Chapter 15
Radio and Operating Tools
The Radio Tools section of the menu contains utilities for general operating.
#Propagation
Current solar and geomagnetic data from NOAA's Space Weather Prediction Center (falling back to hamqsl.com): Solar Flux Index, sunspot number, A and K indices and X-ray class, colour-coded green, amber or red, with a simple HF outlook (20/40 m, 10/6 m, aurora). The window waits for fresh data each time it opens; tap Refresh to fetch again.
#ISS Passes
Predicts International Space Station passes for the next 5 days, for passes higher than 10°. From Station Detail it uses that station's position; from the menu it uses your GPS fix, or the filter centre if there is no fix. Orbital elements (TLE) are fetched from CelesTrak, with wheretheiss.at, AMSAT and ARISS as fall-backs, and kept for six hours; Refresh TLE forces a new download. If no source can be reached, the last TLE is used — a few days old still gives usable times.
Each pass shows the date, maximum elevation (green when 40° or more — the best passes), rise, peak and set times with compass directions and duration. A yellow dot marks a pass you can see with the naked eye: the sky is dark where you are and the ISS is in sunlight. Times are accurate to a few seconds.
The last line gives the Doppler shift in kHz at rise (AOS) and set (LOS) — the largest shifts of the pass; it passes through zero at the peak — for the APRS digipeater on 145.825 MHz and the cross-band repeater downlink on 437.800 MHz. Listen above the nominal frequency as the ISS rises and below it as it sets.
Pass reminder — in Settings → ISS Pass Reminder choose a minimum height (20°, 30°, 45° or 60°) and the app notifies you 10 minutes before each pass that rises that high, with its rise, peak and set times and directions. It uses your GPS position (or the filter centre) and works in the background while the app's service is running.
Satellite mode
The button under the pass list sets satellite mode for the current or next pass higher than 10°. Tune the radio on your RF interface to 145.825 MHz. From the moment the ISS rises until it sets, the app sends your position on RF once a minute with the path ARISS, and then switches itself off. Tap the button again to stop sooner. It needs an RF interface used for APRS; it sends nothing to APRS-IS.
Stations heard through the ISS digipeater are listed under the button, and a notification tells you when your own beacon was repeated by the ISS. They are recognised by the ISS callsign marked as used in the path (RS0ISS*, NA1SS* or ARISS*).
#Barometer
On phones with a pressure sensor, Menu → Radio Tools → Barometer shows the air pressure, the change over the last three hours (steady, rising, falling, or quickly when 6 hPa or more) and a chart of the last 48 hours. A reading is taken every 10 minutes while the app's service runs. With a height set in Settings → Phone Barometer (or a GPS altitude) the figures are corrected to sea level, as weather maps show them; otherwise they are the pressure at the phone.
Set Barometer report to send the pressure as an APRS weather report every 10, 30 or 60 minutes, on APRS-IS and any connected RF interface. It is a positionless report, so your position and symbol are unchanged, and it carries pressure only — other fields are sent as "no data". Readings are best from a phone left still indoors; in a moving car, air vents and changes of height make them less reliable.
#Sunrise/Sunset
Sunrise, solar noon, sunset and day length for today and tomorrow at your QTH (or a station's position), including polar day and night.
#UK Repeaters
The UK repeaters nearest to you — from your GPS fix, or your QTH when there isn't one — from the ETCC's list on ukrepeater.net, nearest first (the same as the RPT button on the map toolbar). Each line shows the callsign, output frequency, modes and CTCSS tone, then the town, distance, direction and channel.
- Band and mode buttons narrow the list (2 m, 70 cm, 6 m, 23 cm, 10 m; FM, DMR, D-STAR, Fusion). Your choice is kept.
- Tap a repeater for its details: output and input frequencies with the shift, CTCSS, modes, channel, locator and distance. Map centres the map on it.
- The list is downloaded the first time and kept on the phone, so it works without signal. It is refreshed when more than a week old.
- Update downloads the list now; Close shuts the window.
Repeater data: ETCC / ukrepeater.net. Repeaters whose keepers asked for site privacy have only an approximate position.
#RepeaterBook
For repeaters outside the UK: opens RepeaterBook's listings within 50 km of your position (or QTH) in the browser. RepeaterBook doesn't let apps download its data, so they aren't listed in the app.
#Geo-Fence Alerts
Described in chapter 17.
#DX Cluster
Connects to the DX cluster at dxfun.com:8000 with your callsign and shows the latest spots (DX call, frequency, band, spotter), updating live. HF frequencies are in kHz as clusters post them (14025.0), VHF and above in MHz (144.174); the band is shown beside each. The header shows Connecting…, Connected, Disconnected or the error if the connection fails. Band chips filter the list (160 m to 2 m). Closing the window leaves the cluster connected, so spots keep arriving; reopen it to see them, and use Disconnect to close the connection.
#Grid Square
Shows your QTH's six-character Maidenhead locator, and converts any grid square (e.g. IO92kk) to latitude and longitude with distance and bearing from you. Show on Map centres the map on it.
#Passcode Calc
Calculates the APRS-IS passcode for any callsign as you type (the SSID is ignored). Copy puts it on the clipboard. You do not normally need this, because the app calculates your own passcode automatically.
#SSID Reference
A table of the conventional meanings of SSIDs -1 to -15 (reproduced in the appendix).