5 Banding the 20m 1/4 wave Junk Pile Vertical

One nice  spring day in 2019, my grandson and I went outside for a walk around the property.  I happened to notice a piece of aluminum tubing I had lying beside a shed.  On further investigation I realized it was half of a 20m beam element that another ham had left behind after a field day.  It had been a half wave dipole for the event and he told me to just keep it.

I asked my grandson, 6yr old at the time if I remember correctly, if he would like to help me build an antenna.  His reply was a curious, "What's an antenna papa?".  So, we had the unforgettable experience of building a ground mounted 1/4 wave 20m vertical together.

A few days ago I got the idea to add more bands to this antenna.  I did some digging around and found some wire, purchased a few pvc fittings and hose clamps, and started putting additional 1/4 wave elements for 17m, 15m, 12m, and 10m.  I know, some of those bands are going to be very inefficient ground mounted, but what the heck, it's amatuer radio, not professional.

The first thing to do was cut the fittings in half and glue pieces of pipe in and drill holes for the wire to pass through.

I then clamped four standoffs around the bottom just above where to main 20m element is clamped to the support pipe. The black mark on the tube is the top of the support pipe for mine.

 

I used a large eyelet to combine all the wire ends for the elements to allow connection to the base of the center aluminum tubing for 20m.

A bolt and wingnut through a hole drilled in the aluminum tube allow connection of the additional wire elements.

Thread the wires through the holes in the standoffs and attach with another standoff at the top,  by tightening the bottom clamp of the top stand off fist then the top just enough tension can be put on the wires to hold them straight so they don't move too much in the wind.  Don't try to get too much tension.  I used salvaged 14awg solid copper I had in the junk pile, if you fasten one end to something solid and grab the other end with pliers and give a couple good stout tugs, the wire will stretch and straighten nicely.  Do this before cutting to the needed lengths for the elements, don't forget to cut longer and prune down. Use 234/f MHz to get your length in feet.

Below is the feed point connection to the vertical.  I currently do not have a BALUN or choke, but would like to get some toroids and wind one for this antenna.

 

This isn't the most efficient antenna, but the cost to performance ratio is rather good.  With only 8 radials directly on the ground, I could improve efficiency with another 8.  I simply lay the wires out on the ground and use landscaping staples to hold the wire down and let the grass grow up over them.  This way I can mow near the base.  I use a broad spectrum herbicide to keep the area where the radials and coax come up to the base so no trimming is needed with a string trimmer that would cut the radial wires.

I haven't had the opportunity to show the modifications to my grandson yet, but he does enjoy listening to me on the air and hearing me tell about working different places around the world.  I get to teach geography and radio by showing him where on maps or Google Earth I have worked, and explaining how the antenna works and how the radio waves propagate around the globe.

Performance report:

The additional bands were added to play on FT-8, a mode I had relegated to useless due to descriptions of how it operated.  I decided it wasn't fair to dismiss it until I had actually used it.  So, I downloaded WSJTx and played a bit on 20m.  I still have mixed feelings about the mode, but I could see it develope into a means to actually send useful messages, more than a SNR report and grid.  I digress from the intent of the this update.....

I have worked the following with the 5 band ground mounted vertical:

eQSL confirmed contacts: 1/7/2023 to 1/17/2023

10m    35         Japan, New Zealand, South, Africa, Isreal, Trinidad & Tobago, etc.

12m    8           Czech, Rep., Russia, Bosnia-Herzegovina, Serbia, France

15m    1

17m    104       Antarctica, Most of EU, Estonia, Denmark, Germany, etc., Panama

20m    221       All over the world, 20 just works.

 

So, to be fair, I didn't spend much time on 15m as you see by the one contact.  That band just wasn't open here for me.  I don't think that was due to the antenna as the PSK Reporter network didn't have as many reports as the other bands.

For a ground mounted vertical with only 8 radials under it, I am very pleased with the results.  The next step will be to add a current choke and more radials!