Can a radio telescope parabolic mirror be made with number hexagons not electrically connected?

Yes — a radio telescope reflector can be made from separate hexagonal panels that are not electrically bonded together, provided certain conditions are met.

This is actually very common in large radio telescopes.

Real-World Examples

• Green Bank Telescope
• Atacama Large Millimeter/submillimeter Array

Both use many individual panels to approximate a continuous surface. The panels are mechanically mounted but are not typically electrically bonded edge-to-edge.

Why Electrical Connection Usually Isn’t Required

At radio wavelengths, the key factor is not DC electrical continuity — it is whether the surface behaves like a good reflector at the observing wavelength.

A reflector works well if:

\text{Gap size} \ll \frac{\lambda}{10}

Where λ is the wavelength.

If the gaps between hexagons are much smaller than the wavelength, the electromagnetic wave “sees” the surface as effectively continuous.

Practical Examples

21 cm Hydrogen Line (1420 MHz)

Wavelength ≈ 21 cm
Acceptable gap size: up to a few millimetres without significant loss.

So for L-band radio astronomy (which I know you’re working in), small unconnected hexagonal panels are completely acceptable.

Millimetre Astronomy (e.g. 3 mm wavelength)

Now the tolerances become much tighter:

• Surface accuracy must be within ~λ/20
• Gaps must be tiny
• Mechanical precision is critical

This is why ALMA panels are extremely precisely machined.

What Actually Matters More Than Electrical Bonding

1. Surface accuracy (RMS error typically < λ/20)
2. Panel alignment
3. Gap width
4. Panel flatness
5. Structural stability

Electrical bonding between panels has negligible effect unless:

• The gaps are large
• You are working at very short wavelengths
• You are worried about static charge buildup (mechanical issue, not RF)

When It Would Be a Problem

• If the gaps approach λ/4, you start getting diffraction and scattering.
• If panels are spaced widely (like a grid reflector), efficiency drops.
• If corrosion causes insulating layers thick enough to create slot-like gaps.

For Your 1420 MHz Work

At 21 cm wavelength:

• 1–2 mm gaps → negligible loss
• Even 5 mm gaps → usually acceptable
• Electrical bonding → not required

Surface accuracy will matter far more than conductivity between panels.