When we compare the IMD of a good amateur radio transmitter almost 50 years ago to that of today's most modern transceiver, we should all be ashamed of ourselves for not demanding better transmitters, just as we have demanded better receivers. It's not the radio manufacturers' fault. We have never asked them to build us better transmitters. It's time to stop calling 30 dBc "good"! Rob Sherwood's.
Radio Receiver Intermodulation Performance
Receiver Test Data
This page gives information about dynamic range performance for some amateur transceivers. The data is from measurements on transceivers that I have borrowed from fellow amateurs or that have been brought to my qth by visitors. I have also made measurements at amateur meetings. Comparisons are made with published information to the extent I have been able to find it. Note that the data from the meetings linked to below contains measurements for many more transceivers than those listed below on this page.
MST Monday - Friday. D Octave 70 87 20 F. Otherwise dynamic range independent of signal spacing.
When intermodulation occurs it can give rise to additional signals that are not present at the antenna. As a result intermodulation distortion on radio receivers needs to be minimise to ensure that only signals received at the antenna are passed through the radio and appear at the output. Intermodulation distortion can also act to mask out wanted signals. If the intermodulation products fall on the same frequency as a wanted signal, they could mask its presence if the wanted signal is not strong, and the intermodulation products are high. As a result, it is necessary to design he radio receiver to have intermodulation performance that is as good as possible to ensure that only the wanted signals are received.