How to build a wine bottle antenna for 40m

WARNING THIS ANTENNA WILL PRESENT VERY HIGH VOLTAGES WHEN IN USE


I found this diagram online and felt compelled to build it.




I gathered up the junk I needed to build it. Not pictured was an air-capacitor that I took from a broadcast band receiver.




I used JB-Weld Brand superglue gel to assemble the bottles. It is made specifically for glass.



I had to trim the cap hat with shears to center the frequency at 7074. If I cut more off, it would center at a higher frequency. My thinking is that I can use this on FT8 without a tuner, and I can use my radio's built-in tuner to use the voice bands.






I was able to make a voice contact at 100w SSB and FT8 at 25w. I think it would take more power, but I would have to change the BNC connecter to something more robust.

PSK report from making one contact.

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[KK1LL]

 

[KK1LL]

 

[KK1LL]

I just realized that the matching network was not connected to the bottle in the first set of pics.
Here is a better angle of the completed matching network.
(The alligator clip is my grounding wire.)

 

[KK1LL]

 

[KK1LL]

Takeaways from this project....

1. Cover all exposed glass with painters tape before gluing. The drying glue's fumes leave a chalky residue all over the glass.
2. Use a more robust connector and air-cap to handle higher wattage. I was thinking about using an N connector and a vacuum-cap to try to go up to 1200w.
3. When tuning the antenna, even your body will cause interference. Make sure you tune it where you are going to use it, and move back when reading your VNA to see if you are influencing it.
4. One man's trash is another man's antenna. Horde all the Christmas-tin garbage no matter what the wife says. Tell her its for science.

 

[KK1LL]

I used all my "takeaways" from above and built a high-power version.

Test and tune tomorrow. (Once the glue sets 100%)

 

[W4LOU]

There's going to be high voltage on this thing so don't shower with it while transmitting

 

[KK1LL]

I made this adjustable cap-hat so I can tune the whole 40m band.

I have marked where to overlap the plates for different frequencies I use.

 

[KK1LL]

20w WSPR

 

[KK1LL]

2W Stats

 

[KK1LL]

I made QSOs at 1000w today !!!!

 

[KK1LL]

I am calling this the final version of my 40m take on the 20m VA3IUL wine bottle antenna.

I find that the capacitor value could be fixed if the top hat was tunable.

This allowed me to put 2 15,000v doorknob caps in series instead of the air variable cap.

With an exceptional ground, I can tune approx 6mhz to 8mhz up to 1000w SSB 300w Digital (Tested) and maybe more.

With no ground at all I can tune approx 7mhz to 9mhz up to 25w SSB and 7w Digital (Tested)
Exceeding these power levels caused swr to climb beyond usable levels.

I would theorize that 100w SSB and 50w Digital would be achievable with even a reasonable ground.
I plan on taking this to the field today and giving it a shot.

Basically the antenna can be tuned by varying the size of the cap-hat.
The quality of the ground will dictate the efficiency of the antenna.
With no ground or less ground, it will require more cap-hat to tune and will handle less power.

More to come...

 

[N4BLS]

I'm curious how this would work in an apartment setting.