April 23, 2015 at 10:23 am #9792
If you look at a topographic map, you can see a break in the terrain. It worked for KPOJ/KPOK/KUPL for decades and later, 106.7 and 94.7.April 23, 2015 at 11:24 am #9795
“A signal running just under two watts from Hillsboro is pretty good!”
At night, it is nothing out of the ordinary. Doubtful if during sunlight hours reception will be usable. You said it yourself, here in Sellwood you were not achieving full quieting. I could barely pick up the signal on my receiver without holding on to the dipole wire to “enhance” reception.
Also, DXing with a good antenna that has gain and directionality is a huge difference over a simple car antenna or a wire dipole on an FM receiver.
They don’t refer to the 60 dBu contour as the limit of interference free coverage for no reason.
It’s not about being only 1.8 watts by itself. It’s more about all the other RF floating around on the channel and adjacent channels. Really. A two watt handy talkie can key up a Mt. Hood repeater and come back nice and clean because there isn’t so much clutter, at least not as much as on the FM dial in the Portland metro.April 23, 2015 at 11:42 am #9797
“you can see a break in the terrain”
You can’t count on complete coverage from the easement in the terrain. KUPL didn’t have it and certainly not Magic 107. After I put the 107.1 translator in for 106.7, and keeping in mind this was 1984, you could ride up or down 217 and listen to your car receiver keep switching between the translator and the primary signal depending on where on 217 you were located.
Alfredo and jr are DXing from a fixed reception point with high gain directional receiving antenna. It’s not the same in a car with a vertical polarized whip or even a diversity in window antenna. You lose weak signals at the traffic lights and if you turn 90º the receiver loses its lock on the signal. When you have so little signal to work with, it’s to be expected. When you are listening to music, there is nothing more annoying then it getting all garbled and fuzzy.
Eventually I’ll grind this out, but my guess is that KSND’s 20 dBu contour is probably running through Hillsboro and Beaverton, so during the day to get full quieting without side rejection (directional antenna with gain like jr and Alfredo), Mt. Scott would have to be delivering 40 dBu which is impossible. KISN’s 1.8 watts has a 40 dBu level that ends about the river to the east and I-84 to the north. Again, I’ll draw it out after I get Parallels 7 installed and run my Win VM.
Hey, I get it. Some of you want oh so much for this signal to be greater than it is, and not to be cold but this is physics, not rock and roll.April 23, 2015 at 12:45 pm #9801Alfredo_TParticipant
95.1 on my car radio is mostly hiss with a weak KSND popping in at times as I drive around the older parts of Hillsboro (where I live). At the low signal levels that we are dealing with, traffic lights and WALK/DON’T WALK signs cause significant interference.
I posted my reception report because I thought it miraculous that I could hear KISN-LP at all; I do not want to mislead anybody into believing that one could simply turn on a clock radio, a table radio, or a portable radio and expect to hear the station from this far away.
P.S.: The antenna that I have used is a 10 element Yagi, pointed due east. If I catch any more tests on 95.1, I will try a few different antennas.April 23, 2015 at 8:38 pm #9951jr_techParticipant
Exactly, Alfredo… In no way did I mean to imply that reception of KISN in Hillsboro is easy. I did not have much time to experiment last night, but did determine that at my home, *way* more than a clock radio or compact stereo or boom box is necessary to receive the station. I was able to find a couple of “hot spots” in my house where the very sensitive/selective Eton E-5 portable AM/FM/SW would receive a reasonably decent (but not noise free) signal… but move 3 feet and KSND would dominate. Fun stuff!April 23, 2015 at 11:14 pm #9981
“They don’t refer to the 60 dBu contour as the limit of interference free coverage for no reason.” Andy, how does this work where the coverage area is defined as being within the 54dbu? Is it still unreliable below 60? By the way, I never meant to infer that reception of the Mt. Scott stations was just as good as from the west hills but I’m sure that break in the terrain helped. I got the impression that KUPL eventually moved because of new population in the dead spots.April 24, 2015 at 12:07 am #9984
Canada, Puerto Rico, U.S. Virgin Islands and Mexico aside, the only exceptions are class B1 and B where the protected contour is 57 dBu and 54 dBu, respectively. The spacing chart for the non reserved (commercial) band 73.207 reflects this so that the proposed station’s 57 or 54 dBu contour will not overlap a co channel’s 37 or 34 dBu. This maintains the same 20 dB margin needed for interference free listening in Class A or C stations where the 60 dBu proposed contour won’t/can’t overlap the existing co channel’s 40 dBu contour. If you are short spaced, you have to be within the limits of the short spaced chart 73.215 AND must make a showing that the contours don’t overlap. For B1, 57 dBu doesn’t overlap existing co channels 37 dBu, proposed 57 dBu doesn’t overlap existing first adjacents 51 dBu, 57 to 97 for 2nd and 3rd adjacent. You will note the margins are the same as they are for all other classes in the A and C groups: 60 to 40, 60 to 54, or 60 to 100 (20 dB, 6 dB and 40 dB respectively). In the reserved band all that matters is that the appropriate contours don’t overlap (except for proposed new stations on Ch. 218, 219, and 220 must conform to 73.207 spacing with adjacent channels on Ch. 221, 222 and 223. Also IF spacing must be maintained as per 73.207. See 73.507 http://tinyurl.com/lf2cg39 and 73.509
The U/D -20 dBu margin for co channels is what is needed as per the FCC 50,50 curves to have interference free reception. The adjacent channels use the 50,10 curves for interference predictions. The Class B1 and B contours allow for less than 1 mv/m (60 dBu) to be protected, and their interference free radius falls between C classes (B1 between C2 and C3, B between C1 and C2).April 24, 2015 at 12:16 am #9985
KUPL moved because whatever was preventing them from being in the west hills in the first place was no longer an issue due to consolidation of ownership and/or wheeling and dealing with other conglomerates (you do this in market x and I’ll do this in market y and we both can move/upgrade, etc.). Same with 106.7. In some cases, they have just signed off on interference being received. The chump channel generation of ownership have no values whatsoever. That’s just one more of the reasons they are the company that ruined radio.April 25, 2015 at 12:25 am #10007
It is my understanding that KPOJ moved from 98.7 to 98.5 because they thought they couldn’t raise power. After the inauguration of Class C1, it was possible to broadcast from one of the TV towers without being short-spaced to Seattle. I don’t know of any other stations that had to be moved, in order for this to happen. They couldn’t move to the west hills on 98.5 because of the IF restriction with channel six.April 27, 2015 at 11:11 pm #10070jr_techParticipant
They appear to be testing again tonight.
Got them on in the Family room (mono only… but not too bad) using vintage Pioneer TX-9100 and attic mounted RS 6 element log-Yagi (local set-up).
Sounded pretty good on the stock Ford car radio… *until* I backed up 3-5 feet and lost them completely.
Yamaha TX950 (on vintage outdoor RS 10 element Yagi, usually pointed at Eugene, but rotated toward Mt Scott tonight) is going nuts, with its multipath indicator indicating severe multipath (or perhaps considerable “AMing” of the transmitter. Crummy sounding in stereo.April 29, 2015 at 3:55 pm #10142
Went to get gas for the lawn mower.
Car parked E-W with the rear window diversity antenna broadside to Mt. Scott. Signal locked and sounded OK. Went up one half block to SE 18th and turned right heading N and signal maintained. A little noisy, but not too bad. Made a left and a right and got on SE 17th and headed N to gas station. Stopped there parked N – S and filled up the gas cans.
Got back in the car, turned the engine on and radio had a huge problem locking on to 95.1. Very noisy and unintelligible. Made a U turn and got back on SE 17th headed S. Signal continued to evade capture, fading in and out of noise. Made a left on Bybee and headed E for two blocks, then made a right to continue S. Receiver was still nowhere near as locked as when the trip started and the initial antenna orientation provided a larger capture surface. I had the pilot locked most of the time but the truth is there isn’t much separation in the signal. I do not know if that is a)the lack of RF or b)the stream they are generating lacking separation or c)the original music of this time period they wish to live in wasn’t known for being stereophonic and often was released in mono. The overall frequency response was acceptable but not great. A distinct lack of low end and not a very crisp high end.
All in all, I’d say this would be about a 5 on a 10 scale. I totally understand this kind of behavior. Trying to lock on to a weak signal (after all, this is way outside the 60 dBu interference free contour which is around SE 52nd) when your antenna is 90º out of orientation will often prevent the receiver from really grabbing the signal. You’re better off tuning off the frequency and tuning back when you are going in a 90º different orientation. If you have an ancient whip antenna, you will not get this same kind of result but you also won’t have near the quality of reception since vertical only FM mobile receiving is a whole can of worms unto itself.
The music, by the way, was awful. They played one “classic” cut (King of the Road) and then cut it off early to play some stupid jingle. BTW, the jingles sound like you are in a radio museum. Very very dated. Kind of like on TV when you are surfing and come across an episode of the Andy Griffith Show. This is tantamount to black and white radio in a HD millions of colors world.April 29, 2015 at 11:30 pm #10152
The song DOES fade out. Did they get as far as “cigarette”?April 30, 2015 at 12:16 am #10155msndrspdxParticipant
Just within the last hour or so, the KISN Everywhere Facebook page has announced that KISN-LPFM will formally sign on the air at 9:51am this Friday morning, May 1. Why? “We ARE 95.1 FM!”
Makes sense to me! I’m assuming that details will be forthcoming in the time between now and then!
Best, Mike 😉April 30, 2015 at 12:28 am #10156
It’s a shame you can’t sign on at 9:51fm. 🙂May 1, 2015 at 10:16 am #10240msndrspdxParticipant
KISN-LPFM now on air. I’m in Sellwood and I have the antenna on my boom box pointed east at the Mt. Scitt transmitter. Once I did, signal comes in fine!
Best, Mike 🙂
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