Preamplifiers and Distribution Amplifiers Help!

[buzzard31581]

I just cut the satellite cord yesterday so I'm just starting my ventures into off-air. I'm learning A LOT. I have a degree in mechanical engineering, but that doesn't help me with electrical stuff. However, I am capable of understanding advanced concepts.

I understand the difference between preamps and distribution amps, how they function, their uses, etc. I'm just not sure how to apply them in my current setup. Here's my report:

http://www.tvfool.com/?option=com_wr...1dda07ce79f7d8

I would like to get (virtual channels) 7, 9, 12, 14, and 25 at a minimum. Channels 8(real), 19(virt) are sister stations to some of the above and I've never gotten 26(real) and never really cared to. No skin off my nose if I can't get any of those.

I have a Clearstream C2V from Antennas Direct mounted in my attic (~25' AGL) pointing in the direction of 7, 9, and 25. All my cables are RG-6. From the antenna there is a 25' run that goes to a 2-way splitter. One side of the splitter goes to a converter box about 5-10' away. I get all the channels listed above on that set. I looked at signal strength and they're all in the 95-100% range. I don't have any other numbers to give that may be helpful. That side of the splitter I'm happy with.

The other side of the splitter has a 30' run to a 4-way splitter on the outside of the house. I only need a 2-way in this location currently, but I may decide to run lines to other rooms. From the 4-way, two lines run about 50' to two TiVo boxes on opposite sides of the wall. This is where I'm losing my signal. One box only gets 7, 12, and 14. These signal strengths are in the 40-50% range. The other box recognizes all the channels, but only displays 7, 9, 12, and 14. These signal strengths are in the 40-60% range. For the rest of the channels on this box it just says it's looking for a signal. If I remove the 4-way splitter and take out a TiVo box and run the line (all 80' of it) straight to the TV I get all the stations (including 8 and 19), no problem. So at this point I'm pretty convinced I just have too much signal loss from the 4-way splitter.

I'd like some input before I go out and buy more equipment only to find out it doesn't work or I really need something else.

So here are my questions:
What would be the most beneficial for my setup? A preamp at the antenna, a 4-way distribution amp in place of the 4-way splitter, a 2-way distribution amp in place of the 2-way splitter, or some combination?

I know you can run a preamp and a distribution amp in series, but can you run two distribution amps in series? What would the consequences be if any?

Is there potential to overdrive the converter box signal if I put in a preamp?


Thanks in advance!

[ADTech]

I'd suggest a 15 dB line amp at the upstream side of that first splitter. That will likely be enough.

[GroundUrMast]

It sounds as if you own the splitters already. As ADTech has suggested, a line amp, AKA distribution amplifier would be plenty to drive the insertion losses of the splitters and cable you've described. The Channel Master CM-3410 and Winegard HDA-100 quickly come to mind.

Presuming the splitters are of decent quality, in theory, there should be no difference between the system performance of an amplifier followed by a discrete splitter, vs. an amplifier with the splitter built in. However, in practice there are things to consider.

As a rule of thumb, it's best to use only one splitter, and to spec. the splitter with the exact number of ports needed. If you follow this rule, you'll avoid excessive losses including those caused by daisy chaining three or more splitters. Then there's the cost to be considered. For example, to serve four sets using 2-way splitters, you would need three 2-way splitters, the first to feed the other two. Then you would need more space and connecting cables... more cost and connections to fail. (If you had only 2-way splitters to work with, be sure to connect them in a pyramid not a tandem chain.)

Another rule of thumb: One amplifier can be too many. Two amplifiers are almost always too many. An amplifier can only take so much signal at it's input before it's driven into overload, which causes distortion and noise to dramatically increase. Unless you have calculated the losses caused by cable and splitters and have matched the amp gain to those losses, you risk overloading the second amplifier.

Your installation does not have losses that would justify a second amplifier... in fact, I would try running a larger antenna for it's passive gain. Which brings up another truism: 'Antenna gain is better than amplifier gain.' Antenna gain can't be overloaded, it does not add noise or distortion and it tends to come with the benefit of increased off bore-sight interference rejection (none of which an amplifier can do).

In an ideal world, all coax would be run to a common location. No run would have any splices mid-span. And all the cable would be tagged. This method may cost a bit more than a daisy-chained installation, but it's the most flexible and far simpler to understand years later. If one home-run cable is damaged, only that run is affected, but failure of the first cable in a daisy-chain affects the entire system.

If I where starting from scratch, I'd go with an Antennas Direct DB4e, outside, in the clear, facing 305° magnetic. I'd point an Antennacraft Y5713 at 125°. Then combine the two antennas using an Antennas Direct UHF / VHF Antenna Combiner. Finally, I would try this with a passive 3-way splitter. I would only add a DA if the need was proven.

[buzzard31581]

Thanks for all the input. I was leaning toward the distribution amp since the one TV has 95-100% signal on all the channels and I didn't want to overload it.

I completely understand that an amplifier can't compare to the gain inherent in the antenna design. An amplifier ends up amplifying noise as well as the signal which is never ideal, but sometimes necessary.

So I searched high and low in my area for an amplifier that I might be able to use and all I can say is this area sucks. I went to six different stores and none of them had anything useful. One had a distribution amp that only gave me 'up to' 4dB gain per output. One had a preamp that only gave me 10dB. And another had a preamp that gave a whopping 26dB, which I knew was WAY more than I needed. The rest had absolutely nothing.

I'll have to resort to ordering something online. Not that I'm opposed to that. I think I spend most of my disposable income at Amazon.

Moving on, I tried a few things when I finally got home. I swapped out the 4-way splitter with a much better quality 2-way. Signal strength improved, but not tremendously and not as much as I needed it to in order to get some of the weaker channels. I then ran the line straight into one of the TV boxes and I saw more improvement. Again, still not enough. I'm at least getting some of the missing channels now, but they continue to cut in and out.

I've attached a crude drawing of my layout in case there was any confusion in my description. Again, I've replaced the 4-way with the appropriate 2-way. If I ever need the 4-way I'll get one.

So based on what I've gathered so far I need to replace the 2-way right before the 50' run with a distribution amp. Is that correct? If so, I know I need a power injector, which usually comes with the distribution amp. My question to that is, is a 50' run too long of a distance to install the injector at the end of or doesn't it matter?

Thanks again!

[buzzard31581]

I completely misread the previous posts. So if I were to put in an amp prior to the FIRST splitter, would the potential to overload the tv at the end of the short run exist as I'm already getting such a high signal strength?

I was actually thinking of getting the CM-3412 and just putting it in place of the second splitter. Would that not work just as well?

[GroundUrMast]

I doubt the first TV will have trouble. But if it does, use the CM-3410 and move it to just after the output of the first splitter, this will leave the first TV/converter with an unamplified feed, and still provide amplification ahead of the cable and splitter losses that feed the TiVo's.

Another way of saying this is, use a separate amp and splitter to maintain maximum flexibility if you need to add to or change the system.

TiVo tuners seem to have a less than stellar reputation as far as OTA performance is concerned. Consider testing reception with the C2 outside and connected directly to one TiVo, then the converter... I suspect you can easily find higher quality signal outside, clear of the attic impairments.

[buzzard31581]

Got it. Now I just have to figure out how to get power to it. There's no outlets in the attic where the lines are. I might be able to tap into one of the outlets on the opposite side of the wall and put in a new outlet right there.

Thanks!

[No static at all]

If I were in your shoes, I would replace the first splitter with the CM 3412. You could also use it to replace the 2nd splitter, but IMO the 1st scenario should provide the best results.

With either scenario I can't imagine you will overload any of your tuners. I have slammed these things with much stronger signal levels & have always had excellent results.

Chaining splitters is not the best way to do wiring , to much signal losses and signal reflections in the system causes problems , pixalation , signal flucuations .

For your reception situation I recommend move the CS2V antenna to above the roof so reception is not blocked to the , north west , west , south east.

To receive the following Digital Tv Channels with a Stronger signal and --> more important --> better Signal Quality.

The Digital Broadcast Tv tuners in Tivo's , take a very dim view of poor signal quality. With the antenna in the attic.

The better the signal Quality is , the better the Tivo's will display a nice steady picture. With the antenna above the roof.

WCTI ABC , Live Well Network , This Tv.

WITN NBC , MyNetwork , Me-Tv.

WNCT PBS.
WUNK PBS.

WYDO FOX.

WEPX ION , Qubo , ION Life.

WFXI FOX.
___________

((((The best way to do coax wiring is have - 1 splitter - that all the separate coaxes is connected to and no other splitters.))))

If you will not do the above 1 splitter recommendation , then.

I recommend do the system like this.

Coax from the Antenna above the roof to the 2 way splitter.

One output of the splitter goes the short distance to the Tv.

Connect a Channel Master CM3410 distribution amplifier to the other output of the 2 way splitter close to the 2 way splitter.

The output of the CM3410 distribution amplifier is connected to the coax that goes out to the location of the 4 way splitter.

At the location of the 4 way splitter , only have a splitter with the required outputs.

If 2 Tv's are connected , use a 2 way splitter.

If 3 Tvs' are connected , use a 3 way splitter.

If 4 Tv's are connected , use a 4 way splitter.

Using the correct splitter with no unused ports will reduce signal reflections in the system.

The cleaner the signal , the better the Signal Quality.

The cleaner the signal quality , the Happier the Tivo's will be.

The Happier the Tivo's are , the Happier You Will Be.

___________________________________

As always , trees and tree leaves do a good job of , reflecting , reducing , blocking , Digital Broadcast Tv reception , and reducing signal quality and so do attics , roofs and houses , including your own roof and house.

It is best the install the CS2V antenna at a location that has the least amount to no amount of obstructions of any type or kind in the directions of reception including your own house.

______________________

Here are some Strong and Sturdy antenna mounts ,

http://www.ronard.com/909911.html , if using a tripod antenna mount use the 5 foot tripod antenna mount.

http://www.ronard.com/34424560.html , if using the eave antenna mount use the #4560.

http://www.ronard.com/ychim.html.

http://www.ronard.com.

Buy the ronard antenna mounts by typing the word ronard in the , http://www.solidsignal.com , search box or buy from ronard.

The CS2V is a Small , Light Weight , Strong and Sturdy , antenna.

[buzzard31581]

As much as I wanted to put it on the roof and run one cable to a splitter to go to the rest of the house, it just wasn't going to happen. We get extremely high winds pretty regularly in this area, not to mention hurricanes, and we just spent several thousand dollars replacing the roof from damage caused by a hurricane. My better half talked me out of it. That and I'm not crazy about climbing up on our high pitch roof.

So attic installation it is. I'll try the CM-3410 before the first splitter and if it makes the short run worse, I'll put it after the splitter. Ordered it last night so it should be here in the next few days.

I'll report back for those interested. Thanks again!

[buzzard31581]

I installed the CM3410 today prior to the first 2-way splitter and then reconnected my second 2-way splitter. I installed a new power outlet in the attic crawlspace and managed not to electrocute myself or catch anything on fire. That was obviously the hardest part about installing it and it wasn't really that difficult.

Results! The short run is still working just fine. On the longer runs, I saw a significant improvement in all channels, but 9 is still giving me trouble. All the other channels are in the 60-80% range now, but 9 is still in the 40's. It's not cutting out anywhere near as much as it was before at least, but it's still not what I would consider watchable or reliable.

I'm wondering if simply elevating my antenna might improve the reception. I could move it up a couple more feet, but I don't know how much it would really help. Again, any input would be appreciated. Should I consider a distribution amp in place of the second 2-way or would it just produce too much noise?

[No static at all]

What happens if you eliminate the first splitter & connect the directly to the line where the problematic reception is occurring?

The 3412 amplified splitter would probably have been a better option to deliver a more even signal to all outlets. The best solution would be to use a 3414 as the only distribution point & eliminate all the power robbing passive splitters.

[buzzard31581]

I moved the antenna a couple feet higher and got a better signal out of the one that was giving me trouble. I'm in the high 60's to 80's on all channels now with the exception of one of the duplicates, which I'm not concerned about since it's a duplicate. I tried adding a CM3412 in place of the second 2-way splitter, but it didn't improve it from what I was getting without it, it actually made it slightly worse. Yes, I plugged it in. Without it plugged in everything dropped to the 30's and 40's, with it plugged in everything was in the 50's to 60's. I think the cable between my power supply and the amplifier was too long though. I don't really have anywhere else to plug it in though since it's located outside. I can live with 60's to 80's though. If it gives me any more trouble I'll figure something else out.

Thanks for all the help everyone!