In plain language: The MPAS 2.0 Horizontal NVIS shape is a low, level 73 ft radiator built for regional lower-HF work—not a vertical with a different tuner setting.
Use this chapter when the communication need is inside the normal skip zone and the site provides two modest supports.
Build the documented shape
- Match the guide geometry: both radiator ends 10–12 ft high and about 73 ft apart.
- Place the 25 ft counterpoise under the radiator from the feed end.
- Keep the wire slightly relaxed and strain-relieved.
- Select a lower-HF frequency that propagation can return at a high angle.
Why an operator chooses it
The geometry and the usable frequency work together. A perfectly assembled antenna cannot create NVIS when the ionosphere will not support the selected path.
Read the site before opening the bag
Listen first, use current propagation information, and keep a second band available. Regional reliability comes from frequency planning as much as antenna shape.
Common ways this goes wrong
- Choosing the band from SWR alone.
- Raising the wire because “higher is always better.”
- Comparing it to a vertical without holding band and time constant.
- Promising omnidirectional coverage as a guaranteed range.
Before you transmit
- Confirm the exact radiator, matching unit, return path, feed line, and support arrangement.
- Keep conductors and supports clear of power lines and uncontrolled public access.
- Reproduce the guide dimensions before experimenting.
- Inspect every connection and begin testing at low power.
- Record geometry, band, tuner state, and the result before changing one variable.
Boundary: The manual supplies a starting geometry, not a universal regional-coverage guarantee.
Use the current source before deployment.
This lesson explains the decision. The official guide controls assembly, ratings, configuration details, and safety.
Open the MPAS 2.0 User Guide · Open the MPAS READY Product Guide · View the current product page
