Numerous pictures of unusual receivers. Some newer. Includes a rare Sommerkamp FR50B. From Vienna in Austria.
http://www.swl.net/oe1002419/swl.htm
An unusual early Yaesu radio.
http://homepage1.nifty.com/kurisu/FR-50.html
VE7DJX, Jan Skirrow. Information on the R-390 series of radios, including some edited collections of e-mail that provide a quick overview of the radio, its quirks and problems.
http://www.islandnet.com/~dma/Boatanchors/
http://members.tripod.com/michaelgellis/mixersin.html
This application note presents the system level trade-offs involved in adding a low-noise amplifier (LNA) to a remote keyless entry (RKE) receiver. The system's sensitivity improves 3.77dB, but the third order intercept degrades by 15dB.
http://www.maxim-ic.com/appnotes.cfm/appnote_number/1836/ln/en
NQ5T provides information about this grand old receiver.
http://home1.gte.net/nq5t/hq180.htm
http://www.hut.fi/~then/mytexts/radiohairiot.html
Details on rebuilding Collins R-390A receivers. Pictures show details of restoration, and documents are available to help you.
http://www.r-390a.us