Re: Question about TP reception, sunrise enhancement, RF Zoo...


Interesting. As for the two on 747 and 774, do you think it would be worth trying them immediately after local sunrise, when KFMB-760 powers down from their 50kW directional night pattern (301.12mV/m, zip 91941 (I'm in 92020 but 91941's "center" is closer to me, and I'm within a couple houses of a 92020/91941 border)) to their 5kW non-directional day pattern (65.01mV/m, zip 91941)? Or would the TPs have already faded enough by then to make it not worth it?

Also, what levels should local signals be below (either as indicated on dBu on a stock PL-380, or in mV/m on v-soft's zip signal site, before I attempt TP reception within a particular range of the dial? It seems that if a signal pegs the meter at 63dBu on-frequency and shows 50dBu several channels across, or is upwards of 3000mV/m on the zip signal site, it seems to block even semi-locals that would be received "loud and clear" if the pest wasn't on. But... what about if the strongest signal is only barely hitting 63dBu (with a 30dBu noise floor nearby), or isn't even cracking 50mV/m on the zip signal site? Do I still need the pests to be even weaker before I attempt ANY TP/TA reception at all?
Alternatively... does an ultralight exist that has better dynamic range than the Tecsun or my Panasonic RQ-SW20? The Panasonic will clearly hear stations that are blocked on the Tecsun... so long as you're sufficiently far off in frequency. Close in, though, strong signals bleed quite far. For example, near the site of KCBQ-1170's 50kW (day), while KCBQ could be loudly heard down into the 900s or maybe 800s if I remember correctly (except for KECR-910 at the same site), KFMB-760 came in quite clear, and I think I may have even been able to get KFI-640, but they I think were completely blocked on the PL-380. Going up the dial the other way, I believe KLSD-1360 was heard fairly well on the RQ-SW20 (even though 1170's splatter continued up the dial all the way to 1710), but was blocked on the PL-380. And, even though in rural areas my PL-380 would have enough sensitivity to hear KERN-1180 Wasco-Greenacres, CA, there was no chance at all here, even though (yes, I'll admit) I tried. Also, KSDO-1130 and KPRZ-1210 was dominated by KCBQ on both radios, although an old Zenith portable from the 1960s I have with a tuned front end was able to pull in either KNX-1070 or XEPRS-1090, or maybe both, even though it too struggled with KSDO.

I was also wondering about something... I've heard you mention KSUH-1450 as a major pest there, and have seen in reviews of a few radios that it could be heard all the way up to 1710 (SRF-M37V/W if I remember correctly). I've thought that KSUH, being 3 miles away from you, was quite a major pest... but is it possible that a few of my local stations - 760 (50kW, 7 miles, night), 1130 (10kW, 6 miles), and 1170 (50kW, 9 miles, day (used to be 5 miles away)) - may be even bigger pests, considering the ground conductivity here, according to the FCC map, is considerably higher than there? BTW, I briefly had a M37 (before I got the PL-380), and found that stations bled across the dial comparable to my Panasonic RQ-SW20 (this was after KCBQ moved to the diplex site farther away). One reason I was thinking that KSUH was a bigger pest was because it is heard 260kHz up the dial at your location, but even when KCBQ's transmitter was closer, they were only heard up to 1260, 90kHz up, on my Panasonic, which I thought had comparable selectivity when I compared it to the Sony. However... I've seen you refer to my location as an RF Zoo. :) So whose pests are likely stronger, mine or yours?

--- In ultralightdx@..., D1028Gary@... wrote:

Hi Stephen,

"Sunrise enhancement" (also known as "sunrise skip") refers to the
temporary period when DX signals from the west (especially from across the Pacific
Ocean) get a significant boost because of rapid changes in the ionosphere.
Every DXing location can receive this "sunrise enhancement" boost, but the
quality and duration of the boost depends on your DXing location. The
strongest and longest "sunrise enhancement" DXing boosts occur on ocean

During the ocean beach DXpeditions this summer in Oregon, it was common to
have a 90-minute period of enhanced South Pacific DX signals around the
sunrise period, with some signals from Australia and New Zealand getting a
boost from S-zero (before the enhancement) up to S9+ (at peak enhancement).
DXers on the East Coast have a similar propagation boost for TA signals from
Europe and Africa, around local sunset.

Here at the 90-mile inland location of Puyallup, WA, the sunrise
enhancement DXing boost is much weaker than at an ocean beach, and it only allows
about 30 minutes of improved TP propagation. This always causes a mad
scramble for DX during the limited time available. For an inland location, the
quality and duration of the sunrise enhancement is related to the distance
from the ocean, the soil type (rich soil is best), obstructions to the west
(like mountains or hills, which degrade signals), and proximity to a large
lake (this helps out, especially if the lake is to the west). To be honest,
however, when your local AM pest situation is so disastrous in your inland
location, even sunrise enhancement isn't likely to bring you many TP's. You
might have a chance for a few "big guns" showing up around 15-30 minutes
before local sunrise in the peak month of October, but I would be very
surprised if any more than that show up in your local "RF zoo."

73, Gary

In a message dated 9/9/2010 2:56:13 P.M. Pacific Daylight Time,
pianoplayer88key@... writes:

Hi all...

I've seen a few references to sunrise enhancement when receiving TPs.
Approximately when would that be relative to local sunrise at the listener's
location - when does it start, and when does it end?
Does TP reception exist to any appreciable level at or shortly after local
sunrise here on the west coast? If so, I'm wondering if I might have a
chance at receiving at least JOUB-774, if not also JOIB-747, immediately after
local sunrise? I've just about given up on receiving either one at night,
because of 43,00 or so RSSI readings on 747 and 774 on my stock PL-380.
KFMB-760, 7 miles away, runs 50kW directional at night (~150 +/-50 kW toward
me), with a ~2900mV/m field @ 1km in my direction. However, at local
sunrise, they drop back to 5kW non-directional, indicating 32,00 on 747 and 774 in
the early afternoon. Also, KKOB-770's signal, being east of me, should
have already weakened considerably, if not completely disappeared by then.
KKOH-780 isn't much of a blowtorch here anyway, so I'm not too worried about
them (I don't think I've ever seen them much past 44-45dBu or so, and often
hides under KFMB's shadow). Therefore I'm wondering... would I have a
chance at all with JOUB-774 after San Diego sunrise?
I am still a bit concerned about my chances with JOIB-747, though. There
isn't really any signal on 750 that I'm worried about, but KCBS-740 is often
heard fairly well (often upwards of 52,25 barefoot), and even frequently
mixes with 10kW IBOC daytimer KBRT-740 (48,25 some places here) after local
sunrise. KFMB does peg the PL-380's display on 760 at 63,25 day and night.
So would I have any chance at all with those two Japanese after sunrise?
Or is even a 30,00 to 32,00 noise floor too much for TPs to overcome? I
thought these were the "big guns" ... but maybe they can't punch through a
43,00 to 50,00 barrier?
What level do my strongest locals need to be below before I attempt TP
reception, and/or what should the noise floor be at or below at 0dB SNR (not
referring to detuning resulting in a 0dB SNR) in 1kHz BW mode?

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