Channel Detection Scan (channels 2-6)

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kyl416
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Re: Channel Detection Scan (channels 2-6)

Post by kyl416 »

The 84 MHz is the bandwidth they reclaimed from RFs 38-51, while the post-repack TV band is RF 2-36. RF 37 is the buffer, it's not allocated for any TV use since it's reserved for radio astronomy. The 5G frequencies start at 617 MHz so there's also a 3 MHz guard at the start of RF 38. 617-652 (RF 38-44) are used for downlink from the towers, 663-698 (RF 46-RF 51) are used for uplink from the phones.

RF 35 and RF 36 are allocated in most parts of the country. Either by full power stations or translators/LPTV/Class A signals in areas between those full power signals.

NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

I would need about a 1000:1 odds to bet a single dollar on rabbitears up to date accuracy. Some of the stuff they list just doesn't exist or is on a different channel.

I realize that 36 is listed in the TV channels range. But I also know that at the very least it has been proposed (both in an NPRM and also as a contingency in the auction bandwidth recovery) to be a guard band for ch. 37. So that ch. 37 would have a guard band both above and below. As mentioned, crowded markets with existing allocation would perhaps be grandfathered in. Not concerned about it here.

kyl416
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Re: Channel Detection Scan (channels 2-6)

Post by kyl416 »

Trip who runs the site works for the FCC and is heavily involved with the repack as part of his day job. The technical data is pulled directly from the FCC's database daily. He's also a regular poster here and has people use their HDHomeRuns to submit data for the live bandscans on the site.

Of course there are changes that don't involve the FCC that he wouldn't know about without being told by someone local or by the station, like new subchannels, affiliation changes, and in some cases LPTV stations changing their major numbers (which they can do as long as it doesn't conflict with another station). There are also numerous LPTV stations currently silent since they're in the process of building out their new facilities, but the lack of available crews is delaying their work. However, if a station is off the air for an extended amount of time without notifying the FCC they can lose their license, like a bunch of HC2/DTV America owned LPTV stations did last week.

What specifically do you see that's either wrong or doesn't exist in your area?

NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

kyl416 wrote: Thu Nov 05, 2020 11:42 pm Of course there are changes that don't involve the FCC that he wouldn't know about without being told by someone local or by the station, like new subchannels, affiliation changes, and in some cases LPTV stations changing their major numbers (which they can do as long as it doesn't conflict with another station).
Yup. That's what I said. I wouldn't bet a dollar on the accuracy. Just because FCC is official source doesn't mean it is up to date either without having an SLA in place.

kyl416
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Re: Channel Detection Scan (channels 2-6)

Post by kyl416 »

What do you see wrong so he can correct it? He's a regular poster here and might see this thread, or you can submit the updates directly to him to help keep the resource up to date for other local viewers like many of us do. It would also help other Windows Media Center users since the next version of the Schedules Direct API, which is used by epg123, is planning to integrate RF data from RabbitEars.

If the major number doesn't match, he can also check into it to make sure the station's change is valid and address it with the station if it's causing a confict. LPTV stations aren't officially assigned major numbers by the FCC, and because of the maximization window and spectrum sharing many LPTV stations had to change their major numbers because of new conflicts. i.e. in NYC WNWT-LD initially attempted to use virtual 6 when WJLP started hosting them on RF 3, despite it being an obvious conflict with WPVI in Philly, so now they're using virtual 37.

There's also numerous LPTV stations that were displaced and have yet to build out their final facilities so they had to go silent once a full power or Class A station was ready to move to the frequency which might explain the channels you see that don't currently exist. i.e. in the New York City listings WASA-LD is currently in the red because they were displaced from RF 25 when T-Mobile paid WWOR to move off of RF 38 early.


Also, you don't need an agreement to get up to date data from the FCC's database. Daily database dumps are available for free on the FCC's website for anyone to use:
https://enterpriseefiling.fcc.gov/datae ... abase.html
So the technical data like RF numbers, Call Signs, Transmitter locations, power, etc should be up to date.

NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

kyl416 wrote: Fri Nov 06, 2020 12:41 am There's also numerous LPTV stations that were displaced and have yet to build out their final facilities so they had to go silent once a full power or Class A station was ready to move to the frequency which might explain the channels you see that don't currently exist. i.e. in the New York City listings WASA-LD is currently in the red because they were displaced from RF 25 when T-Mobile paid WWOR to move off of RF 38 early.
I'll take that as admission that it is not accurate. So we are in agreement.
Reasons for why it is not accurate doesn't change the fact that it is not accurate.
kyl416 wrote: Fri Nov 06, 2020 12:41 am Also, you don't need an agreement to get up to date data from the FCC's database. Daily database dumps are available for free on the FCC's website for anyone to use:
https://enterpriseefiling.fcc.gov/datae ... abase.html
So the technical data like RF numbers, Call Signs, Transmitter locations, power, etc should be up to date.
But an SLA would be needed to guarantee a particular level of accuracy. Otherwise there is no requirement that the data has a certain level of accuracy. With the state of flux right now it is likely to be much less accurate than in typical quiescent times.

My only interest in ch. 36 is whether or not it has been or will be designated as a ch. 37 guard band.
Another thing about chs. 35/36 is that they are available for use by white space devices.

kyl416
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Re: Channel Detection Scan (channels 2-6)

Post by kyl416 »

Because of KORK-CD's 600' height, and the 15 kW power limit for Class A stations, they're more affected by terrain and don't have the reach as other stations on the same tower like KOPB or KGW who are at 890+ feet and full powered signals with 70+ mile contours. RabbitEars has a live bandscan in Vancouver that confirms KORK-CD is on the air:
https://rabbitears.info/tvdx/signal_gra ... r3/KORK-CD

Their sister stations KKEI-CD on RF 36 and KOXO-CD on RF 15 are currently off air because they're in the process of switching to an ATSC 3.0 operation.

The RF 11 listing for Azteca IS there, it's a subchannel of KWVT-LD's signal:
https://www.rabbitears.info/market.php? ... 97#station
It's kind of confusing because instead of keeping all of the RF 11 subchannels on KWVT's virtual 17, Northwest Television uses their 4 LPTV signals to simulcast all of their stations with their individual major numbers to extend their reach around Oregon:
3-1 is a simulcast of KVDO-LD Albany
17-x is a simulcast of KWVT-LD Salem
27-1 is a simulcast of KSLM-LD Dallas
37-1 is a simulcast of KPWC-LD Tillamok

BTW, Can you verify what's on 27-1? Northwest has conflicting information on their websites, one says it's Retro TV, the other says it's AMG TV.


There is no paying the FCC or making a SLA deal to get special data, those database dumps are as up to date as you can get. It's updated daily and comes directly from the LMS server where stations make their FCC filings. It's not only used by RabbitEars, it's also used by commercial sites and businesses too. Now if the station is lying to the FCC and broadcasting from a different tower site or RF number than what the FCC has them authorized for, no SLA is going to cover that, and their RabbitEars listing would be the least of their problems, it puts them at risk of fines and/or having their license cancelled.

RF 36 is a full fledged part of the TV band, it is not protected or considered part of any guard band. Between full powered stations, Class A stations, LPTV and translators, they've allocated it in nearly every DMA.

NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

It used to be Retro. It is currently AMG TV

nickk
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Re: Channel Detection Scan (channels 2-6)

Post by nickk »

The HDHR5-4K firmware and the latest hdhomerun_config utility scans channels 2-36 and 38-51.

The next firmware release for HDHR4 and HDHR5 CONNECT models will follow this same range of 2-36 and 38-51.

Nick

NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

It's a start. An option to override the default would be preferred. Even if only a command line / JSON option that is not GUI accessible.
CSV list of channels or channel ranges. ex: 7-13,14-36

NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

Queried Channel Master Support re: discrepancy between the CM-3201 LTE filter device label (Pass: 5-599 MHz. Block: 600-2000 MHz) and the tech spec page (Pass: 5-609 MHz. Block: 610-2000 MHz).

Not going to cut/paste the response, but to paraphrase. The tech spec is the true range (Pass: 5-609 MHz. Block: 610-2000 MHz). Reason the label is slightly different is due to advertising by wireless providers and that LTE starts at 600 MHz, when in reality it starts at 610 MHz. So the label kind of matches what people are told (sales and marketing).

According to reports of sweeps some people have done the signal is down about 2dB at the upper edge of channel 35 (602 MHz). That's less than the 3.5dB of a two way splitter would be across the entire channel. And down less than a 3 way splitter on channel 36.

Those sweeps are in line with images of the Channel Master tech sheet I've seen online.

My opinion is that this is a good device that reduces pixelation caused by LTE signals within the frequency range that TV tuners, amplifiers, etc. receive. If TV image pixelates even though the signal is strong. Filtering out LTE may be the solution. It has a side benefit of speeding up channel scan through the boatload of now unused channels.

Some third parties are still selling the previous version that is for 700 MHz (Pass: 5-699 MHz. Block: 700-2000 MHz) (up to ch. 51). So be aware of that to avoid getting the wrong one. Probably best to purchase direct from Channel Master. I purchased through Amazon where it is sold and shipped from Channel Master in Chandler AZ.

Also be aware that the 700 MHz version has the same model number CM-3201. So make sure the label and the spec match the one you want.

Here are some links to an image of the Channel Master spec sheet and some sweep results by someone at avsforum.com.
Attenuation of Channel Master NEW CM-3201 LTE Filter for the 14-36 UHF TV Band
https://www.avsforum.com/attachments/cm ... g.2684642/

Attenuation of Channel Master ORIGINAL CM-3201 LTE Filter for the 14-51 UHF TV Band
https://www.avsforum.com/attachments/cm ... g.2681778/

Model: CM-3201 [609] Specifications - LTE Filter
https://www.avsforum.com/attachments/cm ... g.2681392/

NEW Channel Master CM-3201 LTE Filter for Post-Repack Channel 14-36 UHF TV Band
https://www.avsforum.com/attachments/cm ... g.2681474/

kyl416 wrote: Thu Nov 05, 2020 4:35 pm Just a warning before anyone blindly buys that. They now have a newer model that starts at 610 MHz (RF 37) since their original 600 MHz model cuts out RF 36 and the top 2 MHz of RF 35, which causes problems for about 80% of the country. (i.e. in NYC WNBC is on RF 35 and WCBS is on RF 36, while portions of the Portland DMA will have several LPTV stations on RF 35 and RF 36 when everything is done)

Buying it from the Channel Master site should get you the newer model, but a lot of 3rd party retailers still have the 600 MHz model. So if anyone does end up getting the 600 MHz model, they might want to do research at RabbitEars first to check if any channels will be using RF 35 or RF 36 and contact Channel Master to see if they can get an exchange for the 610 MHz model. They should also check their market listing to make sure they don't still have any stations on RF 38-51 in their area since LPTV stations and translators were not assigned repack phases.

BioTurboNick
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Re: Channel Detection Scan (channels 2-6)

Post by BioTurboNick »

jasonl wrote: Tue Sep 29, 2020 9:53 pm Money. WGBH in Boston, otherwise known as the producer of about a third of the shows we think of as "PBS shows", got almost $162 million to move from UHF to low VHF. A ton of viewers in Boston can no longer watch PBS over the air in HD, but $162 million pays for a lot of episodes of This Old House, NOVA, and Frontline, so Boston's loss is our gain.
Damn, is that what happened? I was hoping the transmitter power boost would solve it. I guess no available indoor antennas can handle low-band VHF?

NedS
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Re: Channel Detection Scan (channels 2-6)

Post by NedS »

BioTurboNick wrote: Fri Nov 27, 2020 8:51 pm
jasonl wrote: Tue Sep 29, 2020 9:53 pm Money. WGBH in Boston, otherwise known as the producer of about a third of the shows we think of as "PBS shows", got almost $162 million to move from UHF to low VHF. A ton of viewers in Boston can no longer watch PBS over the air in HD, but $162 million pays for a lot of episodes of This Old House, NOVA, and Frontline, so Boston's loss is our gain.
Damn, is that what happened? I was hoping the transmitter power boost would solve it. I guess no available indoor antennas can handle low-band VHF?
For whatever reason, it's hard to find anyone selling good old rabbit ear antennas these days. You'll need long elements on them, almost four feet long each, to get the full VHF-Lo range.

You could try this: https://matthews.sites.wfu.edu/misc/dipole.html

It works really well.

NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

Yup. A folded dipole is what I was going to suggest giving a try.
Though twin lead doesn't have to be used. Even if not using twin lead a 1:4 balun should still be used if connecting to coax. i.e. 75 to 300 ohm "transformer". It does more than just match impedance. It properly converts the balanced output of antenna to unbalanced coax. i.e. balun

The real trick though is integrating with VHF-hi and UHF antenna.

What you might also give a try first is a traditional old bowtie antenna. You may even know someone who has one laying around that needs a good home. Or could even make one. Typically bowtie antennas are smaller. That is what I'm using (13" x 3" with 25" 300 ohm twin lead feed line; the balun leads add about 5" more to the feed line, for a total of about 30").
Image
But there are no VHF-lo channels here so don't know how far down the spectrum it is effective (lowest here is ch. 8). But bowtie antennas have a very wide bandwidth. If you can manage to get a bowtie work in VHF-lo it very well may also work for VHF-hi and UHF also.

Two big keys to successful use are:
1) the twin lead must exit the bowtie at 90 degrees (ex: straight down or straight back) and run for half wavelength. Then connect to a 1:4 balun (75 to 300 ohm "transformer").
2) take time to find the reception sweet spot. Mount it on a few feet long non conductive stick (wooden yard stick, PVC pipe, etc.) so you can move it around easily while observing signal level and quality.

Avoid using an older balun that may be a true transformer that provides isolation as they have higher insertion loss than newer better designed non isolating baluns. One potential way to check for true isolation transformer type is to ohm out the twin lead to coax. If there is no DC conduction between twin lead and coax then it is most likely an isolation transformer type.

I'm using this Channel Master balun. It has less insertion loss than the old isolation transformer type I was using previously.
https://www.channelmaster.com/TV_Antenn ... -94444.htm

Been tinkering with a few indoor single element antenna types recently. Very difficult to beat the old bowtie.
For a narrow bandwidth like VHF-lo the folded dipole very well may be the ticket though. But integration with VHF-hi and UHF antenna may be problematic. Soon as they are connected together the characteristics change.

In it's most simplistic basic design, a bowtie is two half wave dipole antennas. One rotated n degrees clockwise and the other rotated n degrees counter clockwise. Rotating a dipole results in increased bandwidth. For space savings the ends of a dipole can be bent up or down. In the case of the criss-crossed dipole this results in a closed ended bowtie. Though the bent ends of the bowtie don't actually have to be electrically connected each other.

jasonl
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Re: Channel Detection Scan (channels 2-6)

Post by jasonl »

A bowtie style design would still need to be huge to pick up low VHF. https://www.changpuak.ch/electronics/Bu ... signer.php will calculate the numbers, and at 79MHz for channel 5 it wants 1.5m long legs, and the antenna overall ends up about 3m*1m. Better off with a (folded) dipole. A UVSJ could be used to combine, or you could just do what Winegard does on some of their antennas and use 1/4 wavelength stubs to short out the UHF frequencies while passing through the VHF. Should be about 4.5" long each.

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