[stampeder]

This Preamplifier Comparison Chart was modified by holl_ands from an original chart at Solid Signal to show Max Input for two Strong Signals. It was reformatted into PDF form by stampeder with permission of holl_ands for the digitalhome.ca OTA Forum.

If you have any questions about the data in the chart please post in this thread.

Also see tczernec's Loss Calculator Spreadsheet in this post: http://www.digitalhome.ca/forum/showpost.php?p=877838&postcount=604. To use it, make sure to download it rather than using it online.

Another excellent tool is majortom's Cascaded Noise Figure Spreadsheet: http://spreadsheets.google.com/ccc?...rN2poRTVIalpwT3c&hl=en&authkey=CPbi9aYO#gid=1

Cheers

 

[cottagers]

Hey Burito,
What type of antenna do you have now? I picked up an antenna booster for about 10$ canadian at princess auto in Mississauga. I am not sure if they have any left but it made a big difference. It was an RCA and it had similar gain to a channel master but I think they were clearing them out.
You may be able to repoint your antenna a bit to pick up fox but it could make you loose other channels. I had to get a rotor to get all the channels properly.

 

[buritto]

I have an antenna on the roof, I'm not sure what the name is but everyone who has an antenna on there house (and there thousands upon thousands) has the same one as me.

It's a "big boy" antenna

I had FOX before with very little trouble and for the past few weeks the channel has been useless. I loose signal on it every couple of seconds. When I do get it in I check my strength and I have 9 bars on my Sammy 151 which is mre than enough to pull it in but then BAM! I loose it.

That Channel Master link looks like I'd have to go on the roof to install it? So that's not an option...but with FOX carrying the Super Bowl....

Would this help? http://www.radioshack.ca/estore/Pro...hack&category=VideoAmplifiers&product=1501118

EDIT:

Well for the first ime in weeks I got FOX without any problems tonight

 

[bareeves]

CVH100 signal booster

IM going tomorrow to try the 25db version - its 60 bucks..but some time the weather can impact the receiver ability lock in abc - its a crap shoot some nights...

 

[Mastermc]

CVH100

IM going tomorrow to try the 25db version - its 60 bucks..but some time the weather can impact the receiver ability lock in abc - its a crap shoot some nights...

Thanks bareeves, I bought the VH100 and it works great, it is a 100% improvement on my reception. Before I couldn't get NBC or Toronto 1. Now I am receiving them both.

What is the difference between the 10db with 25db version? Any additional improvements?

 

[tricky]

OTA Amps, Preamps, Splitters, Filters, Other Signal Gear

My 4228 with CM 7777 pre-amp picks up Buffalo 90% (Approx 60 Miles) and Toronto 90% (approx 70 miles) while looking through an enormous (to me) maple tree hey it might get better during the winter molt And it picks up Erie as well but thats free from obstruction.
The receiver senses 3 channels from Rochester but not enough strength to see anything.

 

[Yaamon]

Lost some channels after splitting the CM4228 signal

I installed the splitter last night and hook up the other tv and lost two channels.

Nbc from Bufalo and Fox from Rochester.

Noticed that on the Buffalo channels the signal bar went down by 2 to 3 bars.

Hopefully no sweat I ordered a 7775 and should be getting it today.

 

[JohnnyG]

This is the perfect application for a pre-amp, so you should be fine afterwards.

 

[stampeder]

My 4228 with CM 7777 pre-amp picks up Buffalo 90% (Approx 60 Miles) and Toronto 90% (approx 70 miles) while looking through an enormous (to me) maple tree...

You and robcreaser both have mentioned good signal success despite tree obstructions, but in my case I have to guess that its a combination of my location in the very deep fringe from SeaTac with the type and size of the trees here. I should clarify that I get local DTVs (CIVT and KBCB) just fine with the help of the preamp, as well as a bunch of analogs stations too.

 

[stampeder]

Testing the Risk of the Preamp Overpowering the ATSC tuner

Yaamon, you have more tests to do! (the fun never ends ) because you need to see if there is now a risk of the preamp overpowering the ATSC tuner (snow, distortion, etc.)

1. get the preamp installed and powered up
2. on TV #1 leave the ATSC tuner's signal strength meter on the screen on one of the weaker stations and do the following steps as quickly as possible
3. disconnect TV #2's antenna feed from the splitter while TV #1 is up and running and note the signal strength difference
4. now check all DTV and analog channels on TV #1
5. get TV #2 hooked up again as quickly as possible

During #3 if you notice a sharp jump upwards on the meter to 100% on such a weak station you are possibly at risk of overpowering your receiver. Imagine stations that were already at 100% now getting that power boost and you start to see the problem. If you have such a situation you will need to install an attenuator on TV #1 so that in the future if TV #2 is ever disconnected for more than a small amount of time you will avoid overdriving TV #1's ATSC tuner.

Another scenario: if in the future you decide to further split the connection into a DVR or VCR or FM Tuner you can do all those steps again to see if its time to remove the attenuator from TV #1.

 

[Yaamon]

Thanks I could not wait and went home with a friend to help me with the ladder.

After I hooked it up No signal. Went back on the roof and connection was fine damm, then I realized that I could not boost the signal after the splitter.

So I connected it directly to one rec with the amp disconnected the splitter and there was the signal.

So I ended up spliting the signal in the bedroom after the amp and sent back the other feed to the family room.

All the Toronto ones are still full strength and The Rochester ones are back but the signal did not increase on those compared to one feed before the splitter.

I will try and play with the position of the antenna and hopefully can swing it a bit more south to east.

 

[stampeder]

After I hooked it up No signal. Went back on the roof and connection was fine damm, then I realized that I could not boost the signal after the splitter.

There are splitters on the market that allow power injection upstream on one of the connections. Was that what the problem was? Also, the preamp needs to be as close as physically possible to the antenna or else you end up amplifying line noise, which is a no-no.

 

[stampeder]

Preamp Advice from Tigerbangs

If you need a good preamp for your antenna, the two best choices commercially available are the Channel Master Titan 7777 and the Winegard AP 8275. These are all-channel preamps, but work well for UHF. The Radio Shack preamps have a high noise level, which works against the signal-to-noise issues of DTV broadcasting: they are generally frowned upon for DTV use because of their high noise level.

The Channel Master Titan 7777 has dual antenna inputs: one for UHF only and one for VHF-UHF combined signals: the inputs are selected by a switch on the preamplifier.

The Channel Master 4228 8-bay UHF antenna has good reception on high-band VHF channels 8-13, and is best used with an all-channel preamp.

 

[stampeder]

UHF Signal Shadow guesstimates

A general rule of thumb (not necessarily accurate for some conditions - your mileage may vary) is that UHF TV signals at a given strength tend to remain somewhat strong behind a large, solid obstacle (building, hill, grove of large trees) above a line at about 30 degrees downwards from the top of the obstacle.

Below that line you are in a signal shadow and may not get a good signal. Again, this is just an old rule of thumb and is open to wide discrepancies. I mention it because it explains why antennas in somewhat shallow ground depressions sometimes pick up strong UHF TV signals anyways.

Now all you can do is test, I guess. Make sure you have good antenna gear.

 

[Yaamon]

There are splitters on the market that allow power injection upstream on one of the connections. Was that what the problem was? Also, the preamp needs to be as close as physically possible to the antenna or else you end up amplifying line noise, which is a no-no.

Yes the problem was the splitter.

I mounted the pre amp right on the mast, cable from the Balun to the pre amp and then cable down.

 

[kwtoxman]

It was my understanding that you should be using a distribution amplifier to bring your signal back up, and not a preamplifier

preamplifier for weak signal area
distribution amplifier for weak signals to multiple sets

Am I wrong?

kw................

 

[HDTV101]

I told you you will need an amp

Now get a Rotor Motor too.... it will make things more easy to aim and fun.

 

[HDTV101]

It was my understanding that you should be using a distribution amplifier to bring your signal back up, and not a preamplifier

preamplifier for weak signal area
distribution amplifier for weak signals to multiple sets

Am I wrong?

kw................

An Amp is an Amp... but with an antenna the best place for the amp is right at the antenna.... this is why we have the amp mounted right at the antenna.
These amps are powerful with up to 28dB gain... more then enough to compensate for long cable runs and splitters. Splitters typically case a 3 dB loss when inserted in the line. Distribution amplifiers are more for cable TV signal boosting and when you have an Amp on your antenna to also have a distribution amplifier too will most likely overload and give poor results.

 

[Yaamon]

Yes, HDTV you are right. Roto oh no me don't want to go back on the roof again.

Can the new rotor be programmed the ones I remember was a dial that you turn and when the ghost images went away on analog channels you stop.

I have seen customers tape number on them to let them know where to stop.

I can get all Buffalo stations fine, and Rochester runs the same as Buffalo on prime time tv if Iam not mistaken. There is no real need for a roto unless I get bored and just want to have more channels.

The Titan 2 7775 pre amp is rated for UHF only and 26 DB gain at only 2FB noise.

 

[stampeder]

It was my understanding that you should be using a distribution amplifier to bring your signal back up, and not a preamplifier

You are correct, but... Yaamon is located quite a distance from the Buffalo NY stations so going for the solution that injects the least amount of noise (the preamp) was sensible. Heck with his initial signal strength its entirely possible that somebody could run a distribution amp alone and love the results, but I sure do not recommend it. If Yaamon had specified that he was going to drive several TVs then we would be looking at adding a distribution amp below the preamp. Check out the preamp posts in this thread:

http://www.digitalhomecanada.com/forum/showthread.php?t=26857

As for the rotator, I hate to say "I told you so!" but I did!