Known facts confirmed
- Coverage to the house worked before the repeater move.
- Repeater was relocated ~50 yards to a different building with a "better" antenna.
- New antenna install was not tested with any equipment (no SWR meter, no analyzer) — verified only with handhelds standing near the site.
- Repeater performs well everywhere else in the district post-move.
- A rocky ridge sits between the house and the repeater site.
What "works everywhere else" rules out ruled out
A bad SWR, damaged connector, wrong coax, or mistuned/off-resonance antenna degrades output in every direction, not one bearing. Since the rest of the district is fine, a broad antenna-health problem is unlikely to be the root cause — even though it was never actually measured.
Still worth a cheap SWR check to fully close this out (see Step 1 below) — "unlikely" isn't "impossible," and it costs nothing to confirm.
1. Ridge now blocks this specific path most likely
Knife-edge diffraction over terrain is extremely sensitive to exact geometry — tens of feet of horizontal or vertical shift can move a path from "just clears" to "blocked." Moving the antenna 50 yards and changing its mounting height could easily put the ridge squarely in the line toward the house on this one bearing, while every other direction in the district (different bearings, different terrain) is unaffected.
Fits the symptom pattern exactly: one specific bearing dead, everything else fine or better.
2. Downtilt / narrowed vertical pattern possible
A higher-gain "better" antenna often achieves that gain by squeezing the vertical beamwidth, sometimes with added electrical downtilt to boost near/mid-range coverage. That can weaken long or marginal-elevation-angle paths (like a 3-mile edge-of-district shot) even while broadly improving typical coverage — which matches "works great everywhere else."
Diagnostic steps
Fix paths
| Cause confirmed | Fix |
|---|---|
| Antenna mistuned/bad SWR | Free — retune or fix the connector/coax. No further action needed. |
| Downtilt/pattern issue | Ask the department to adjust mounting/downtilt on the repeater antenna. Free-ish, may need a return trip up the tower. |
| Ridge blocks new path (terrain) | Not fixable by tuning. Either get the antenna raised/moved again, or build a Radio-over-IP (RoIP) link at the house (below). |
Test-first, before spending on RoIP
Put a proper base/mobile radio at the house with a real external antenna mounted as high as practical (roof mast, ~15-20ft+). A handheld indoors with a stock antenna is close to worst-case RF; a mobile radio + real antenna often closes a marginal gap on its own, even with a partial terrain obstruction. Cost: ~$150-300 (used mobile radio + base antenna/coax). If this works, no RoIP needed.
If terrain truly blocks it: RoIP options
| System type | Option | Notes |
|---|---|---|
| DMR (MOTOTRBO/Hytera) | IP Site Connect / IP Multi Site Connect | Manufacturer's built-in feature for linking a remote site into the same system over IP. No 3rd-party box needed — just a repeater/IMR at the house added to the existing IPSC network by whoever holds the codeplug. |
| Analog conventional | BridgeCom BCR-220 (or Omnitronics IPR) | Turnkey RoIP appliance handling audio/COR/PTT interfacing over the network. ~$500-800 all-in with a base radio. Recommended balance of cost and reliability. |
| Analog conventional (budget) | AllStarLink / svxlink DIY node | Raspberry Pi + URI interface cable + used mobile radio, ~$200-350. Cheapest option but requires Linux config and has no vendor support — riskier for something meant to work reliably during a call. |
Common to any RoIP build
- Base/control station radio at the house programmed with the department's exact RX/TX split and tone/color code — your handheld talks to this locally, not to the department directly.
- External antenna, mounted high — this hop is now just covering the house/yard, not the 3-mile path, so it's an easy RF problem by comparison.
- Wired network connection (not Wi-Fi) for the RoIP box — low bandwidth but latency/jitter sensitive.
- UPS/battery backup on the radio, RoIP box, and modem/router — power loss during a storm is exactly when this link matters most.
- Department's radio tech should program the home unit and provision their side (COR/audio ports or IPSC site slot) rather than a mismatched DIY config.