When you get to a certain level of performance, receiver noise floor doesn't matter as the atmospheric noise will be a lot higher when an antenna is connected. Same with sensitivity, a receiver can measure very sensitive on test equipment but that gets lost when an antenna is connected, unless the antenna is a 3ft clip lead.
Close spaced dynamic range is the money shot (pardon the pun) when it comes to receiver performance, you have to spend a lot of money or lots of engineering brain power to get good numbers there. This is also what makes or breaks a radio for serious contesting in crowded bands with high power SW stations all around.
Many years ago it took serious preselection, high level mixers with LOs running up to 1 watt, multiple conversion schemes and other tricks of the trade to achieve really good performance. Now there is more knowledge on using roofing filters, novel mixer technology and DSP to enhance receiver performance at less cost to the consumer.
When receivers rate well on the close spaced dynamic range area they are usually quieter due to the receiver not creating lots of IMD internally which raises the noise floor when an antenna is connected due to lots of high level signals spanking the 1st mixer. Once you get used to a radio that ranks high on Rob's list its hard to go back to a receiver that's low on the list, they just seem too annoying and fatiguing to listen for any length of time.
Not everyone needs ultimate performance but its nice to check Rob's site before buying a new HF receiver or transceiver to make sure you are getting what you expect.
prcguy
