[Robcope]

Any advice on a good preamp would be greatly appreciated?

Rob

 

[texasbrit]

The CM7777 is the most recommended, unless you have some very close in stations that might overload the preamp, in which case most people would recommend the Winegard HDP269.
but it depends on why you need a preamp, which antenna do you have and which distant stations are you trying to receive?

 

[David MacLeod]

if needed I have good luck with the cm3044 distribution amp.

 

[Grentz]

I have had great luck with some of the radioshack ones as well. The one I use is older and I cannot find it on their site anymore, but it works great and I am about ~35 miles out.

 

[Kansas Zephyr]

RS amps don't have the best S/N ratios.

I too, would recommend the CM7777.

 

[David MacLeod]

I've been told that often a dist. amp works better, are you having problems with a station when only feeding 1 tuner or does it work ok until you split it a few times?
I have not experienced it, but I've read pre-amping in this issue causes pixelation and overloads.

 

[Grentz]

RS amps don't have the best S/N ratios.

I too, would recommend the CM7777.

Still works great though, have had up to about 10 splits off my single antenna and it works great. All stations come in crystal clear when without it all have noise.

On digital stations, my signal goes from 40-50 to 95-100 with the amp

 

[Scott in FL]

I've been told that often a dist. amp works better...

The knock against distribution amps is usually that they have a higher noise figure than pre-amps. A pre-amp is used at the antenna to set the noise figure, and a distribution amp is used downstream to distribute the signal. However, the NF of the CM3044 distribution amp isn't that bad: 3.5 dB. If you're going after weak signal UHF, the CM7777 NF is 2.0 dB at UHF (1.5 dB better, which can make a difference).

The gain figures are about the same, and you'll have a difficult time overdriving the CM3044. It's max output is specified as 23 dBmV. That's almost 1/4 volt!

The CM7777 can be mounted outside, important if you have an outdoor antenna (a pre-amp should always be mounted as close as possible to the antenna). Also, the CM7777 has lightning/surge protection at its input, a switchable FM trap, and out of band rejection filtering.

On the other hand, the CM3044 costs $40 less.

I'm not a fan of RS amps. They tend to have high noise figures and poor lightning protection. I worked at a local TV station that bought RS amps, and they never made it through our lightning season before winding up in the trash. True, you can probably pick up a RS amp quickly and locally, but spend the extra money and wait a few days for a really good pre-amp to be delivered.

 

[David MacLeod]

last week I added a rotator and the cm3044, with 3 tuners hooked up it was ok but adding the fourth killed it on 2 stations. I hemmed and hawed over which way to go, since the majority of my signals are super strong I figured DA was best way and did away with all splitters. the cm3044 is mounted exterior but is extremely well protected, now all 4 tuners operate at no less than 90% strength. I've even, just to test, split off 2 runs and added a tuner to each and it was still good.
from what I could tell most of my loss was due to the splitting, I;m sure every situation is different but this worked best for me.

 

[Scott in FL]

The gain figures are about the same, and you'll have a difficult time overdriving the CM3044. It's max output is specified as 23 dBmV. That's almost 1/4 volt!

Whoops... I have to correct myself. When it's relative to power, dB is 10log. But for voltage its 20 log. So 23 dBmV would be 14 mV (not 200 mV).

Still, that's a healthy maximum output spec. And a decent noise figure.

 

[Paul E Fox II]

So knowing all that...

My antenna is inside my house, in the attic and I get pretty good signal on my HD/DTV channels.

However, since we have several OLD sets and plan on using the DTV Converter Boxes for OTA...I used a simple 2-Way splitter...the upstairs converter box has great signal on all channels but since the run is longer down to my theater where the HD21 lives, I'm now suffering from quite a bit of signal loss here. I presume that will only get worse as I continue to split the signal from the antenna.

At MOST, I'll need five (5) runs from my antenna to various sets around the house...and in all likelihood, I'll really only need four (4). Will the CM3044 do what I need or should I look at one of the newer CM3418/CM3414 (depending on outputs necessary) to help?

Since I'll probably be doing this for my grandparents, my Father/Mother In Law and my Dad and Mom, I'd like some options before jumping in and buying the wrong item. Who knows, they may even want and HD-DVR at some point and if I have the OTA stuff already working...I'd be one step ahead!

 

[David MacLeod]

as a test I ran 6 off from the 3044 (2 way splitter on 2 runs) with each run averaging 25 feet and it worked fine for me. thats no guarantee it will work for you of course, but if you deal with solid signal and have an issue I bet they would work with you.

 

[Partner45]

What do you really want? The header for this thread says the 'BEST' pre-amp. You want the best, well here it is.

http://www.researchcomms.com/hdtv.html

concerning the HDTV
preamplifier system.

The costs of the units are:
Type 9260 LNA £55.00 Noise .4 dB, Gain 23 dB UHF
Type 9254 LNA £55.00 Noise .4 dB, Gain 23 dB VHF/UHF
Type 9255 PSU £30.00 Power Supply
Type 9252 Masthead Case £13.00
Insured air mail to USA/Canada £19.00

Wise man once told me, for 2 bits more, you can go first class.

 

[AntAltMike]

...you'll have a difficult time overdriving the CM3044. It's max output is specified as 23 dBmV. That's almost 1/4 volt!
...

Manufacturer's max output levels are almost impossible to analyze. Channel Master commonly lists the maximum output that an amplifier can gain with four equal strength analog channels without developing more than 0.5% sync compression. Then, somewhere along the line, they published the exact same Max output numbers but called them the level at which the amp develops -45dBc of cross modulation.

The problem with amplifying off-air signals that vary in strength is that various intermodulation products appear all over the spectrum, and when they land on the weakest channels, they decimate them even though the amplifier is running well below its rated maximum output.

Furethermore, I consider the Winregard max output numbers to be a complete joke. I once compared two Channel Master 23dB UHF gain preamps and two Winegard 23dB UHF gain preamps, and the Winegards had slightly higher published max output levels, but my weak station, digital channel 59 from Baltimore, got beat to a pulp by the Winegard whose strong stations were about twenty dB below the max rated output, whereas the Channel Master preamps didn't comparably beat up the weak channel 59 signal until I drove the strong signals to within ten dB of the max rated output, and I know the problems wasn't with the stronger signals flooding my Accurian tuner, because I then ran the amplifier outputs through a tuned, channel 59 bandpass filter but the signal quality degradation persisted.

 

[Cmnore]

I just bought a CM 7020 on eBay. It is a discontinued model. Looks like it is a robust unit though. Anybody own one already?