: ON - Ottawa, Vanier, Gloucester, Orleans - OTA



flavoie
2010-11-15, 02:00 PM
Hi guys,

Posted pictures of my new setup here, the antenna is now on the roof (look down for my user id):
http://www.digitalhome.ca/forum/showthread.php?t=24755&page=41

This was done yesterday, and I am still getting WNYF, from 4pm yesterday up to now, about 2pm.

my TVFool at my new location, for your reference and base of comparison:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d9fbe32262c5a2e

Using a 4228hd unmodified, CM7777 and quad shield cable all the way before it enters the house. A rotor helps fine tuning reception of WNYF, and I intend on keeping the antenna in a single spot aiming at WNYF.

At the current pointing location, without moving the antenna, I also get WNPI, WCFE and all local digital channels. I don't care much about analog channels so I have not watched them yet. All my locals I get from CF from the back of the antenna are strong, as well as HC channels and WCFE and WNPI. The only exception is WNYF which is going to weak but no errors on reception, i could be on the edge of seeing pixelation here this afternoon but i think so far so good.

skipticum
2010-11-16, 02:07 PM
Good setup flavoie.
I see that WNYF (real channel 18) does not appear on your TVFool analysis. That means TVFool is "fool" in your case. In my case, I get different TVFool analyses, depending on if I provide my full address, my Lat and Long (from google earth) or using the zoom option from TVFool map analysis.

Like you I get WNPI, WCFE and WNYF (WNYF only at night) and all the local channels from my setup in the attic. I finally (yesterday) setup a CM2221HD with CM7777 on the peak of my roof (~35ft). With this setup all my local channels are at 100% Q, which completely masked WNPI and WNYF (cannot get them). Therefore, I slightly attenuated the signal by using a 2-way splitter and a roll of 150ft RG6 coax cable (this is what I have at hand now), and voila was able to pull WNYF and WNPI (but still only at night). My objective is to be able to get WNYF during the daytime, not only at night. Seing that you are able to do that is giving me hope that I may be able to get it during the day. I think I may not need the CM7777 preamp...

tvlurker
2010-11-16, 02:42 PM
Good setup flavoie.
I see that WNYF (real channel 18) does not appear on your TVFool analysis. That means TVFool is "fool" in your case.


No, WNYF only appears in "pending" on TVFool because the FCC still has the station in Contruction Permit status. If you go to the interactive map featurem and select "Current and Pending", you'll see WNYF.
But once you generate the "Radar Plot", the pending stations are filtered out.

In my case, I get different TVFool analyses, depending on if I provide my full address, my Lat and Long (from google earth) or using the zoom option from TVFool map analysis.


I find it's always best to use the zoom option. Whether the added precision is accurate is an interesting question.

flavoie
2010-11-16, 03:00 PM
I generated my TVFool by zooming in to my roof at the intended install location and then hitting the Radar plot. It can't be closer to the actual install location. I may not have the exact height though at 35 ft.

My TVFool shows WNYF at -7.8dB NM, which, as tvlurker mentioned, is seen when you hit "Pending applications included".

It was also tvlurker who told me (way back) that my suggested plan of a 4228hd and a cm7777, in my location according to TVFool, pointed directly at WNYF, should work with WNYF and all digital locals working. Thanks tvlurker :) I didn't expect to get WCFE as well considering the narrow beam of a 4228, but i get it just as strong as WNPI.

The way I understand the simple math is... take your TVFool NM figure (-7.9dB) + your antenna gain for this channel (4228hd=13dBi or 11 dBd for channel 18, not sure which one to take here) then - preamp noise margin (2dB for cm7777) and this gets me a positive value of 3.1 or 1.1. You'd want this figure as High as 10 or more to account for attenuation due to weather, leaves, etc.
I don't have any trees in my way. Actually my antenna is the highest thing around, just waiting until lightning hits (yes, it is grounded).

flavoie
2010-11-16, 03:14 PM
skipticum, i think you'll want to hold on to your preamp to get such a deep fringe channel. I pretty much went overboard and optimized every step of the install to get these results, and the cm7777 is one if the key parts of it.

The good news is, you have a way better location than mine ! It should be easier for you to get WNYF.

I have quad shield rg6 cable going to my low-loss surge arrestor/grounding block, then normal rg6 cable inside (which i may replace to quad shield rg6 later) going to a single Hauppauge 950Q usb tuner, one of the best tuners out there.

Aiming makes a difference too. It can be hard turning an antenna just 5 degrees. I can do that with the rotor.

The 4228 is a higher gain antenna than your 4221, and your tuner may or may not be as good than the 950Q.

I've got a Hauppauge HVR-2250 waiting in a box. it should be as good (crossing my fingers here)

flavoie
2010-11-16, 04:17 PM
Tried it again with online maps then radar plot. I am now getting -8.8dB NM for WNYF. So there's some hope for you guys with similar results, it can be done...

tvlurker
2010-11-16, 04:59 PM
... take your TVFool NM figure (-7.9dB) + your antenna gain for this channel (4228hd=13dBi or 11 dBd for channel 18, not sure which one to take here)

dBd. From the TVFool help page at http://www.tvfool.com/index.php?option=com_content&task=view&id=57&Itemid=89
Antenna gain is the only quantity that should ever be ADDed to the NM value. Most antennas will specify their gain in dBd or simply dB, and this is the value that should be used. If an antenna's gain is specified in dBi units, then you need to subtract 2.15 in order to get the equivalent value in dBd units.

I think TVfool shows about -9 dB NM for my location for WNYF, and I have trees in the way, so I don't think I'll be as lucky as you are.

jrmclean
2010-11-16, 07:13 PM
Great job flavoie...I'm sure the kids will miss the 4228HD off the play structure.

Your trouble finding solid studs with a roof mount is exactly why I'm very hesitant to do that. I'm very leery of leaving my perfectly sound roof with holes in it that aren't securing the tripod.... However, I'm going to have to get my gear outside if I want rock solid reception now that the great summer weather is gone. WNYF and WWNY are still great in the evenings, but since November I've noticed more breakups and picture problems during the day.

Do you think you'll use the rotor much, or is it just to get the best signal by fine tuning?

HWP
2010-11-16, 07:33 PM
Your kids won't have to wear safety goggles on that play structure anymore with those sharp bowties now gone.

I was nervous about holes in my roof, too. I thought about it a bit during the first few storms. Now I don't worry at all. I'm too busy enjoying my 29 digital and 1 analog channels. Your roof won't leak if you do it right. There's a good thread here about how to protect your roof when mounting through the shingles.

It sounds like Ottawa is starting to get a very decent OTA channel selection if you're willing to make the effort.

flavoie
2010-11-16, 08:54 PM
I'll be using the rotor for fine tuning reception, but first and foremost to make sure I don't need to go back to the roof again just to re-aim. Back when I made the decision, I was planning to use an installer. I didn't want the installer to go back and re-aim when something was wrong. The rotor was worth the expense compared to what an installer would cost each time.
Since then, I found a generous soul a lot less afraid of heights who helped me out and climbed with me. I have not mentioned him so far because I don't know if he wants the enormous praise and recognition.

The Waterproofing thread:
http://www.digitalhome.ca/forum/showthread.php?t=104181

I used 3M Super88 tape for the coax connectors only. Some use plumber's grease and other things, check in the thread above.

I will be unscrewing and adding 2x4 wood blocks between trusses, underneat the places where the lag screws did not find go into trusses. Almost mentioned in the thread above.

Then i will reapply what i applied already, one of the roofing tar variants mentioned in the thread above, the Bakor ultimate roof patch from Rona. Other kinds mentioned in the thread above must be just as good.

skipticum
2010-11-20, 08:45 AM
In my setup and location it seems that CityTV-DT (real channel 17) is killing the much weaker reception of WNYF-LP (real channel 18). I'm wondering if any one has similar problem to mine, and how to remedy this situation. Currently, I have CM2221HD antenna mounted on the peak of my roof at a 35 foot elevation, a CM7777 preamp and HVR950Q tuner. I get all my local channel at 100% Q, even without the preamp, but I can get WNPI and (at night) WNYF-LP only if I use a two-way splitter and a roll of 50ft coax cable. Do I need attenuator(s)? I couldn't find any in the Source. Anyone knows where to get a variable attenuator, as I think it might help a bit.

The funny thing is that with my attic setup, two home made GH antennas, I can get WNPI-DT all the time and most of the time at nigth get WNYF-LP...

flavoie
2010-11-20, 10:16 AM
skipticum, it is a good idea to try attenuators, you can find attenuators in stock here, I posted it in the shopping forums:
http://www.digitalhome.ca/forum/showpost.php?p=1144738&postcount=737

If you're not sure about the exact value of attenuation you need, you could also try a variable attenuator, which they also have.

skipticum
2010-11-24, 03:02 PM
flavoie, are you still receiving wnyf during the daytime? I'm also wondering about the SNR readings for wnpi and wnyf. I have an cm2221hd on my roof that can get wnpi (reliably with SNR about 22) and wnyf (not very good with SNR between 14.8 and 16.5). My location is very good for receiving wnyf-lp, but now I'm wondering if I should've bought the cm2228hd instead to get a better lock on wnyf.

flavoie
2010-11-24, 05:13 PM
I wish I knew. Right now my cables outside are cut in an attempt to finish up the job nicely on the side of the house. First attempt didn't work so i left the cables cut instead of terminating them and have to cut them again and reterminate the ends again a few days later. I'll let you know when i'm done and can see a signal again :)

flavoie
2010-11-24, 05:19 PM
Since you have a Hauppauge 950Q as well, we can compare our SNR readings. WNPI gets a 27 out of 27 pretty much all the time. WNYF goes from about 22/24 down to 16.5 worst case in the afternoon. That was up to last Sunday Nov 21st when I cut the cables. Being a higher gain antenna, yes, the 4228hd should help, you'd need to figure out how much gain you would add with a 4228hd. I thought the 4228hd narrow beam would be hard to get WCFE, but it's no problem when I point right at WNYF. All locals are fine too, I get CF from the back of the antenna, most at SNR 24 and better, with CKXT at around 21. All HC channels are at 27/27.

skipticum
2010-11-25, 01:15 PM
flavoie, thanks for the quick reply. Now I got the situation under control by doing two simple things to the CM2221hd antenna. First, I put two screens (36” wide each) right at the front of each Cm2221hd reflector panel. The current reflector width for the CM2221hd is 24”. The screens are directly attached to the existing reflector panels with plastic ties. The height of the screen are maintained the same as the CM2221hd reflector height. This addition increased the gain of the antenna for the low channels, especially for the WNYF (now with SNR 18.5 to 26. Before the mod, it was maximum SNR 18.5) and WNPI (SNR of 27/27 all the time) WFCE (always at 27/27). I get all my local channels at SNR of 27/27 all the time, even without the mod. Last week the high wind pushed down my antenna almost parallel to the inclined roof and I was still getting my locals at SNR 27/27!! The screen is a chicken wire screen (3/4X3/4 inch mesh) from Lowes, cost me about $9.99 (I used only half of it). Second, I tilted my antenna (back) about 5 to 10 degrees to the horizon. The latter assured stable reception and it may contributed to the increase in the SNR.

I highly recommend that you do the screen mesh mod, because it is easy, and your CM2228hd is actually two CM2221hd side-by-side. It is reversible and easy, just cut the plastic ties and remove the screens, if desired.

Because my locals are too strong relative to WNYF, especially CityTV (the strongest of the bunch in my situation), I have Adjacent channel problem (CityTV real channel 17 next to WNYF real 18). I used a variable attenuator. Although the attenuator helped a bit, only the screen mesh mod made a real difference in my situation. I knew adding a screen would work, because of my experience with previous builds of GH10 and my special GH build (I call YGH super). For my latter GH build I designed a special high gain antenna (gain of 17.2 DBi at channel 18 (frequency 497)) to put in my attic where I had to play with different screen designs with NEC2 software. With it I was able to get WNYF at night from the attic

flavoie
2010-11-25, 01:44 PM
That's great news :)
Never seen a 4228hd hack that is relevant for channel 18, so i'm curious to see how it would work out on a 4228hd, unfortunately i won't be testing it.

My attempts on balun and splitter hack for channel 18 were all failures, so it's nice to see someone successful with something on 18. I am not going on the roof again (yes this may be wishful thinking). I fixed the lag screws which didn't have a truss backing with 2x4 and 2x6s and now i'm done for the roof part, well i hope so.

flavoie
2010-11-25, 01:48 PM
You got UV-rated tie wraps right ? I shouldn't be asking this to someone making antennas... When i removed some tie wraps from another coax setup, the tie wraps just broke in my fingers.

flavoie
2010-11-25, 02:15 PM
By the way, if you think you have an adjacent channel problem, check my TVFool (my homepage under my profile links to my TVFool) and you'll see I should be having a worse time with 17, but it's fine.
I think you have made your antenna more directional with a narrower beam, and that's a good thing if you want the peripheral local channels (17,...) to be attenuated more vs the US ones.

I think with the almost 90 degree angle you have with HC, City at 17 should be attenuated a lot more than mine, yet i am fine. Now that you've potentially turned the gain down on the sides and raised the gain on the front, you fixed 2 problems: your locals channels being too strong and your distant channels being too weak.

Alternatively, you may have had too much power from the preamp coming to your tuner, period. That would have required a bit of attenuation as well. Splitting the signal would have done the same job (which you did).

skipticum
2010-11-25, 07:43 PM
I think you may be right about the adjacent channel issue, since I'm able to get WNYF with my attic antenna with no difficulty (only in good nights though). And I think the problem is the pre-amp is providing too much amplification in my case. Also my cable runs are all less than 50'. I always felt that I needed a much smaller gain pre-amp. I got the cm7777 as part of a package that included the CM2221hd, 100' coax cable, cm balun and a J pole. Given my location, I think I would never need such a high gain pre-amp...