[mythtv-users] cable distribution amplifiers

James L. Paul james at mauibay.net
Mon Mar 8 02:47:43 EST 2004


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On Sunday 07 March 2004 3:03 pm, Josh wrote:
> We sell them at radioshack, and 75% of the time they come back the next
> day. I'd stay away from them if possible. A better option is to reduce
> cable runs where possible and look for worn through insulation and
> shielding as well as rust on the ends. A good high quality cable helps too;
> get some of that quad shielded stuff for the longest runs in your house if
> you feel like replacing.

In general, I disagree. I won't comment on the quality of any Radio Shack 
products, but the purpose of a distribution amplifier is to provide multiple 
outputs at unity gain from a single input. In other words, it's an active 
component that greatly reduces signal loss compared to a passive splitter.

Signal loss due to poor quality cable or long cable lengths can be significant 
too, but loss due to passive splitting is very often the major issue to 
overcome when feeding several devices from a single cable. A distribution 
amplifier can often be the only solution.

That said, quality of the components is everything. Cheap passive 4-way 
splitters can be your worse enemy, and poor quality distribution amps can be 
hardly better. I've seen good quality passive splitters outperform bad amps. 
High quality cables are a must, regardless of how you split the signal.

> If you must go with a cable amp, put it as close to the cable entry point
> in your house as possible. Otherwise you run into Garbage in -> Garbage
> out.

True to a point. This has nothing to do with distribution amps though. It 
applies to gain amplifiers. Distribution amps do not amplify the signal above 
the level of the input, they simply apply enough gain to the outputs so that 
they are the same signal level as the input. Gain amps usually provide a 
single output amplified up to 10 or 20 db.

Use a gain amp at your entry point to pump up your signal level to overcome 
loss in your house cabling. Use a distribution amp at your entertainment 
center to overcome loss caused by splitting your signal to multiple devices.

FWIW, Radio Shack used to sell a distribution amp for about $50, which the 
discontinued a few years ago. For a few years they didn't have any 
distribution amp product, only gain amplifiers. Sometime in the past year 
they began selling a new distribution amp for about $75. It provides 4 
outputs. It is part number 15-1169, and does not appear in their catalog on 
their website.

BTW, I don't have any affiliation with Radio Shack at all, other than buying 
the odd part from them now and again.

> Good luck
>
> -----Original Message-----
> From: mythtv-users-bounces at mythtv.org
> [mailto:mythtv-users-bounces at mythtv.org] On Behalf Of Tony Lill
> Sent: Sunday, March 07, 2004 6:46 PM
> To: mythtv-users at mythtv.org
> Subject: [mythtv-users] cable distribution amplifiers
>
> Since I've added my mythtv box with it's 2 capture cards, my cable
> signal has been a bit weak (go figure)! Has anyone tried a cable amp,
> and do they work well?
> --
> Tony Lill,                         Tony.Lill at AJLC.Waterloo.ON.CA
> President, A. J. Lill Consultants        fax/data (519) 650 3571
> 539 Grand Valley Dr., Cambridge, Ont. N3H 2S2     (519) 241 2461
> --------------- http://www.ajlc.waterloo.on.ca/ ----------------
> "Welcome to All Things UNIX, where if it's not UNIX, it's CRAP!"
>
>
>
> !DSPAM:404be19d228751964012570!
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