If you have a hard time hearing your own downlink but have no trouble hearing other stations, you may be experiencing “desense.” Desense is where your transmitter signal overloads your preamp (or receiver) causing it to become temporarily less sensitive.
Desense problems can occur on any frequency and even commercial radio installations sometimes experience these problems, but it is especially common when transmitting on 145 MHz and receiving on 435 MHz to work the mode V-U satellites.
Read the article A Simple Desense Filter for Mode-J Satellites by Anthony Monteiro, AA2TX at
http://www.amsat.org/?page_id=2136