Start with the contacts and site, then choose the TDL shape. The fastest-looking setup is not useful if its footprint, pattern, or tuner requirement does not match the operating job.
The point is not to memorize one diagram. It is to select the documented geometry that fits the job and then preserve the parts that make that geometry a complete antenna.
What this means in the field
- The ground vertical uses the smallest footprint, while the delta loop offers a broader configuration when two whip directions fit.
- This is not permission to leave the antenna installed permanently or to evade property rules.
- Plan the coax route, guy-free clear area, and recovery path before raising the whips.
The complete TDL behind the answer
- The CHA TDL is a fast-deploying 3.5–54 MHz field system built around two fully extended SS17 whips, a 25 ft 4 in loop wire, a TDL Hub, a HYBRID-MICRO or HYBRID-MINI matching transformer, a spike, and 50-ohm coax.
- Inverted delta loop: the normal rapid-deployment configuration, with two SS17 whips forming the upper sides and the supplied wire completing the loop.
- Ground-mounted vertical: one fully extended SS17 becomes the vertical radiator and the supplied loop wire becomes the counterpoise.
- V-dipole or horizontal dipole: optional-mast configurations using both fully extended SS17 whips and the matching transformer at the feed point.
Band and matching reality
The published operating range is 3.5–54 MHz. The guide describes 10.1–54 MHz as the most effective range and requires an antenna tuner or coupler on 3.5–7.0 MHz. Installed SWR, site, geometry, feed line, and nearby conductors still matter.
Before you transmit
- Keep the complete antenna and coax away from overhead power lines.
- Choose a stable support and clear the area where people could contact a whip, wire, guy line, or feed line.
- Begin tuning at low power and observe the radio, feed line, transformer, and nearby equipment for RF feedback or heating.
- Review RF-exposure requirements and medical-device precautions before transmitting.
Make the next setup easier
Record the chosen configuration, transformer, band, tuner state, orientation, height, counterpoise or loop-wire route, coax, analyzer reference plane, and on-air result. That small field record is more useful than a remembered “good SWR.”
This page makes the operating decision easier to understand. The current guide still controls assembly order, dimensions, power limits, and safety.
