Tag Archives: K9AY antenna

Antenna Update

We are rapidly approaching June and grass cutting season is in earnest here in Wisconsin. We are over 3 inches ahead on rainfall this year and while we’ve had below average temperatures for the most part the grass hasn’t noticed.

It’s only been 6 months since I completed laying the thirty 30 foot radials for my 4BTV and they have already largely disappeared into the grass.

Where are the radials?

November 2016

To be fair, we delayed cutting the grass in the area that contains the radials until yesterday in order to give the grass a nice growth run. My XYL cut the area without incident. No radials wrapped around the mower deck! To insure an event-free experience I used approximately 500 landscape staples. That’s about one staple every two feet for each of thirty radials. Maybe a wee bit of overkill but worth it in the face of pulling the mower deck to undo tightly wound radials.

The last thing that I added to the 4BTV late in the fall was DX Engineering’s reinforced lower tube. It was extraordinarily windy late last fall and I don’t have any guys on the 4BTV. Additionally, it is located in an area of the yard that directly faces the prevailing winds with a long unimpeded run across a large farm field so it takes the brunt of the wind. The base tube withstood a lot and in all likelihood would have been fine but I didn’t want to be out there changing a bent antenna tube in January so the reinforced lower tube was cheap insurance.

The K9AY worked very well this past winter and there were no issues with winter winds. It is now in the folded position for yard and garden season.

K9AY Folded

It neatly folds up into a space of maybe two square feet providing plenty of room for my lovely XYL and her antenna killing machines to drive about in pursuit of all manner of lawn and garden care.

XYL and new antenna mangler

The lawn tractor was enough of an antenna menace. Now she has a Honda Rancher with which to inflict damage to my ground mounted antennas! Tomorrow is our 29th Wedding Anniversary so she’s a keeper. We’ll see about the ATV. : )

 

 

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K9AY Complete

Today I finished running the cables for the K9AY down to my shack so my station is now fully operational with a receive only antenna.

K9AY

K9AY antenna

K9AY wire highlight

K9AY antenna wires highlighted

The yellow dashed lines highlight the Northeast\Southwest loop and the red dashed lines highlight the Northwest\Southeast loop.

K9AY base detail

K9AY base detail

Operator actual size

Operator actual size

In the spring I’ll spray paint the arms some combination of brown and green so that they blend in better as opposed to the lovely gray that they are now. The arms are the only part that you can see from the house. Once they are painted the antenna will be reasonably stealthy, to the degree that an antenna comprising a 24 foot pole with two loops of 85 feet of wire supported by four 16 foot arms over a circular area 30 feet in diameter can be called stealthy.

You know what I’m going to be doing all winter.

 

K9AY Update

It’s been a busy few weeks of growing antennas before the onset of winter, which actually is officially antenna season. No one works on antennas when it’s warm and dry. Antenna work is supposed to be done when it’s cold, wet, and hopefully snowing. I admit to being non-compliant to this long standing tradition.

All of the mechanical and electrical work is complete for the antenna. In order to enable folding I elected to forego the multi-conductor connector for the antenna legs and borrowed an idea from Andrew, VK1AD and his linked dipole design and chose to use bullet connectors. a carabiner, and a slightly modified plastic electric fence egg insulator for each leg of the antenna. The carabiners and egg insulators aren’t as nice as Andrew’s sister clips but they’ll do for now.

Mechanical and electrical leg connections

Mechanical and electrical leg connections

Next was the task of getting the cables back to the house. It’s a run of about 250 feet which is way more than I was going to dig with a shovel. I rented a self-propelled bed edger that has an attachment for trenching dog fencing wire and ran a trench from the antenna location back to the house.  The trencher worked great and made a nice 5-6″ deep trench.

Trench

Trench

I laid the control cable and the feedline next to the trench and worked out all of the coils so that they both lay nice and flat in order to drop them cleanly into the trench. With the cables in the trench I completed the electrical connections at the antenna.

The cables for the antennas enter through a port on a workshop portion of our garage. From there they will make their way to my shack in the house. It was late in the day when all of this work was complete and I wasn’t going to have time to get the cables to the radio but I could get the radio to the cables. I hauled by TS-590SG up to the workshop, connected the K9AY control box to the control line and feedline from the antenna, and then connected the output to the radio, and lo and behold IT WORKS! I sat out in the workshop as the sun was setting and tested with stations on 40m, 80m, and 160m in addition to DX-ing AM broadcast stations from all across the country. The switching works fantastic! It’s really cool to be able to electrically rotate the antenna to hone in on a signal.

Thus far I am very pleased with the results but there’s still more work to do. I need to properly terminate the cables from the antenna in the workshop and make the runs to the shack. Once this is complete the K9AY will be a very useful tool as winter closes in and the low bands open up.

As I was DX-ing the AM broadcast stations I was reminded of Jean Shepherd and a few of the shows (for example, 1971 02 xx DX Ham Radio CW)  in which he talked about his dad and his old receiver. Imagine if he would have had a K9AY!

 

K9AY progress

This all started back in June when Gary, W9XT (Unified Microsystems) gave a presentation at the Wisconsin Amateur Radio club meeting about some updates that he recently made to his K9AY antenna . At the time I didn’t have a radio with a separate receive antenna input so while interesting I filed it away as something to build at another time. But that changed in July when I obtained my TS-590SG. Now my gears starting whirring.  The planning started in earnest. The first problem to solve was location. Where could I put a K9AY antenna such that it wouldn’t be bothered? While we have enough room it’s still a 30 foot diameter circle of antenna space and I didn’t want it to be disturbed by lawn tractors, ATVs, snowmobiles, dirt bikes, etc. Was there some means by which to create a smaller footprint?

As I was reading the original K9AY article in the September 1997 issue of QST the part that added to the footprint problem for an original\standard implementation were the support ropes that essentially create the loops. These two supports make a 30 foot diameter circle more like 40 feet in reality. That’s moving the footprint in the wrong direction. What if the supports could be moved to the inside of the circle? As I was doodling the shape of the loop, dividing it into the four right triangles that comprise it, and working out the lengths of the legs and the angles the shared leg of the bottom and top triangles emerged. (Sorry, I’m an engineer…I figure if Pythagoras went through the trouble to sort out the math the least we can do is use it whenever possible if for no other reason than to check his work.) What if the shared leg could be a support of some kind? This would certainly help to solve the footprint problem.

The shared leg

The shared leg

This led to some more conceptual drawings ultimately resulting in this design:

K9AY design

K9AY design

And once the supports were on the inside of the circle the next logical improvement was to hinge them in some manner such that they could be moved upward out of the way of any number of wheeled conveyances if needed.

K9AY support arms detail

K9AY support arms detail

With this design the diameter of the antenna circle was 30 feet, not more and could be substantially reduced if necessary to a few feet.

With the design in hand the next step was a design review and site choice meeting with my XYL. After some hemming and hawing a suitable location was agreed upon and construction began. Thankfully I have two strong sons, my youngest, Ben, manning the post hole digger to make the hole for the 4×4 post that would form the base of the antenna.

Ben

Ben and the base

The base was placed in the hole accompanied by a bag of Quikrete. The next step was to build the arm holders which were constructed from 2×8 treated lumber.

Arm supports

Arm supports

The next step was to bolt in the arm supports, constructed of 2×4 treated lumber.

Base complete

Base complete

I considered a few different materials for the support arms including Crappie fishing poles but in the end settled on schedule 40 PVC conduit mostly because it’s readily available and very inexpensive. If it doesn’t work for some reason I’ll update the arms to some other (better?) material.

Support arms attached

Support arms attached

I did not want the antenna wire to bear all of the weight of the arms so support ropes were needed. I constructed an attachment plate out of Kydex to fit at the joint of the mast pieces to provide a place to attach the support ropes to the mast.

Arm support rope attachment plate

Arm support rope attachment plate

And likewise another Kydex plate was constructed for the top to provide a place to attach guy ropes and the top supports for the antenna wires.

Top support

Top support

Given that the support mast is 24 feet tall all of the arm support ropes, guy ropes, and antenna wires had to be assembled and attached before erecting the mast. This creates a considerable amount of spaghetti on the ground but with some proper management and the help of my older son, Dominic (W9KKX) the mast was erected. The mast guy ropes are attached to some nearby trees in locations high enough such that they don’t reach the ground and allow the antenna support arms to fold inward unobstructed.

Obviously to support folding, either the antenna wire has to move along the ends of the arms or I have to detach the antenna wire from the base. I’ve chosen to use a waterproof multiconductor plug to enable quick detachment of the antenna wires from the K9AY control box that will be located at the base of the antenna.

K9AY

K9AY

The day was drawing to a close. As I was orienting the antenna wires and attaching the arm support ropes and the guy ropes the first owl of the evening started to hoot, sounding the end of the work day. The majority of the mechanical work is complete. I need to place the antenna wires in the ends of the arms and then begin the electrical work. Thus far the design seems to be working out largely as planned. We’ll see how it holds up through the Winter. I can’t wait to “hear” this new antenna.