The V-Soft number probably is based on a location in that ZIP code that is closer to the tx site, and more in the main lobe of the radiation pattern.
Probably so. Searching 92020 on Google Maps points to a location maybe 1.5-2 mi NNW of me. KCBQ is 9.3mi N of me, and their main lobe is focused approximately southwest.
The data for their 50 kW daytime pattern of Sept 2005 from a site at 32 50.367 N 116 59.517 W shows a tri-lobe radiation pattern with maximum ERP at 154 degrees. Another lobe was centered on 226 degrees towards San Diego, and there was a fairly deep null between them.
If you can post the distance and bearing from the old KCBQ site to your location then an estimate of their field could be made there.
Wow, no wonder it had such a huge blowtorch signal here back in the day!! Distance and bearing from them to me was 9.818km (6.1mi), 153.62°. So what would the day (and night - their drop was quite noticeable) field have been?
I suspect that even if I had a radio with good selectivity, midday reception of 1180 KERN (381.42km, 144.33° toward me) would have been impossible then... although if you know of an inexpensive portable (GE SuperRadio approx max size/price, maybe Sangean PR-D5(?) ok, prefer ultralight more like Sony SRF-59 but with digital tuner) that could do it without any splatter/blocking/desense from 1170 I wouldn't mind knowing which one(s).
Your mention of a tri-lobe pattern reminded me... I remember I used to be able to hear them fairly well in the mountains north of San Bernardino near Crestline in the daytime when I'd go camping there, as well as at friends' houses near Riverside, Bloomington, etc. Now it's a no-show, or at least very weak in Moreno Valley if there's any trace at all.
Is there any chance of some radio-locator style estimated coverage map existing for that previous pattern?
Oh... and is there any chance you may be using the 4nec2 software to calculate those fields, or do the part 15 research you've posted in other threads? I have downloaded it in the last few months, and was recently trying to figure out a few things (one being the behavior (field at specified distance, for example) of an electrically very short antenna with a short (or no) ground plane), but so far don't know much about how to use it yet.