World’s Largest SteppIR array

This is a fairly interesting presentation about an array of 6 4 element SteppIR antennas at K9LTN.  Check it out here.

Rohn Catalog Online

From a query on TowerTalk today, I did some searching for an online version of the ROHN tower catalog.  Found one here in PDF format.

Blog and Website work

Just got the blog setup today, and so I’ve added some older content that was on my webpage.  We’ll see how this format works for me, but I think it will work out OK.  It is also good for me to get to know WordPress, since we have a website at work that uses WordPress.  Seems to work pretty well for what I need.  We’ll see how things pan out as I add more content and start adding pictures.

Nothing radio related tonight.  Too much website work.

This years station upgrade plans

This summer I plan on making some changes and upgrades to the station to enhance my so2r operating.

First I’m going to make my “temporary” tower I put up in the fall more permanent. The tower is currently 30 feet of Universal Tower aluminum tower that sits on a temporary base. This base section was custom made by Universal by taking one of their flat roof mounts and adding 4 spikes on the bottom so it could be pounded into the ground. This has worked well, however it requires several people to raise/lower the tower due to the base. The plan is to purchase another flat roof mount and modify it to serve as a permanent base. The Universal Tower base sections are all designed to provide enough support for the tower to be self supporting. I don’t have this need in my situation, so I don’t need or want as large a base. The plan is to put 12″ or 18″ threaded rods through the mounting holes in the flat roof mount and bend the bottom end into an L or J to provide some grip in the concrete. Then I’ll use that mounted in about a 2′ x 2′ x 2′ base as the base for the tower. This should provide more than enough base support to more easily raise/lower the tower with my current falling boom setup.

Another project is to add a 40M wire rotatable dipole to my tower. This would be accomplished by adding 16 foot fiberglass poles to each end of the C3S boom, (adding about 12 feet on each end) making 36 feet available to support a dipole. The dipole would be supported at the top of the mast (which is about 4 feet above the C3S), then run out to the ends of the fiberglass poles. The remainder of the antenna (about 14 feet) would drop straight down. I don’t have a NEC model of a c3s (although I may try to put one together), however over a 2 element 15M yagi, the dipole and yagi do not seem to have much interaction, which is where you might expect the problem to be.

This year has been my first year of more serious SO2R contesting. One major thing I realized is that I need a better 2nd antenna for 10/15/20M. Currently I have a 20/40m dipole that is my 2nd antenna for the high bands. If I need to be on 15 and 20, then 20 gets the dipole. This is not a satisfactory solution. I’ve tossed around the idea of replacing the C3S with a quad and feeding each band independently, however I have the ability to put up a 2nd very small beam on the back of the house. I currently have a Cushcraft MA5B that I plan to modify to be a 10/15M 2 element beam. The MA5B has both capacitive and inductive loading so the elements are physically short. This provides a nice compact antenna, but I’ve affectionately referred to it in the past as a directional dummy load. The antenna has capacity hats between the boom and the 10/15m trap assembelies. While it is clear that the trap assemblies have some inductive loading built into them (the 10/15m trap is one unit, where typically there is some space needed between the 10 and 15 meter traps to make the element resonant on 15M), it would seem that the internal capacity hat could be replaced with an appropriate length of aluminum tubing. This would mean that the antenna would be a full size 2 element beam on 10M, and have only a small amount of inductive loading on 15M. My theory is that the antenna will preform better in this configuration than with the capacity hats in place. We’ll see this summer.

I also want to add a real bulkhead entrance of some kind where the coax enters the house. Currently the coax comes through a basement window, and the window is closed as tightly as possible with some foam insulation to make up the difference. The coax lines then run to my somewhat homebrewed 2×5 switch matrix which is just inside the window. This is not ideal on many levels (cold air getting in, occasional water problems, lightning protection, etc.). I’d like to replace one pane of glass on the window with an aluminum sheet and for now place bulkhead connectors to bring the coax into the house (eventually these will be replaced with bulkhead mount lightning arrestors). Then I’d like to bring the 2×5 switch closer or into the shack, so that it is more easily accessible.

Another reason for moving the switches is to get the closer to the amplifiers. Eventually I will need to add some stubs for certain bands to attenuate out of band harmonics that interfere with the other station. From what I’ve read, the closer these are to the transmitter, the better.

Watch here for updates on the progress of these projects, including photos.

73 de Al, KE1FO