Step 04 — Passes
When and where to point
Enter your location to see upcoming passes for all tracked amateur satellites. Each pass card shows AOS and LOS times, azimuth, a sky-arc diagram, and the frequency plan you'll need.
Contact console
Your operating position at a glance — set your callsign and grid, filter to the kind of contact you want (FM, SSB/CW, APRS, SSTV, or a beacon), then track live: compass bearing, elevation, AOS/LOS countdowns, and uplink/downlink frequencies Doppler-corrected every second.
Set your callsign
grid not set
Set your operator info and location, pick a satellite (filter by what you want to work), then press Start tracking for a live compass bearing, elevation, and Doppler-corrected uplink/downlink updated every second.
Pass predictions
Enter your location, then get upcoming passes for every tracked amateur satellite — AOS/LOS times, azimuths, a sky-arc diagram, and a Doppler-corrected frequency plan for each pass.
How to read a pass card
Reading a pass card
AOS — Acquisition of Signal. The satellite rises above your minimum elevation. Start listening now.
MAX — Maximum elevation. Best signal. Transmit now if you haven't already.
LOS — Loss of Signal. The satellite drops below your minimum elevation. Sign off gracefully.
Pass quality
Overhead (60°+) — Excellent. Long contact window, strong signal.
Good (30–59°) — Solid contact, reasonable duration.
Low (15–29°) — Workable but brief. Obstructions matter more.
Marginal (<15°) — Difficult. Good for monitoring, not first contacts.
Arc diagram
The sky arc shows the pass path projected overhead. The outer ring is your horizon (0°), inner rings are 30° and 60° elevation. Green dot = AOS, red dot = LOS.
Your Location
Location required for pass predictions.
Field tools
Supporting utilities for the operating position — live antenna aiming, a mutual-pass sked finder, grid math, transponder passband matching, and a QSO logger you can export to ADIF.
Live antenna aiming
Real-time compass bearing and elevation for the satellite you select — plus a countdown to the next pass. Best used outside, during a pass.
Live Antenna Aiming
Not set — search a place or use GPS
Press Start tracking to see a live compass bearing and elevation for the selected satellite, updated every second. Best used during a pass — check the pass finder above for timing.
Sked finder
Find a window where you and another station can both see the same satellite, for a scheduled mutual contact.
Mutual-Pass Sked Finder
Find when you and a remote station can both see the same satellite — the windows to schedule a contact. Enter both stations’ Maidenhead grids.
Grid solver
Convert between Maidenhead grid squares and lat/lon, and get the distance and bearing between two grids.
Grid Square Distance & Bearing
Enter two valid 4- or 6-character Maidenhead locators (e.g. CN87 or CN87up).
Passband matcher
Check which slice of a linear transponder's passband your uplink and downlink land in, so you stay inside the inverting bandplan.
Linear Transponder Passband Matcher
InvertingTransmit (uplink)
435.1500
MHz · USB
Listen (downlink)
145.9350
MHz · LSB
Inverting transponder: tuning your uplink UP moves your downlink DOWN. Doppler is estimated from the chosen pass phase — for an exact figure, read the range rate from the live pass finder above. Frequencies update as you slide; find a clear spot on the downlink, then set your uplink to match.
Session log
Keep a running log of the QSOs you make during the session, then export it as an ADIF file for your logbook.
Session Log → ADIF
0 QSOs · stored locallyBefore the pass checklist
Check AMSAT's satellite status page. Birds can enter safe mode or change transponder frequencies without notice.
Enter both frequencies in your radio as a memory pair. Use separate VFOs for full-duplex monitoring.
SO-50 requires a 74.4 Hz burst first, then 67.0 Hz continuous. AO-91/92 need 67.0 Hz. ISS needs none.
Look at the arc diagram above. Have your antenna pre-aimed at the AOS compass bearing 60 seconds before the pass starts.
5W into a Yagi is usually more than enough. Start low and increase only if you can't hear yourself on the downlink.
"CQ satellite, this is [callsign] portable [grid square]" is the standard opening. Grid squares help other operators confirm the contact.
Save your setup
Your location and filter settings are saved in the URL and as a cookie — bookmark the page or use the Copy link button to share a pre-configured view. Pair this with the frequency reference on your phone before heading outside.