Reception issues

daltrey99

DTVUSA Jr. Member
#1
Hello,
First let me say I am new here and just cut the umbilical cord from the cable company. I live just north of Boston. I mounted an Antennacraft 5MS921 antenna on the roof and ran a 50 foot cable into the house. I connected it to my splitter that has 4 output connections. Now the problem lies in that on my TVs that are digital, I only get a few of the channels. The TVs that I use a digital converter I get about 30 channels. Now if I disconnect the splitter and put in an RCA DT140M, I get all of the channels on the digital ready TVs but a few of the channels get pixiated and the signal goes in and out but the channels on those TVs that I did not get before are perfect and strong. Does anyone have any solutions or advice so that I can get all of the channels on all of the TV's and not just the ones with a digital converter on them? Please help
Thank you!,
Jamey
 

dkreichen1968

Moderator
Staff member
#2
Hey daltrey, what does the "radar plot" from TV Fool look like for your location and antenna height. Please post the URL from your report here. Omni directional antennas are the "right" antenna in a few situations, but in most cases an unidirectional or bidirectional antenna works better. I have a feeling that the vast majority of your stations are coming from one direction.

Thanks,
Dan
 
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daltrey99

DTVUSA Jr. Member
#3
I did some research and I am wondering if it is the antenna. It is showing that it is for the Yellow zone. Those channels come in great. The ones that do not work without the booster are the further away ones. Would a yellow/Green antenna do better? Here is the stats for my area. TV Fool

My antenna is rated for 20 miles. The other one I am looking at shows a range of 40 miles. I am thinking buying it and trying it out.
 
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dkreichen1968

Moderator
Staff member
#5
you may need a pre-amp up on the aerial, not a distribution amp.
His antenna comes with a 20dB pre-amp integrated into the antenna.

A little house cleaning. Jamey, do you have the power inserter installed between the antenna and the 4 way splitter? An unpowered pre-amp will attenuate (decrease) the signal. On the other hand, don't try to double amplify the signal, in general it will only make reception worse.

I do see why you got an omni-directional antenna after seeing your tvfool. The mileage rating on an antenna is generally meaningless. The natural unamplified gain of the antenna (dBd), and directionality (half power beam width and front to back ratio) are more important specifications. TVfool gives relatively strong signals for stations in your area out to 50 miles.
 
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daltrey99

DTVUSA Jr. Member
#7
His antenna comes with a 20dB pre-amp integrated into the antenna.

A little house cleaning. Jamey, do you have the power inserter installed between the antenna and the 4 way splitter? An unpowered pre-amp will attenuate (decrease) the signal. On the other hand, don't try to double amplify the signal, in general it will only make reception worse.

I do see why you got an omni-directional antenna after seeing your tvfool. The mileage rating on an antenna is generally meaningless. The natural unamplified gain of the antenna (dBd), and directionality (half power beam width and front to back ratio) are more important specifications. TVfool gives relatively strong signals for stations in your area out to 50 miles.
Yes the power inverter is installed on the line coming into the house direct for the antenna and is before the split. If I unplug it, all signal is lost so I know it is working. I just find it odd that the TV with a digital converter works flawlessly but other digital TVs do not get all of the stations like the one with the converter. Strange.
 

dkreichen1968

Moderator
Staff member
#8
What channels do you get now, and what channels do you want? If you're primarily concerned with the channels from 223 to 227 degrees magnetic then a directional antenna may be your best bet. On the other hand, I also think that a Channel Master CM-3010 (bidirectional antenna) pointed south (north) would work well for you. Omnis are really limited especially for digital reception.

The difference in TVs (tuners) may be tuner sensitivity, or bad cables. Check your cables!!!
 
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daltrey99

DTVUSA Jr. Member
#9
I think that I forgot to mention, I have this currently installed on my rear sunroom roof. Do you think it would make a difference if I installed it higher on the second floor roof?
 
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MrPogi

Moderator, , Webmaster of Cache Free TV
Staff member
#10
I thing that I forgot to mention, I have this currently installed on my rear sunroom roof. Do you think it would make a diffeerence if I installed it higher on the second floor roof?
YES, absolutely. The general rule is "high and outside".
 

dkreichen1968

Moderator
Staff member
#12
I think that I forgot to mention, I have this currently installed on my rear sunroom roof. Do you think it would make a difference if I installed it higher on the second floor roof?
Yes, you want it above roofline for the best performance. Especially since you're looking at signals from multiple directions.
 

dkreichen1968

Moderator
Staff member
#13
Another rule is to buy an antenna that gets all your channels WITHOUT an amplifier and add amplification if you need it for distribution losses.
The antenna has a 20 dB amp and the system has a minimum of 11 dB of loss. Lots of green and yellow signals. Get it up on the second story roof, and I think his problems will for the most part be resolved.
 

Jim5506

DTVUSA Member
#15
Another general rule is the more directional the antenna is the longer the range and vice versa.

Also, antenna manufacturers generally exagerate their distance estimates.

I don't think altitude will add enough gain to compensate for lack of range - once you achieve LOS height does nothing for you.
 
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dkreichen1968

Moderator
Staff member
#16
I don't think altitude will add enough gain to compensate for lack of range.
Based on what? Antennas have gain, not range. Next month I'm going to take my loop antenna up on Mount Herman (9000+ feet) to see how much "range" it has... Fort Collins, Cheyenne, Casper, anyone want to make a pool?
 
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Jim5506

DTVUSA Member
#17
Gain is an expression of performance with signals from a certain distance at a certain wattage and are relatively equivalent.

Line of sight does you no good if you don't have enough gain in the antenna to put a usable signal at the tuner.
 
#18
Also, antenna manufacturers generally exagerate their distance estimates.
I gotta tell you, the specs on a CM 4221HD say range "up to 45 miles" and I almost didn't buy one for that reason. Almost went for a DB4e, since they claim up to 65 miles. The DB4e wouldn't fit where I needed it (top of desk) because of the extra 4.5 inches. But from everything I read, the gain figures, etc. are just as good for the 4221HD.

Well, I get 12 stations from the Willis tower in Chicago, 48 miles away, with 100% reliability -- better than the stations from Milwaukee 36 miles away. I think you have to go by the NM rating on tvfool and forget about everything else except local obstructions (trees, hills, walls ...).

Maybe I should be mad at Channel Master for underestimating range ...? :evil:
 

dkreichen1968

Moderator
Staff member
#19
Gain is an expression of performance with signals from a certain distance at a certain wattage and are relatively equivalent.

Line of sight does you no good if you don't have enough gain in the antenna to put a usable signal at the tuner.
Let's put it this way. WLWC at 48.6 miles has a predicted Noise Margin of 13.9 dB. Let say the integrated amp has 4 dB of noise. 13.9 - 4 = 9.9 dB, which means his antenna would have to have -9.9 dB of gain on channel 22 in that direction not to receive that channel.

Jim, face it, at this point, I can just pee further and higher than you can!!! ;)
 
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Jim5506

DTVUSA Member
#20
I thought this was a discussion, not a contest.

I though I read somewhere that tuners generally have 6dB noise, plus other factors...

That antenna might actually have -10dB gain, that's why it needs a 20dB amplifier.

DTV reception is more of an art than a science, all the calculations in the world can't substitute for real world experimentation.

If it works, great, but IMHO it's doubtful.
 
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