October 21, 2020 at 11:49 am #48392DarkStarParticipant
Does KGW’s move displace KWVT? Weren’t they on RF 27?
With ATSC stations can use adjacent frequencies without problems.
KOIN is on 25, KJYY-LD is on 26, and KSLM-LD (KWVT) is on 27. With KGW’s move, KJYY-LD will be displaced.October 21, 2020 at 9:26 pm #48404LinleyGParticipant
I can find KGW’s application for rule making but I’m unable to find any action the FCC has taken. RabbitEars.info shows the application as Pending. Is it there and I didn’t find it?
DTV transmitters inherently dump a fair amount of splatter (interference) into their adjacent channels. If the difference in amplitude gets too large the splatter from the bigger signal will cause interference problems to the lower power station by driving the S/N below threshold.
DTV stations are allowed by the FCC to operate on adjacent channels as long as the lower adjacent channel is 28dB or less greater in amplitude and/or the upper adjacent channel is 26dB or less greater. (CFR 47 73.623(c)2) I have never heard an explanation for the two dB difference
LinleyOctober 21, 2020 at 10:11 pm #48405washnotoreParticipant
Back on October 13 the FCC issued a “Notice of Proposed Rulemaking”. While the FCC initially granted KGW’s request. It still must go thought a comment period. And other regulatory steps before the FCC can do a final grant order.October 22, 2020 at 3:26 pm #48423
” I have never heard an explanation for the two dB difference”
The last several pages do show how the calculations are made but fail to discuss what you’re really asking.
It raises several questions in my mind including:
Are there guard bands on the end(s) of the allotment? Are they equal in bandwidth?
The upper end is always > frequency than the lower end by 6 MHz. Any calculation based on f will therefore be slightly different on the opposite ends of any channel. Check out the discussion in the earlier pages of the bulletin where they discuss what coverage is to be considered.October 22, 2020 at 5:15 pm #48430
This is what I’m trying to understand, from the above linked report:
The D/U ratios for co-channel interference to DTV service in Table 5A are only valid at locations where the signal-to-noise ratio is 28 dB or greater for interference from DTV and 25 dB or greater for interference from analog TV service. At the edge of the noise-limited service area, where the signal-to-noise (S/N) ratio is 16 dB, the co-channel D/U ratios are 21 dB and 23 dB for interference from analog TV and DTV, respectively. At locations where the S/N ratio is greater than 16 dB but less than 28 dB, D/U values for co-channel interference to DTV are as follows:
To protect DTV reception from DTV co-channel interference, minimum D/U ratios are computed from the following formula:
D/U = 15 + 10log10[1.0/(1.0-10-x/10)], where x = S/N – 15.19 dB.
The quantity x is the amount by which the actual desired S/N exceeds the minimum required for DTV reception.October 23, 2020 at 2:42 am #48442
Looks like k283bl 104.5 is back on the air. It’s a simulcast of KKWA 96.3 Way-FmOctober 23, 2020 at 11:34 am #48448
That’s what it was before. I assumed that they shut it down because it interfered with the White Salmon station. They had an authorization to remain silent that expired on July 27th and the link didn’t turn up anything but there isn’t a “D” in front of the listing either, indicating that the station has been deleted. I would think that running different programming would interfere with their 60dbu contour in Gresham or at least cut down on a listenable signal closer to Portland.October 23, 2020 at 2:57 pm #48455Scott YoungParticipant
It doesn’t sound to me like the west hills 104.5 translator is on. I was over by Llord Center this morning and Me-TV FM was solid in the car. At home I can hear most of the west hills translators on a little Sangean, but all I hear on 104.5 is a little bit of Me-TV FM like I normally do. No sign of Way FM.
October 26, 2020 at 2:31 am #48493
- This reply was modified 1 month ago by Scott Young.
It’s 2:27am on Oct. 26th 2020. I’m picking up K283BL right now rebroadcasting 96.3 KKWA instead of KXXP white salmon. I’m located just south Mt. Tabor. Usually during the daytime hours I picked up 104.5 Metv fm. Is K283BL doing some programming test authority?October 26, 2020 at 11:33 am #48497
There’s something strange going on: When I copy and paste K283BL into CDBS, I get no entries but if I put in 104.5, Portland and OR, it comes right up! (Edit) Apparently, it’s been back on since July! I found it in rec.net: https://licensing.fcc.gov/cgi-bin/ws.exe/prod/cdbs/forms/prod/cdbsmenu.hts?context=25&appn=101818560&formid=910&fac_num=140415October 30, 2020 at 9:48 am #48591
I noticed that K283BL turn on their translator after 1am and only on air for few hours and shut off after 5 or 6 in the morning.October 30, 2020 at 11:04 am #48597Alfredo_TParticipant
Years ago, I heard the hours of 1 AM – 6 AM referred to as the “experimental period,” during which AM stations can obtain authorization from the FCC to temporarily transmit using daytime antenna patterns and power levels for the purpose of “DX tests.” I was not aware that any kind of experimental period existed for FM. What is happening here?October 30, 2020 at 11:12 am #48598
Midnight to 6 AM is and has been the experimental period for over 50 years and is mentioned in the rules many times. It is not tied to any specific action or band rather the actions are tied to it. In other words, you can do certain things but only during those hours.October 30, 2020 at 11:28 am #48600
Why does this affect FM? I can’t think of any technical reason why its testing times would be limited.October 30, 2020 at 8:33 pm #48608boisebillParticipant
Maybe K283BL has their Lamp Timer set up backwards. Shuts off when it’s supposed to turn on. 😉
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