[IRCA] LW NDB - 42 mi typical GW range? Or is my stock PL-606 really that deaf?

[Stephen Airy <pianoplayer88key@xxxxxxxxx>]

I was on my way south from Riverside, CA, this afternoon, so I decided to see how far the "SB" NDB on 397 kHz could be heard on my stock Tecsun PL-606.  When I was just leaving Temecula on I-15 heading south, I made this recording at around 5:33pm PDT on 2011-10-23 about 42 miles from the transmitter site at a heading of approximately 162°.  Their transmitter site is approximately 34°3'23.2986"N 117°21'58.0608"W.
http://www.mediafire.com/?4ptyh5178s38rji
The radio was sitting in the back window of a 2006(? - maybe 2008 I don't know for sure) Honda Accord, and set to 1 kHz bandwidth, using only the supplied internal ferrite bar antenna.  The signal strength was indicating 15/00, but if you listen very carefully (headphones REQUIRED (preferably ones with good isolation, not the cheap ones that typically come with consumer radios - I'm using JVC Marshmallow model #HA-FX38 or something like that which I believe are around $20 at malwart ;) )) you may be able to make out parts (or if you have exceptional ears, all) of three repeats of "... -..." in ~1000 Hz CW.
 
Is that the typical expected range of an LW NDB signal?  Or.. how much improvement could I expect by using a different LW antenna with my PL-606?  For example, if I had one of Gary Debock's LW FSL antennas or 7.5" LW loopsticks, should I expect a midday signal more like this, but at 32°45'38"N 116°56'42"W (about 92.8 mi / 149.3 km @ 165°)?
Sound: http://www.mediafire.com/?2fiwyatrsu7a593
Photo: https://picasaweb.google.com/118228966367965758611/TecsunPL606#5666915364042427250
(The actual signal had quite a bit less background noise than is audible in the sound.  I made the mistake of recording it about 15-20dB or so too low and had to raise the volume after the fact.)  The signal was so strong here, in fact, that I was able to hear its 2nd harmonic (794) with the Sony SRF-59.  http://www.mediafire.com/?u9p9n1buvtn5sw7
 
Speaking of LW FSLs, $150 is way out of my price range for building an antenna.  Is there something that's more like $20-40 or so that I could build that would be a noticeable improvement (sensitivity going from undetectable to armchair copy or from readable-but-weak to full quieting, selectivity / blocking/desense improving so I can hear, on MW for example, stations around 30-100 µV/m without any adverse effects from first-adjacent 3-10 V/m signals on one side and maybe 30-100 mV/m or so on the other side)?
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