[stampeder]

I'm really shocked at CHEK proposing to stay on 6, given their proximity to SeaTac and the very aggressive wireless companies down there wanting to grab up spectrum. Their IC PT allotment is for channel 49 at 105kW ERP, which would be excellent. Staying on 6 with a big ERP would give them terrific coverage, mind you.

Similar conversations on this topic were going on in several threads so I've collected them here in this thread. To me the intent to transition any TV station in Canada to a VHF-LO channel is wrong for many reasons. It is technically suspect, and it is anti-consumer.

 

[roger1818]

I'm really shocked at CHEK proposing to stay on 6, given their proximity to SeaTac and the very aggressive wireless companies down there wanting to grab up spectrum.

I am not sure if anyone is really interested in VHF-LO as it has many interference issues and requires very large antennas. About the only good proposal I have seen is to use half of 5 and all of 6 to extend the FM band for digital radio, but that would be years away.

 

[micah]

I am not sure if anyone is really interested in VHF-LO as it has many interference issues and requires very large antennas. About the only good proposal I have seen is to use half of 5 and all of 6 to extend the FM band for digital radio, but that would be years away.

I don't really know if interested is the right word. I've contacted CIII in ontario, and they (despite my protestations) intend to stay on RF6:

Thank you for your continued interest in CIII, and its Paris
transmitter.

Canwest intends to broadcast its Paris digital signal on Ch. 6, as
assigned by Industry Canada. We will be reviewing the broadcast
effectiveness of our digital transmitter and antenna configuration at
Paris, and determine the need for, and feasibility of, any alternative
configurations.

Canwest will certainly take your comments under advisement, and we
appreciate your feedback.

And from what I gather, the assignment has already been approved, so like you said, we cannot intervene

 

[roger1818]

I don't really know if interested is the right word. I've contacted CIII in ontario, and they (despite my protestations) intend to stay on RF6

Just so that people understand the context of my original post, I was talking about other wireless companies. I agree that some TV stations are showing an interest in remaining on VHF-LO to save money.

And from what I gather, the assignment has already been approved, so like you said, we cannot intervene

That is very unfortunate. Lets hope reception is better than we are expecting (I don't know about in Paris, but here in Ottawa, Global will be using almost as much power post transition as they are now in analog) and if not, they come to their senses quickly and change allocations.

It is always possible that this is just a temporary move and Global hopes to buy /A\ to have local stations in both Ottawa and London so that they can shut down these repeaters. It is likely wishful thinking on my part though.

 

[micah]

I agree that some TV stations are showing an interest in remaining on VHF-LO to save money.

How is that? Because its just administrative overhead or is there actually a cost to switching stations?

That is very unfortunate. Lets hope reception is better than we are expecting (I don't know about in Paris, but here in Ottawa, Global will be using almost as much power post transition as they are now in analog) and if not, they come to their senses quickly and change allocations.

It is always possible that this is just a temporary move and Global hopes to buy /A\ to have local stations in both Ottawa and London so that they can shut down these repeaters. It is likely wishful thinking on my part though.

Wishful thinking indeed (I do think that'd be great). Also, they're looking at a ~27x power reduction in Paris, so I'm quite worried!

 

[downbeat]

How is that? Because its just administrative overhead or is there actually a cost to switching stations?

There's certainly lower capital costs for a VHF broadcaster by simply re-using an existing antenna and refitting an analog transmitter to make a digital one, if the model allows.

 

[stampeder]

VHF-LO power savings means less $$$

The laws of physics and electromagnetism tell us that across the RF spectrum as the intended frequency rises, the wavelength shortens and the power required to achieve the same coverage area rises. Thus, a VHF-LO channel requires/uses a great deal less power than a VHF-HI or a UHF assignment but also requires a much bigger antenna for proper reception.

So, if your station is requiring less power, it is therefore not costing as much in electricity bills. That is where the big savings come in for Global, over the length of time that they remain on channel 6.

Nevertheless, I am quite irritated with Global for staying on VHF-LO channel 6 due to all the trouble it will cause with OTAers having to rig such a big antenna just for them.

 

[Jake]

a great deal less power

Can you quantify that?

 

[stampeder]

Formula regarding Power, Frequency, Wavelength

Can you quantify that?

Arrgh! Jake, you're going to make me go look through my dusty, musty old electronics text books for the equations...

I've asked in the Antenna R&D Forum if anyone has the formula: http://www.digitalhome.ca/forum/showthread.php?t=129626

 

[Jake]

I was hoping you would pull out a napkin and after a few minutes say "typically 50:1" or some such ratio.

 

[stampeder]

Those brain cells in charge of remembering that formula went to sleep long ago and never woke up again but I'm sure someone in the other thread will post it.

 

[stampeder]

CIII Channel 6 - appropriate article to send Global

The following is significant for Global since they intend to transition to Channel 6 in Ottawa and Paris, ON - in a post about CHEK Victoria and why it should not stay on VHF-LO Channel 6, Alex1978 posted this great item:

http://www.digitalhome.ca/forum/showpost.php?p=1150968&postcount=1265

 

[roger1818]

That is where the big savings come in for Global, over the length of time that they remain on channel 6.

While still true, the savings are as substantial after transitioning to DTV. Experience in the USA has shown that VHF stations need more power than expected for DTV. This is especially true with VHF-LO where they found they need almost as much power for DTV as they did for analog (another topic I know). I am not sure how this effects the amount of power needed for different bands, but I think it puts VHF-LO close to VHF-HI for DTV (but I could be proven wrong on that one).

Nevertheless, I am quite irritated with Global for staying on VHF-LO channel 6 due to all the trouble it will cause with OTAers having to rig such a big antenna just for them.

To me, a bigger issues is FM interference. It isn't such a big deal in more remote areas where the few FM stations there can be kept at higher frequencies where they cause fewer problems and can easily be filtered out with a band shifted FM trap, but in urban areas (such as Ottawa) where the FM band is filling up, we are getting more and more powerful FM stations at lower frequencies (below 100MHz) that can't be filter out with a band shifted FM trap (that doesn't kill channel 6).

On a related note, another benefit for not using channel 6 is it allows existing FM stations below 100MHz to increase their power and makes it easier to add more FM stations withing the existing FM band.

 

[Blackburst]

Using Channel 6 is possible. But, you really need more power. WRGB-DT is at 30kw on channel 6. Even the problems with channels 7-13 can be better handled with more power. WWNY-DT is using 24kw on channel 7.

But, I would prefer that originating stations be allowed to use that much power, not re-transmitters. I don't see why Global has a retransmitter in Ottawa. That town should have another local TV station with a Global affiliation.

 

[stampeder]

Using Channel 6 is possible. But, you really need more power.

There has been an ongoing discussion in the U.S. within the NAB about how VHF DTV signals, even when increased to flamethrower mode, still do not penetrate urban areas as well as UHF signals. That article says the same thing, and we've discussed it here at this site before, so personally I'm quite against the use of VHF-LO channels for DTV.

 

[roger1818]

A lot of this comes down to urban vs rural needs. As stampeder says, UHF penetrates buildings better than VHF, but VHF will travel through trees better than UHF. There is also less RF noise in rural areas and people are more able and willing to install a large outdoor antenna there. For these reasons I have maintained that VHF should be saved for serving rural areas and UHF should be used for urban areas. As for VHF-LO, it could be saved for remote analog transmitters and channels 5 and 6 could be used to extend the FM band in urban areas.

Obviously the policy makers don't seem to see things the same way I do however.

 

[roger1818]

Thunder Bay Stations also to Stay on VHF-LO

Two more stations planning on staying on VHF-LO are CHFD-TV and CKPR-TV in Thunder Bay (Global and CBC affiliates owned by Thunder Bay Electronics Limited). CHFD will remain on 4 instead of the allotted 46 and CKPR will stay on 2 (instead of the allotted channel 49).

 

[roger1818]

here in Ottawa, Global will be using almost as much power post transition as they are now in analog

Correction. They will be using less than 1/10 of the power they are using now in analog. I don't see how anyone will be able to receive this without using a deep fringe VHF-LO antenna (or better yet, a cut channel Yagi) at urban distances and then filtering it to death with a network of sharp notch filters, each tuned for the high power, low frequency FM radio stations broadcast from the same tower. That will be like $500 just to receive one station. I guess we will have to wait and see to find out for sure though.

(I know this is off topic for this thread, but I am wanted to reply to the message in the thread I found it.)

 

[Jase88]

VHF Low assignments

I suppose those stations moving to DTV on a VHF low assignment haven't followed (ignored, perhaps?) the lessons learned by US stations that have had issues doing the same.

 

[roger1818]

I suppose those stations moving to DTV on a VHF low assignment haven't followed (ignored, perhaps?) the lessons learned by US stations that have had issues doing the same.

Either that or they don't care about their OTA viewers and are only concerned about saving money. It is also quite possible that the executives who are making these decisions just don't have a clue.