[kwlug-disc] Future of [Rogers] PVR (wrt HDMI)? Black boxes? MythBuntu?

Andrew Kohlsmith (Mailing List Account) aklists at mixdown.ca
Mon Sep 28 00:34:25 EDT 2009


On September 16, 2009 02:03:39 pm Jason Locklin wrote:
> >> Keep us posted as to your progress and success, please.

> > Will do.  I've informed the wife that if she wants TV this winter I need
> > to get this done before it gets cold. :-)

> I'd love to year how it goes, planning on doing something similar
> myself. Looks like all the digital channels we may be able to pick up
> are UHF, so no need for a big VHF antenna (UHF-only antennas are often
> cooler looking anyway IMHO).
> http://www.digitalhome.ca/forum/showthread.php?t=109935

> I'd love to know if anyone has managed to pick up Buffalo and Toronto
> with something like the CM-4228.

So. I've got some preliminary findings.

I bought the ANT-2109; it was the biggest corner reflector yagi from Digiwave, 
and about $40 from Research Electronics behind Williams in Waterloo. Orion has 
them as well, for about the same price. I really wanted to try their 91XG 
clone, but I figured let's start at something with the highest likelihood of 
working and optimize at the right time. :-)

The antenna's very solid (they actually inject plastic into the hollow 
aluminum passive elements, which I thought was a neat trick) and it's about 5' 
long.  I installed it in my attic instead of uglifying the roof, although I 
may end up putting it on a 15' pole on the roof.

I also purchased a CM-7777 low noise amplifier (preamp) - After doing some 
reading it's the second-best LNA available, with 26dB gain and a 2dB noise 
figure. The top-rated amp is a Kitztech amp (KT-100VG, $60 from kitztech.com), 
which is a variable-gain amp, up to 20dB but with an amazing 1dB noise figure.  
I actually paid $100 for my amp, so I may have been kind of foolish there, 
without buying both and comparing I'll never know which is a bigger factor: 
1dB better noise figure or 6dB gain. It's certainly not something obvious.

I am able to pick up CBC, CTV and Global reliably (that is, any time of the 
day). I am also picking up CITY and OMNI 1 and 2. With the exception of 
Global, which transmits out of Stoney Creek, these are all from the CN Tower.  
I spent the better part of the weekend cursing and aiming, cursing and aiming 
in the attic. I picked up all these and several others when I just had the 
antenna lying on the ground kind of half-assed aimed, but once I put it on a 
mount I lost everything.  I ended up using a couple of tie-wraps to secure the 
reflector and then very slowly doing some fine-tuning trying to pick up CITY and 
Omni 2, which are the weakest stations on the tower.

I also pick up two or three different stations out of Buffalo. I just watched 
the Fifth Estate and then flipped to Buffalo to watch a little CSI Miami. It was 
a good episode with beautiful women playing volleyball, but then a dead body 
in the sand ruined everything and I had to turn it off.  :-)

All of these stations are digital and HD; I am not worring about analog 
reception at all at this time. I also broke off half of one of the passive 
elements on the antenna trying to get it aimed "just a little more" against 
one of the rafters. :-(  I'm sure it's affecting performance to some extent, 
but without replacing the antenna and retesting I can't tell for sure.

Anyway there are a couple of tricks I'd like to pass along.

1) rip out the POS balun in the ANT-2109 and replace it with a $2 balun you 
can find at Wally World, Radio Shack, Orion, Home Depot or a thrift shop.  The 
balun that the antenna comes with is utter crap.  I am going to be 
experimenting with a coax loop balun, as testing over on digitalhome.ca seems 
to show it's a stellar balun for UHF.

2) dvbtune can't tune ATSC cards without a little patch. I wasted a LOT of 
time with this until I discovered it was silently failing to tune.  Best bet 
is to use a TV and work on getting a station pulled in, then tweak the 
antenna, move away from it and see what difference it made to the picture. I 
could find CBC pretty quickly, then woudl jump to CTV, and then over to OMNI2 
and CITY (the weak transmitters) to try and tweak the position.  Do this at 
nighttime when propagation is best, secure the antenna and then see what you 
can get in midafternoon when propagation is worst.

3) Check and recheck your wiring; I had the TV up in the attic with me after I 
got sick and tired of dvbtune/w_scan not giving me consistent results. I used 
the method described above and then went back to the tuner card.  I am 
backfeeding the home coax and there is a run of crappy cable in there 
somewhere, so once I clean that up I'm sure I'll get better results with the 
tuner card. The HVR-2250 is supposed to have a really good receiver (low noise 
and high sensitivity).

4) Antenna position is not ... "normal." What I mean by this is that lying on 
the attic floor, I pulled in something like 19 analog and 16 digital stations, 
but when I put the antenna on a mount 4' higher, I got nothing. Putting the 
antenna on a few cross-beams refused to give me anything, but holding it 2' 
above them I could see a signal. There are also all kinds of near effects where 
your own body influences what kind of signal the antenna receives. It's a royal 
pain to try and pull in weak stations!

But yeah... change out the balun (experiment with a few! they're the cheapest 
part of the whole system) and patience (several days worth) is needed to make 
this work.  I did a lot of research and you don't seem to have any CLEAR 
advantage by spending your money on the 8-bay channel master antenna. In fact, 
one extensive site showed how they used poor baluns as well, and how their 
"new and improved" design is actually worse than their older antennas.

I might also try experimenting with different driven element designs, but I'm 
also kind of lazy. Unless this stops working or I really get the itch to pull 
in some more stations, I think I'm going to be leaving things more or less how 
they are.

OTA HD is definitely doable in Kitchener-Waterloo, and can be done for about 
$100 to $150 in parts, depending on what you choose. It takes some patience 
and perseverance to get it working beyond CBC-HD, though.

-A.




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