Big 121 said:
They were back around 4:30 or 5pm or so yesterday afternoon.
I wish I could get advance notice (preferably several hours to a day) of when both those signals will be down in the middle of the day for (preferably) at least a half hour or more. I've been wanting to do some comparison reception on various ultralight radios, when they're off the air, of stations between 870 and 940 and between 1140 and 1200 near my house (9.3 miles S of their site), and across the entire band within 1/8 mile of their tower site. Preliminarily, I think I might be able to get 900 KALI West Covina (this one would be difficult due to its directional pattern), 910 XEAO Mexicali (and possibly the one in Oxnard but I'm not sure), 920 XESDA Ensenada or KPSI Palm Springs, 1160 XEQIN San Quintin, and 1180 KERN Wasco-Greenacres, while 910 and 1170's locals are off the air.
Even better, especially for the test at home, would be if 600, 690, 760, 910, 1130, 1170 and 1360 could all be down at the same time. (As for 600, due to them being a EAS station, and 1360, IIRC, being a backup, I'd be ok with them just dropping power so that their 0.1 mV/m contour doesn't go east of Avocado Bl, or whatever it takes so they'd be unreceivable without a longwire antenna at my house about 8 miles east of their towers.) Coinciding with a region-wide power outage would be even better. Last year's mid-September outage did help a little, but not all the stations were down/out simultaneously. I would especially like it if, sometime this year (and not around a holiday weekend or in the middle of August when I may or will be out of town), a combination of power outage and stations operating at reduced power could cause the ambient man-made noise level to be below about 0.1 µV/m (I assume natural noise would be considerably higher), and the strongest broadcast field intensity to be below 0.1 mV/m, in an area bounded by Avocado Bl, Chase Av, Jamacha Rd & Route 94.
Problem is there is the consideration of lightning noise typically being higher in the summer, though. The best time I would think would be when lightning noise is the lowest (nearest active lightning at least 16,000 km away) and D-layer absorption is total. I don't want *ANY* skywave for the experiments - if a signal before entering the D-layer could spontaneously boil tungsten due to the high RF fields, then upon exiting the D-layer on its way up should be so weak that even in an underground screen room that field would be undetectable on expensive test equipment.
(I wonder how many dB of attenuation that might be...)Speaking of D-layer absorption, how would I know when it's total? I was going to try some experimenting in my back yard around 2:30pm or so, but I was getting some fading on a station on 1670, and I was using only an ultralight and Select-A-Tenna. I would prefer to have rock-solid signal strength stability for some of the experiments I'm wanting to attempt. Would any of the solar indices give any indication as to the completeness of D-layer absorption? Also is there any possible suggested way to test shortwave reception using rock-solid stable weak live over-the-air (not test) signals? (A major problem in my case would be I don't think I have any active SW transmitters near me that can be received/decoded on my Tecsun PL-606.)
Back to the Q... am I the only one that has noticed they have a rather interesting pattern of doing their day/night power switch? In the evening, I notice they will shut off the 50kW rig and within like 1/6 second or so fire up the 2.9 kW. About 10 seconds or so later, it'll go off and stay off for about 10 seconds, then return. In the morning the situation is reversed. The 2.9 kW will go off for about 10 seconds, then come back on. Then about 10 seconds or so later it'll shut off, followed in about 1/6 second by the 50kW blowtorch coming on. Any idea why that is? In some ways it is actually helpful to me, cause I can use the several seconds when they're off the air to try to DX co-channel and adjacent stations. Also for quite some time I had noticed their nighttime transmitter was about 70 Hz or so off frequency. The last couple nights though, they seem to have been within a few Hz so I guess they got that corrected?
