Can a Dish Pre-Amp help you?

[Wizard555]

DISH PRE-AMPLIFIER NOTES

If you suspect your desired Satellite signal level is too low you may want to consider a In-Line Pre-Amplifier, also known as: "Inline Satellite Dish Signal Amplifier". You can find them here:

Agile Passive and active VSAT Amplifiers

These points must be said right up-front:

*** No matter where you install a Pre-Amp, a bad or noisy signal IN will result in amplified bad signal OUT. ***

*** As with any amplifier, a Pre-Amp CAN NOT boost signals that are not there and a Pre-Amp will NOT clean-up signals already in deep noise at the Dish. ***

Pre-Amps can boost your signal(s) by as much as 10dB and in fact some claim they have a Pre-Amp gain higher than 20dB, but that is just a claim. It is easy to see signal gain on my lowly sat-finder meter and on the receiver signal level bars after installing a Pre-Amp. I have not measured actual Pre-Amp gain on my test bench, but I may do so soon.

There are volumes written about internal 'noise' created within the Pre-Amps from the active electronic components inside. Pick on a Pre-Amp with the LOWEST noise figure... the lower the number the better (expressed in dB).

The Pre-Amp cost is much lower than a 30" dish too. The 30" dish offers true gain and the Pre-Amp has solid state gain, but see the notes about internal Pre-Amp noise.

* Install your Pre-Amp right after your LNB or directly after your switch. Never be tempted to install your Pre-Amp at the receiver where you have already suffered your Switch and coax line losses! If you are suffering from poor signal level, pixalation or many missing channels a Pre-Amp installed at the receiver will do you no good because as mentioned above, you have already lost signal(s) via your switch and coax.

* Pre-Amps also help overcome long coax runs too. Considering all the dB losses thru the coax line, connectors, motor, switch(es), etc. A Pre-Amp may really make a considerable difference for you!

Also keep in mind that all LNBs, Pre-Amps and Switches demand power. If you have a super long coax run you may be starving for voltage already at your dish! The addition of a Pre-Amp (if starving for voltage) may only show a slight improvement on your Meters because it's not working at peak efficiency. For this reason you want to use the best coax possible and quality RG-11 may be your best choice. There is more copper conductor than RG-6 and lower coax voltage losses because of it.

More quick notes about coax. Always select quality coax for your installations! I have a roll of "RG-6" no name coax, but the center conductor is so tiny that I don't know how a connector could make good contact to it! Of course I didn't notice that small conductor until I was about to install a connector to it. That roll never did get pressed into service. Belden is the coax I like best. Also use black coax (rather than white) because it does better at surviving the suns UV rays over the years.

* Motors also present current demand, but only when they move. However, motors DO cause signal loss thru them, even when they are not moving. In fact anything installed on your coax line introduces a dB loss factor ~ even the connectors. Therefore, install your Pre-Amp as close to your LNB as possible and the output of the Pre-Amp then goes to the motor... before you have the motor dB loss hits.

* IF you have a Switch, install the Pre-Amp at the OUTPUT Port of your Switch. Now all of your LNB's will be amplified by a single Pre-Amp, but you will suffer the dB losses the switch, coax jumpers and connectors present after the LNBs.

* IF you have multiple Switches and LNBs, a Pre-Amp will help overcome the dB losses the Switches present. In this case try multiple Pre-Amps just after the LNB's before the Switches. (See more notes on this below).

* IF you have multiple dishes, you may want to install a Pre-Amp only on the Dish/LNB that is starving for signal, but I would rather see all Switch Ports amplified.

* Weather-protect your connectors! This is a must.

* Make SURE the Pre-Amp you select is designed for Satellite Frequencies because many Pre-Amps are designed for UHF/VHF/FM ONLY! Most Pre-Amps appear identical in size so use care when selecting yours! Read the specifications and look for those designed to include the 950MHz thru 2400 MHz range. Any of the three Pre-Amps shown at the above link should serve you just well.

CONCLUSION:

Pre-Amps are about 3-1/2 inch long and 3/4 inch square. The body is solid metal and the bottom cover is soldered in place. Female "F" connectors are on each end as shown in the attached photo.

I installed my Pre-Amp on a 30" dish with motor because I like to do a lot of 'fishing' and many satellites are often too weak even with the larger dish. For me this is most evident for the satellites on the horizon. The Pre-Amp really boosted those weaker satellites as shown on my receiver meters and in great video too.

In my estimation, Pre-Amps are WELL worth the money when they are installed properly!

WARNING!!!

Some Pre-Amps are supplied with a special wall mounted AC power supply that provides DC up the coax to power the Pre-Amp, but I do NOT recommend them. Also it is very possible that the inline module that sends the voltage up your coax may actually block switching voltages your receiver supplies to your switches! That same inline module also introduces signal losses too.

Buy Pre-Amps that require no special external power supplies and only those that are powered by receiver/LNB line power. Because Pre-Amps use about 15 milliamps of power they really present no great load to the line or receiver power supply. However, four Pre-Amps may demand too much power from your receiver so use Pre-Amps only where you need them.

SPECIAL NOTE:

Pre-Amps should NOT be used in all installations because they may push some receiver's Automatic Gain Controls to full saturation and that MAY cause picture distortions. I personally did not witness any sign of AGC (Automatic Gain Control) overload on any satellite I watched on my Viewsats, Coolsats or Sonicview.

Hope this helps...
Wiz555

[Sadoun]

Very nice write-up. Thank you for your efforts and info.