Reply to thread

Message

<blockquote data-quote="Jens Bacher" data-source="post: 130528" data-attributes="member: 1220">Re: IEMs - Separate antennas or combine combiners?You could, but it would demand a combiner with bigger input capability, and you would make more intermodulation products.Think of it this way:An AC-3 consists of 4 rf amps and a passive combiner. (and some filtering) Each amp has a net gain of 6db, and a maximum input around 100mW. The Rf amps in the 3 AC-3&#039;s will each see 30mW (one carrier) Each carrier is amplified to 120mW (+6 dB) and then put into a combiner with a theoretical loos of -6dB. End result is 4 carriers a 30mW on the output.If you took the output of the 3 AC-3&#039;s into a 4. AC-3 each Rf amp in the last AC-3 would suddenly see 4 carriers of 30mW, which it is not rated for. It would also see the intermodulation products from the previous combiner, and amplify them. Result would be a very &quot;dirty&quot; Rf output.You could make a workable system by exchanging the 4. Ac-3 with an AC-3200 (it takes 250mW on each input) and use isolators on the outputs of the 3 AC-3&#039;.</blockquote>

[QUOTE="Jens Bacher, post: 130528, member: 1220"] Re: IEMs - Separate antennas or combine combiners? You could, but it would demand a combiner with bigger input capability, and you would make more intermodulation products. Think of it this way: An AC-3 consists of 4 rf amps and a passive combiner. (and some filtering) Each amp has a net gain of 6db, and a maximum input around 100mW. The Rf amps in the 3 AC-3's will each see 30mW (one carrier) Each carrier is amplified to 120mW (+6 dB) and then put into a combiner with a theoretical loos of -6dB. End result is 4 carriers a 30mW on the output. If you took the output of the 3 AC-3's into a 4. AC-3 each Rf amp in the last AC-3 would suddenly see 4 carriers of 30mW, which it is not rated for. It would also see the intermodulation products from the previous combiner, and amplify them. Result would be a very "dirty" Rf output. You could make a workable system by exchanging the 4. Ac-3 with an AC-3200 (it takes 250mW on each input) and use isolators on the outputs of the 3 AC-3'. [/QUOTE]

Verification