Coverage and propagation studies
RF coverage studies over real terrain, not a circle on a map.
Longley-Rice coverage maps for one site or a strongest-site composite of several, point-to-point path studies, TSB-88 tile reliability, receive-site surveys, microwave link budgets, and sectored CBRS site studies. Every one runs over real USGS elevation data at your actual site, and every one prints as a report under your operation's name.
A live study of FCC license WQQS321 on registered structure ASR 1210193: 451.7 MHz, 224 watts, 620 feet. Every figure on screen came off the license.
Eight questions, eight studies.
Coverage work is not one tool. What you run depends on what someone asked you, so these are grouped by the question rather than by the menu item.
How far does it reach, and how good is it out there?
LMR area studies and terrain-shaped contours
A contour answers how far. An area study answers how good, and where. Signal level is computed bin by bin across the whole service area over real USGS ground profiles and painted into usage classes, from a portable inside a building to a mobile on a roof antenna, with the square miles each class covers.
- Longley-Rice radial sweep, up to 360 radials, drawing the actual irregular coverage polygon: shorter into the ridge, longer down the valley
- Talk-out and talk-in both, because a system that reaches a subscriber it cannot hear back is a system that fails in service
- Land-cover clutter from ESA WorldCover, scaled by band, rather than one flat correction
Which tower covers what, and where do they overlap?
Multi-site LMR studies
Two to eight sites run on one grid and composited so every point takes the strongest site. Talk-out paints the composite in the same usage classes as a single-site study; talk-in treats the sites as voting receivers, so a portable counts as heard if any site hears it. A second layer colors each point by the site that serves it, with the square miles each site carries alone.
- An overlap band where the second site is within a handoff margin of the first, which is where roaming thresholds get set
- Each site loaded from its own license, with one shared receiver, reliability and usage losses across the study
- Labeled as a strongest-site composite, never a simulcast prediction: capture and delay spread between sites are a separate study
Will this one link work?
Point-to-point path studies
Two coordinates in, and the actual USGS elevation profile between them comes back sampled about every 10 meters. Longley-Rice point-to-point runs over it and reports line of sight or obstructed, the path loss, the received level, and the margin over the threshold you set.
- The terrain profile drawn as a side view, with the Fresnel zone and earth bulge, so an obstruction is something you can see rather than a number to take on faith
- Receive thresholds derived from the modulation and the receiver, or entered directly, never guessed
- The reverse path worked at the same time, since the two directions do not share a margin
Will every one of these sites hear it?
Receive-site surveys
One transmitter and a whole list of receive points: storm sirens, SCADA outstations, fire-station alerting receivers. Upload the list as a spreadsheet export, click the points on the map, or type them. Every point gets its own terrain profile, its own predicted level, and its own margin, in one document.
- Each site solved individually rather than sampled off a painted grid
- A point that fails reports why it failed instead of dropping out of the table
- Sorted weakest first, because the weakest site is the one that decides whether the system is accepted
Will it pass coverage acceptance?
TSB-88 tile reliability studies
The public-safety coverage-acceptance method: a uniform tile grid, a real Longley-Rice median for every tile, and predicted area reliability against the target you set, using the channel performance criterion you enter from the TSB-88 revision the system is designed to.
- The criterion is a required input, never assumed on your behalf: a reliability number computed against a threshold nobody chose is a number nobody can defend
- Reliability reported per tile and as an area percentage
- Receive antenna gain from the TSB-88 Annex D tables, cited to the table it came from
Where does this CBRS site reach, and what class is it?
CBRS site studies
A sectored 3.5 GHz site over real terrain: up to six sectors, each with its own azimuth, EIRP, beamwidth and downtilt, combined so every point takes its strongest sector. Coverage is painted against the RSRP target you design to, with each sector's share of the area, and the report prints under your operation's name.
- Trees and buildings dominate at 3.5 GHz, so land-cover losses follow ITU-R P.2108 for built-up and tree cover, on the dominant land cover of each cell, rather than a figure scaled up from UHF
- A handheld at street level or a fixed outdoor terminal, chosen in one step: the terminal sets the subscriber height and gain, and the clutter the standard applies at that height follows
- Category A or B derived from the EIRP and the height above average terrain under 47 CFR 96.41 and 96.43, with the reason stated, and a configuration above the Category B limit refused
- An estimate of the PAL Protection Area at the -96 dBm contour of 96.25, and the -80 dBm line of 96.41(d) showing how far the site could reach a neighbor's, both labeled as planning estimates since the SAS makes the authoritative calculation
Will the backhaul stay up?
Microwave path studies
A full fixed-microwave link budget between two sites: free space and gaseous loss, antenna gains, EIRP, receive signal, and fade margin, with Vigants-Barnett multipath and ITU-R P.530 rain availability worked out to the annual percentage.
- Rain zone resolved from the site coordinates rather than picked off a menu
- Path clearance at the k-factor you specify, with the Fresnel zone drawn
- A Part 101 interference screen against licensed paths in the FCC data, with the controlling exposure named
Does the proposed station clear the incumbents?
Short-spacing and contour-overlap studies
The study a frequency coordinator runs before anyone files. Pick the license at a site and its frequency, power and heights load as filed, or enter a new station by hand. The study applies the FCC rule for the band and names every station that passes, fails, or needs a letter of concurrence.
- Contours drawn on the FCC's own propagation curves, at the height above average terrain of every radial
- Incumbents come from a full weekly copy of the FCC licensing database, not a sample
- A letterheaded report to attach to the concurrence request
What the numbers rest on.
A coverage prediction is only worth the inputs under it. These are the inputs, stated plainly, so you can judge the output.
The Irregular Terrain Model
Longley-Rice, the model the professionals use, at the reliability level you specify, with terrain roughness measured from the elevation data around your actual site instead of guessed from a menu.
Real elevation data, sampled tightly
USGS 3DEP at 1/3 arc-second, roughly 10 meters, cached per tile. Path profiles sample at about that spacing rather than smoothing a long path down to a handful of points.
Your antenna, not an assumed one
Upload a pattern file (MSI Planet or NSMA) or give a beamwidth, point the boresight, set the tilt, and the contours and tile studies follow the pattern instead of assuming omnidirectional.
Loaded from the license, not retyped
Enter a callsign and the site coordinates, frequency, antenna height and ERP fill in from the FCC licensing copy, so the study runs on the numbers actually on file.
Service and interference contours at the dBu the rules set for the band, shaped by real terrain rather than drawn as a circle.
Something you can hand a customer.
Every study prints or downloads as a PDF under your operation's name, with the parameters, the results, the map, and the assumptions written out, and exports as a KMZ that opens in Google Earth with the coverage draped on the terrain. Save the inputs and reopen the study later to change one number and run it again.
A saved study stores the inputs rather than the results, so reopening it recomputes against today's FCC data and today's terrain cache. You never present a number whose age nobody can tell.
The same WQQS321 study, downloaded as its report: your letterhead, every input, the served area by class, the map, and the method written out, with the planning-study notice on every page.
The multi-site study, exported as a KMZ and opened in Google Earth: the composite draped on the terrain, a pin per site with its numbers, the best-server layer a tick away, and the inputs and notes in the file so it stands on its own when forwarded.
What every study shares.
Directional antenna patterns
Upload a pattern file (MSI Planet or NSMA) or give a beamwidth, point the boresight, set the tilt, and the contours and tile studies follow the pattern instead of assuming omni. Patterns live in a shared library for the whole operation.
Save a study and come back to it
Any study on a map page saves under a name and the customer it belongs to: the site, the antenna, the thresholds, the environment, and for a receive-site survey the whole list of points. Load it months later, change the one thing that moved, and either save over it or keep the original and save a copy. Only the inputs are stored, never the results, so a reopened study recomputes against today's FCC data and today's terrain instead of showing numbers whose age nobody can tell. The form marks itself edited the moment you change anything, and asks before it throws unsaved changes away.
KMZ export for Google Earth
Every map study exports as a KMZ: the coverage overlay draped on the terrain, contours and paths as placemarks, a pinned legend, and the inputs and planning notice in the file, so a customer or a consulting engineer can open the study in Google Earth without an account.
Letterheaded study reports
Every propagation study, channel search, paging channel search, short-spacing study, and TOWAIR screen prints or downloads as a PDF under your operation's name: parameters, results, the map, and the planning-study disclaimers, kept in a report history and ready to hand a customer or attach to a coordination request.
What these studies are, and what they are not.
These are planning studies. They are built from published models and real terrain data, and they are good enough to size a system, site a repeater, and show a customer why. They are not a measurement, and no prediction replaces a drive test on a system that has to be accepted.
Sentinel RF is not an engineer of record and does not provide professional engineering services. On life-safety and public-safety designs, the output is there to inform licensed engineering review, not to stand in for it.
The interference screens are screens. A Part 101 microwave screen is the homework that makes coordination go quickly; the prior coordination notice still follows. A short-spacing study names who needs to sign a letter of concurrence; it does not obtain one.
Keep reading
Cited answers
Your service manuals, procedures and bulletins become a library every tech can ask. Every answer names the document and page, and it says so when the library does not cover the question.
RF calculators
Site intermod, short spacing, AM protection, shared-site exposure and desense, Fresnel zones, coax loss, ERP and the small stuff. Five of them run free on this site.
FCC license search
A full, weekly-refreshed copy of ULS and the antenna structure register, with leases and market licenses included, searchable by callsign, licensee, FRN, frequency or area.
License monitoring
Watch lists for licenses and towers, lighting-outage alerts from the FAA feed, and area watches for new towers and licenses near you.
Run one on a site you already know.
Put in a callsign you have driven. If the study does not match what you found in the truck, we want to hear about it.