Global Ottawa DTV Transition - Aug. 16, 2011 - update in Post #331

[flavoie]

Mike a channel cut yagi for ch6 would give you great gain. Next in line would be VHF low antenna like the y-5-2-6, but I really like my VIP-302sr which is bit lower gain on VHF low but very respectable but also good gain on VHF hi.
Of all those the channel cut would be the smallest of all.

I found 2 threads for single cut yagis. Check for 5y6s.

[Trip]

Originally Posted by Humbar

They can't just increase the power. They will need to apply to Industry Canada to get approval, and that may require co-ordination with the FCC. Who knows how long that may take.

They can seek to operate at higher power via TO though. WRGB operated at 30 kW under STA while awaiting Canadian concurrence on a permit to boost to that level on a permanent basis.

(TO in Canada = STA in US, from what I understand.)

- Trip

[roger1818]

Originally Posted by mike infinity

I am still trying to understand why the rabbit ears don't do better on my roof compared to on my deck ~15' lower elevation.

It all depends what the root cause of your problem is. If it is FM interference, in increasing elevation won't help. Are you using an FM trap?

[roger1818]

Originally Posted by roger1818

I get it about 95% of the time (though it is too early to say for sure).

My reception has been quite reliable for Global over the past few days. The only issue I had was caused by a power failure (my HTPC is on a UPS but my amp isn't).

[mike infinity]

Originally Posted by roger1818

It all depends what the root cause of your problem is. If it is FM interference, in increasing elevation won't help. Are you using an FM trap?

I am using a cm7777 with fm trap set to "in". I attached the rabbit ears to the VHF in and set the mode switch to "separate". I have tried both unpowered rabbit ears and powered ones. I have had more luck with the powered ones with the gain set to minimum. I got 80% signal for a minute or two on my deck but I have been unable to duplicate this condition since.

Right now I have switched back to cm4228 alone in combined mode and I can get 65% locked on ts reader but the stream is chock full of errors. I get that same result with the rabbit ears 99% of the time on separate mode so the rabbit ears seem pointless for now.

I am wondering if it's worth all the hassle to try a single cut or 302 (which would have to be in my attic)...especially when many are having mixed results with that antenna as well.

[flavoie]

mike, the 302 or other VHF lo antennas are too big for your roof mount?
A single cut yagi would be smaller.

Have a look at these for lengths. The 5y6s could be your template.
http://www.digitalhome.ca/forum/showthread.php?t=139654

http://www.digitalhome.ca/forum/showthread.php?t=96013

Of course if you found the 5y6s somewhere you wouldn't have to build it.

[Domer2011]

Lots of good advice here and thanks to all whom post. But really I think we've been sold a bill of goods again by another Gov blunder. Didn't they ask the tech's if this transition could be done smoothly before it was ok'd years ago. Let the various departments involved we're paying by complaining to sort this out. Start at digitalhome.ca then the others.

[roger1818]

Originally Posted by roger1818

My reception has been quite reliable for Global over the past few days.

I spoke too soon. A couple of my wife's recordings on Global quit after about 10 minutes likely due to reception issues. Hopefully a better signal amp will fix that though. Just need to decide if I should get a CM-7777 or a kitztech (with my RS FM trap of course).

[flavoie]

My 2 issues with my Kitz were 1- perceived lower reliability when used outside & had to build your own box for outside. This is not a problem for you. 2- Having to put an FM trap in front, resulting in a higher noise figure than the Kitz by itself. I would always be second guessing myself whether after putting an FM trap in front, if the noise figure would end up being actually worse than a 7777.

[Trip]

I'm glad you commented flavoie, because when I read roger1818's message, I was going to suggest the Kitztech due to the lower noise floor as observed in side-by-side testing. But if the FM trap is going to wipe out that advantage, then I cannot make a recommendation.

- Trip

[roger1818]

Originally Posted by Humbar

They can't just increase the power. They will need to apply to Industry Canada to get approval, and that may require co-ordination with the FCC. Who knows how long that may take.

Co-ordination with the FCC shouldn't be a problem. The closest American station on channel 6 is WRGB in Schenectady, NY and considering they are broadcasting with 32.2kW with an HAAT of 392m, it shouldn't be a problem for CIII to get a similar power with a lower elevation.

The bigger issue will be the Canadian stations. Both CBMT and CJOH-TV-6 are on analog 6. CBMT will be shutting down at the end of August but CJOH-TV-6 will remain on air, but they may not be eligible for protection in September since they have been allocated channel 49 post transition. Regardless, Global may not be allowed to increase their power until September.

[tvlurker]

It was my understanding that the Noise Figure of the preamp is not the controlling factor in the Noise Margin of VHF-Low stations.

Do people actually find better results with a Kiztech compared to either no preamp or a standard preamp with a Noise Figure in the 3 dB range?

I would think that a directional antenna would help more with environmental noise than a preamp.

[roger1818]

flavoie, nit picking here I know but an FM trap shouldn't add much if any noise but it will attenuate the signal a bit which will amount to the same thing.

tvlurker, I hadn't thought of that but you might be right. Since I am already using a 5Y6S about the only more directional antenna would be a 10Y6S which would not fit in my attic. So if a lower noise amp doesn't work the only other option is to move the antenna outside which would both increase the signal level and lower the environmental noise (or wait to see if Global increases power).

I am borrowing an older CM Spartan preamp to see if it helps before going out and buying one.

[flavoie]

roger1818, yes that is what I meant. Adding insertion and other losses in front of your preamp by adding the FM trap and needed small coax cable lengths amounts to increasing your preamp (or System) Noise Figure, whatever we wish to call it. I think you are currently doing everything humanly possible in your attic so it just tells me how bad the Global Ottawa situation currently is.

[mike infinity]

Well. I managed to do it with...of all things...my rabbit ears.

At first I thought it was a fluke that I got 80% signal with the rabbit ears for a few minutes on my deck with ts reader (I use a remote desktop on my android tablet to view my media center pc while a tweak the antenna).

I decided to give it one last try. I measured 34.5 inches on my powered rabbit ears...set both ears to horizontal position and pointed them at CF on top of a pole on my deck. The signal locked and remained steady with ts reader.

Of course, wmc still can't see it so I installed NPVR. It picked it up right away. I watched for 15 minutes and saw no macroblocking and held steady at 80% signal.

I am encouraged that if I pick up a 302 that it might work in my attic since the rabbit ears work outside.

Not all is perfect...I have been fiddling with npvr but still cant get the audio stream to play or the guide to populate (I'm not sure how the guide works yet in that software).

I would prefer WMC due to its integration with the rest of my network. I will keep searching for a solution on that end.

FYI: I am feeding the rabbit ears into the CM7777 VHF input with the mode switch to SEPARATE and FM trap to IN.