OK, quick question. I have been eyeing this as a pan adapter for my TS-940, but would also like to use this as a stand alone reciever. Can you build one reciever to cover 1.8 to 30 or are you limited to one band per RX?
YES, You can use a softrock Ensemble II RX($74) and tune it to your radios (TS-940) IF Frequency of 8.83 mhz and use it as a panadapter from an IF tap just by tuning that frequency, and then also if you wanted direct connect it to an antenna and use it as a full HF multi-band receiver.
The original softrocks were single bands, those are the ones that are only $20 each. The Ensemble II RX is the multiband receiver that can cover the entire HF band (eg 1-30 mhz), and go for $74.
There are new models based on the Ensemble that you can build for 2m,4m,and 6m. I am nearly finished building a 2m now, to be my second ensemble based softrock, and after that I have a RXTX kit in the drawer to build a full softrock based CW/SSB transceiver.
Here is how to use the softrock as as panadapter on a TS-940 and do exactly what you want to do, and the same thing (connecting to an IF tap for use as panadapter) applies to many radios as well.http://www.wu2x.com/sdr.html
I actually use my ensemble with an RF TAP not an IF Tap from my FT-450, so it acts as an independent receiver right along side the 450, but shares the antenna with the FT-450, and takes advantage of the 450's preamp, antennuator, additional band pass filters and RX/TX switching circuit. That is documented on my blog: http://ws4e.blogspot.com