The dish is a parabolic reflector and serves as a passive amplifier - the first stage of amplification. The signal that hits the dish is reflected to the LNBF at the focal point, located out in front of the dish. A lot of power is lost by the time the compressed, digital signal travels back from a satellite 22,300 miles out over the equator.

The 24" dish has almost double the gain and since heavy rain blocks the signal, the extra gain can make a big difference. Many people order the 24 inch dish as the second dish for HDTV or foreign channels, but since it only picks up one satellite you will still need a Dish 500 to get all the other channels.

The Dish 500 is an elliptically shaped parabola, with a skew adjustment, so it picks up two satellites at the same time.

It would take two 24 inch dishes to replace one Dish 500 and three 24" dishes if you also want HDTV or foreign channels. For three dishes, you will also need an SW-64 switch to connect all three dual LNB's to up to 4 receivers. Unless you have a great deal of rain fade, three 24" dishes is probably an overkill.

Depending on the number of receivers and the type of LNB on the Dish 500, the two dishes can be connected with either an SW-21 switch, an SW-44, or an SW-64 switch.

LNBF = Low Noise amplifier Block downconvertor Feedhorn. Today, LNB is the common term. The LNB is the most critical electronic part of a satellite system, before the receiver. A better LNB can improve audio/video quality.

The front part of the LNB is the feed horn. It's like a funnel that catches the signal that bounces off the dish. The transponders (channels) are polarized circularly, odd number channels going one way and even numbers going the other. Voltage from the receiver in the house switches from 13V to 18V and changes the polarity automatically, when you change the channels. The LNB amplifies the signal and converts it down from the 12 GHz range to 950 - 2,000 MHz.

The downconverted signal can then be run through a high quality RG-6 coaxial cable into the satellite receiver. A dual LNB has two connectors, so you can connect two receivers.

There are two primary factors in the LNB to bring in the best audio/video. Noise Temperature, which is measured in degrees Kelvin and amplification, or gain, which is measured in Decibels and calculated logarithmically. High gain is of no value unless the noise temperature is very low. Although they try to make every part perfect, nothing is ever perfect. There are many component parts in an LNB and all have plus or minus tolerances, so there can be big differences in the audio/video quality you see inside.

The LNB is made to our specifications and checked on a spectrum analyzer. Although individual print outs are not available, typically, these LNB's show 60+ dB and 18 degrees Kelvin. This is more than twice the gain and a much lower nose temperature than many factory LNB's.

List price for the 24" dish and commercial Dual LNB is $299, but your cost is $145 + $25 shipping. List price for our commercial Dual LNB is $115, but your cost is $85 + $12 shipping

NOTE: Our 24" dish and commercial LNB works great with DirecTV. However, it would take two 24" Dishes and the appropriate switch to replace a Dish 500.