Thread: Is there an advantage to variable gain distribution amp to pre amp?

I contacted both Wineguard and Channel Master technical service. They suggested I keep my existing attic mounted Channel Master directional antenna with rotor. Wineguard recommended a HDA 200 distribution amp so I could adjust gain to my liking. Channel Master recommended CM-0068DSB pre amp. Any thoughts? Also thanks to all who may have given me antenna suggestions in another thread. Looking at all possibilities. My TVfool info

TV Fool

To answer your question as best I can:
The Pre-amp will add less noise than a distibution amp to the recieved signal. Used at the antenna.
The Distribution amp will amplify the signal more, adding more noise, but will cost less.

My personal recommendation from your TVFool:

Don't use an amplifier where you are.
You are too close to need one.
I also live 8 miles from the local towers.

I use distribution amplifiers to add noise when I can't attenuate.
I have one attenuator and two distribution amps from when I started learning digital TV.

Attenuating usually works best

Using an amplifier helped analog TV show up much better.
Digital TV doesn't care nearly as much.
What kills Digital TV for most is what we called ghosts in the analog days and is referred to as multi-path in Digital TV.

You should receive all but the CW station easily.
The Fox and CBS station may need some attenuation(weakening) since they are VHF and will have more strong multi-path signals interfering.

If you're trying to DX, then good luck buddy! I wish you the best.
TV DXing is not my forte. My recommendation is for stable reliable reception for your stations to your north and west of you.

handymantoo,

I'd agree with meinename on just about every single point he makes, specially you being TOO close for a Pre Amp !

I'm not sure I'm understanding what you're trying to do, is it to get that CW reception better? IF that's the case, it being a "2 Edge", the usual/only way to deal with that is MORE HEIGHT ! And, you're already at 20'.

Can you come back and post exactly what you needing/trying to do ?

Have a good Day !
S.W.

I am trying to get local and stations in Boston. I have two 722 k(4 tuners) one tv and 2 fm receivers. The antenna I have when pointed 35 degree toward Boston works great for one 722k. When I split to add anything else I start to loose Boston Stations.

The only time I've pulled 2Edge channels reliably was VHF signals at 45 miles away.
No amp at that time either.

So I'd only bet on WWDP coming in reliably.
And by reliably I mean 1-5 hiccups (audio drop-outs or bad pixels) per 10 mins.

Both of the amplifiers you were suggested add way too much noise for what you are trying to do.
The Winegard adds 4dB of noise
The Channelmaster pre-amp adds 3.7dB
For what you're trying to do you need something that adds less than 2dB of noise, closer to <1db but that starts getting +$100 expensive.

This is the closest distribution amp I can find on Channelmaster's site:

Channel Master CM 3418 | Antenna | Cable TV Amplifier

But it adds 2.7dB of noise which I think is still too much...

You listed 6 needed outputs. Forgetting the FM ports, I know I can get away with a high-quality 4-way for the 8-mile stations

Channel Master CM 3214 | Antenna | Cable TV Splitter

The cheap splitters branded under Phiilips and such that are sold around here in stores caused me more loss and trouble than they were worth.
I started collecting splitters from the local Comcast installers
Made a world of difference. the 4-way splitter linked above is one such splitter that I have.

Coax cable connectors also make a difference.
It is My personal opinion is that using non-compression connectors harms digital reception near as much as multi-path or other factors.
Almost all of the coax connectors (I'm talking about F-connectors here) besides Hex-crimp and compression that I've used in the last 4 years are rubbish.
Using slip connectors are only for strong FM and as a jump-cable between analog (RF Ch. 3/4) devices.

Cables with connectors like these need to have those connectors replaced with compression connectors:
[ame="http://www.amazon.com/100-RG6-Coax-Cable-Connectors/dp/B000HSEMBI/ref=sr_1_2/181-5072292-3910145?ie=UTF8&s=electronics&qid=1258686881&sr=1-2"]Amazon.com: 100&#39; RG6 Coax Cable with F Connectors: Electronics@@AMEPARAM@@http://ecx.images-amazon.com/images/I/11qf5qycg1L.@@AMEPARAM@@11qf5qycg1L[/ame]

Back on topic:
Care to share some pictures of the wiring for suggestions for how to improve?

Originally Posted by handymantoo

I am trying to get local and stations in Boston. I have two 722 k(4 tuners) one tv and 2 fm receivers. The antenna I have when pointed 35 degree toward Boston works great for one 722k. When I split to add anything else I start to loose Boston Stations.

OK. You are absolutely close enough to get stable reception at the 8 mile average distance you are at, that a pre-amp/amp shouldn't be needed. But when you are using an 8 way splitter (are you?) you have a -11dB loss per port. Added to that of course is the length of the cables themselves. Add to that an additional -.5dB loss per connection point (and don't forget about any baluns being used as there is a loss there also), and by golly you'll find that you do need an amp/pre-amp.

The biggest difference between a pre-amp and an amp is that a pre-amp has a seperate power supply. Distribution amps generally have a higher noise level than a distribution pre-amp does. Variable gain amps are nice because you can customize the amp output level for your situation very easily. Adding noise to a system for the sole purpose of attenuation as has been suggested is not something I would recommend. Actual attenuators are the ideal solution.

Now getting back to what you want/need, I recommend something that is very effective, low cost & low noise. You already have all the attenuation you can handle, so what you need now is to recover some of it so you don't have any dropouts. The only way that will happen is with a low noise pre-amp.

The trouble with the suggested CM 3418 is that each port is amplified. That is where you will get into trouble. What you want is the best low noise single output pre-amp, such as this:

[ame="http://www.amazon.com/Motorola-Booster-484095-001-00-Bi-Directional-Amplifier/dp/B000066E6Y/ref=sr_1_1?ie=UTF8&s=electronics&qid=1258691206&sr=1-1"]Amazon.com: Motorola Signal Booster 484095-001-00 Bi-Directional RF Amplifier:…@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41HG8Q6hI6L.@@AMEPARAM@@41HG8Q6hI6L[/ame]

You can get it on eBay or other electronics web sites, so look for the best price. And it doesn't have to be Motorola (though I do like them the best) as the EXACT same specs are used by other makers. Myself, I have one made by NexxTech (the one in my signature). Same thing, different name. I believe Channel Master also sells their own brand. Just as a FYI, I got mine for $7 shipped from:


Consumer Depot, Major Online Electronics, Computer Wholesaler Liquidator

They may or may not have more deals like mine. Mine was listed as a demo/display unit.

Anyway, connect the antenna lead to the pre-amp input, the amplified output to the input of the 8 way splitter. You should terminate the unused ports on the 8 way with 75ohm terminators and you should be all set.

The comments made about having quality 'F' connectors are spot on. You want the best you can get. A compression tool and fittings can be had for a reasonable price also on the net. I cheap compression tool is fine for the average homeowner since it isn't being used in a professional, day in day out, manner.

So if you do what I said, you will have your losses back and might gain +1dB if your lucky. If you're real lucky you might get an added channel or 2 that wasn't possible to get before the pre-amp was added. Let us know what you decide to do and how it works out.

What is so great about compression connectors? I thought their main purpose was speed and ease of use. I have a compression tool that I bought at home depot; it is more the consumer variety, not pro grade, but it works for me. Prior to that I had a hex crimper.

The Wineguard HDA 200 has a seperate power supply. I prefer Wineguard or Channel Master. Look at the specs for the HDA 200 and see if it will work. Also I have a Hex crimper. Can it be used? The F connectors are really tight.

Originally Posted by Centex

What is so great about compression connectors? I thought their main purpose was speed and ease of use. I have a compression tool that I bought at home depot; it is more the consumer variety, not pro grade, but it works for me. Prior to that I had a hex crimper.

Reasons I'll give for compression over hex but but probable not nearly a full list or completely accurate:

• Full contact with shield braid and foil
  
  • Hex has 6 points of contact at best to the shield braid and foil, compression goes all the way round
  • Better conductivity having more contact
  • Less signal loss than Hex having the extra contact.
• better weatherproofing usually
• Much less likely to be pulled off/out

As for Ease of install:
Compression simply requires a good strip, flip back the foil, slip a connector on, compress, and finally pull to see if the connector slips at all.

Hex, as I understand, requires make sure the braid is pinched under the 6 flat parts of the connector. And after all that fuss, the connector can still be pulled off...
To those who may read who can make a good crimp, good for you!
There are those of use who aren't that good with a hex crimp or have only used compression.

Originally Posted by handymantoo

The Wineguard HDA 200 has a seperate power supply. I prefer Wineguard or Channel Master. Look at the specs for the HDA 200 and see if it will work. Also I have a Hex crimper. Can it be used? The F connectors are really tight.

Can it be used? Sure.
But how well do you know how to use it?
Did you use it once/a few times or have you used it many times and are familiar in making a good crimp?

As for the amp I think you are wasting money on the HDA-200
I have two similarly rated amplifiers (24dB ampli., 4dB noise) and neither helped at all trying to get the similarly rated 2edge stations.
In fact they hurt my locals.

But that's my experience, You may have a totally different experience.