Signal Amplifiers (Amps, Preamps, Distro Amps) - See Chart in Post #1

[Yaamon]

I just cleared my in box. Sorry.

I live near Mcowan and 14th Ave.

There is no reason why you are not getting Toronto 1 and CFTO.

Maybe when you were trying CFTO was down as they were last week or before. Try 40-3.

You should not need a preamp unless you split the signal? My signal before I split was fine on all local channels.

[jeneral]

This thread has gotten a little confusing for me. What's the general consensus, pre-amp on mast and passive splitter, or no pre-amp and Active Distribution amplifier?

I'm going to be moving to a new place in Mississauga and I'd like to get a 4228 installed on the roof. If the pre-amp option is best, I'll get the installer to do that at the same time. I'd like to have the signal split in four at least (family room, bedroom, computer room, basement) maybe even 6 if I go for dual tuners in some spots.

I'm going to be at Britannia and 9th Line, does anyone in the vicinity recommend a rotor? I haven't tested my current indoor antenna (Silver Sensor clone) at the new location yet, but I currently receive all available channels and I'm only 3 KM east of the new place.

[stampeder]

Originally Posted by jeneral

I'm going to be at Britannia and 9th Line, does anyone in the vicinity recommend a rotor? I haven't tested my current indoor antenna (Silver Sensor clone) at the new location yet, but I currently receive all available channels and I'm only 3 KM east of the new place.

You should get the same stations if the difference is only 3Km. That's assuming no big buildings or hills are now in the way.

[HDTV101]

Originally Posted by jeneral

This thread has gotten a little confusing for me. What's the general consensus, pre-amp on mast and passive splitter, or no pre-amp and Active Distribution amplifier?

I'm going to be moving to a new place in Mississauga and I'd like to get a 4228 installed on the roof. If the pre-amp option is best, I'll get the installer to do that at the same time. I'd like to have the signal split in four at least (family room, bedroom, computer room, basement) maybe even 6 if I go for dual tuners in some spots.

I'm going to be at Britannia and 9th Line, does anyone in the vicinity recommend a rotor? I haven't tested my current indoor antenna (Silver Sensor clone) at the new location yet, but I currently receive all available channels and I'm only 3 KM east of the new place.

I live off of Britannia between 9th and 10th Line. are you in the new Churchill Meadows development?

[jeneral]

Originally Posted by HDTV101

I live off of Britannia between 9th and 10th Line. are you in the new Churchill Meadows development?

Sadly, no. I bought an older semi (built in 99) just north of Britannia and a stone's throw from 9th line.

I notice you're using a 9032 with a rotor and an amp. Do you need to use the rotor for DTV? I was hoping to aim the 4228 towards Buffalo and hoping the TO channels would get picked up on the side. Do you split the signal to multiple televisions? Did you install the antenna yourself (if so, how much do you charge )?

[HDTV101]

You really only need a rotor if you want to get fancy and try to pick up other stations like Rochester, or Erie. When I have my 9032 pointed at Buffalo I can still pickup the Toronto stations well. If you’re using a 4228 then you've got a much wider pickup pattern then the 9032 and that’s going to be good in your case with not using a rotor. It should work just fine.

I have an amp on the antenna.... makes a huge difference for Buffalo stations... mainly NBC. I have a 2 way splitter inside that feeds my digital OTA box and the other is for analog UHF channels on my TV.

I did install everything myself... maybe I could help you do your own install if you have all the equipment.

[RASCL]

After I repositioned my antenna to the roof, pre-amp (cm 7778) located at the antenna, a single direct run (about 120') of RG-6 cable directly to the amp portion of the CM7778 located about a foot from my T151 I was able to get all of the Toronto and Buffalo channels including the WB WNYO 49-1 from Buffalo although weak.

As soon as I split the signal to supply an analogue signal to the tv, I lost 49-1 completely. After reading some of the threads it looks like I need to add a distribution amp.

My questions are:
1) Is adding a distribution amp the right approach? MATV distribution amp?
2) Should the distribution amp be installed between the pre-amp and amp or after?

[stampeder]

Originally Posted by RASCL

After I repositioned my antenna to the roof, pre-amp (cm 7778) located at the antenna, a single direct run (about 120') of RG-6 cable...

You just hit on the main issue - 120 feet of RG-6 is costing you about 5 or 6db of signal at UHF frequencies. Add the signal cost of the new splitter/cable/lead to the TV, which is as much as 3db. Given that your antenna (a CM3010a as you mentioned in another thread, with a CM7778 preamp) is giving you all its got just to bring in the other Buffalo stations, you start to see why the signal on the weakest station dropped out under that load.

Originally Posted by RASCL

1) Is adding a distribution amp the right approach?

1) If the signal is strong enough and clean enough at the end of the 120 foot mark of RG-6 but starts to die off with any downstream splits, you could add about 10db of signal strength at that point with an amplifier to offset the losses shown above. My preference, and if you'd like a bit more insurance of clean signal, would be to put a 10db amp in place at about the 80 to 100 foot mark. Of course you could just test to see where it should be placed to get the cleanest, most powerful feed.

Originally Posted by RASCL

2) Should the distribution amp be installed between the pre-amp and amp or after?

2) How many taps do you want running off the antenna? A distribution amp with 4 or more taps would be great if you want to drive several TVs, FM receivers, PVRs, etc. but if its just one TV you may find that a single in/single out amp will do the trick - it depends on your particular layout. No matter which one you choose, that amp will be the final source that all internal house cable strings will branch out from.

The schema is: antenna -> preamp -> outdoor cable downlead -> amp -> indoor branch cable -> TV or FM receiver

If you want to stay with your CM3010a antenna, an inline amplifier is your ticket. OTOH, a move to a higher gain antenna like a CM4228 feeding into your CM7778 would mean probably never having to worry about the load again. Hope this helps!

[RASCL]

Thanks Stampeder,
Lot's of decisions.....

1) To shorten the cable length, I could move and strap the antenna to a closer chimney to the tv. The only issue to this would be that the chimney bricks are breaking away and are in need of repair. This is why avoided it originally. I have a feeling that this move to shorten the cable length in itself would solve the problem.

2) I like the option of adding the 10db amp half way along the cable run. Does it make sense to add a 16db or greater inline amp?

3) If the above fails, I'll probably goto replacing my 3010A with your recommended CM4228 in the spring.

In it's final configuration I think I'd like to be able to supply signal to 2tv's, my T151, A PVR and at least 1 FM receiver although if I get the 4228 antenna then I'll use the 3010A specifically for the second t.v.

At the end of the day, I'm still doing rather well with channels as the only channel that I'm not receiving is 49-1.

[stampeder]

Yep, you're on the right track with shortening the lead, but if it means causing damage to the chimney don't do it. I would suggest that since you're only looking at driving 3 devices (2 x TV and FM) you leave the mount as is and just go with a single in/single out 10db amp (you can get a reasonably priced RCA 10db amp at Home Depot or there are much higher quality ones out there). You should put it inside near where the cable enters the building, but bear in mind you'll need to supply 120VAC to power it wherever you mount it. You don't want to have the amp any closer to the antenna because amps are noisier than preamps and you want the signal to be as clean as possible for as long a distance as possible. If all the amp has to do is drive the internal cabling it will do just great. Amps don't need to be so stringent about noise as preamps because internal cable runs are comparatively short and shielded.

You asked about a high output amp (15-20db) but that level of signal could damage some gear, so people who drive their indoor connections with that kind of power need to put 3 to 6db attenuators on all their gear. It may sound redundant, but the payoff is that you rarely if ever have line loss anywhere indoors by adding 2 or 3 more devices.

[gordee78]

So in my search of NBC and UPN, I went ahead and purchased a channel master 7775 preamp from Sal's TV in scarborough.

As a refresher I'm receving all of the Toronto stations ok, and receiving almost all the Buffalo stations ok with the exception of NBC (WGRZ) and UPN. (As a side note, 7-1 seems to have disappeared since yesterday) I'm located in Toronto, up on Avenue and Lawrence. My setup is a CM-4228 with 30ft of cable to a samsung CRT with (H)DTV tuner built-in -- no splits or anything.

So I get up on the roof and put the 7775 in. Mike at Sal's tells me that the preamp is probably overkill, but will help on the really snowy days. Turns out that on EVERY single channel the power level to my Samsung TV is 10 - 20% worse! This includes CBC, and CTV which are coming in at 90%. I verify connections, and I verify that the amp indeed is 'doing' something. If I remove power to the power injector, power levels drop an additional 20%. But if I plug it in again power levels go up, but never to as high as they were without the preamp. With the preamp not do I not receive NBC (Which I steadily receive 1 bar but no picture), but I also loose WUTV (29-1) and ABC (4-1) comes in choppy if even at all. After a good 2 hrs of testing, it appears as though if the mast-mounted preamp is installed I immediately get a huge insertion-loss... (About 20-30%) whether or not it is powered.

Has anyone had this behavior before? There isn't much to my setup, nor is there anything to configure on the CM-7775 so it looks like I'm stuck with a bad preamp?? Suggestions?

Also as another aside (I'm an electrical engineer) I took apart the 7775 -- these things are a 2-sided hand assembled pcb! It's no wonder they cost this much!?! Also ... it appears as though the bottom half of the pcb is non-populated? It's a wonder why CM does not offshore this assembly ... we could have this preamp for less than $20...

[Yaamon]

gordee first of all you the pre amp does not have a pass through so if you unplug the power it wont work properly.

The pre amp has to be plugged in or completely removed from the setup.

If all your signals are down with the preamp then yes you are over driving the samsung receiver.

You can either remove the preamp or add some attentuation to the signal maybe 6 to 9 db.

Because of your location you maybe in a valley/lower elevation and that is causing problems with Nbc & Fox.

Most of us that lives north of the Cn Tower and in the gta you have to point the antenna more south east to get a max signal from Nbc. You have to compromise between Sun and Nbc.

The antenna needs to be pointed west for Sun and south east for Nbc. If you can get these two stations in good strength then your antenna is aligned properly.

Where you installed your antenna is the view clear pointing south ? Where do you have your antenna mounted ?

[987654321]

Your results are not the least bit surprising to me.

The first rule of antennae installation is: "Preamps should only be used as a last resort". This is especially true in areas of high signal level.

Always go for better antenna and different placement (usually higher).

What you are seeing is the result of signal overload (probably from the strong UHF analog signals on the CN Tower - both direct and reflected signals).

[gordee78]

Originally Posted by 987654321

Your results are not the least bit surprising to me.

The first rule of antennae installation is: "Preamps should only be used as a last resort". This is especially true in areas of high signal level.

Always go for better antenna and different placement (usually higher).

What you are seeing is the result of signal overload (probably from the strong UHF analog signals on the CN Tower - both direct and reflected signals).

Yes ... unfortunately that is what I suspected. The better part of the two hours of troubleshooting on the root was adjusting antenna angles and positioning ... according to the compass I am aimed directly for the WGRZ station ... but there are a number of larger houses and 100yr old trees in the way in the distance. The antenna is pretty much as high as I can go, chimmney mounted on my little bungalo (while there are gi-normous 2/3 storey houses all around). So I guess it is so-be-it for now. Anyone want a CM7775 ?? =)

[stampeder]

Originally Posted by 987654321

The first rule of antennae installation is: "Preamps should only be used as a last resort."

Amen to that, but I thought the first rule was "Let's put it even higher!"