100+ mile daytime DX, poor vs. good soil conductivity, etc...


YEOWZERS!! I just looked up the distance from Wildersville to Nashville, and I find it amazing that WSM's signal is so weak so close, especially considering the 50kW and low dial position! So does the "4" soil conductivity REALLY make it THAT bad? Here in Southern California (ok, so the soil conductivity is a wee bit higher), 50kW KNX 1070 comes in loud and clear here near 32°45'40"N 116°56'50"W...


1070 KNX Los Angeles, CA (1) - 4:00pm, PL-380, 6kHz BW, 54dBu - 50kW ND, 111.02mi, 313.53°. This was recorded in the house in a spot where the signal is stronger than other places. Normally the RSSI is around 42-45dBu, with 640 KFI (50kW ND, 98.85mi, 321.74°) averaging 6dBu weaker, even though it's about 12 miles closer.

With the Select-A-Tenna outside, it comes in at 63dBu, which is the max my PL-380 will indicate...


Also, I can hear 3 stations 1kW or less over 1200kHz that are 195 miles away. Recordings, along with a notes text, are available...
The 3 stations, all transmitting from the same stick near Santa Barbara, CA, are 1290 KZER (0.5kW), 1340 KCLU (0.65kW), and 1490 KSPE (1kW).

Also, in reply to someone's comment that they couldn't hear "fringe" stations on Radio-Locator...


That's my barefoot PL-380 recording of 960 KIXW Apple Valley, CA. The station is about 122 miles away, and radio-locator says their "fringe" signal ends about 27 miles north of me, so I'm basically about 30% outside their fringe contour. The reading was 30dBu RSSI, 0dB SNR. I suspect that if my radio wasn't being desensitized by several local blowtorches on 600, 690, 760, 910, 1130, 1170, and 1360 (by going inside a car, which attenuates the signals something like 15-24dB or so across the band, I can get a 2-5dB higher dB SNR than dBu RSSI on some semi-locals, for example 1550 XEBG might indicate 15-17dBu RSSI, 18-22dB SNR), the signal would sound stronger.

Also... am I the only one who can reliably hear an FM station 200 miles away?


That is 103.3 KVYB Santa Barbara, CA, 212 miles away.

So what are your experiences? Does improved soil conductivity really make THAT much difference in the reception distance of AM stations? Or is your "threshold" for determining whether or not a station is there higher than mine, or is my radio (except when it's desensitized by local blowtorches) just more sensitive?

--- In ultralightdx@..., Rick Robinson <w4dst@...> wrote:

On 7/19/2010 4:15 PM, Stephen wrote:
"I've always had a special interest in daytime AM DXing and your catches remind me of some catches I've gotten where you you can just barely hear a signal and have to draw a conclusion of what you got based on ruling out any other possible stations on a given frequency which in this case, there are none on 680 and 810 you could have heard there from any place else so it has to be from San Francisco."

After listening to the MP3 of 680kHz, I find it similar to my daytime
reception of WSM 650 when in Wildersville, TN. There is just not enough
audio to make a definite decision regarding the station ID. By the fact
that WSM is the only station that could possibly be received on 650kHz
at that time and place I deduced that it was WSM. As for my log, I
waited until I could make a positive ID later in the day of WSM. Wait
until winter and a definite ID will most likely be possible on 680. If
this is the condition in the middle of summer, winter reception of this
station at this location is a definite possibility.

My $.02 worth.

Rick W4DST

--- In ultralightdx@..., "osage_archer" <timchandler2001@...> wrote:

Sorry, I don't even know what your point is. None of those "fringe" stations can be heard at all here in the daytime, certainly not with a barefoot PL-380 and not even with my 24" passive loop which can boost the signal levels by 25-28 dbu. Just because you read something on radio locator does not make it so! And I also would not presume to tell you what you can and can't hear from your location, nor would I question your veracity.

Tim C.

--- In ultralightdx@..., "Stephen" <pianoplayer88key@> wrote:

I took your search link, and changed it to search for "fringe" stations, and I can see 5 stations over 100 miles, including WSM-650 at 188 miles.

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