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Portland, Oregon bandscan from Eugene

B

bobdavcav

What causes the drastic difference in reception? I remember I asked about something similar up here in Seattle, but I would think that the difference in ERP to a different direction wouldn't be that great, would it?
92.3 KGON was practically non-existant last night when I tried it.
93.1 I thought I heard KRYP a little weaker than KGON last night, but both were unlistenable. I am not surprised at KRYP since it is a C3 running about 1.6 kw at 386 meters, but KGON is 98 kw from the same site.
93.9 a listenable KPDQ-FM with some static.
94.7 I think the radio was trying for a stereo signal, but probably couldn't get one due to 94.5 being so close. I'm not sure where KNRK broadcasts from.
95.5 a strong KBFF in full stereo
97.1 a strong KYCH
98.7 a very weak but listenable KUPL from the KGW TV tower
99.5 a religious translator completely blocking KWJJ
100.3 very weak KKRZ, though easily listenable through the static
101.1 a very strong KXL-FM, I think they're on a slightly taller tower at the KGW site.
101.9 I was surprised how weak KINK was, considdering I sometimes hear them up here at my home in the Seattle area. I wonder if the translator in Cottage Grove has anything to do with that? The 100.5 station licensed to Cottage Grove had a signal comparable in strength to KPDQ-FM.
103.3 KKCW in full stereo great signal!
104.1 KFIS in full stereo, 6.9 kw at about 95 miles!
105.1 KRSK running more than 3 times the power from a higher antenna about as strong as KFIS. Apparently, 104.1 has a great signal too.
105.9 no sign of KFBW, I just heard a weak I presume K-Love translator.
106.7 KLTH strong. The guy that runs that tuner on globaltuners.com says he regularly gets an hd lock on KLTH.
107.5 a very weak KXJM, which may have something to do with the KLVU translator at 107.3. Why such drasticly different results from only 3 transmitting antennas?
 
I don't think there was any ducting this morning or last night, though there could have been down there. I just checked a few of the Vancouver BC frequencies that usually come in down here when there is ducting and nothing unusual there, no sign of BC stations. I could understand if KKCW was in full stereo why KKRZ may be fading in and out of stereo, but why would two stations broadcasting from the same antenna have such different results, one being barely listenable through static while the other is in full stereo? KGON sounded a little better this morning, and I was actually able to get a listenable signal on KRYP running only 1.6 kw! Wouldn't it make sense that KGON, running 98 kw gets out farther than KRYP, which is running 1.6 kw from the same antenna?
 
I've noticed that in Corvallis and Eugene the signal strength from Portland stations changes minute to minute. That long valley has a lot of tropo in almost any weather. Back in the 60's my cousins in Eugene had a big antenna tryiing to watch Portland TV. Some evenings there were periods where there was nothing on some channels. But most of the time it was watchable. Antenna went away when cable showed up at the house.
 
bobdavcav said:
....Wouldn't it make sense that KGON, running 98 kw gets out farther than KRYP, which is running 1.6 kw from the same antenna?
Click to expand...

Not necessarily. Power does not always equal better signal. There was a class C licensed to Corvallis on 103.x (I don't recall the exact channel). The station was on a short tower with a 5 bay ERI antenna. They had a crummy signal full of multipath in Salem and points north towards Portland. Nobody ever thought anything of it.

Then one afternoon, the old RCA transmitter burned up leaving the station off the air. The only solution was to order another transmitter and get a high powered exciter to get something on the air. At the time, 50W exciters were about the biggest things going, so that's what they ordered. When they put it on the air, the station suddenly had a terrific signal in Salem and all the way north to into Gresham right up to the outskirts of Portland. The signal was weak in the mid valley, but could also be heard well all the way to Eugene. So, when the new transmitter arrived and was installed a few weeks later, the signal went right down the tubes again.

Months later, I discussed this phenomena with another engineer from Alaska. He'd had a similar experience in Juneau where they had found that interference went through peaks and nulls as the power increased. Ultimately, they had found that 42kW served far better than 100kW.

Sometimes, there's more to the equation than just power.
 
Those high-powered mid-valley FMs could be heard with solid signals between Bend almost to Burns.
Think there was some knife-edge propagation over the mountains going on.
100 kw KRSP Salt Lake City on their AM tower was solid in Boise for hours at a time while those way up on Farnsworth didn't show up much. Biggest problem you have with high power on a low tower in a city is that the neighbors get you on their teeth. A good reason to take it somewhere else.
 
There are three FM sites in Portland: Sylvan, Skyline and Stonehenge. The Sylvan Tower is several yards from the old KOIN-TV tower and boasts Class Cs KXL-FM, KINK and KLTH, C0 KXJM and C1 KUPL on the main master antenna. Lower on the same tower are C1s KMHD and KQAC and C2 KBVM. The Skyline Tower, somewhat supported by the old KGW-TV tower, holds Class Cs KKRZ and KKCW, C0 KOPB and C1s KRSK and KFBW. Stonehenge is home to Class Cs(until someone downgrades them to C0 status for HAAT deficiency)KGON, KBFF and KYCH, C1s KBOO, KPDQ-FM and KWJJ, C2 KFIS and C3 KRYP. At the absolute top of the same tower is a separate directional antenna for C2 KNRK. Also coming soon to the Stonehenge Tower will be new occupants, C1 KNRQ and C3 KWLZ.
 
I imagine this interference doesn't affect all frequencies equally? KPLZ has a great signal in the Seattle metro, though I also think the processing on that station has something to do with that. KUBE and KCMS are on the same tower, yet their signals aren't nearly as good. KCMS has a number of bad spots with 54 kw as a C1. KUBE has just about as poor of a signal running a much higher power than KCMS, the same as KJR, which has a great signal. Does processing have anything to do with the way signals travel as well? I've noticed KBKS does not have nearly the signal it used to, and the processing has changed at least once in the past 4 years. Back in 2008, the over-modulated signal was huge and stood out to me except for one bad spot. Since CC bought the station, the processing has changed to something heavy on the high end and what seems to create lots of multipath.
 
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