Here's some really comprehensive data on
transmitted noise characteristics for many current transceivers.
If you're wondering which radio would be a good choice for
stringent multi-transmitter applications such as SO2R contesting,
Field Day operation, or simply not bothering your nearby ham
neighbor when you're both on the air, you may find this of
interest:
http://lea.hamradio.si/~s53ww/TX%20noise/TX_noise.html
73...
Randy, W8FN