Sensitivity rating of HD radio

[awj223]

> Only car radios made my Fujitsu Ten (Eclipse) have decent AM
> sections that can do something close.  It is fairly
> selective and pretty sensitive when compared to what else is
> out there.  ALL of the other brands (Sony, Kenwood, Clarion,
> JVC, Panasonic, Sanyo, Alpine etc) have horrible front ends
> for AM.
>
> The Eclipse is not as bright as other AM sections, so with
> sensitivity and better selectivity, there is a tradeoff.
> But I can drive in Queens and hear LI AM's and WTIC and WBZ
> with the Eclipse where, on other car stereos, these stations
> are washed (or images of other local strong stations pop up)
> as the recievers go into overload.

Aren't the closest local stations (in Queens) to WTIC and WBZ only second adjacents (WINS, WEPN, WHLI)?

My OEM receiver has no trouble with second adjacents.  I can hear KCBS/740 just fine, even though 50 kW KFMB/760 is only 10 miles away AND directional toward my area.

However, when I'm listening to KNBR/680, the same receiver does a poor job rejecting noise from XETRA/690, 30 miles away.  It's listenable most of the time, but the chatter is extremely annoying.

Given what you've said about what the Eclipse can do in Queens, I'm still not convinced that it is selective enough.  The benchmark I'm comparing to is my Sony ICF-SW7600GR portable.  This one IS selective enough to get rid of the chatter completely, but doesn't work well in the car because of the car body acting like a giant Faraday cage.

[pianoplayer88key]

selectivity curve of IF filter that should be in a radio with 3kHz analog response:

0dB    +-----------
-3dB   |           |       
-12dB  |           |       
-24dB  |           |       
-48dB  |           |        
-96dB  |                   
-144dB |            |       
-180dB |            |       
-240dB |            -------       
-300dB +---+---+---+---+---+
   +/- 0   1   2   3   4   5KHz