Meriden ARC Web Site | Castle Craig Chapter 10-10


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QRT for Antenna Repair
#1

I am now QRT for the next 3 to 4 weeks for repair of the SteppIR and upgrades to the VHF and UHF antenna systems on the tower.

-73-

Al - N1API
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#2

This morning with some help from my brother I got the lifting fixture on the tower and the tower lowered. Then I started to take the various parts off that was needed to tip it over.

First unbolt and drop the rotor down so that the tower was free to turn when I secured the lifting wire which will tip over the tower

Next I needed to take the bolts off the base where the tower mounts to the base and loosen slightly the large bolts that secures the tower to the fixture. NOT AN EASY JOB! Tough as the large bolts are tight, probably from being up so long. You don't want the nuts looser than about two threads or so as this is the only thing holding the tower to the base and is the pivoit point where the tower folds over. Lastly I had to take the bolts out for the ring that opens up when the tower comes over. This is the ring that when to tower rotates it is the top pivot point of the "tube" which is the tower.

I have to tip the tower slowly and when the first element gets close to the ground collapse the first section of the fiberglass element. I found what I expected the director tape is all the way out. After collapsing the first section I do the same for the second and third sections. I can then remove the fiberglass element.

Once that is done I can remove the other side of the element which is fully extended. Normally I would not remove them if I was doing some service on something other than the motors but because I am replacing the elements I, (FORTUNATELY), had to remove the other tube. (It comes off fully extended by the way.)

Now the shock..... I removed the Reflector tube first and was taken totally by surprise to find that the tape was out on one side of the motor! "SHIT" and a few other expletives I sad out loud this EHU is bad also. A further shock when I went to coil the tape it came out of the motor. The tape had separated from the EHU. Something we NEVER expected from the ground tests we did.

After a call to Fluid Motion, they suggested for piece of mind I send ALL the EHUs back and have them checked since the antenna has been up since 2005.

What a day! I am totally wiped out. This not an easy job and something that I don't want to do again any time soon!

Tomorrow I'll be removing the motors and getting them packed up to send off. I hope to have them off by tomorrow afternoon! I'll be out back working by about 10 AM tomorrow morning. I've got to get out and get some bubble wrap to for the parts to pack them.

I've added some pictures so you can see what things look like.

Picture one - The tower tipped over with all elements attached.
Picture two - The copper-beryllium tape sticking out of the director element
Picture three - The "pipe bomb" where all wires meet. This will be replaced with a WX proof box.
Picture four - The tower pivot point - this really, (and two pining screws), are all that holds the tower in the fixture. Note the ring on top that steadies the tower when it is erect.
Picture five - The assembly as it sits with the motors on the boom. They come off tomorrow. Note the single element between the director and driven element, that is the 6 meter passive element that makes the antenna a four element beam at 6 meters.


Attached Files Image(s)
                   

Al - N1API
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#3

I need to have the "N" connector on the coax at the antenna redone.

Does anyone have the tools and is able to do one connector for me? I will need to get up to Newington and get a new N connector but I do not have the crimper tools needed for the job.

This is a "ground job". The "N" connector that is on there now will be cut off and the new one installed.

Can anyone help? Please reply by private message here or my email address.

Thanks!

Al - N1API
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#4

I need engineering help and possibly some assistance with two parts of my antenna rebuild and tower up grade project.

First of all I am trying to figure out why I can't pull the StepIR motor control cable, (a 12 wire 22 gauge cable) back out toward the house a couple of feet, then after cutting it pull it back toward the tower and pull a new cable through the 6" PVC tube. Because it was the last cable that I put in, I thought that it would be just sitting on top of the three coax cables and one rotor cable. I guess not. Maybe it just needs someone "feeding" it from one side while pulling from the other. There is one 90 degree turn underground and one 180 degree turn above ground. I guess I could just push the new cable in but I would have to figure a way to put a messenger rope or wire thru first. It is about a 75 foot run across the yard.

The other issue is with the new 432 MHz antenna. I purchased a new 2 meter beam and also a 432 MHz antenna and assembled them both. I got the SWR down to 1.1:1 at 144.200 good enough for me.

The 423 antenna I can't get the SWR under 3:1. The SWR is 3.1 at 430 Mhz and 4.1:1 at 440 MHz. I've tried everything I can think of. It matches with what Cushcraft calls their "Redi Match". We would know it as a gamma match. I tried a number of things, (beside all the way out and all the way in on the gamma match). I tried using the driven element from the dual band beam because it was a little shorter figuring shorter element higher frequency. I also tried the dual band beam's gamma match tube it is shorter. No luck. Finally a Hail Mary try. I used the gamma match tube from the old 2 meter antenna to see if I increase impedance and match the antenna no luck. The last thing I did was to take off the tower and move away to the picnic bench to see if the SWR changes and it does not.

I believe that the yagis are about 25 ohms so I would need to double that to match 50 ohms on the antenna.

Any ideas on these? Perhaps if someone gets on the 6 meter net tonight they can ask and see if anyone has any ideas. The 432 antenna is only 4 feet long and two screws it's off the tower. I could take it someplace if someone can help.

Any ideas on either please email me here or at my regular email address.

Thanks


AL N1APi
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#5

I sent an email out today asking for progress report on my ECUs and Controller and got an answer that they have been "processed". I'm guessing that means they are repaired. I have not got a ship date yet, also looking at my credit card I don't see a charge yet. If they ship this week I expect that it will be same day next week that I get the parts back. I'm just about done with all the outside work. I just have to get the WX proof box mounted on the side of the house and the wires dressed on the house and seal up the wires coming out of the box.

Also need to clean up the ring that the tower spins around, (wipe out the old grease, and put new grease on the ring and tower).

Finally I have to put the new wires in the box in the tower but would like to have the ECUs to do the box all at once then test the ECUs on the ground to make sure everything is wired correctly. Would take about two days to get back on the air if I had all the parts.

Al
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#6

I expect that Fluid Motion will ship my ECUs and Controller Monday by FedEx. All of the ECUs have been rebuilt, two with new housings, (they ALL had small cracks in them), tapes and lead wires and the driven element had a new housing and lead wire, the tape, (elements), were good. The control box has the new Automatic Lightning Protection Board and the latest version of software called "Mustang".

If so I should have it by Friday and can begin to start to reassemble the beam, connect all the wires at the beam and test the motors on the ground to make sure they are wired correctly and all work. There is a test mode built in to the controller that feeds out about 6" of tape on each motor as you test it. Once that is done the new fiberglass poles go on, I have all new poles, clamps and mounts and also a way to seal the open end of the pole but leave it open for moisture to be able to dissipate. I'll put fiberglass screen material over the end and cap them with plugs that have holes in them.

After that I can start to stand the tower up, it has to come up a little at a time so I can attach each "bottom" fiberglass pole element, and heat shrink the the joint as I expand them. With the beam fully assembled it sits at about a 45 degree angle. Then I stand it up close the ring and put the pins in the support fixture. I've got all new hardware. I reattach the rotor and, (with some help), take down the lifting fixture. The last part, (and what takes the longest), is to crank it up to the full height. That takes a couple of hours a few turns at a time. Depending on shipping I'm shooting for the 14th of June to be back on the air but it may be a day or so later. I hope to be on before the weekend.

I'm most curious to see how the new VHF and UHF antennas perform but unfortunately I'll be missing the ARRL VHF Contest this weekend to see. There is a 10-10 Spirit of 76 QSO party that runs the week of July 4 and it will be interesting to see if 10 opens and I get to check performance there.

Wish me luck!

Al - N1API
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#7

I got the ECUs and controller back today. I was a little confused when I opened the boxes because the ECUs were open and there was a cover and gasket included along with 25 feet of wire and some coax seal in the box with the controller.

It seems that they forgot to include the hardware to close the ECUs and also the instructions on how to wire them up. My old ones were prewired and closed.

They are going to zip me out the hardware kits and also an instruction sheet on how to wire them up. The lead wire sits in the groove along the radius of the housing.

A couple of pictures attached:

This is how they come in the box. The cover and gasket are not shown. The hardware should have been in the open space.
   

Here's a close up of the workings. You can see how the two tapes are feed from the reels out to the elements. Also a closer view of the terminal block and groove that the lead wires go to in order to feed out to the terminal box on the boom. This part is all new to me as all the old ECUs had gray housings and each one had about a 10 foot lead on it. If you look closely at the upper right hand corner of the photo those heavy copper wires go to the female "N" connector. where the coax attaches. I'll bet that heavy, (looks like ferrite), thing is a balun of some sort. The other ECUs don't have this and can be either the director or reflector. The actual motor that drives the reels is under the white plate.

   

Still shooting for the weekend to get back on the air.

Al

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#8

I have the ECUs all wired and the new control cable connected. The Coax is connected to the driven element. Basically the antenna it done with the exception of attaching the elements.

Tomorrow I will test the function of each motor. The test pushes out about 6" of cable from each ECU as you test it then reels it back in. Once this is done the fiberglass elements can be assembled and the tower started to be stood up.

Tomorrow is the shopping day so I expect to do this later in the morning. If anyone would like to come over and watch, I'd appreciate the company. If you have a 2 meter HT with you, you can watch as each ECU is tested and relay to me what you see. Would save me running up and down the stairs.

This is the part of the assembly I'm most anxious about if something is wrong there's a lot of checking that needs to be done to find the issue. But if it's all right then it's onward and upward, (literally)

Al
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#9
What time? I'm at work in the AM.
K1RCT - Rob
W1NRG Station Activities Manager
Home Email

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#10
(06-17-2016, 06:04 PM)KC1ACN Wrote: What time? I'm at work in the AM.

Well tomorrow, Saturday, I'll get out there in the morning. Somewhere between 9 and 10 AM and start to put the elements back on.

I got the ECUs tested today, (with some difficulty), as there is a bug in the new controller software that had me thinking there was a wiring problem, also I had to go up to Cable and Connectors and get a DB25 cable to test at the antenna itself. (I did not know that you have to be at the antenna when testing the motor so you can see what's happening or someone has to be there watching when you test). But the software bug in the test mode made me think that I did something wrong and I spent most of the afternoon checking my wiring and talking to SteppIR until they figured out what was wrong. And that the error is not there in the normal operate mode.

Will take me a day or so to get all the elements back on and all stood up and locked down. Once that is done I can take the lifting fixture off, (with help), and I'm, (finally), done!

Al
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