I'm trying to understand the relationship between uplink and downlink frequencies on AO-73's inverting transponder. The specs show 435.150-435.130 MHz uplink maps to 145.950-145.970 MHz downlink, but I'm having trouble visualizing where my signal appears.

If I transmit LSB on 435.140 MHz, should I expect to hear my signal on 145.960 MHz USB? The inverting relationship means as you tune uplink higher, downlink decreases but the math isn't clicking for me.

Running an IC-9700 and just want to make sure I understand this correctly before my first linear bird attempt. Any clarification would be appreciated!

Think of it like a mirror - the transponder inverts everything. The frequency ordering is reversed, and USB/LSB are swapped. For AO-73, use this formula: Downlink = 581.090 - Uplink. So 435.140 uplink = 145.950 downlink.

The standard convention is to listen on USB downlink while transmitting LSB uplink. You've got the frequencies right - 435.140 LSB up gives you 145.950 USB down. Just remember to tune the uplink while transmitting to keep your downlink signal steady!

Welcome to linear transponders! I struggled with this concept too initially. AMSAT's book "Getting Started with Amateur Satellites" has excellent depth on finding yourself on transponders. The IC-9700 satellite mode handles the inversion automatically once configured properly.