Hy-Gain AV-18AVQII Trap Caps

When I started in amateur radio, I wanted to get an antenna that would not take up a lot of space but cover a lot of bands. The requirement was also that it be free standing. I ran across the AV-18AVQII antenna, and the advertising said it required no guy wires. So I bought it!

Unfortunately, when I installed it, it bowed like a banana. Reaching out to Hy-Gain, they tried to assist me in fixing the issue. The advertising was indeed incorrect, and they had that fixed, but I was still stuck with an antenna that I liked but I couldn't support properly.

I made it work, but have since moved but still wanted to stay with that premise of it being free standing. I also noticed the caps on the traps were pretty beat up and cracking, so I designed a base and cap set to help support the antenna more than the standard setup does.

Hy-Gain used what appear to be nylon spacers in the bottom of the traps, but the problem is that the spacers were too far up, so it would introduce wobble. The base caps I designed slide around the outside of the trap tube, adding better support. I did not do the same for the top trap.

The bottom cap has a slot so you can gauge how far up the tube the cap has been installed. The inside has a slot so the lower cap will still fit on the trap without having to unscrew the outside trap shell.

I wrapped the antenna tube with electrical tape to make sure the lower cap had a good tight seal around the antenna tubes. Also did the same with the top cap. I'm happy to say it has been free standing for a year without issues! I even used PLA and it has withstood summer heat and winters in the Midwest US.

Print instructions

Print Settings

Printer: Wanhao Duplicator 4

Rafts: No

Supports: No

Resolution: .2mm

Infill: 85-90%