Mostly Done

The tower is now mostly done.

The HF antenna is up, as are the 2m and 70cm yagis.  The rotor is installed, and rotates.  Mostly. There’s a tree in the way of the HF beam, so it can’t rotate.  I have a guy with a boom truck coming to fix that little issue. I still have coax runs down the tower to make.  And install some 3″ conduit for the coax entry.  And the lightning protection box.  And build a rotor protector.  Polyphaser wants entirely too much money for theirs.

I had planned to run the conduit today, and mount the box for the lightning protectors, but I got called to go to work instead.  Since work pays the bills, and it should be overtime, I’m not complaining.

I came up with a simple system for grounding the antenna coax at the bottom of the tower.  I’ll be working on that a bit more to get it perfected, then I’ll post some info and pictures when I actually get to that stage on the tower.

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Tower Grounding

Here's a brief summary of the grounding on my tower as it stands today.  It's not perfect, it's not even ideal.  It's a major compromise.

I ran a 2" copper strap from one tower leg to a ground rod about 20' away.  The strap is buried underground, but only about 4 inches deep.  The reason it is so shallow is due to limestone being 6" below grade.  The ground rod is a standard 5/8" diameter copper clad rod, 8 feet long, made by Erico.  The connection to the tower is a #2 copper wire pigtail that was brazed to the strap with Harris Stay-Silv 5 brazing rod, the wire is then clamped to a tower leg with a bronze ground clamp.  I purchased the brazing rod at a local welding supply house.  The connection to the ground rod uses a similar pigtail, which is then Cad-Welded to the ground rod using a "One-Shot" purchased from Tessco.

A second ground wire is connected to the tower the same way, then the strap runs to a ground rod, connected with another pigtail.  The strap continues on and will eventually be connected to the single point ground for the coax entry panel, which is still a work in progress.  There just hasn't been enough time…

My main electrical service is grounded, again via a #2 copper wire, to an existing 8' ground rod at the electrical meter.  There I have a 4-way Cad-Weld One Shot, with a #6 wire running to another ground rod for the telco ground, a #6 going to yet another ground rod, and a #2 going to the ground rod mentioned in the previous paragraph, this wire provides the REQUIRED bonding connection between all the services and the tower.  It can not be stated enough that this connection is extremely important.  Do not skip the bonding step.

The electrical service panel is protected with an LEA whole-house surge protector.  The telephone line has secondary protection after it enters the house, just inches from my electrical panel.  I'm using Polyphaser IS-MPT-200 protectors.  I like these because they are cheap, and they seem to work very well. [edited to add: I've been told these are no longer available]  I have a small punch-down block for the phone lines so these work nicely for me.  I'm using two because my voice and ADSL come into the house on separate pairs, with a telco provided splitter at the network interface device. All coax will be protected by Polyphaser units, and I'm looking for a suitable rotor protector.  Polyphaser makes one, but its rather pricey at around $150, half the price of the entire rotor!  ICE also makes one, but I haven't bit the bullet and ordered one yet.

At some point, I'll draw a picture of all of this so it makes more sense.

One additional thing I did was to have my entire re-bar cage welded together, and welded to the anchor bolts for the tower.  In the event of a lightning strike, their will be no opportunity for arcing inside the concrete foundation.  This also allows the foundation to act as a "Ufer Ground".

There will be more to be said about lightning protection later on.

Stacking Tower

I'm way behind on updating here.. The tower itself is up.

Homebrew Ginpole

I home brewed my ginpole using an actual gin pole head I bought on ebay.  I added a 10 foot section of 1" galvanized pipe.  I didn't buy any brackets, so I used u-bolts to attach it to the tower.  Not recommended.  And I would much prefer about 12' of 6061-T6 aluminum pipe to the galvanized. goinupgoinup2

I still don't have my house bracket built.  I'm hoping the tower is a bit sturdier once I do. I'm waiting on parts from Cushcraft for the A3S, it sounds like they should be shipping early next week.  My mast pipe has arrived.  I wanted a seven foot pipe, and the 1 5/8" galvanized pipe I had is very heavy and would be a real pain to get up the tower.  I opted for a seven foot piece of Schedule 80 6061-T6 extruded pipe.  I found a very reasonable price for it, around $40, and was able to get a couple pieces of brass from the same supplier.  More on those in a future post.

So at this point I'm ready to install the rotor and mast, and the 2m beam.  The grounding is substantially complete, or as complete as it will get at this time considering that I'm way over my allotted budget for this project.  I think it will be "good enough", although it is certainly not ideal, but considering the rock it's hard to get an ideal grounding system installed.  I found some major issues with my current grounding that were fixed.  I'll post more about the grounding in the future. Hopefully I'll get that house bracket built this weekend.

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Tower Construction – Part 3

Just a few more updates.

Tower Base Bottom 10 Foot Section Two sections after a coat of Cold Galvanizing Compound The Cedar Rapids Hamfest is Sunday.  I will be on the lookout for a nice 2m Yagi to use on SSB. Tomorrow I will be working on tower grounding.

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Tower Construction – Part 2

Some photos this time around.

To build a tower you have to dig a hole.  A pretty good sized one.  In my case a minimum of 30" square and 48 inches deep.  No problem.  In normal soil.

I don't live on "normal soil".  Our neighborhood is notorious for limestone.  Even the electric utility had issues bringing in power due to all the rock in the ground.  There's rumors that basements were dug with the help of dynamite.  I don't know about that, but what I do know is that I ran into my fair share of limestone.  It starts about 6" below the topsoil.  And it stops, well, I don't know where it stops.  I can't dig that far.  But I'm guessing it goes down a long ways since there is a quarry about 1/4 mile east of us.

Needless to say it took me awhile to dig that hole.  And in the end I rented a jack hammer to help me get through all that rock.

t2

Just a few of the rocks I dug out.

I ended up making it to 48".  I originally wanted to go 60" pretty badly, but after all that rock I'd had enough.  That and finding a place to get rid of all that rock.

The Rohn tower book says that the concrete base should be 6" above grade.  Or maybe it says 4" above grade.  I don't really remember.  Many hams leave the concrete several inches below grade, their thought process being that when they take the tower down they can just dump some soil there and plant grass.  Good in theory.  My concern was water, more specifically, rust.  I don't like rusty towers.  By keeping the base above grade I'm hoping to avoid any rust on the base of the tower.

t3

So here's the hole, and a 2×6 form to square it up.

t5

We added a welded rebar cage, and the J-bolts for the base plate.  And of course, the concrete.

t7

Robert (I didn't catch his call), Jay (KC0AKJ), and Cliffy (KC0RFN) mixed concrete.

t8

I had the easy job, driving the concrete buggy!  Best $75 ever spent.  Pushing wheelbarrows of concrete uphill would not have been fun.

t10

And here we are, 3500 pounds of concrete mix later.

I'm a bit slow at getting the pictures posted, it's been nearly two weeks since these were taken, so I'm a little bit further along than this.  More to come.

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The Shack

hamshack1

I just realized that there are no pictures of the shack on the site. The shack is very small.  We don’t have much usable space in the basement, so it was a challenge to set up an area for radios.  It was decided to carve out an area just over 6′ by 6′ in one corner. I built a couple of walls, installed a new ceiling, new carpet, and plenty of electrical.  I squeezed in kitchen countertops on two walls, installed some shelving, and utilized 5′ of wall cabinets that were already there. It’s not much space, but it seems to work out pretty well.

shack-clean

The biggest problem is keeping it clean.

My other “shack” is in my Blazer. There I have a Yaesu FT-7800 Dual Band, and a Radio Shack HTX-10 10m all-mode mobile.  Working 10m mobile is a lot of fun.

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Tower Construction – Part 1

hole

Here is the latest on the new tower. So far I have acquired:

  • 40' of Rohn 25 tower
  • The concrete base plate
  • A Rohn heavy duty house bracket (which needed some modifications)
  • galvanized concrete anchor bolts
  • new Rohn hot-dipped galvanized leg bolts

And so the digging of the foundation has begun.  And it's been an uphill battle due to the property being situated on top of solid limestone.

The foundation will be approx 30 inches square, and four to five feet deep, depending on how hard it is to dig the rock once I hit the 4 foot level. You can see behind me next to the house some of the big chunks of rock that I've broken up and pulled out of the hole.  Good times.  Most of the rock is breaking into baseball sized pieces. There was about six inches of top soil over the rock.  This may explain why my lawn dries out so quickly in the summer.

This past weekend I visited KA0ZOZ and acquired a used Cushcraft A3 tri-band beam, a Yaesu G-800SA rotor with 60+ feet of rotor cable, and a Kenwood TS-711A 2m all-mode radio.  This has me even more fired up to get the hole dug!  I still need to find a 2m yagi to use for SSB, and a bunch of coax.  I'm thinking the Cedar Rapids Hamfest next month will be a good place to look.

I have a feeling the worst may be yet to come.  I need to find a way to drive a few more ground rods, and trench in some wire between them and the single point ground bus bar at the coax entrance.  I also plan to utilize a 'ufer' ground by having the rebar welded into a cage and bonding it to the tower legs.

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Meteohub

I’ve been working with some nice software called Meteohub to interface a Peet Bros Ultimeter 2100 to the Internet.  Meteohub was originally written to run on a Linksys NSLU2 NAS device, to provide a low power, low cost, very small form factor device. It’s a great concept, and works great, when it works.

The problem I experienced was that stability and reliability was poor, at best.  It started out great, and the box ran flawlessly for a month or more, until the power went out. Then it wouldn’t reboot.  After a couple of attempts it started up and ran fine.  For a week.  Then another week.  Then nothing.

I found that the USB flash drive had stopped working.  Apparently a common problem, as flash memory is of variable quality, especially the mass retailer variety USB thumb drives, that generally aren’t designed for 24×7 operation with software continuously writing to them.

Meteohub has several other “approved” hardware options, but most were more money than I wanted to spend, and required ordering from companies I’d never dealt with, and didn’t really seem to be setup to deal with selling in small quantities to customers.  So my search has begun to find a more reliable platform to run on

Which brings me to where I am now.  An HP Compaq device, originally intended to be a “Thin Client” device on a LAN.  No fans, no hard drives.  Reasonably small, much smaller than a PC, but larger than the NSLU2 devices.  Mine is about 9 inches tall, 8 inches deep, and 2.5 inches wide.  It has an external 24W power supply, so energy consumption is low (I have not yet measured it on my Kill-a-Watt).  It has a LAN port, 4 USB ports, an RS232 port, and even has keyboard and VGA ports, which will help when initially setting the device up.  These units are available in different configurations, memory size, CPU, etc.

Mine had a smallish IDE Flash memory drive in it.  I don’t recall the size, but it was in the MegaByte range, and I need about 4GB of space for MeteoHub to be happiest.  My plan is to pull out the included Flash drive and install a Compact Flash memory card in it’s place.  I found the needed adapter and cable on eBay for a few dollars.

I haven’t yet powered the system up, but I hope to be able to do that soon and see how it works out.  With a little luck I’ll have the Independence weather station reporting into the Weather Underground site again within a couple of days.

Edit to add:  This system worked out great, until the fire station was struck by lightning and killed the power supply and ethernet ports.  I’ve never replaced that system, but since I was given a Davis Vantage Pro station to install at the home QTH I built another Meteohub box from an older Mini-ITX motherboard, and an IDE to CF adapter.  Works great.

Update: March 1, 2021. For at least the past year I’ve been using a Raspberry Pi running WeeWx to upload my data. It seemed as though development of Meteohub and stopped, and WeeWx is well supported but a bit more of a learning curve to setup.

I have some tower sections

I now have three 10 foot sections of Rohn 25G tower sitting in my yard. I hope to get started soon getting that thing up in the air.

I still need a 36″ house bracket. Rohn gets $249.00 plus freight for their heavy duty “universal” model which supports both Rohn 25 and 45 (more on that to come). I think I’ll check to see if the local welding shop can make me one. Of course Rohn leaves most of the dimension out of their engineering drawings, but maybe they can figure it out.

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