S.M4-145-SB
4-stack dipole array, 137-153 MHz, split boom
Description
- The S.M4 is an array of phased centre fed folded dipoles mounted on an aluminium mast for PMR / Trunked radio applications.
- Each folded dipole balun assembly and associated harness junction is completely encapsulated in poyurethane resin, totally preventing moisture ingress.
- At VHF the antenna disassembles and flat packs for ease of shipping.
- Former Skymasts brand product.
Specification
| Electrical | |
| Frequency | 137 – 153 MHz |
|---|---|
| Max. Input Power | 500 W |
| 3 dB Beamwidth, H-Plane | 180° (offset configuration), 360° (omni configuration) |
| Polarisation | Vertical |
| 3 dB Beamwidth, E-Plane | 16 ° |
| Impedance | 50 Ω |
| Gain | Omni 5.7 dBd Offset 8.7 dBd |
| VSWR | < 1.5:1 |
| Front-To-Back Ratio | > 7 dB offset |
| Antistatic Protection | All metal parts DC-grounded (Connector shows a DC-short) |
| Environmental | |
| Ingress Protection | IP68 |
|---|---|
| Mechanical | |
| Elements | 12.7 dia. x 1.6 mm wall aluminium alloy grade 6063T6 |
|---|---|
| Connection(s) | N(f) on RG213/U cable |
| Boom Material | 63.5 mm dia. x 6.3 mm wall aluminium alloy grade 6082T6 |
| Fasteners | Stainless steel grade A2-70 |
| Length | 6m (supplied in two sections) |
| Element Clamps | Diecast Al / Zinc alloy |
| Historic Brand | Skymasts |
| Wind Load | 799 N (160km/h) |
| Weight | 27 kg / 59.52 lb |
| Balun Encapsulant | Polyurethane Resin U-600 |
Ordering Codes
| Model | Product No. |
|---|---|
| 4-stack dipole array, 137-153 MHz, split boom | S.M4-145 -SB |
PROCOM A/S reserves the right to
amend specifications without prior notice
PROCOM A/S • Smedetoften 12
DK 3600 Frederikssund • Denmark
Generated : 2026-06-28
Version 1