Now, what ? are the chances that you just googgled into this ANTIQUE RADIO SITE with your apparently MUCH newer piece of equipment.

But for what its worth, the DX aspect is relevant to the setting used for the reception of a weaker station while the Local is self
explanatory as to the received stations being strong ones. On the DX stations the equipmemt is adjusting its gain and sensitivity to
the max in order to pull in that weak station,that it is tuned to; for the LOCAL, it is diminishing the circuit gain, so as to not overload the stages, and have
distortion onset.

The BLEND is associated with the FM circuitry and is tailoring the Stereo demodulator circuitry for reponding to fluctuating signal conditions.

TECH REF:(Hot Link)
http://www.freepatentsonline.com/5113446.html

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That above referenced circuitry was initially incorporated into auto receivers, where the signal level would be fluctuating with different driving
locales experienced.

Overall, it sounds like the root of your problem would be solved with more FM signal input into the receiver. Investigate the getting of a stronger
signal into the receiver from the use of better/stronger external antenna, or even its placement to a higher position, should you be using a simple
wire dipole that is almost lying on the floor, or else not fully stretched up and out out into its "T" configuration.Or, if just certain weaker
stations are being of concern, the optimum pick up pattern is where the broadside of the "T" is oriented towards the station being tuned to.