Will CM4221HD Get Upcoming VHF-HI Channels? - Canadian TV, Computing and Home Theatre Forums

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post #1 of 24 (permalink) Old 2010-02-22, 05:07 PM Thread Starter
 
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Question Will CM4221HD Get Upcoming VHF-HI Channels?

Not only is CTV and CHCH going to be VHF but it is going to
significantly drop it's power. Is there specs on how well the
4221HD does on VHF-Hi?
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post #2 of 24 (permalink) Old 2010-02-22, 06:18 PM
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4221 design and future VHF reception?

I've had luck with receiving a good 40% signal strength VHF12.1 from Erie at 50+ miles and good analog VHF from Toronto using 4221's new HD and with the older 4221 designs. But I've had much better luck with my DIY build from a beta-design that is under consideration as a future 7-51 VHF/UHF antenna.
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post #3 of 24 (permalink) Old 2010-02-22, 07:53 PM Thread Starter
 
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Hey Canuck, My 4221HD is pointed at Buffalo, and Toronto is 10 miles
away from me coming from the side, Do you think the 4221HD will
get VHF 9 at 2kw and also Hamilton is southwest 35 miles with channel
11 in VHF at 6 or 7 kw, could it be possible to get this? or maybe
adding a amplifier that has VHF on it because currently I have
only a UHF pre amp. I wouldn't mind paying 50-80 bucks for
a VHF/UHF pre amp to get those 2 channels forever free, because
I like CTV's HD content and chch plays some pretty good movies
at night.
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post #4 of 24 (permalink) Old 2010-02-22, 08:47 PM
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If you get 9 & 11 analog off the edges now with that 4221, then you win without changing anything.
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post #5 of 24 (permalink) Old 2010-02-22, 09:34 PM
 
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Honestly I wouldn't be too worried about VHF 9 digital at 2.4 kW.

Remember that
a.) It's VHF meaning less power needed to cover the same area.
b.) It's digital, so it needs substantially less to cover a similar area.

I don't think the coverage of CFTO post-transition is for any of us GTAers with small UHF antennas to worry about. Unless you're talking fringe. It will be significantly less for sure, but certainly not horrible. It's more than kilowatts you know...

But we shall see.
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post #6 of 24 (permalink) Old 2010-02-23, 06:15 AM Thread Starter
 
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some specs for VHF hi would be good, But I did do 2 hardware
hacks (removing plastic and flipping the balun), I think city TV
is 1.2kw and I get it really good, so at 2.4kw I should get this,
But I'm still not to sure about the CHCH from hamilton the analog
is ugly as hell I guess because of the cable runs and only a UHF pre amp,
but going from 60KW to 6kw , Someone said
VHF needs much less power to reach us, But is 6KW really enough?
I guess now I might need a VHF/UHF pre amp, Is the channel master
spartan 3 pre amp good? because I can get it for a unbelievable deal.
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post #7 of 24 (permalink) Old 2010-02-23, 11:18 AM
 
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According to TV Fool city is at 2KW but I also think its very directional which helps reception north of the city. I live in Newmarket and I get a nice clean signal on CITY_DT with my antenna peaked towards Channel 49 in Buffalo. I get very little signal from Global, SunTV, and OMNI1 unless I re-peak my antenna. For now for me its a waiting game to see where things are after 2011.

From my own personal experience I don't think CFTO-DT on RF9 at 3KW will be too much of problem for fringe areas. As I've stated above I currently get CITY-DT at 2KW with very little tweaking. Compare that to RF9 at 3KW and I think most of us will be happy post transition. City is only 2KW and way up in the UHF band, CFTO-DT will be (post transition) much lower in the band and has a little extra power this will help its coverage area.

Out of curiousity all other things being equal what is the ratio of Digital to Analogue power required to provide equal coverage area? I know its not a simple answer but a ballpark figure?

Example would RF9 analogue at say 300KW have about the same coverage area as RF9 digital at 3KW? Is it about a 100:1 ratio?

Vive le transition!
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post #8 of 24 (permalink) Old 2010-02-23, 11:39 AM
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Quote:
Originally Posted by New2OTA
what is the ratio of Digital to Analogue power required to provide equal coverage area? I know its not a simple answer but a ballpark figure?
ERP is a calculated value, not a measured one, and it is too complicated a set of formulae for even most ballpark figures of ▒5kW, for instance. It depends on how granular you need the guess to be. 2kW can make a world of difference between 2 different stations, usually for a variety of other reasons that just broadcast power. Just like with home OTA reception, location (in 3 dimensions) is everything.

About the only time you can make a rough guesstimate is with 2 stations on nearby channels (like 32 and 34, for example) on the same tower at almost the same height with the same transmitter at the same input power, and even then you still haven't taken into account the beam pattern, tilt, and other factors.

A perfect example of different variables is KOMO-DT in Seattle, which just changed the position of their broadcast antenna on their tower, made no other changes, yet have had a correspondingly large boost to their coverage area.
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post #9 of 24 (permalink) Old 2010-02-23, 11:46 AM
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Proximity to the Canadian post-transitional VHF-HI stations will be a big factor in how well/poorly a CM4221HD will do. The OP is in Mississauga, which tells me that he will do fine there, but for people who live in the fringe to deepest fringe areas of several Canadian cities scheduled to have VHF-HI stations there might/will be problems.

Perhaps someone might want to post in the Channel Master 4221HD Hardware Hacks For Better Performance thread to ask whether NARODs can be added to that antenna for positive VHF-HI gain.
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post #10 of 24 (permalink) Old 2010-02-23, 11:53 AM
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Nobody can say with certainty how reception will change post-transition. We do know that significant problems were experienced in the US with VHF reception after the transition.

Comparing existing analog reception may help somewhat--but there will be big changes to ERP in the digital world. So even that is a gamble.

Of course these VHF stations may apply for a UHF designation, or even higher ERP in the interim.

The best advice I could give is to do your VHF-antenna research prior to conversion, should a purchase and installation be required. Or--if you want to best protect yourself--go with a 7-51 antenna.

It's too bad that we haven't seen any "real world" reviews of the C-5 compact VHF from Antennas Direct. As this antenna--if a decent performer--would be a good solution for those with balconies (apartment/condos) or those wanting a low-profile antenna system.

DMX 68' tower, HyGain HAM 5 rotator, Antennas Direct DB8e & C5, Channel Master 7777 preamp, Siemens surge protection. TiVo Roamio DVR
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post #11 of 24 (permalink) Old 2010-02-23, 12:44 PM Thread Starter
 
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I e mailed channel master and asked what the specs for vhf-hi are,
I will post it if I get it, but another hack with narods sounds like
a good idea along with a vhf/uhf pre amp.
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post #12 of 24 (permalink) Old 2010-02-23, 12:47 PM
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Quote:
Originally Posted by stampeder View Post
The OP is in Mississauga, which tells me that he will do fine there, but for people who live in the fringe to deepest fringe areas of several Canadian cities scheduled to have VHF-HI stations there might/will be problems.
At my location in Mississauga, CFTO analog 9 came in clear as a bell when I had a 4221. My current HD-8000 gives almost identical results.

Is one result predictive of another (post transition)? Maybe not but I'm 18 miles away from the CFTO transmitter and I can't imagine I will notice any difference after August 2011.
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post #13 of 24 (permalink) Old 2010-02-23, 03:46 PM
 
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I still use CFTO analog to receive the TVGOS signal. My current setup - stacked 4221hd'S, 23 miles from the CN Tower and behind a LOT of trees, was unable to provide a steady-enough signal. Installed a set of rabbit ears lower down the mast, and the problem was solved.

To address the OP's question, I don't have any specs but I'm not so impressed with the 4221's VHF-HI performance.

ymmv, of course.

Steve
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post #14 of 24 (permalink) Old 2010-02-23, 06:29 PM
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When CFTO,CHCH return to VHF high at low power ,I think you find many drop outs do to static from motors,switches etc.Many USA VHF -hi stations have appied for max power and are getting approved because of the problems.Rochester has applied for the full 30kw on VHF hi.Cant see CFTO 2.4kw cutting it.

Attic CM 4248 at Buffalo,M4 at Buffalo.VHF yagis at Toronto .
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post #15 of 24 (permalink) Old 2010-02-23, 07:57 PM
 
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I'm currently using CM4221HD with a CM7778 preamp. I have the amp set as combined VHF/UHF. CFTO 9 and CHCH 11 are absolutely perfect. I'm not expecting any problems post transition for these as the towers are close. But keep in mind, this is primarily a UHF antenna. CKVR post channel 10 and CKCO 13 I wouldn't expect to get if they are even receivable in Mississauga. If need be, I can get a VHF high antenna and connect to the preamp. A hack to add NAROD's for VHF Hi would be nice as the VHF spar style antennas are quite large.
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