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Guest Message by DevFuse

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Local Reception


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20 replies to this topic

#1 OFFLINE   kevinturcotte

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Posted 12 June 2010 - 06:13 AM

I'm trying to pick up a specific channel. I've attached my chart from tvfool.com I'm using a Channel Master 4228HD antenna http://www.crutchfie...HD.html?tp=3261. I'm playing with it, and right now I can get channel 10 in perfect. As far as alignment goes, if I'm getting 10, shouldn't I also be getting 23 in as well? Is the fact that I'm getting 100% on 10 and 0 on 23 an indication that I'm NOT going to get 23? Would a different antenna maybe have better results, or should I just stop trying at this point?
And yes, Directv does provide my locals in HD, but they don't provide them all, and the ones that they do, I'd like a backup for.

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#2 OFFLINE   Scott in FL

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Posted 12 June 2010 - 08:05 AM

The gain for that antenna on channel 10 is about 5 dB. On channel 23 the gain is 11.6 dB. So about 6.6 dB more gain on channel 23.

TVFool shows channel 23 about 6 dB lower, so only considering power at the antenna terminals they're about even.

Coax loss and the noise factor of your first RF stage are going to favor channel 10. But I think the real culprit is the 2edge path for both. That's a tough path and throws all this math out the window. Multipath and diffraction are going to play significant roles, making prediction difficult.

#3 OFFLINE   kevinturcotte

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Posted 12 June 2010 - 08:10 AM

The gain for that antenna on channel 10 is about 5 dB. On channel 23 the gain is 11.6 dB. So about 6.6 dB more gain on channel 23.

TVFool shows channel 23 about 6 dB lower, so only considering power at the antenna terminals they're about even.

Coax loss and the noise factor of your first RF stage are going to favor channel 10. But I think the real culprit is the 2edge path for both. That's a tough path and throws all this math out the window. Multipath and diffraction are going to play significant roles, making prediction difficult.


I don't think there's too much coax loss. There's maybe 50 feet between the antenna and the tuner. I'd bump it up to quad shielded RG11 if you think it would help, but I doubt that (Maybe a dB or 2)?
I'm just *NOT* going to get 23 am I?

#4 OFFLINE   BattleZone

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Posted 12 June 2010 - 09:02 AM

It's very possible that a high-quality pre-amp would solve the problem. There are no guarantees, of course, but they often make all the difference. As Scott says, the 2Edge is really the issue. Take a look at the side view profile for that station and you'll have a better idea.

#5 OFFLINE   kevinturcotte

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Posted 12 June 2010 - 09:04 AM

What would be recommended for a preamp? And how would I look at the side view profile?

#6 OFFLINE   gfrang

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Posted 12 June 2010 - 09:34 AM

What would be recommended for a preamp? And how would I look at the side view profile?


Chanelmaster 7777 stay away from Radio shack preamp's,i have a Winegaurd but i think the Chanelmaster is the best.

#7 OFFLINE   kevinturcotte

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Posted 12 June 2010 - 09:47 AM

The bottom of the antenna is at 12' so the top is almost 15'. Would a 10' increase help much/any?

#8 OFFLINE   Scott in FL

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Posted 12 June 2010 - 10:27 AM

It's just too difficult to predict. My daughter lives in the mountains of Central PA and has trouble receiving two stations from Altoona: ch 24 and 32. Same distance, same compass bearing. TVFool predicts ch 32 to be 2 dB lower at her house (-68.4 vs -70.5 dBm). So very similar results for both stations. The path is 2edge. Channel 32 just refuses to come in, but ch 24 is OK.

What I did was take a CM4221 antenna and CM7777 preamp and just walked all around the roof until I found the best location. It's that unpredictable. I found a hot spot that sort of works OK for ch 32, but it's not solid at all. Channel 24 is fine.

You might want to try that. Try to find the best location. An additional 10' might help, but it's impossible to predict.

#9 OFFLINE   gfrang

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Posted 12 June 2010 - 10:42 AM

Channel 10 is vhf high and channel 23 is uhf both are in the same direction and distance,i would look at the antenna and see if the uhf elements are connected.

#10 OFFLINE   kevinturcotte

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Posted 12 June 2010 - 10:44 AM

Channel 10 is vhf high and channel 23 is uhf both are in the same direction and distance,i would look at the antenna and see if the uhf elements are connected.


I'm getting other UHF stations.

#11 OFFLINE   Scott in FL

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Posted 12 June 2010 - 10:45 AM

The CM4228HD antenna is a UHF antenna that has about 5 dB of gain on ch 10.

#12 OFFLINE   gfrang

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Posted 12 June 2010 - 10:47 AM

Could channel 23 be down?

#13 OFFLINE   kevinturcotte

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Posted 12 June 2010 - 11:02 AM

The CM4228HD antenna is a UHF antenna that has about 5 dB of gain on ch 10.


Not actually interested in ch 10, but would think if I could get that, I could also get 23?

#14 OFFLINE   gfrang

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Posted 12 June 2010 - 11:18 AM

One thing is to try a rescan.

#15 OFFLINE   BattleZone

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Posted 12 June 2010 - 04:14 PM

What would be recommended for a preamp? And how would I look at the side view profile?


Many recommend the ChannelMaster 7777.

If you click on any individual station in the list grid, you'll see a side profile of the signal path, with any terrain features that are in the way and the predicted signal path:

Posted Image

#16 OFFLINE   Jim5506

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Posted 12 June 2010 - 09:27 PM

CM7777 will overload with 6.1 and 8.1 so close.

Try the Winegard HDP-269 pre-amp.
Tuners: Hopper 2000; Hopper w/Sling; 3 Joeys; Samsung SIR-T351; Accurian 6000;2 X HD TiVo; 2 X TiVo Series 2 Stand alone; Panasonic Showstopper 2000
Dish 1000.2 @ 110, 119, 129; dish 500 @ 61.5
Antennas - CM4228; RS U75-R; coathanger; Funke PSP.1922 (stillin the box); paperclip
Displays: Sony VPH D50Q with HD Fury HDMI input; Hitachi 57F59; Sony Bravia LCD;Sanyo 32" LCD; Panasonic 42" plasma
Sony 80GB PS3; Toshiba HD-DVD

Give me a Finco colinear array and I'll rule the world - HA-HA-HA-HA!

#17 OFFLINE   kevinturcotte

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Posted 13 June 2010 - 07:33 AM

Many recommend the ChannelMaster 7777.

If you click on any individual station in the list grid, you'll see a side profile of the signal path, with any terrain features that are in the way and the predicted signal path:

Posted Image


This is what tvfool gives me for a side view.

#18 OFFLINE   Jim5506

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Posted 13 June 2010 - 05:05 PM

UHF does not propagate nearly as well as VHF, even with increased power levels, you just can't match VHF for fringe and deep-fringe reception.
Tuners: Hopper 2000; Hopper w/Sling; 3 Joeys; Samsung SIR-T351; Accurian 6000;2 X HD TiVo; 2 X TiVo Series 2 Stand alone; Panasonic Showstopper 2000
Dish 1000.2 @ 110, 119, 129; dish 500 @ 61.5
Antennas - CM4228; RS U75-R; coathanger; Funke PSP.1922 (stillin the box); paperclip
Displays: Sony VPH D50Q with HD Fury HDMI input; Hitachi 57F59; Sony Bravia LCD;Sanyo 32" LCD; Panasonic 42" plasma
Sony 80GB PS3; Toshiba HD-DVD

Give me a Finco colinear array and I'll rule the world - HA-HA-HA-HA!

#19 OFFLINE   kevinturcotte

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Posted 12 July 2010 - 04:52 PM

I've tried another antenna, the Antenna Direct 91XG http://www.antennasd...TV_Antenna.html. With it, at the same height as the other antenna, I managed to get a 24 on channel 23 without a preamp. This is at 12 feet. I know nothing's absolute, would I potentially get a usable signal if I went up to 22 feet?

#20 OFFLINE   Jim5506

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Posted 12 July 2010 - 06:22 PM

How much does the potential signal strength change on your TVFool report from 12 to 22 ft? That would be a good estimation.
Tuners: Hopper 2000; Hopper w/Sling; 3 Joeys; Samsung SIR-T351; Accurian 6000;2 X HD TiVo; 2 X TiVo Series 2 Stand alone; Panasonic Showstopper 2000
Dish 1000.2 @ 110, 119, 129; dish 500 @ 61.5
Antennas - CM4228; RS U75-R; coathanger; Funke PSP.1922 (stillin the box); paperclip
Displays: Sony VPH D50Q with HD Fury HDMI input; Hitachi 57F59; Sony Bravia LCD;Sanyo 32" LCD; Panasonic 42" plasma
Sony 80GB PS3; Toshiba HD-DVD

Give me a Finco colinear array and I'll rule the world - HA-HA-HA-HA!




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