Daniel Gilbert is a solar expert who started solarguide.com to share his knowledge and experience with the world, helping people find ways of renewable energy for themselves or their families in any way they can! When he’s not blogging about these topics on off-grid power systems like how best spaced out your panels should be; you might find him spending time exploring new opportunities such as researching battery storage solutions - which could make electric cars more practical than ever before by giving drivers access even when there's no outlet nearby (or at least very few).

WQ4RP Lightning Protection System

Having witnessed firsthand what lightning can do to a completely unprotected station, I decided to do things differently when the time came to rebuild the Excalibur Site.

The following photo is from a lightning strike that entered the shack five years ago via a balanced feedline.  There was no grounding system in place, so the lightning energy flowed through a wall stud and an ARRL Antenna Handbook on the book shelf on its way to ground.  The wall stud burned almost completely through, and the thick handbook was turned to fine ash.  The building was subsequently dismantled.

lightning strike at AA4XX radio shack turns ARRL Antenna Handbook into powdery ash

 

How many of us have thought our equipment  was safe just because we disconnected the feed line(s) from the ATU and/or radio?

The lightning protection plan currently being implemented at WQ4RP is based on several months of research and consultation with experts on the subject of mitigating the damage to radio stations resulting from either nearby or direct lightning strikes.

The sobering news is that a serious level of lightning  protection necessitates the need for a comprehensive grounding system–unless you really think that a few feet of ground wire and one, or two, or a hand full of ground rods are going to provide an effective energy sink for several hundred (or possibly thousands ) of amps of lightning energy.

I contend that while it may not be possible to guarantee 100% immunity from a direct lightning strike to one’s tower, tower mounted antennas, typical backyard dipole, or associated feedline(s), it is entirely possible to substantially increase the odds that such a strike will have most of its energy dissipated in a protective ground system well before it has a chance to get into your shack or radio equipment.

This post is not intended to be an in depth treatise on the why and how of lightning protection for amateur radio stations, but rather a description of what steps the KnightLites at the WQ4RP Excalibur Site are taking to minimize the risk to people, the shack, and the antenna system.

Interested readers are encouraged to study the following links:

http://www.radio2way.net/Polyphaser%20Guide.pdf
http://www.w8ji.com/station_ground.htm                                                                                         http://www.bidstrup.com/w7ri-lightning-grounding-rfi.htm

For the Single Point Ground Entrance Panel WQ4RP, a panel was purchased from KF7P   (http://www.kf7p.com/KF7P/Welcome.html)   Chris, KF7P is providing a valuable service to the amateur radio community with his functional, beautifully crafted entrance panels and associated components.

The RG8x  feed line from the big 160M vertical is connected to an Alpha Delta TT3G5O Surge Suppressor.  The coax shield is connected to the large copper plate (thru a large bolt on the surge suppressor), which in turn provides a low inductance path through the ground strap to the ground rod. The TT3G50’s patented gas discharge chamber  will shunt potentially damaging lightning energy from the coax’s center conductor to ground.

Thanks to Alex KC4PHJ for his generous donation of four additional surge suppressors which will soon be installed on this panel.

KF7P SPE Panel

The ground strap from the entrance panel above terminates at the ground rod below.  The ground rod clamps for the copper strap are also manufactured by KF7P.

 

This grounding strap will be removed from this ground rod within the next few weeks and connected to a comprehensive grounding system.

SPE Panel Ground Rod

 

Several hundred feet of trenching was done the weekend of July 4th, using a rental trencher that could dig down to 36″.  The going was slow but steady, taking about nine hours to complete all the coarse work.  This included time to extricate the beast three times from soft dirt and rookie maneuvering on my part.  Thanks to a 4WD vehicle and a strong chain, the trencher was persuaded to rejoin terra firma all three times.

Excalibur Pulling Out Stuck Trencher

 

The goal of the trenching was to create three ground circles, or halos–one around the shack, one around the tower, and one around the 160M vertical.  Additionally, two long feed line/control line trenches were dug–one from the shack to the tower and the other from the shack to the 160M vertical.  The goal is to have all three halos bonded together to the single point entry panel at the shack so all three halos and associated feed line trenches are at the same potential during a lightning strike.  There will be no isolated grounds in this system.

Below is a photo of the ground halo around the tower.  The trench at 2 o’clock is for the feedlines, control, and power lines to the tower.

Excalibur Tower Ground Halo

 

A number of 8′ long copper clad ground rods (30) will be driven vertically 2′ below grade into the trenches, spaced 16 feet apart and bonded together (using cadwelds) with #4AWG solid copper ground wire.  This process will be highlighted in the next blog, as most of the cadwelds are on backorder for another week.

 

Below is a picture of the ground halo around the shack. The intersecting trench at 7 o’clock is 16′ long will provide additional grounding with an additional ground rod.

Excalibur Shack Ground Halo

 

I decided to invest in a used heavy duty hammer drill to drive the thirty ground rods.  The first test has been a complete success, as it took 30 seconds to drive this 8′ rod down three feet into rocky clay soil.  I then hit a big rock and leaned on the drill for 1 minute until the rock fractured and the rod easily completed its descent into the trench.

Excalibur Hammer Drill Ground Rod 15 sec

 

In case you are wondering which drill I’m using, it’s a Bosch Model 11311EVS with  an SDS MAX 5/8″ ground rod driver bit. This bit does not deform the top of the rod as it’s being hammered in.  Incidentally, the hammer drill absorbs most of the pounding, so the process is not too hard on my 64 year old bones.

Here’s the rod driven about 12″ below grade, with the original conical head undistorted.  I challenge anyone to do that with a sledge hammer.

Excalibur Hammer Drill Ground Rod Completely Sunk

 

Mid Summer is usually a dry period in central North Carolina, but numerous thunderstorms have visited this area over the past few weeks, with the trenches now filled with tadpoles.

 Excalibur muddy trench

At least the clay is thick enough that it is not flowing back into the trenches.  It will be a happy day when the trenches are filled with ground rods, ground wire, and coax!

Stay tuned for part 2, where we will be installing the ground rods and firing off the cadwelds.

72,  Paul  AA4XX

WQ4RP Shack Gets a New Floor

Many hours were spent deciding on which type of flooring would be best suited for the WQ4RP remote radio shack.

In the end, southern yellow pine 1″x 6″ lumber won out, as this is the same type of flooring I installed in my log home almost forty years ago, and I knew this type of flooring would send the message that you are now entering a special place.

The pine boards were installed over a red vapor barrier.  The vapor barrier limits the amount of moisture that can migrate into the shack from the ground.  The pine boards were just a few inches longer than the 12′ length of the building, so with a little trimming the installation went quickly.  This is not tongue and groove– I simply selected the straightest boards I could find at my local Home Depot Lumber Department and arranged the boards for minimal gapping.  This method worked out very well.

Excalibur SYP Flooring

 

It took about three hours to trim and lay out all the boards.  I allowed the loose flooring to acclimate a couple days before screwing each board into the floor joists.  Here’s the floor after the first sanding:

Excalibur Sanded Floor

 

After final sanding and puttying the screw holes, the floor was sealed with four coats of urethane based Spar varnish, which resulted in a beautiful protective finish that enhances the natural yellow pine color and texture.

I then turned my attention to the operating table.  Seeing how well the floor turned out, I decided to use the same lumber to build the operating table.  First a frame was built out of 2 x 4’s, which was secured to the wall studs.

Excalibur Operating Table Frame

 

I screwed the pine boards into the underlying support frame and used natural colored wood putty to cover the screw holes.  Here’s the finished product after final sanding and four layers of Spar varnish.

Excalibur Operating Table Completed

This floating table is roughly 32″D x 82″W and ended up being strong enough that I could put all my weight on the front edge without any flexing.

A couple shelves will be installed above the table as time permits.

BTW, I am not a carpenter.  If I can do this, anyone can!

In the next installment, we’ll share some of the current work that is going on at Excalibur regarding a comprehensive lightning protection grounding system that uses hundreds of feet of ground wire and thirty ground rods.

72 de Paul,  AA4XX

Excalibur II Site Improvements – Drywall

Since it has been several months since the last report on the rebuilding of the KnightLite’s QRP operating site WQ4RP, I wanted to share some of the things the KnightLites have been up to.

In April, Marty W4MY spearheaded the installation of drywall for the walls and ceiling of the shack.  Our Drywall Fest team consisted of Marty W4MY, Marc W4MPS, Chris AA4OO, Dick N4HAY, et moi AA4XX.

Excalibur Sheetrock 1

W4MPS (L) and W4MY (R) cutting drywall

It was quite exciting to see the shack’s transformation as new drywall sheets were installed.  The purple drywall was chosen because it is mold and mildew resistant.

Excalibur Sheetrock 2

Chris AA4OO (F) and Dick N4HAY (R) securing the drywall with screws

The fiberglass insulation had been installed in the walls a month prior to the drywall work.  AA4XX finished putting in the ceiling rafters and associated wiring and insulation a few days before the Sheetrock Fest.

Excalibur Sheetrock 3.JPG

AA4OO and N4HAY secure first drywall ceiling panel

W4MY took responsibility for mudding the joints and trimming the door and windows over the next two days.  Marty’s generous sharing of time and materials to complete this phase of the project is greatly appreciated.

Excalibur Sheetrock 4

Master Craftsman Marty, W4MY

Under Marty’s tutelege, AA4XX took responsibility for the sheetrock finish work–sanding, priming, and painting.  Our teams’ work turned out fabulously.  It really helped to be able to draw on each others talents for this project.

Excalibur Sheetrock 6

With our spiffy new interior walls and ceiling completed, the next logical question was,  OK, what about the flooring?

Stay tuned, as that will be covered in the next post.

CQWW160M CW Contest from KnightLite’s Excalibur QRP Antenna Site

Dick (N4HAY/ZS6RSH) and I decided to enter the CQWW160M CW Contest  as a multi-op,  meaning two or more operators share a single transmitter and callsign. As there is no QRP multi-op category for this contest, we would be competing with stations running KW amplifiers.

The advantages of running QRP multi-op is that we could both plan on getting some sleep during the long 5PM-8AM nite time shifts, we were working toward a common goal, and we could operate assisted mode.  

Our main goal was to have fun and to see how our newly constructed Excalibur 160M vertical would play.

Station WQ4RP

Station WQ4RP consisted of a Ten Tec Argonaut VI, running 5W output into the Excalibur vertical loop.  We used N1MM+ logger with a WinKeyer.

 

CQWW160 CW 2016 station

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Building a 160M Vertical Loop with Elevated Counterpoise

Initial Planning

Several years ago, I had the good fortune to be introduced to Gene Bowman, WB4MSG, at the Winston-Salem Hamfest.  I recognized Gene’s callsign because of his top place finishes in many contests.  I was particularly interested in what kind of antenna he used on Top Band.

Gene told me that if I had a few minutes, he would be glad to have me come by his house so I could see his antenna farm.  I was fascinated to learn that Gene had placed 1st Place QRP World during the recent CQWW160M SSB Contest with his 160M loop. Gene mentioned that a full write up of his 160M antenna appeared in Jan 2010 QST  (160 Meter Inverted Delta Loop by Charles Kluttz, W4TMR,  pp.40-41).

I built my own version of Charlie’s 160M loop shortly thereafter and was quite pleased with its performance.  The vertically polarized loop showed noticeable gain over my high 160M dipole for stations beyond my local area, and after a short while I found myself no longer using the dipole.

As a result of a severe lightning storm in August 2011, all my antennas were damaged to the extent that I had to start all over from scratch.  Fast forward to Jan 2016, it was high time to get back in the game. With the help of two local QRP friends Chris N4PBQ, and Dick N4HAY, plans were hatched to resurrect the Excalibur Antenna Farm, beginning with a Top Band antenna.  It was decided to rebuild a version of the W4TMR Vertical Loop.

 

N4PBQ digging hole for 160M support post

Chris, N4PBQ digging the hole for the support post

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Knightlites Excalibur Site Gets a New Radio Shack

A few months ago, Dick N4HAY, Richard N4PBQ, and I spent a number of hours cleaning up the remains of the original Excalibur radio shack, a site that has hosted many QRP events over the past ten years.   As some of you may recall, The original shack was substantially damaged by a direct lightning strike during the Fall of 2011.

Moving forward, we are pleased to report that a fairly large supply of building material was delivered to the KnightLite’s Excalibur antenna site on Jan 1, 2016.

 

Excalibur building materials delivered

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A QRP Odyssey to Portsmouth Island


Throughout my life, I have often felt the need to seek nature’s solitude.  When I was a young lad, I would walk a couple miles to my best friend’s house, and then we would continue walking to one of several farm ponds on the outskirts of our small town to do some fishing or to explore the surrounding woods.

Years later, I still find myself seeking quiet, out of the way spots, whether it be deep in the woods, along a riverbank, or at the sea coast.

I invite you to return with me to one of those special places, Cedar Island, which I first visited in 2003, and have later returned to several times.

 

Cedar Island Sign

 

Cedar Island is easy to find.  You take NC Hwy 12 East until the road dead ends at the Pamlico Sound.  As you approach Cedar Island, you will see vast areas covered with sawgrass and narrow waterways.

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