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Old 2-Aug-2012, 9:45 PM   #1
Cabal
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Antenna suggestion mounted on lower roof

TV Fool report here: http://www.tvfool.com/?option=com_wr...9900db0209c300

I'm looking at working with a 5-foot mast and wiring left behind by the previous homeowner (or replacing the latter). It's on a lower roof set back about 15 feet from the house, and will be 15-20 feet in the air when all is said and done. I would prefer to reuse this location rather than setting up something new on top of the house. The direction of the local tower farm (230 magnetic) would put the antenna pointing to the right of the chimney from the second picture.

Given the need for *some* VHF to pick up Fox locally, and hoping for a smaller setup. I was considering the DB4e + CS2-V VHF reflector attachment (see http://www.digitalhome.ca/forum/show...&postcount=371) + pre-amp. Given the disadvantage of being on the back side of the roof and the location outlined above, would I need a full Yagi instead? Also, any considerations for vertical tilt? Thanks.
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Last edited by Cabal; 2-Aug-2012 at 10:05 PM.
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Old 2-Aug-2012, 10:00 PM   #2
GroundUrMast
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The reality is, you'll be 'shooting' through the entire building structure. You would be far better off mounting a CS-2v (CS2 Complete) on the chimney where it can 'see' over the edge of the roof. If that is a non-starter, how about trying a DB4e and Antennacraft Y5713 in the attic?


A long boom Yagi will tear the J-pole off the roof in the next wind storm. And it may or may not clear the roof. Tilting is up is not going to buy much if anything... You have LOS if not for the building obstructing your shot.

Last edited by GroundUrMast; 2-Aug-2012 at 10:05 PM. Reason: Opinon re. long boom Yagi on J-pole
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Old 2-Aug-2012, 10:12 PM   #3
Cabal
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Great, thanks for the input.
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Old 2-Aug-2012, 11:59 PM   #4
teleview
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Tv Reception.

As has come up -> repeatedly <- in other question askers posts.

KCWX is not transmitting on channel 8 so that leaves the reception of KCWX channel 5 to receive.

Install a All channel antenna.

All channels are , VHF low band 2 thru 6 , VHF high band 7 thru 13 , UHF band 14 thru 51.

Install a Winegard HD7084P antenna above the roof so the antenna is not blocked by the house or by the roof.

Aim the HD7084P antenna at about 240 degree magnetic compass.

For 1 Tv connected install a Channel Master CM3410 distribution amplifier.

For 2 Tv's connected install a CM3412 distribution amplifier.

For 3 or 4 Tv's connected install a CM3414 distribution amplifier.

The CM distribution amplifiers are not , direct weather proof , so run a coax from the antenna to a location that has electric power for the CM distribution amplifier.

And connect the antenna coax to the CM distribution amplifier there.

Most attics have electric power outlet.

Or can put the CM distribution amplifier at a other location that is out of the weather and has electric power.

Of course the coaxes that go to the tv's will also connect to the CM distribution amplifier.

Last edited by teleview; 3-Aug-2012 at 3:08 AM.
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Old 3-Aug-2012, 12:11 AM   #5
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Tv Reception.

Here are some above the roof antenna mounts.

http://www.ronard.com/909911.html , http://www.ronard.com/34424560.html , http://www.ronard.com/ychim.html , http://www.ronard.com.

Buy the ronard antenna mounts at solidsignal by typing the word ronard in the solidsignal search box.

Here are some places to buy antennas and etc. , http://www.solidsignal.com , http://www.winegarddirect.com , http://www.amazon.com , http://www.channelmasterstore.com.
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Old 3-Aug-2012, 12:44 AM   #6
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Tv Reception.

Also as has come up --> repeatedly <--.

Texas housing is Real Big on metal backed insulation in the attic.

Radiant Barrier , does a great job of , reducing , reflecting Tv transmissions (multipath) and blocking tv transmissions.

When Tv antenna is in the attic.

Does the attic have metal backed insulation??

Also the signal strength of KCWX channel 5 is not that strong , putting antenna in the attic will further reduce signal strength.

Last edited by teleview; 3-Aug-2012 at 1:12 AM.
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Old 3-Aug-2012, 12:48 AM   #7
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@teleview, when I saw you refer to a smaller antenna I was concerned. However, the 7082 is reasonable.
But, if reception of KCWX is a priority, then using a large antenna mounted high enough to have an unobstructed view toward 246° compass is vital. The Winegard HD7084P has about 7.4 dB gain on CH-5. If mounting higher provides an increase in NM, then this has a much greater chance of working well.

@Cabal, Try running a new TV Fool report at higher levels. An NM value of 17 dB or greater puts you in range of stable reception of KCWX using an HD7084p equipped with an Antennas Direct CPA-19 preamplifier.

Last edited by GroundUrMast; 4-Aug-2012 at 5:53 AM. Reason: Ackowledge teleview's ammended recomendation
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Old 3-Aug-2012, 12:59 AM   #8
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Tv Reception.

Install a HD7084P.

KCWX is not transmitting the CW the programing is actually MyNetwork. http://www.mynetworktv.com.

I think that MyNetwork is a must have. I know I would not dump it over a antenna issue.

And also KCWX has , This Tv. http://www.thistv.com

http://www.en.wikipedia.org/wiki/KCWX.

http://transition.fcc.gov/fcc-bin/tvq?call=KCWX.

Last edited by teleview; 3-Aug-2012 at 3:06 AM.
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Old 3-Aug-2012, 1:04 AM   #9
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Tv Reception.

I strongly recommend Do Not use the CPA-19 preamplifier or any other all channel preamplifiers , there far to many Strong Tv transmissions that will most likely over load any preamplifier and be the cause of bad or no reception of some digital channels.

Last edited by teleview; 3-Aug-2012 at 10:20 PM.
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Old 3-Aug-2012, 1:19 AM   #10
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I'm agreeing that adding KCWX to the line up is desirable.

The key will be how high can the antenna be mounted. A noise margin of 8.9 dB is and antenna gain of 7.4 dB is not enough to overcome the low-VHF noise and typical distribution losses.

A pair of HLSJ's can be used as a preselection filter on the input of the preamp. One HLSJ between the antenna and preamp and the second down stream of the preamp... just after the power inserter for the preamp.
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Last edited by GroundUrMast; 3-Aug-2012 at 1:45 AM. Reason: HLSJ vs. UVSJ
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Old 3-Aug-2012, 1:28 AM   #11
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Tv Reception.

Even if running the numbers says the reception is ify.

It is better to go for the reception.

Then to just give up.

-->With out a VHF low band capable antenna above the roof <--.

Then that is giving up.

And what will this preselection filter do to the VHF high band channels 7 thru 13 and UHF band channels 14 thru 51??

Last edited by teleview; 3-Aug-2012 at 2:51 AM.
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Old 3-Aug-2012, 1:31 AM   #12
teleview
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Tv Reception.

My recommendation is now set.

One antenna above the roof , HD7084P antenna connected to a CM distribution amplifier.

Mounting a antenna above the roof of a one story house is about 25 feet above ground.

The coax/s that go to the Tv/s will connect to the distribution amplifier , the coax from the the HD7084P antenna will connect to the distribution amplifier , the distribution amplifier can be located in the attic , most attics have a electric outlet in the attic or the distribution amplifier can be at a other location that has electric power outlet and is out of the weather.

Last edited by teleview; 3-Aug-2012 at 3:14 AM.
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Old 3-Aug-2012, 1:49 AM   #13
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It would pass CH 7 and higher unamplified.

Antenna to common port of the first HLSJ, amp connected to the low port. High port feeds the high port of the down stream HLSJ. The amp out feeds the low port of the down stream HLSJ.

I'll draw it up...
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Old 3-Aug-2012, 3:31 AM   #14
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Thanks for the feedback. Agreed that having MyNetwork and thisTV would be preferable. Both of those (along with KVBO) seem to be problem channels for the locals due to their low power output, even for those as close at 8 miles and in direct sight of the antennas (http://www.avsforum.com/t/336964/aus...#post_22059636). But they may also not be set up well.

I believe I have exclusively blown-in insulation, but I'll need to check. The attic has very little human-serviceable area and is a little precarious with a 2-story drop in much of it, so an exterior antenna is pretty much the only (and probably preferred) choice.

The reason I mentioned a pre-amp from the start is I'll be looking at up to 100 feet of cable, depending on final location (whole-house patch panel has multiple runs to the cable demarc, and I'd prefer to continue using that).

Thanks again.

Last edited by Cabal; 3-Aug-2012 at 3:53 AM.
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Old 3-Aug-2012, 3:45 AM   #15
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Tv Reception.

A whole house patch panel is the best way to go.

If given the option most people will nix a whole house patch panel because they just don't really understand all the problems that will be solved now and down the road with wiring issues that will develop by not having a whole house patch.

The 100 <> feet of coax from the roof to the patch panel is not my main concern.

Its the 60+ NM (dB) at 15 feet antenna height will go up with the antenna now above the roof of a 1 or 2 story house.

Even the CPA-19 high input preamp will be over loaded when the received signal strength goes higher and higher on those strong Tv stations.

Last edited by teleview; 3-Aug-2012 at 3:58 AM.
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Old 3-Aug-2012, 4:04 AM   #16
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Tv Reception.

Please post a tvfool report with the antenna height that you think the will be with the antenna above the highest part of the roof that the antenna will be mounted so roof is not in the way of reception.
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Old 3-Aug-2012, 4:09 AM   #17
Cabal
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This is the same location at a height of 30 feet: http://www.tvfool.com/?option=com_wr...9900a162895b54 . It looks like it meets all the criteria.

The Wife Acceptance Factor for something as large as the HD7084P on the top of the roof is going to be pretty low, though. I do have another one-story roof over a portion of the garage which has an unobstructed view of the skyline in the appropriate direction. That may work out in the end.
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Old 3-Aug-2012, 4:21 AM   #18
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Tv Reception.

It happens every time.

Receiving All those , many , many , many , many , many , Free Tv channels in Crystal Clear Digital Broadcast Tv.

Raises the the low point of view to Over The Top High Point Of View.

And she will be saying , get the antenna higher and get a bigger antenna , get more channels.

Last edited by teleview; 3-Aug-2012 at 4:25 AM.
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Old 3-Aug-2012, 5:31 AM   #19
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Tv Reception.

Ok , because you know that you have a patch panel and you used the word , Demarc , a short version of the word Demarcation.

I am hoping you have some understanding of what is going on here.

I will do something I almost never do when helping people with words and pictures only.

If required to get reliable reception of channel 5 through the distribution system.

Install a second amplifier , yes I know , I said it.

A VHF only preamplifier , Winegard AP3700. http://www.warrenelectronics.com/antennas/AP3700.htm.

With the HD7084P antenna at 30 feet that makes 14.4 NM(dB) for channel 5 and a antenna gain 7.4 NM (dB) at channel 5 , that makes 21.8 NM(dB) a respectable number.

So try reception with out the VHF only preamp first.

Last edited by teleview; 3-Aug-2012 at 6:17 AM.
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Old 3-Aug-2012, 5:37 PM   #20
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@teleview, I'm all in favor of adding KCWX to the lineup...

The AP3700 covers all of the VHF band, CH-2 through CH-13, which is fine in this case... there aren't enough other strong VHF signals to cause a problem. The only reason to use the CPA-19 with HLSJ filters is that it narrows the bandwidth to real channels 2 through 6. Low cost and simplicity argue for the AP3700.

I'm not following your math though,
Quote:
With the HD7084P antenna at 30 feet that makes 14.4 NM(dB) for channel 5 and a antenna gain 7.4 NM (dB) at channel 5 , that makes 21.8 NM(dB) a respectable number.
I calculate a net NM value that's much different... The NM shown for KCWX, CH-5 in the 30' TVFR is 11.6 dB, not 14.4 dB. The 13 dB correction factor I use is neither overly optimistic nor pessimistic. The 6 dB tuner NF may be a bit optimistic, and 0 dB distribution losses is obviously beyond optimistic. The Net NM of 3.4 I've calculated becomes negative when I plug in the losses of 100' of coax plus a 4-way split, certainly when I use a more realistic tuner NF.

@Cabal, I have no doubt that if you install the HD7084P, you'll enjoy great reception of a lot of signals. Given the relatively small difference in price between the CS2V and the HD7084P, go with the 7084... it's the only way to have a chance at seeing the signal from KCWX, real CH-5. If you have some difficulty with that one station, it would be because of it's low signal level at your location and the presence of additional noise in the low-VHF band (CH-2 through CH-6). Additional height would be one of the few remaining options to pursue if you found reception of the KCWX signal unreliable.
Attached Images
File Type: png KCWX CH-5 Net NM 30 ft Estimate.png (48.4 KB, 389 views)
Attached Files
File Type: pdf CPA-19 as a VHF only --UHF By-Passed-- Amplifier.pdf (20.5 KB, 498 views)
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