BigIR installation

This really turned into being less of a project than I expected. I had really planned on this being stretched over a period of about two weeks but actually fell together in about 3 days.


Trench cut with Stihl

My installation was a little more complicated by the fact I was installing the BigIR about 140′ away from the house and burying the control cable and coax. So this required a trench along with cable that was direct bury rated.

Some people feel it’s adequate to install regular coax and control cable inside a sleeve like hose or PVC piping. It might be fine however any project I have ever had involving buried pipe ends up with water/condensate, etc in it regardless of how well it is sealed. So unless I have a place for it to run down hill and drain I avoid this method.

Ground Rod

Ground Rod

That said it took a couple hours to make a 4″ deep trench to install the cable. I just used my Stihl mini cultivator to do the work. It basically has four star wheels on it and I removed all but one wheel to make the trench (see gallery at bottom of page).  I used a claw hammer to clean out the new trench and dropped the two cables (8 wire control and Davis Bury Flex) in and covered them with dirt moving towards the house  in 4 foot increments.

1/8" Dacron rope for guys

1/8″ Dacron rope for guys

Next I dug a 4′ deep hole with the help of my cousins power post hole digger. It took longer to get it out of the back of truck than to dig the hole.  The BigIR supplied mounting pipe is only 24″ long. You end up with about 8″ of pipe sticking out of the concrete so that means you only have about 16″ of tube in the concrete.  I added a non structural tube from the bottom of the

Stainless guy bolt in trees at about 12'

Stainless guy bolt in trees at about 12′

supplied tube to a bed of gravel in the bottom of the hole for drainage purposes and to help hold the height of the tube in the concrete.  In retrospect and if I had to do it over again I would have installed a schedule 40 steel heavy wall pipe that telescoped with the other one.

Although ground rods are not supposed to help with RF ground I installed a 8′ copper clad rod with a 1″ wide strap and 2 clamps to provide a good electrical ground.

Outside Junction box

Outside Junction box

The BigIR is rated for 50 mph winds without guys and 70mph with one set of guys. Where my antenna is located I doubt it will ever see 50mph winds but once elevated it just didn’t “feel” right so I opted for one set of guys. I used 1/8″ Dacron attached to stainless steel eye-bolts in the trees.


Terminal Strip

The BigIR requires 4 wires for the antenna control and an additional 4 for the 80 meter add-on kit.  I added a box below my balun and run the buried cable up into the box and made connections (solder and shrink wrap) to the two 4 wire cables going to the SteppIR.

Radials ready to go with ring terminals soldered on.

Radials ready to go with ring terminals soldered on.

Inside the shack I screwed a terminal strip to the bottom of the bench and attached the bury cable to one side and a more flexible rotor cable to run to the SteppIR SDA 100 controller. You will note I have several white wires going to a single connector. This is because I used tel-co burial cable with “pairs” and I terminated them all to the same connector to avoid confusion and possible RF issues.

6" staples to hold down wire until grass grows up and round.

6″ staples to hold down wire until grass grows up and round.

As I mentioned previously I decided on sixty radials 60′ long.  I have read that ground radials only help on transmit. I am not going to argue this as I am not qualified.

However, I ran two days without radials and did hundreds of A-B test in 1/4 and 3/4 wavelength mode comparing it to my 270′ long balanced line fed antenna tuning both antennas before comparison and I would swear the radials helped my receive after adding them.  Might have been better signal to noise ratio or something but it did seem to make a better receive antenna. At least for me 🙂

Soldered Ring Terminals

Soldered Ring Terminals

On my AutoCAD drawing I calculated there are 74″ between the outer tips of the radials (at 60′) to make a proper fan and get 60 radials.

So I started at  DX engineering ground plate and starting working outward 2 radials at a time. Stapling inside my trench around antenna and  then at far end to hold it straight and then of course all the staples in between. I bought 1000 staples and still have a few to add.

Below is a gallery of installation pictures including some additional ones not shown above.



Dry fit of radial plate for strap length
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General BigIR

BigIR assembly

How does it perform?