[Elecraft] Sub-rx or P3?

[Jack Smith]

  There are low cost alternatives to the P3, such as (cheapest) an 8 MHz 
Softrock Lite II board or the more expensive but better integrated 
LP-PAN, so that it is possible to discover how useful a panadapter is 
without a major financial commitment.

If a panadapter turns out to be useful, you can then later decide 
whether to add the P3 or stay with the lower cost solution.

You can also use the Softrock or LP-Pan as a sub-receiver, but it's not 
nearly as well integrated as the K3's internal sub-receiver.

Jack K8ZOA