CM-4228/7777 is marginal. What now? - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 26 Old 12-14-2011, 04:38 PM - Thread Starter
Advanced Member
 
6volt's Avatar
 
Join Date: Feb 2004
Posts: 677
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
A CM-7000 DTV STB is the bare minimum tuner sensitivity that I can live with.

I just brought home a Samsung TX-P3071 HDTV w/ATSC tuner and it is a piece of junk compared to the 7000. (7000 got 2,4,11,13,16,19,22,53, TX-P could not get 2,11,53!!!)

I realize that was Samsung's 1st ATSC tuner (I think) but I am concerned that even with all the new DTV boxes, the 7000 and the Zenith 901 were considered to be "the best."

Does it take more signal to lock in a HD signal over a SD digital signal?

How does "the best" DTV STB box compare to "the best" integral tuners or stand alone tuners?

It would be nice to be able to buy a ATSC HDTV and have it work, but I guess that is never going to be an option for me, right?

So that leaves:
  1. Buying TV's only with highest rated tuners
  2. Investing in an OTA DVR box with killer tuner
  3. Improve my antenna/amp system

A bit on my antenna/amp system:

I have the antenna on a hospital IV rack with wheels so I can position it anywhere on my porch to get signal. I have found one position that gets everything on the 7000. I could find no position which would bring in the missing 2,11,53 on the TX-P.

The 4228 is old and dinged and bent and rusted. I know the new ones are not supposed to be as good as the USA ones, but might I get a few more dB from a new antenna? Still a 4228?

I have .3 acres and was planning to survey my property to see if there is a sweet spot somewhere at ground level.

I really don't want to put the antenna up on the chimney w/rotor but I guess it is coming to that. My porch faces Pittsburgh so it does well in that direction. In the opposite direction (through my house) there are a couple stations that I think I might be able to get. The mast/rotor might solve that.

If there were OTA DVR boxes w/rotor control, I'd be real gung ho to set that up, but I don't think anyone makes any. TVRO had it all over DTV in that regard?

Also, If I have the 7777 mast mount but 150-200' of cable run to TV, I'm concerned about signal loss due to the run. I have tons of RG59 but maybe I should use 6 or 11?

Found this nifty primer: http://www.hdtvprimer.com/ANTENNAS/basics.html
6volt is offline  
Sponsored Links
Advertisement
 
post #2 of 26 Old 12-14-2011, 05:09 PM
Advanced Member
 
pacofortacos's Avatar
 
Join Date: Apr 2009
Posts: 734
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 21
I wonder if you could use a FTA sat. system and use it's motor control as a rotor system?
A few have the OTA and DVR part covered and the most all have a motor control system.
pacofortacos is offline  
post #3 of 26 Old 12-14-2011, 05:51 PM - Thread Starter
Advanced Member
 
6volt's Avatar
 
Join Date: Feb 2004
Posts: 677
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Hummmm, FTA satellite is something I haven't thought about for a good while.

If one is after free OTA, then FTA should be considered.

If those FTA STB's do OTA too, w/DVR, that might be the car's meow, provided they include actuator settings for OTA channels.

This needs looking into...

THanks so much!
6volt is offline  
post #4 of 26 Old 12-14-2011, 06:15 PM
AVS Addicted Member
 
arxaw's Avatar
 
Join Date: May 2002
Posts: 10,909
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
For long cable lengths, definitely ditch the RG59. And the antenna will probably work better if permanently installed as high up as possible. This is not always true, but usually is.

WRT the 4228HD; in actual installs, I have had excellent results, and I would say, it performs at least as well as the old model CM4228, at least for the channels receivable in our area.

If you post a link to the TVFool results for your address, it would be possible to see if perhaps a different antenna might be a better choice for your location and channels.
arxaw is offline  
post #5 of 26 Old 12-14-2011, 06:37 PM - Thread Starter
Advanced Member
 
6volt's Avatar
 
Join Date: Feb 2004
Posts: 677
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Here is a Fool printout: http://www.tvfool.com/?option=com_wr...40330ac3088ddd

In my defense of the use of the 4228, there are no VHF LO. Since the 4228 has pretty good VHF HI its a pretty good selection in my opinion.

There is also a huge 80' tall maple tree right in my line of sight about 100' from my antenna. If I put the antenna out in my yard, I think I can get that tree out of my line of sight of the horizon.

Even if I put my 4228 on my chimney, I'm still dealing with that maple tree.

But who knows, maybe that tree scatters the signal and I get some crumbs(!)

Thanks
Tom
6volt is offline  
post #6 of 26 Old 12-14-2011, 06:56 PM
AVS Addicted Member
 
arxaw's Avatar
 
Join Date: May 2002
Posts: 10,909
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I have oaks in one direction and pines in another. They never bother my reception except occasionally in the very strongest wind.

Per your TVFool, I would put the existing antenna up on the roof and replace all old cable with RG6.
arxaw is offline  
post #7 of 26 Old 12-15-2011, 06:59 AM
AVS Special Member
 
Tower Guy's Avatar
 
Join Date: Dec 2003
Location: Altamont, NY
Posts: 1,578
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by 6volt View Post

Also, If I have the 7777 mast mount but 150-200' of cable run to TV, I'm concerned about signal loss due to the run. I have tons of RG59 but maybe I should use 6 or 11?

I predict that the 7777 can't handle the strong signal (-28.4 dbm) from WEMW even with the 4228 aimed away from the station.

Potential solutions are:
1. Horizontally stacked antennas to null WEMW. (A pair of C2s or 4 bays stacked 18" apart. This assumes that WEMW is operating DTV channel 19 and not analog 56. http://www.hdtvprimer.com/ANTENNAS/ganging.html)
2. A 91XG with it's high front to side ratio.
3. A lower gain preamp with less line loss.
Tower Guy is offline  
post #8 of 26 Old 12-15-2011, 08:21 AM
Member
 
gcd0865's Avatar
 
Join Date: Dec 2005
Posts: 191
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 14
6volt:

I have a 4228 (also the old version, but in new condition) up on my chimney on a rotor (about 25 feet above ground level), and it works very well without any amplifier for UHF stations on my TVFool report down to around 0.0 dB NM and for some stations down to around -9.0 dB NM. In my area, that receives pretty much everything within 60-65 miles, especially in the evenings. For VHF-high stations, it is good down to around +10.0 dB NM on my TVFool report, as it has about two-thirds of the VHF-high signal capture capability of a Winegard YA-1713 (from my previous testing).

Given the relatively low signal strengths in your area (except for the one nearby station), having the antenna on your porch is not high enough for it to "see" over most normal area obstacles such as houses and some trees. If possible, you might consider doing a temporary test at roof/chimney height, holding the antenna and rotating it in different directions while someone else inside checks the tv for signal strengths on your tuner's meter. You might also try taking a pair of pliers and carefully bending any blatantly bent portions of the antenna reasonably back in line first. If your existing antenna works well up at roof level, then you can invest in a rotor instead of a new antenna, as your stations are in different directions around you. In general, the 4228 is one of the best antennas around, and you might do just fine with it even if it's a bit rusted.

If you're using RG-59 coax, that's definitely hurting your reception as well. There is a significant jump in signal preservation going from RG-59 to RG-6, and an additional jump (albeit smaller) going from RG-6 to RG-11. The most noticeable differences with either jump will be on the higher UHF channels, as signal losses per foot of coax increase significantly as you go up the channels, and you have several UHF stations in your area between channels 38 and 51.

I also agree with the previous comment that your very close station might be overloading your 7777 amplifier, which is not known for high input capability. Perhaps you might try taking it out of the equation (both the mast unit and the power inserter near the tv) for temporary testing. If the 7777 is indeed overloading from that nearby station and hurting your reception across the board, adding a channel 19 filter from TinLee or similar supplier or switching to a high-input-capable amplifier like a Winegard HDP-269 might solve the overload problem while still amplifying your remaining signals nicely.

Hope this is helpful - good luck!
gcd0865 is offline  
post #9 of 26 Old 12-15-2011, 11:22 AM - Thread Starter
Advanced Member
 
6volt's Avatar
 
Join Date: Feb 2004
Posts: 677
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Thanks all for the suggestions.

One thing that amazes me is that the alledged MEMW LOS uber signal is simply not there. No such channel has ever been received by myself or local friends. Could it have something to do with the -CD suffix???

So I guess I should not be overloading the 7777. With my porch mount, the 4228 alone was nowhere near enough. Only with the 7777 did things come in nicely. I did notice on one DVD recorder, there was a very faint trace of herringbone which is what I believe one would see when a tuner is being overloaded. But that appeared to be a problem with that particular recorder.

One big thing, however, I am right behind a ridge with 5-10 deg azimuth to view horizon. My cousin who is not even 1/8 mile from me is on the "other side" of the valley and just basks in signal! She gets everything with an RCA 1250 powered antenna.

If I go to the highest elevation of my property, I probably pick up 10' in elevation and also maybe lower the horizon by 1/2 degree. Since there is a steep gradient in the 1/8 mile to my cousin's house (the high point of my property is right in that direction) I might get lucky. However, that part of my property is a body diagonal in distance so my cable run will be >150 feet.

I did read a discussion about 59 -v- 6 with regard to the shielding. They said that 6 had foil which was good for high freq, but when dropped down to composite/component, there is leakage. RG59 has the copper braid which is proper for this lower frequency.

Perhaps I should run 6 or 11 to my 7777 power/receiving module and from that, rg59.

Also, I am definitely suffering from severe multipath. Moving the antenna on the porch an inch or 1 deg can be the difference between a good signal and one that is unusable.

I was thinking with multipath and digital, if digital "packets" have a time code, an advanced tuner could "sort them" as they are collected in a buffer. This would virtually eliminate multipath if the packets were intact. Read that the Zenith 901 DTV converter box was "the best" for multipath. I have a NIB one that I'm refusing to open but that is an interesting claim. BTW, the 901 is FS(!)

I think the first thing I should do is get my big cord reel of 59 and put that antenna in the far corner of my property and see what happens. and start looking for that Alliance Rotor controller STB too.

Thanks again,
Tom
6volt is offline  
post #10 of 26 Old 12-15-2011, 11:35 AM
AVS Special Member
 
Tower Guy's Avatar
 
Join Date: Dec 2003
Location: Altamont, NY
Posts: 1,578
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by 6volt View Post

One thing that amazes me is that the alledged WEMW LOS uber signal is simply not there. So I guess I should not be overloading the 7777.

Also, I am definitely suffering from severe multipath.

That makes sense, without WEMW the 7777 is fine.

The trick to resolving multipath is an antenna with an extremely narrow horizontal pattern. The 91XG beats the 4228.
Tower Guy is offline  
post #11 of 26 Old 12-15-2011, 01:37 PM
Advanced Member
 
pacofortacos's Avatar
 
Join Date: Apr 2009
Posts: 734
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 21
"If those FTA STB's do OTA too, w/DVR,"

I am currently using two, with another on the way, my favorite is the Sonicview Hd8000 but it is just tooo much $$ now and supply is limited.
I also have a ebox Hd unit, but haven't played with it much yet.
Just ordered a nfusion HD unit, will be here in a week or so.

I have a homemade antenna that IMO works better than the 4228 - at least for me. I'm up higher than you are though But I have to aim right into my neighbors house

I can pick up Youngstown if I point it just a touch to the north, but I loose one or two in Pittsburgh. It is oh so close, if only my beamwidth was a few degrees wider! If so I could grab from Youngstown to Altoona ( well channel 6 and 8 not sure where their towers are).
pacofortacos is offline  
post #12 of 26 Old 12-15-2011, 01:38 PM
Advanced Member
 
pacofortacos's Avatar
 
Join Date: Apr 2009
Posts: 734
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 21
OH and my homemade is in the attic, so it doesn't have to fight weather - other wise I'd have to use heavier aluminum.
pacofortacos is offline  
post #13 of 26 Old 12-16-2011, 04:00 PM - Thread Starter
Advanced Member
 
6volt's Avatar
 
Join Date: Feb 2004
Posts: 677
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Turns out that WEMU is an FM station - I guess they took out TV licenses and have not used them. They are public and if they turn on their TV signal, I will be hurt bad(!)

Some interesting tvfool studies:

Bad channels are 2, 11, 53

At my home address @ 8' get
11.9 7.6 6.7 NM(db)
At the address of the next property up the hill where I would try to put my antenna:
10.0 5.3 42. it got worse! why! higher elevation, lower azimuth to horizon!!!
At my home address @ 28' get
18.1 14.9 12.8

Clearly putting the antenna on my chimney will help a lot - maybe enough.

I should try putting it in my attic first though.
6volt is offline  
post #14 of 26 Old 12-17-2011, 09:51 AM - Thread Starter
Advanced Member
 
6volt's Avatar
 
Join Date: Feb 2004
Posts: 677
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Interesting observation:

Today, my CM7000 was bringing in 2, 11, and 53 at 100% signal strength.

The TX-P was able to pull in a couple of block jumbled frames on 11.

2 and 11 bring back the station #'s but that is all.

Sad how the CM7000 brings in channels so much better - I wonder if there could be something wrong with the TX-P tuner. The channels it does bring in seem OK.

I'm going to see if I can find another line amp laying around here somewhere and run the signal through that (in addition to the 7777) to the TX-P. Next experiment is to put the antenna in the attic. I think I may have just enough head room to do that.
6volt is offline  
post #15 of 26 Old 12-17-2011, 10:30 AM
AVS Special Member
 
tylerSC's Avatar
 
Join Date: Jun 2010
Location: Mauldin SC, 29607
Posts: 4,029
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 79 Post(s)
Liked: 89
Since that TX-P is an older generation tuner, that is probably the problem. The newer Samsung tuners have much better sensitivity, and that CM7000 was also a very good tuner. I would get a newer TV with a better tuner, or a better external HD tuner box. Otherwise, a 4228 or 91XG and a 7777 preamp is usually a very good set up for fringe applications.
tylerSC is offline  
post #16 of 26 Old 12-17-2011, 10:31 AM
AVS Addicted Member
 
arxaw's Avatar
 
Join Date: May 2002
Posts: 10,909
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Newest tuners deal with multipath a lot better than tuners several generations back. Chipsets have improved significantly.
arxaw is offline  
post #17 of 26 Old 12-17-2011, 10:40 AM - Thread Starter
Advanced Member
 
6volt's Avatar
 
Join Date: Feb 2004
Posts: 677
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Yeah, the TX-P is probably their first HD tuner (ugh). There is a LG 30FS4D superslim w/matte screen for sale locally. I get the feeling it would be superior in just about every category. Maybe time to "upgrade."

_______________________________

Some antenna experimentation (this may be indicative of multipath distortion in which case the 4228 may not be optimum?)

Put the antenna on stand at the bottom of the porch steps (antenna bottom now 4' off ground instead of 8' on porch) and with a lot of excessive up tilt was able to get 11 nicely, but antenna wanted so much up angle that other stations would not come in.

Put antenna on a table so now 7' off ground, in front of porch and things got worse. In fact, to get the best set of channels, the antenna likes to be on the porch, however 11 is no longer possible. Sure would be nice to have a signal strength meter to help aim the antenna. A spectrum analyzer would be nice (!)
6volt is offline  
post #18 of 26 Old 12-17-2011, 12:10 PM
AVS Addicted Member
 
arxaw's Avatar
 
Join Date: May 2002
Posts: 10,909
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
If you're "upgrading," why not just get a set with 6th+ generation tuner? Many brands (LG, Sony, Sanyo to name a few) have tuners deal with multipath a lot better than older generation tuners.
arxaw is offline  
post #19 of 26 Old 12-18-2011, 08:22 AM
AVS Special Member
 
kenglish's Avatar
 
Join Date: Jan 2000
Location: Salt Lake City, UT, USA
Posts: 5,392
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 31
Quote:
Originally Posted by 6volt View Post

Put the antenna on stand at the bottom of the porch steps (antenna bottom now 4' off ground instead of 8' on porch) and with a lot of excessive up tilt was able to get 11 nicely, but antenna wanted so much up angle that other stations would not come in.

Put antenna on a table so now 7' off ground, in front of porch and things got worse. In fact, to get the best set of channels, the antenna likes to be on the porch, however 11 is no longer possible. Sure would be nice to have a signal strength meter to help aim the antenna. A spectrum analyzer would be nice (!)

Remember, the 4228 (like all UHF-only antennas) is not designed for VHF. Any signals outside the UHF band are going to come in better at off-angles (sidelobes). When you tilt the antenna up, or off-point it in azimuth, you are just lining up on one of the two or more sidelobes, which are not in the main direction of the antenna. That puts the UHF stations off-angle.

Try a UHF Yagi and also a separate VHF antenna. You can get a preamp with separate inputs for the two bands, and a combined output. 200 feet of RG-6 would then be OK.

Ken English, Sr. Engineer, KSL-TV.
"The postings on this site are my own and don't necessarily represent the Company positions, strategies or opinions."
kenglish is offline  
post #20 of 26 Old 12-18-2011, 08:37 AM
AVS Addicted Member
 
arxaw's Avatar
 
Join Date: May 2002
Posts: 10,909
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by 6volt View Post

...Does it take more signal to lock in a HD signal over a SD digital signal?...

No.
arxaw is offline  
post #21 of 26 Old 12-20-2011, 07:15 AM - Thread Starter
Advanced Member
 
6volt's Avatar
 
Join Date: Feb 2004
Posts: 677
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
I think I may have made a big mistake with the 4228 setup.

I have it on a hospital IV stand which sits on plastic casters that I roll around on my wooden porch.

When I had the antenna sitting on the sidewalk in front of the porch, it seemed to work better even though it was about 4' lower. When I raised if off the sidewalk by putting it on a utility cart, it got worse.

I believe the 4228 backplane is not grounded.

I know the "whiskers" go to a pair of buses which comprise the "twin lead" output of the antenna. I suspect the backplane is not connected to one of those buses which means it must get its grounding from the mast.

When the IV stand was on the concrete sidewalk (which was wet also), I believe it was getting a modicum of grounding.

I think I need to ground that backplane and see what happens (!)

Could I be on to something?

Thanks
Tom
6volt is offline  
post #22 of 26 Old 12-20-2011, 10:32 AM
AVS Special Member
 
Tower Guy's Avatar
 
Join Date: Dec 2003
Location: Altamont, NY
Posts: 1,578
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by 6volt View Post

I believe the 4228 backplane is not grounded.

Could I be on to something?

I doubt it.
Tower Guy is offline  
post #23 of 26 Old 12-20-2011, 10:37 AM
AVS Addicted Member
 
arxaw's Avatar
 
Join Date: May 2002
Posts: 10,909
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Lots of variables come into play.
You moved the antenna to a different elevation. Moving higher or lower can put certain channels into dead or hot spot. See: http://www.hdtvprimer.com/ANTENNAS/siting.html
The ground was wet, which may affect signal reflection off the ground.
Grounding the reflector can affect reception.
arxaw is offline  
post #24 of 26 Old 12-24-2011, 06:57 AM - Thread Starter
Advanced Member
 
6volt's Avatar
 
Join Date: Feb 2004
Posts: 677
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
One thing I noticed when they talked about all the sensitives of placement, they talked about distances of "feet." On my porch, I can move the antenna inches or a few degrees and go from a good signal to no signal.

One other factor may be that my house is stucco, so the antenna is about 6' from a large, irregularly shaped "ground plane."
6volt is offline  
post #25 of 26 Old 12-24-2011, 08:03 AM
Thread Ender
 
WS65711's Avatar
 
Join Date: Mar 2003
Location: Covington, LA OTA & Charter CableCard
Posts: 4,133
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 69 Post(s)
Liked: 63
Quote:
Originally Posted by 6volt View Post

... I can move the antenna inches or a few degrees and go from a good signal to no signal............

Symptom of multipath.

Don't ever make the MISTAKE of buying a Samsung TV..
They consider THIS
normal on a two month old set..
WS65711 is offline  
post #26 of 26 Old 12-24-2011, 10:22 AM
AVS Addicted Member
 
arxaw's Avatar
 
Join Date: May 2002
Posts: 10,909
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by 6volt View Post

One thing I noticed when they talked about all the sensitives of placement, they talked about distances of "feet." On my porch, I can move the antenna inches or a few degrees and go from a good signal to no signal.

One other factor may be that my house is stucco, so the antenna is about 6' from a large, irregularly shaped "ground plane."

The screen mesh in the stucco would be a huge reflector plane. It often effectively blocks reliable indoor reception, too.

Moving the antenna a few feet would probably affect VHF more. But with UHF wavelengths being much shorter, moving a few inches in any direction can dramatically affect its reception.
arxaw is offline  
Reply HDTV Technical

Tags
Channel Master Cm 4228 8 Bay Hdtv Uhf Antenna Cm4228hd
Gear in this thread - Cm4228hd by PriceGrabber.com

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off