Uploaded October 2025 | Updated September 2026, 3 weeks ago
Today we’re commissioning the COMTEK / DX Engineering 40m 4-Square Antenna system here at DX Commander HQ. This is one of the most powerful setups for the 40m band — insane signal strength and front-to-back ratio. In this video I’ll take you through the build, wiring, tuning, fault-finding, and finally the moment of truth… including working Japan at +20dB over S9!
If you’re interested in serious DXing or contesting on 40m, the 4-Square is a game-changer.
Thanks to:
Tim Duffy K3LR and the DX Engineering team for the Comtek
Stefano at Messi & Paoloni for the 75 ohm coax
Martin and Mike for radial work and installation help
👉 Subscribe for more antenna builds, on-air tests, and DX Commander behind-the-scenes!
0:00 – Introduction & overview
0:20 – What is a 4-Square?
1:00 – Direction switching explained
1:45 – The COMTEK / DX Engineering controller box
3:00 – Wiring up & dummy load
4:45 – Software control with OM module
6:30 – Clickity-click relay tests
9:20 – Thank you DX Engineering
10:30 – Dummy load install
12:00 – Coax routing challenges
14:00 – Phasing line connections
16:30 – Trimming & tuning elements
19:00 – Resonance checks & adjustments
23:00 – Chat with Tim Duffy K3LR
24:30 – First tests & fault-finding
27:30 – T-piece troubleshooting
30:00 – Fixing a duff PL259
32:20 – Retesting antenna
33:15 – LIVE QSO with Japan (+20dB over S9!)
35:10 – Final thoughts: cost, complexity, and performance
#dxengineering
#dxcommander
Today we’re commissioning the COMTEK / DX Engineering 40m 4-Square Antenna system here at DX Commander HQ. This is one of the most powerful setups for the 40m band — insane signal strength and front-to-back ratio. In this video I’ll take you through the build, wiring, tuning, fault-finding, and finally the moment of truth… including working Japan at +20dB over S9!
If you’re interested in serious DXing or contesting on 40m, the 4-Square is a game-changer.
Thanks to:
Tim Duffy K3LR and the DX Engineering team for the Comtek
Stefano at Messi & Paoloni for the 75 ohm coax
Martin and Mike for radial work and installation help
👉 Subscribe for more antenna builds, on-air tests, and DX Commander behind-the-scenes!
0:00 – Introduction & overview
0:20 – What is a 4-Square?
1:00 – Direction switching explained
1:45 – The COMTEK / DX Engineering controller box
3:00 – Wiring up & dummy load
4:45 – Software control with OM module
6:30 – Clickity-click relay tests
9:20 – Thank you DX Engineering
10:30 – Dummy load install
12:00 – Coax routing challenges
14:00 – Phasing line connections
16:30 – Trimming & tuning elements
19:00 – Resonance checks & adjustments
23:00 – Chat with Tim Duffy K3LR
24:30 – First tests & fault-finding
27:30 – T-piece troubleshooting
30:00 – Fixing a duff PL259
32:20 – Retesting antenna
33:15 – LIVE QSO with Japan (+20dB over S9!)
35:10 – Final thoughts: cost, complexity, and performance
#dxengineering
#dxcommander
