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post #1 of 1712 (permalink) Old 2010-03-13, 11:57 PM Thread Starter
 
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Location: Wolf Grove Road, Lanark Highlands, ON
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Lightbulb ON - Kanata, Barrhaven, Nepean, West of Greenbelt - OTA

I've read the Knowledge Base & FAQ's. that was mind bending in a good way!
Thanks Stampeder for the background info and pointing me in the right direction.
I would like to post a description and photos of my antenna set up and ask for comments on what I could do to enhance reception on 2 digital channels.
Overall I am very happy with my TV reception.

I am receiving 3 digital channels perfect
CBC 4-1
SUN 20-1
OMNI1 27-1

and 2 more that pixel out and/or loose audio sometimes.
CBS 7-1
Fox 7-2 and several others that I am not interested in.

I also get 5 analog channels very good to perfect
Global 6
CTV 13
OMNI2 14
TVO 24
AChannel43 and several others that I am not interested in.

I would like to know if the reception of the 2 digital mediocre channels (7-1 & 7-2) can be improved. CBS and Fox broadcasting from Carthage Watertown USA. (TVfool report says 85 miles away)

My setup
Two 30 year old antennas that I set up 20 years ago 36 feet high on tower beside house with a Radio Shack mast mount preamplifier cat.# 15-1108. The preamp made a huge difference 20 years ago and still does for all channels.
From the preamp antenna unit to preamp power source is 40 feet.
Preamp power source to line splitter is 15 feet.
Splitter to analogue TV is 10 feet.
Splitter to the main digital LCD TV is 30 feet.

Yagi is pointing at 7-1 and 7-2 160degT (these are the two channels that pixel out sometimes) tvfool says 166degT 85 miles away.

Bowtie is pointing 40degT (sort of inbetween the rest of the channels I want) 29 miles away...some channels listed by tvfool as 31degT and the others are listed as being 80degT. (all good reception)

Here is the link to my tvfool report http://www.tvfool.com/?option=com_wr...b7c81ef5279b9c





Rookie questions...

1. Which end of the wide single bowtie antenna is the front? (I pointed the bowtie toward the desired channels...is that correct?)

2. Any suggestions on how to improve reception on 7-1 and 7-2?

3. Any comments on setup and age of components?

BTW...the slight bend on one of the horizontal poles on the bowtie antenna was from the great ice storm of 1998...could have been alot worse!

Thanks,

Rudy
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post #2 of 1712 (permalink) Old 2010-03-14, 01:32 PM
 
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Location: Franktown, Ontario CM4228HD with 7777 to two Samsung LCDs and WinTV on my WiFi network
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Looks like we are in the same boat Rudy!

We both want that elusive channel 7 to come in...

You should be able to get more channels out of Ottawa though. 9-1 and 66-1 should be there no problem for you as well.

Regards
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post #3 of 1712 (permalink) Old 2010-03-14, 01:52 PM
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First step, is to stop quoting those phoney "virtual channel" numbers (7-1,7-2), and instead find out (and post) what *real* "physical" channel is being used. The physical channel determines the frequency/wavelength, and thus dictates the antenna requirements.

EDIT:: ah.. in this case, you probably mean WWNY (CBS), which (rare) uses *real* physical channel 7. Excellent.

Now, what channel was that yagi designed for ?

Cheers
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post #4 of 1712 (permalink) Old 2010-03-14, 08:46 PM
 
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Location: Belleville. Ontario
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Question

Is that twine lead your using, not 75 ohm coax?

Winegard PR8800, YA1713, Zenith7777 Preamp, 42" Aquos 120hz, Samsung UP5000 Blu Ray/HDDVD, C/Ku Band, Directv H21, 22.
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post #5 of 1712 (permalink) Old 2010-03-14, 09:04 PM Thread Starter
 
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Location: Wolf Grove Road, Lanark Highlands, ON
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PrinceLH
Yes it is twin lead from the antenna to the mast mount preamp antenna unit. The rest is coaxial all the way to the TV. I set it up 20 years ago and have not touched it since.
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post #6 of 1712 (permalink) Old 2010-03-14, 09:22 PM Thread Starter
 
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Location: Wolf Grove Road, Lanark Highlands, ON
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mlord,
I would try to edit my post and put in the real physical numbers but I do not have the edit button in that post???...
Since I am mainly interested in improving reception for 2 channels I will do that now...yes channel 7 WWNY (CBS) and WNYF-LP ch35-2 (28) Fox(SD) both broadcasting from Carthage-Watertown.

Not sure if I understand what you mean by what channel was the yagi designed for...
I have it pointed at Channel 7 WWNY (CBS) and WNYF-LP ch35-2 (28) Fox(SD) both broadcasting from Carthage-Watertown.
Any suggestions for improved reception?
Thanks...RD

Quote:
Originally Posted by mlord View Post
First step, is to stop quoting those phoney "virtual channel" numbers (7-1,7-2), and instead find out (and post) what *real* "physical" channel is being used. The physical channel determines the frequency/wavelength, and thus dictates the antenna requirements.

EDIT:: ah.. in this case, you probably mean WWNY (CBS), which (rare) uses *real* physical channel 7. Excellent.

Now, what channel was that yagi designed for ?

Cheers
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post #7 of 1712 (permalink) Old 2010-03-15, 12:03 AM
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Quote:
Not sure if I understand what you mean by what channel was the yagi designed for...
That yagi antenna appears to be a narrowband yagi, meaning it was likely designed for enhanced reception of a very small number of channels. I'm wondering if you know the model number, or the design frequency/wavelength of it.

It's difficult to guess, but based on the larger size of the bowtie, I would suggest that the yagi is most likely designed for VHF-hi, somewhere amongst channels 7 through 13. The bowtie itself appears to be some kind of VHF-low design, though it does have a smaller director (VHF-hi?) in there for some reason.

Neither antenna will work very well at all for channels 14 and higher, which are UHF with a much shorter wavelength.

So, depending upon the design frequency/wavelength of the yagi, it might be perfect for channel 7, or not.

And for your other desired channel 28, you'll need to have something else in place.

Or I could be totally misjudging the sizes from the photo. Measurements would help a lot.

Cheers
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post #8 of 1712 (permalink) Old 2010-03-15, 01:30 AM
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I should have read this earlier - the top one is definitely a Delhi VHF-HI model (I own an unused one). 30 years ago if it was bought in Ottawa for Ottawa channels that means it is either for 9 or 13 but not both, because those models have steep dropoffs on the adjacent channels so they're not good for the whole VHF-HI band. I wish I could tell the element lengths better but I can't tell from the photo.

As for the other antenna, I mistook it for a VHF communications rig so I'm stumped on it, although the single elements look about the right width for a channel 6 TV antenna, which again makes sense for Ottawa.
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post #9 of 1712 (permalink) Old 2010-03-15, 09:43 AM
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Quote:
Originally Posted by stampeder View Post
I should have read this earlier - the top one is definitely a Delhi VHF-HI model (I own an unused one). 30 years ago if it was bought in Ottawa for Ottawa channels that means it is either for 9 or 13 but not both, because those models have steep dropoffs on the adjacent channels so they're not good for the whole VHF-HI band. I wish I could tell the element lengths better but I can't tell from the photo.

As for the other antenna, I mistook it for a VHF communications rig so I'm stumped on it, although the single elements look about the right width for a channel 6 TV antenna, which again makes sense for Ottawa.
OK, let's get things straight here.
1. 7.1(WWNY) and 7.2 (SD relay of 28.1) are both on the same physical channel, so if you can get one you can get the other

2. If the antenna was installed 30 years ago pointed towards Watertown, it was most probably a channel 7 antenna. It's probably similar to one of these.

3. Based on your TVFool results, it looks like your net system noise margin for channel 7 with an RS preamp is pretty close to 0 dB. ( = about -3.9 dB(TVFool NM) +12dBi(antenna) -7 dB(guesstimate of RS Noise Figure). I think you'll need 5 to 10 dB of fade margin for reliable operation -- you've got 1 or less. Ken Nist over at http://www.hdtvprimer.com/ANTENNAS/basics.html doesn't think much of the RS 15-1108. (Note -- the 7dB noise figure quoted above is for UHF channel 30. It's probably worse for VHF ch. 7 -- and your modern tuner probably has a BETTER noise figure than that! Unfortunately, it's masked behind a noisy preamp)

Translating all this geek-speak for a rookie -- your preamp is adding enough noise to the system that your marginal channel 7 is not coming in well enough. Replacing the preamp with something with better specs for channel 7 (a better noise figure -- typically, you can get 3 dB noise figures for VHF with a Channel Master or Winegard preamp) will improve the reliability of the signal.

Re-aiming your antenna might help, but I don't think being 5 degrees off is going to change much.

So the first step would be to get a better preamp -- more stable, and with a better VHF noise figure. Unfortunately, that means you have to climb up there to replace things. The channel 7 VHF antenna looks to be in pretty good shape, and the only way to get more gain for channel 7 would be to add another identical antenna. I think the preamp upgrade is the better route, and they're easier to find! (You can easily get at least a 3dB improvement with a better preamp, and 3dB is the most you could hope for from a second antenna.)


Stampeder wrote:
Quote:
I should have read this earlier - the top one is definitely a Delhi VHF-HI model (I own an unused one). 30 years ago if it was bought in Ottawa for Ottawa channels that means it is either for 9 or 13 but not both, because those models have steep dropoffs on the adjacent channels so they're not good for the whole VHF-HI band.
Jon, I don't think so. Thirty years ago channels (4,) 9 and 13 had already been at Camp Fortune for 12 years. CF is only 30 miles away, and TVFool reports NM in the 40dB range. A 10-element yagi would have definitely been overkill for Ottawa stations (at the time, that would have been 4,6,9,13,24,30,40 -- all at Camp Fortune, although I don't think the OP was interested in 9,30,40 en franšais). And the fact that the yagi is pointed south to Watertown is kind of a dead giveaway.
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post #10 of 1712 (permalink) Old 2010-03-15, 09:46 AM
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Quote:
Originally Posted by mlord View Post
And for your other desired channel 28, you'll need to have something else in place.
mlord, don't get confused by the virtual channels. When he says 28.1, he means the 7.2 subchannel. 28.1 is the PSIP for the HD version of WNYF on 35.1. 35.1 has a null to the north, so it doesn't even show up in the TVFool report. Amazingly, Syracuse and Utice stations show up there before a whisper on 35. (And even if there wasn't a null, Channel 36 Franktown is in his way.)
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post #11 of 1712 (permalink) Old 2010-03-15, 11:25 AM
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tvlurker, You beat me to it. I was planning on saying almost exactly the same thing. I agree it is likely tuned for channel 7 and as such is an excellent antenna for receiving WWNY and WNYF (SD).

I also certainly agree that replacing the pre-amp is the first thing Rudster should do.

My next question is how is he combining the Yagi and the Bowtie antennas? Optimally he should be using a signal injector such as a Jointenna. If he is using a broadband signal combiner, he could gain another 3dB of signal with this.

As for the Bowtie, it certainly is a curiosity. I am not convinced that it is for channel 6 only as the director is significantly smaller than the reflector (to answer your first question Rudster, the small element on the bowtie should be pointed towards the station). I am thinking it was designed for all of VHF, though it does seem to be doing a good job of receiving UHF for him as well. If he turns it a bit more towards Herbert's Corners he might be able to pick up CJMT-DT on 66, though it might be on too high a channel for that antenna. Otherwise, he might want to add a UHF antenna to the mix.

After the analog shutdown, he might be able to replace the bowtie with a VHF-HI antenna, assuming Global doesn't use Ch.6.
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post #12 of 1712 (permalink) Old 2010-03-15, 12:46 PM
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Alternatively, he could use a preamp with separate UHF and VHF inputs -- feed the the Channel 7 yagi only to the preamp, and split the bowtie antenna with a uhf/vhf combiner in reverse, and feed only the uhf side to the uhf input on the preamp. The signals on the Ottawa VHF locals shouldn't need preamplification. Or, if the OP wants to invest in a separate UHF antenna for Herberts Corners, then feed that to the UHF input, and leave the Ottawa unamplified as an input to s seaparate combiner.

What he really needs is a DBGH or a parabolic UHF with a very low noise preamp to get ABC/CW WWTI on 21 and WPBS on 41 from Watertown.

Last edited by stampeder; 2010-03-15 at 03:32 PM.
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post #13 of 1712 (permalink) Old 2010-03-15, 03:34 PM
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Bringing in the detectives :)

Quote:
Originally Posted by tvlurker
And the fact that the yagi is pointed south to Watertown is kind of a dead giveaway.
Thanks, I hadn't thought of that but it explains it perfectly.

Rudster, I'm going to copy your photos into the Antique, Used, and/or Mystery Antennas! thread to see if we can get a better sense of what your lower antenna is all about. We'll keep working on your reception here but we'll try to I.D. that antenna there.
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post #14 of 1712 (permalink) Old 2010-03-15, 03:59 PM
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Quote:
Originally Posted by tvlurker View Post
Alternatively, he could use a preamp with separate UHF and VHF inputs -- feed the the Channel 7 yagi only to the preamp, and split the bowtie antenna with a uhf/vhf combiner in reverse, and feed only the uhf side to the uhf input on the preamp. The signals on the Ottawa VHF locals shouldn't need preamplification. Or, if the OP wants to invest in a separate UHF antenna for Herberts Corners, then feed that to the UHF input, and leave the Ottawa unamplified as an input to s seaparate combiner.
He could do that. I still think the other option is better. I am not convinced that the UHF performance of that bowtie antenna is good enough to survive the VHF/UHF band separater/combiner and feel the UHF antenna would be much preferable.

Quote:
What he really needs is a DBGH or a parabolic UHF with a very low noise preamp to get ABC/CW WWTI on 21 and WPBS on 41 from Watertown.
I think he has a much better chance of getting WNPI on 23 than WPBS and I doubt if he could get WWTI reliably.
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post #15 of 1712 (permalink) Old 2010-03-15, 04:11 PM
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Originally Posted by roger1818 View Post
He could do that. I still think the other option is better. I am not convinced that the UHF performance of that bowtie antenna is good enough to survive the VHF/UHF band separater/combiner and feel the UHF antenna would be much preferable.

I think he has a much better chance of getting WNPI on 23 than WPBS and I doubt if he could get WWTI reliably.
I agree.
I just figured that since he wasn't mentioning PBS as a desirable channel, aiming a separate UHF for South Colton (WNPI) would probably lose any chance at WPBS or WWTI. But you're right, it is a better bet.

I had thought of a South Colton UHF antenna to get him WWNY from WNYF-LD when/if it launches in addition to WNPI, but since he already has the channel-cut yagi for channel 7, which comes in a better NM than WNYF ever will, a new preamp should be easier than a new UHF antenna for a channel that may not be approved for years yet.
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