the Elevation Rotor control box.  The red wire brings the 29 VDC from the elevation rotor controller and the white and green wires allow the relays in the EA4TX unit to connect that voltage to the UP and DOWN circuits for controlling the elevation rotor.  The blue/yellow wires at the bottom right go to the inclinometer and provide feedback from it for the elevation angle of the antennas.

Oops!  In later testing of the unit, I found that I could only control the Elevation Rotor to move DOWN by pressing the front panel button on the ARS-USB unit.  The UP button did nothing.  In checking out the reason for that, I found I had forgotten to install a jumper between Pins J2-3 and J2-6 on the ARS-USB board.  I only had the red wire connected to J2-6 which supplied the 29 VDC just to the DOWN point in the Elevation Controller.  Once I connected that jumper, I was able to control both UP and DOWN directions from the ARS-USB unit.

Also today I wired the inclinometer to the cable which runs out to the tower and wired the plug to the other end to connect to the EA4TX unit.  Then I powered on the EA4TX ARS-USB unit for the first time and checked out the inclinometer.  It WORKS!  I can move the inclinometer and watch the Elevation reading on the EA4TX smoothly change.  Now I need to fabricate a small bracket to mount it to the fiberglass cross-boom.

I chose to go with the inclinometer because I felt my old elevation rotor might not have a good potentiometer for read-back of the elevation angle.  And, it was possible that I might have to use a satellite (TVRO) jack screw for my elevation system and would need the inclinometer for that.  You can see an image of the inclinometer on the right.

Finally, I connected the Yaesu G800-DXA azimuth rotor to the EA4TX ARS-USB controller.  The feedback of the rotor position worked correctly and when I rotated the Yaesu, the azimuth position could be seen changing on the EA4TX unit.  I was also able to push the buttons on the front of the EA4TX controller and cause the Yaesu to rotate.  That is what this box will do (under computer control) when the system is being used.

Today yielded several SUCCESSES in the 2-M EME Project process.  Step-by-step I continue to move forward.  Some of the additional project goals which are included in the total project are:  1.  Checking/Testing each component part as I complete it.  2.  Labeling of all cables, wires, etc. so there is no confusion at a later time.

This was helpful yesterday as it was one of those "1 step forward and 3 steps backwards" days for me.  I wasted a good bit of time unsuccessfully searching my junk box locations for a couple of parts that I know I have but so far have eluded me.  Then I proceeded to finish up the wiring of the EA4TX ARS-USB controller and when wiring a small 6-pin plug to the wires coming from the elevation rotor control box, I wired the UP and DOWN buttons to the wrong pins.  Of course, I did not realize that until I had completed wiring the connector including heat shrink and all.  Then, I had to take it apart and do it again!  Plus, I had done such a NICE job on it too!  At least the "Checking/Testing" portion of my work was successful in finding my error and I was able to fix it while everything was still on the bench.

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.

Friday, March 31, 2017

W8TN's 2-M EME Project

My last post was about my grandsons digging the hole for my new tower.  Why do I need a new tower?  Well, I'm building a moonbounce (EME or Earth-Moon-Earth) station for 2-M and need a place to mount the antennas.  This project has been in the planning stages for over 3 years now.  About 14 months ago I started to get serious and placed the order for one antenna.  Delays in shipping that antenna led to me adding a second antenna to the order and the 2 antennas were received from England on July 5th last year.  I chose the InnovAntenna 13el 144MHz LFA yagis as about the longest I could reasonably put up at my QTH.  Each antenna has 16.12 dBi Gain at 144.100 MHz on an 8.003m (3.85 λ or 26.26 foot) boom.  Two of them spaced 4m apart horizontally should give 19.05 dBi (16.9 dBd) total gain. This amount of antenna gain coupled to a 1,000 watt amplifier should give me a modest moonbounce station using WSJT software.  I will, of course, be limited to a single polarity and thus subject to dealing with Faraday Rotation but I should be able to work dozens if not hundreds of stations off the moon.

Block Diagram of 2-M EME Station
One major reason for choosing the LFA (Loop Fed Array) antenna is that it has been specifically designed to reduce the amount of noise that is normally received off the back and sides of the antenna.  The tight, highly suppressed pattern and closed loop fed system ensure everything from rain static to man-made noise are heavily reduced.  This is pretty much an essential feature of an antenna that is trying to hear the super-weak signals being reflected back from the moon.  It has a really excellent G/T figure (-1.33dB @ 144.100MHz) showing it is hearing very little from the rear and sides of the antenna.

To the left you can see the current block diagram of my 2-M EME station.  It has evolved as this project has progressed.  Click on any photos to see a larger image.

I started out planning for an extremely simple configuration that would just allow me to make the occasional EME QSO.  But, as planning progressed, I kept adding features to make it the most efficient and productive station I could manage.  To that end, I added the EA4TX Antenna Controller that when connected to software on my computer will automatically keep the antennas always pointed at the moon without the need for me to manually adjust the rotors.  I then added the BG7TBL GPS Disciplined Oscillator that will take signals from the GPS satellites and produce a highly accurate 10 MHz reference signal for my Elecraft K3S to ensure it is precisely on frequency.  This is very important with WSJT signals so I felt this would be something that would remove the necessity of my needing to manually insure the frequency accuracy of the radio.

Everything else in the system was chosen to keep the signal losses as low as possible.  Toward that end the preamp will be located as near as possible to the antennas.  The preamp will be directly connected to the T/R relay with a right-angle, double-male N-connector.  All control lines will be shielded.  All computer lines will have ferrites installed on them.  Low loss cables will be used throughout the system including 7/8-inch Heliax for the TX feedline.  The antennas are mounted right outside the shack to keep feedline losses to a minimum.  Using just two antennas is not going to make me a Big Gun.  But, if I can make those two antennas and the rest of the station perform to their maximum ability, I will do well.

I then decided to add the FUNcube Dongle to the system to allow me to see all the stations which I am able to hear who are bouncing off the moon at any particular time without the need to tune around for them or set schedules to work them!  Unlike HF, you usually can not "hear" the signals from the moon but the computer can.  However, it needs for you to be pretty close to the frequency of the signal in order for the computer to decode it.  The FUNcube Dongle is a SDR (Software Defined Radio) just the size of a USB Thumb Drive.  It can listen to a range of frequencies and decode (using the MAP65 software) all the stations in that range of frequencies at once.  You can think of it as acting like the CW Skimmer of moonbounce.  On the right you can see an image of one of the output screens in MAP65 when I ran it and used a sample file for testing.  You can see that it shows the frequency of each station along with what they were transmitting.  I am so excited to give this a try on real live EME signals!

One other very important part of this 2-M EME station is a good low-noise preamp.  To take full advantage of that item it needs to be mounted as close to the antennas as possible.  I purchased a couple of these preamps from WA2ODO and on the left you can see the Noise Figure Meter printout from the best of these two preamps.  Putting such a low-noise preamp right at the antennas will help to keep the system noise figure as low as possible.

As I continue to progress with this project I will Post articles here on my Blog about various aspects of what I'm doing.  Hopefully, before long I will be able to post the images of my first EME QSO's in a LONG time.  I was on 2-M moonbounce back in the 1980's but only made about a half dozen QSO's with CW.  It was huge fun but I'm expecting this new incarnation to be an order of magnitude better!