Good point Bob, in my humble opinion "Low Noise" is about -115 @ 1 Hz dropping to about -165 @ 10KHz for 5 MHz about 3dB higher for 10MHz. Which from my testing will tax the noise floors of a fair number of application specific products. It is true that most of these distribution amps sold today were designed at least a decade ago, so there may be chips today that can meet or exceed those products on paper for DIY projects but it will still be a challenge for most of us. Thanks for your input Thomas Knox
> From: kb...@n1k.org > Date: Mon, 5 Jan 2015 19:59:39 -0500 > To: time-nuts@febo.com > Subject: Re: [time-nuts] Any reason not to use one power amplifier and > splitter for distribution amplifier? > > Hi > > Any time you run into terms like “low noise” it pays to think about what that > means to you and your system. A quick scan of the posts here over the years > will show that different definitions of low noise do exist. The same is true > of system requirements. An offset that matters to one may have no impact at > all on another system. > > In some cases -155 dbc/Hz at 10KHz or 100 KHz is “low noise”. In other cases > “low noise” is -180 dbc/Hz. In either case, *delivering* a clean signal > without spurs and crud is far from simple. In many long cable run cases, the > cost of fancy cables, high performance magnetics, and all the other “stuff” > is more than the cost of simply locking up a quiet oscillator on the end of a > “dirty” cable. I don’t think I’ve ever seen a setup that tries / needs to > “distribute” < -170 dbc/Hz signals over anything bigger than a rack. I’ve > seen *lots* of systems that regenerate those sort of signals many times over > (= in many different boxes) to get around distributing them. > > Bob > > > > On Jan 5, 2015, at 2:15 PM, Tom Knox <act...@hotmail.com> wrote: > > > > Happy New Years All! I have seen a number of discussions on various > > approaches to distribution amps discussed on Time-Nuts ranging from DYI to > > products intended for Video. > > I thought I my weigh in with one point of interest; It seems like long term > > performance is pretty easy, but a low phase noise solution is quite a > > different story. Looking at the number of application specific products > > from MicroSemi/Symmetricom and other manufactures claimed and even more so > > real world specs vary a great deal so apparently it s not easy to just > > throw something together with great or even good close in phase noise. So > > depending on your labs direction in the future it may be worth researching > > and investing in an application specific distribution amp. I like the > > MicroSemi 4036B but there are a number of very good products out there on > > the surplus market selling for a small fraction of their original cost. > > Cheers; > > Thomas Knox > > > > > > > >> From: bill.ric...@verizon.net > >> To: time-nuts@febo.com > >> Date: Sun, 4 Jan 2015 08:29:34 -0500 > >> Subject: Re: [time-nuts] Any reason not to use one power amplifier and > >> splitter for distribution amplifier? > >> > >> A cheap and dirty equivalent of a pass thru terminator that I use is a BNC > >> t > >> connector with a 52 ohm bnc terminator. I guess you could use a CATV 75 > >> ohm > >> F type with an adapter. Maybe that combination would produce too much > >> garbage. > >> > >> 73, > >> > >> Bill, WA2DVU > >> Cape May > >> > >> > >> > >> --- > >> This email has been checked for viruses by Avast antivirus software. > >> http://www.avast.com > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
