For months now, AM 760's signal strength at night has been the same as their day strength (when they're licensed at 5kw). Does anyone know why they've cut power? Isn't this a violation of their license terms (they're licensed for 50kw at night)?
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AM 760 no longer 50kw at night?
- Thread starter Signal Geek
- Start date
760 would not be able to operate 5 kW NON directional at night as it would interfere with WJR in Detroit. KGB 760's night pattern null must be aimed at Detroit.
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Like was stated earlier in other KGB/KFMB threads it's probably due to the on-going construction at the 760 site to diplex 600 KOGO onto the towers.
Yup - one can go read this thread about KSCO in Santa Cruz: https://www.radiodiscussions.com/threads/ksco-am-santa-cruz-ca-whoops.755077/
'Drop power to 1k, and we'll be fine.' said someone some time in the past.
$20,000 fine for that decision.
...except they were doing so before. 5KW non-directional protected WJR before the directional power increase. It should now!
Semoochie, 760 San Diego has always had a directional nighttime pattern. So even in the years before the nighttime boost to 50kw, it was directional.
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That's correct, when KFMB 760 was 5 kW fulltime they were required to be directional at night. I could watch the S meter on my receiver go up at least 6dB after their pattern change at sunset up here in the SFV. Now the difference is more like 10 dB when they use 50 kW at night...but I'm pretty sure the null's field strength is the same as with 5 kW.
It's funny to recall that several decades ago when the FCC was trying to find a way to give AM daytimers some kind night coverage, many non-directional night power assignments bordered on the ridicules. Back in the day KUTY 1470 Palmdale's 5 kW non-directional daytime facility was located right next to lake Palmdale providing an excellent ground plane. The FCC assigned the station a mighty 9 Watts for nighttime operation. But I don't think that was ever used. Years later they got authorization to move the facility to an area east of Lancaster and build a 4 tower (DA-2) directional system with 5 kW fulltime. Owner/engineer Dale Ware once told me that earning his PhD was actually easier than upgrading KUTY .Getting over the FCC hurdles seemed to take forever and was a nightmare.
On the other hand, I think it was in Radio World, I read that after the 1989 Bay Area earthquake, when the KGO antenna system at San Jose was nearly destroyed, the engineering folks at KGO almost immediately contacted the FCC to ask what non directional power could they use in either a wire antenna or perhaps in one of the towers if any were still usable. Apparently they got their answer in about 5 minutes: 20 kW. They were amazed.
On the other hand, I think it was in Radio World, I read that after the 1989 Bay Area earthquake, when the KGO antenna system at San Jose was nearly destroyed, the engineering folks at KGO almost immediately contacted the FCC to ask what non directional power could they use in either a wire antenna or perhaps in one of the towers if any were still usable. Apparently they got their answer in about 5 minutes: 20 kW. They were amazed.
The nighttime directional for (I really still want to call it KFMB) KGB is north-south. Even at 5kw, it blasted into Sacramento at night.
Interesting that San Diego and Detroit are about 2,200 miles apart. Yet KGB still needs a directional antenna at night to protect WJR, whether KGB is broadcasting at 50,000 watts or 5,000 watts.
There are/were two Class I-B stations on the same frequency and neither has/had to use a directional antenna to co-exist. KNX Los Angeles and CBA Moncton shared 1070. Each was allowed to broadcast at 50,000 watts non-directional because LA and New Brunswick are about 3,300 miles apart. (CBA moved to FM in 2008.)
There are/were two Class I-B stations on the same frequency and neither has/had to use a directional antenna to co-exist. KNX Los Angeles and CBA Moncton shared 1070. Each was allowed to broadcast at 50,000 watts non-directional because LA and New Brunswick are about 3,300 miles apart. (CBA moved to FM in 2008.)
Not only that, but why does KGB have to protect WJR in the first place, other than some antiquated FCC policy? There is no way in the world that either station can interfere with the other, even if both ran 50 kW ND. And outside of the Midwest and southern California, who cares? Who, other than a few hundred hard-core DXers, will listen to either station outside of their own core areas?
OK, I haven't dxed in over 40 years. I probably knew at one time that 760 was directional at night. If they're running 5KW ND, they could probably get away with dropping to 1KW. Are we sure that they're ND? They could be using the old towers if they're still standing.
I don’t think anybody really knows what power they are at or what is going on. This all seems to be mere speculation. But, I will say that AM 760 KGB can be heard in Phoenix at night, which used to never happen before. 🤔
And again, that's the calculus that got KSCO, Santa Cruz into hot water with the FCC:
https://www.radiodiscussions.com/threads/ksco-am-santa-cruz-ca-whoops.755077/#post-6539430
I didn't mean that they should just do it. They'd still have to contact the FCC about a temporary change.
The app was for 10kw and the FCC apparently dismissed it
Midwest TV, then owner of KFMB-AM, withdrew the application and gave no reason why. Had the application been approved, they would have maintained the current nighttime parameters, but operated with 10kw.
Geek mode off.
So remind me again why KGB-AM needs to run 50kw at night? Even 10kw at night would cover the market the same as the higher power. And the skywave might even get up to the Almond Capital of the World!
I don't have a good answer to that. Midwest asked for the 50kw in the 80s, back when they were still doing good numbers and had the Padres. Even then, I didn't really get it. Their 5kw nighttime directional came in like a local in Ukiah in the 70s...that's 110 miles north of San Francisco---about 625 miles north of San Diego. What were they trying to hit that they couldn't already?
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