Incentive Auction Discussion

[Trip]

I wonder if channel 6 doesn't offer the same bandwidth that other channels do in order to guard against interference at the bottom end of the "FM dial".

Digital TV on channel 6 is no different than on any other channel.

- Trip

 

[harshness]

Digital TV on channel 6 is no different than on any other channel.

Aside from the fact that it abuts a substantially different bandwidth usage scheme that inhabits frequencies centered as little as 100KHz away? I'm inclined to believe that there had to be some reason that the FCC changed their minds about the Sacto PBS station.

How much guard band is built into ATSC at the top of the 6MHz and is there reason to believe it may not have been sufficient?

 

[Peter Parker]

It is different in that it is so close to FM frequencies.Non profits on the lower FM frequencies often complain about the potential for interference.I am not sure I buy it but they do complain.

 

[Trip]

Aside from the fact that it abuts a substantially different bandwidth usage scheme that inhabits frequencies centered as little as 100KHz away? I'm inclined to believe that there had to be some reason that the FCC changed their minds about the Sacto PBS station.

https://apps.fcc.gov/edocs_public/attachmatch/DA-06-991A1.pdf

That document notes that KVIE originally elected channel 9, but then was ultimately granted channel 6.

http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-06-150A1.pdf

And on pages 19-20 of this document is KVIE being moved off channel 6 and onto channel 9.

While the channel 6-FM issue is noted here, the footnote points to an earlier FCC document which speaks to the problems of low-VHF in general. KVIE was the only one handled in this particular document, but several other low-VHF stations also went through more than one iteration before landing on a final channel number. (KUSD, WSKY, KCWX, WWMT, WCES, WABW, KRMA, WDIQ, and I think WMOW.)

How much guard band is built into ATSC at the top of the 6MHz and is there reason to believe it may not have been sufficient?

The FCC rules do require a showing that there won't be interference between digital TV channel 6 and FM. In the FM-into-TV6 direction, there is a rule 73.525 about it which was written in the 1980s and has not been updated, but is still being applied in the same way (for better or for worse). In the other direction, there is no specific rule about what a showing must contain, but there is a rule requiring a showing.

I don't know what the internal guard bands are off-hand.

- Trip

 

[harshness]

So there's no evidence to support your claim that RF 6 is no different from any other channel and some that suggests that it might be capped based on how things turn out.

It seems like bouncing from channel to channel (82MHz to 186MHz) would have a financial impact as well as a coverage area impact. Surely not as much as someone moving from 43 to 3, but probably not a simple matter of tweaking an oscillator.

 

[Trip]

So there's no evidence to support your claim that RF 6 is no different from any other channel and some that suggests that it might be capped based on how things turn out.

I believe the burden of proof is on you. You're the one making the claim here. I've attempted to point you in the right direction.

Do channel 6 stations have to make a showing (or FM stations near channel 6 stations)? Yes. I said so. Otherwise, channel 6 stations are no different, from an equipment/modulation/signal point of view from any other ATSC TV station. (I don't know what you mean by "capped" either.)

If you choose not to believe me, as you have done several times, that is your right. I seek only to correct the record so others do not become confused by your postings.

- Trip

 

[harshness]

I believe the burden of proof is on you.

You made the unqualified claim that there is no difference between RF 6 and any other TV channel so the burden is on you to provide evidence that what you said is true. What little evidence you've offered has only hinted at supporting my claim that proximity to FM radio is likely an issue and something that the "owner" of RF 6 will suffer versus most other channels.

It is possible that all of the DTV-prescribed bandwidth is usable, but given what we've see thus far, it doesn't seem very likely.

Perusing the RabbitEars database, it appears that a lot of the stations currently using RF6 are low power and/or located where there isn't much other RF traffic. WPVI Philadelphia is a notable exception.

 

[Trip]

Perhaps the issue here is that we're debating over what constitutes a "difference." I'm arguing that a channel 6 DTV signal looks the same on a spectrum analyzer, uses the same amount of bandwidth and filtering, etc., as one on channel 5. I'm not arguing that FM interference in either direction isn't an issue (though I will say 73.525 vastly overstates the amount, being based on measurements made in the 70s). Just that there's nothing unique to the signal itself that is different, like how stations on channel 14 have extra filtering to protect land mobile.

I thought you were arguing that type of difference; are you?

- Trip

 

[Trip]

And in a stunning display of back-on-topic-ness, the first stage of the auction closed today at something like $23 billion dollars.

Far short of the $88 billion required to close the auction.

On to stage 2...

- Trip

 

[mrc54]

Or stage 3 or 4. This auction is a joke.

 

[Trip]

In what way? It's designed to go through multiple stages so that supply meets demand. Supply and demand did not meet in stage 1.

- Trip

 

[Voyager6]

The gap shows how unrealistic their expectations were.

 

[harshness]

I'm arguing that a channel 6 DTV signal looks the same on a spectrum analyzer, uses the same amount of bandwidth and filtering, etc., as one on channel 5. I'm not arguing that FM interference in either direction isn't an issue (though I will say 73.525 vastly overstates the amount, being based on measurements made in the 70s).

I'm arguing that RF 6 became a blighted property with the advent of DTV. It is not about the fact that they're using the same modulation scheme but the likelihood that there just isn't as much you can do with the channel in terms of coverage area and perhaps even bandwidth as with most other channels. Those are the practical measures of value and the industry has shown its disdain by substantially vacating the channel for serious use.

Just that there's nothing unique to the signal itself that is different, like how stations on channel 14 have extra filtering to protect land mobile.

Having to take remedial steps is like Charlie Brown picking the ugliest Christmas tree on the lot.

Clearly, not all TV channels have the same value because they can't all be utilized equally. These auctions are about establishing a value and if you believe that all channels are functionally identical, you're not exercising business sense or a being a conscientious student of Physics. You can do a cannon ball into the pool, but you have to mind that there can be no splashing on the deck around that pool when you do. Where's the equity in that?

 

[Trip]

The gap shows how unrealistic their expectations were.

Whose expectations? The prices were set by the auction mechanism. At 126 MHz, buying out all the TV stations necessary for that amount of spectrum would have cost $86 billion. Wireless companies weren't willing to spend that much. So the amount will go to 114 MHz, fewer stations will need to be bought, most of those who are still bought will go for a lower price, and we'll have a new number.

It's how supply and demand work. Demand was much lower than supply. Supply will be decreased and we'll see how much demand increases.

- Trip

 

[harshness]

The gap shows how unrealistic their expectations were.

The expectations of whom? That's the magic of having one body make the goals and another making the policy to reach those goals. Where I work, we call it the "infinite capacity model" where Sales assumes that if they can sell it, it will be delivered on time. One of the side effects of assuming that everything is the same.

 

[harshness]

Supply will be decreased and we'll see how much demand increases.

Perhaps you'll recall what happened last time someone said "let them eat cake".

 

[Trip]

I'm arguing that RF 6 became a blighted property with the advent of DTV. It is not about the fact that they're using the same modulation scheme but the likelihood that there just isn't as much you can do with the channel in terms of coverage area and perhaps even bandwidth as with most other channels. Those are the practical measures of value and the industry has shown its disdain by substantially vacating the channel for serious use.Having to take remedial steps is like Charlie Brown picking the ugliest Christmas tree on the lot.

Clearly, not all TV channels have the same value because they can't all be utilized equally. These auctions are about establishing a value and if you believe that all channels are functionally identical, you're not exercising business sense or a being a conscientious student of Physics. You can do a cannon ball into the pool, but you have to mind that there can be no splashing on the deck around that pool when you do. Where's the equity in that?

Okay, we're on the same side then. I would argue channel 6 has always been a problem, just that FM was much later in developing so a lot of the problems were hidden. When stations fled channel 6 (and the rest of low-VHF, for that matter) with the DTV transition, FM stations filled those gaps and now there could be problems being placed on channel 6. That's why WPVI wound up working as well as it did (which isn't saying much). Being on channel 6 for analog meant that the FMs had to protect it since it was there first.

There are no bandwidth differences between channels 6 or 14 and other channels. There could be coverage issues but I don't think there are any channel 6 stations on channels that weren't occupied by analog channel 6 stations, so they've never been encountered due to what I mentioned in the above paragraph.

Of course, we're not repacking stations to low-VHF unless they agree to accept money to do so, and even then the algorithm is designed to avoid placing stations on channel 6 if possible. Stations on UHF which are repacked to channel 14 will get their expensive filtering paid for by the FCC, but the algorithm also avoids channel 14 where it can to minimize that problem.

Perhaps you'll recall what happened last time someone said "let them eat cake".

I don't understand your point. All I'm saying is that if the price is too high, it wasn't going to close, and that's okay. Who is the FCC to prejudge the result? For all anyone knew, the wireless companies wanted the spectrum badly enough to pay that much. We keep hearing about the so-called "spectrum crunch," right?

- Trip

 

[harshness]

I would argue channel 6 has always been a problem, just that FM was much later in developing so a lot of the problems were hidden.

The problems weren't hidden so much as the part of the FM radio band that RF 6 used was modulated as FM radio. Now that that's no longer an option, we see where all TV channels aren't so much the same.

All this time we've been counting channels and maybe we don't have as many as we think.

 

[Trip]

The problems weren't hidden so much as the part of the FM radio band that RF 6 used was modulated as FM radio.

73.525 has very strict protections for TV stations from FM interference. Analog TV sets didn't handle the presence of very strong adjacent FM signals very well. So the problem was largely hidden from the general public because of strict rules that kept FM stations away from channel 6 TV stations unless they were co-located with the channel 6 station in question and coordinated with them.

- Trip

 

[localclassictvfan]

Read something that the minimum channel to go to went up to RF 31, hopefully it continues. Seems cell phone companies may not have the money to afford all the signal space