Radio reference guides
Antennas, feed line, station types, CB, and repeater setup — field notes for operators and preppers. Pair with calculators on the tools hub.
Handheld vs mobile vs base
| Type | Power | Antenna | Best for | Limits |
|---|---|---|---|---|
| HT (handheld) | 0.5–5 W typical | Rubber duck, optional whip | Walking, go-kit, first radio | Short range without repeater; battery life |
| Mobile | 25–75 W typical | Mag, lip, NMO roof mount | Vehicle emcomm, road travel | Needs 12V and metal ground plane |
| Base | 50–100+ W | Mast, yagi, vertical, wire HF | Home shack, net control, HF | HOA, lightning protection, space |
Decision help: What radio to buy first · Handheld quick-start guides · Mobile install guides · Base station guides · ERP calculator
Common antenna types
Quarter-wave vertical
Simple 2m/70cm ground-plane or mobile whip. Easy to build and tune. Length calculator
J-pole / slim Jim
End-fed collinear for VHF/UHF base. Often hung from mast or PVC mount.
Yagi / beam
Directional gain for weak signals or VHF contesting. Needs rotator for HF/VHF aiming. Yagi calculator
Dipole / wire inverted-V
Classic HF antenna between trees or masts. Antenna length calculator
NVIS
Low horizontal wire for regional HF (300-mile class). Emcomm and ALE-adjacent work. NVIS tool
Mag / lip / NMO mobile
Vehicle mounts — mag needs steel roof; NMO is professional permanent mount.
Antenna placement — mobile & fixed
Mobile (vehicle)
- Best: Center roof NMO mount — maximum ground plane, away from obstructions.
- Acceptable: Trunk lip mount, elevated hatch bracket — keep coax run short.
- Caution: Mag mounts on composite roofs — add ground straps; rain and speed affect SWR.
- Route coax away from ABS brakes and ignition noise sources; ferrites on long runs help.
- Check SWR on the bands you use before a deployment. SWR notes
Fixed (home / field)
- Get as high and clear as practical — tree line and metal roofing block VHF/UHF.
- Separate VHF/UHF and HF antennas by several feet when possible to reduce coupling.
- Field deploy: mast + guy lines, sandbags, or push-up pole — never work alone in wind.
- Lightning: disconnect and ground when not operating; proper arrestors for permanent installs.
- HF portable: inverted-V between trees beats HT rubber duck for regional NVIS-style contacts.
Coax & connectors
| Connector | Common on | Notes |
|---|---|---|
| PL-259 / SO-239 (UHF) | HF/VHF mobile, older HT adapters | Thread carefully; check center pin length |
| N-type | Base VHF/UHF, LMR-400 runs | Weather-resistant; preferred for permanent |
| BNC | Test gear, some HT adapters | Quick connect; not ideal for permanent outdoor |
| SMA / RP-SMA | HTs, Wi-Fi, some DMR | Watch reverse polarity on Chinese HTs |
| MCX / MMCX | Compact HT internal pigtails | Fragile — minimize mate cycles |
Coax types: RG-58 — short HT pigtails only. RG-8X / LMR-240 — mobile and short base. LMR-400 / RG-213 — longer base runs. Loss adds up on 70cm — use low-loss coax for runs over 50 ft. Balun notes · Tuner basics
Repeater setup — field & fixed
Operating through a repeater (most operators)
- Program offset (±600 kHz typical on 2m), PL tone, and correct mode (FM vs DMR).
- Identify legally; pause after keying for repeater tail.
- Use offset calculator and East TN repeater list.
Field temporary repeater / cross-band
- Coordinate frequency with EC or NTIA/state band plan — no improvisation on emergency freqs.
- High elevation antenna + battery/solar power; monitor temperature on continuous duty.
- Document input/output/PL on ICS-205 for incident comms.
Fixed repeater ownership
- FCC coordination (PRISM/UMV) for ham; GMRS requires license holder compliance with ERP and antenna rules.
- Duplexer tuning, backup power, remote control, and regular maintenance logs.
- See East TN repeater reference for local examples.
Citizens Band (CB) quick reference
CB (26.965–27.405 MHz, 40 channels) is license-free in the US, 4 W AM / 12 W SSB PEP limits on many export radios. Useful for highway travel and some rural communities; not a substitute for ham emcomm infrastructure.
| Channel | Freq (MHz) | Common use |
|---|---|---|
| 9 | 27.065 | Emergency / REACT monitoring (voluntary) |
| 19 | 27.185 | Trucker / highway traffic |
| 36–40 | 27.365–27.405 | SSB upper sideband (longer range when conditions allow) |
CB is separate from ham and GMRS — different band, power, and culture. For property and emcomm, prioritize GMRS or ham. CB channel tool if on site.