Hi One thing worth checking:
The impedance at the “sum” port may or may not be 50 ohms. It’s worth checking before you go to extreme lengths to come up with a “perfect” 50 ohm amp. ====== Since part of the world likes 75 ohms, it’s also worth taking a look at the isolation numbers with the sum port terminated in 75 (or 75 / 4) ohms. There are a number of high power / low noise amps out there (apparently) designed for cable distribution systems. Bob > On Jul 19, 2015, at 5:56 AM, Charles Steinmetz <[email protected]> wrote: > > Dave wrote: > >> Some time ago I mentioned I'd bought a couple of Minicircuits 16-way power >> splitters with the intention of making a 10 MHz distribution amplifier >> * * * >> Here are the ISOLATION results. >> * * * >> CONCLUSIONS >> * * * >> 6) Despite the Minicircuits data sheets imply there are two isolation >> figures for "adjacent" and "opposite", I measure 3 different values for >> each splitter, not 2. > > As I posted on January 8, there are actually four different cases in a 16-way > splitter. You have found that the port-to-port isolation of two of the four > cases are indistinguishable in practice in the MCL splitters. > > The datasheets do not imply that there are only the two cases. MCL simply > specified the best ("adjacent") and worst ("opposite") cases, without > specifying the intermediate cases. > > Good luck with your DA system. For simple distribution of a frequency > standard, it should work very well. I use a similar system with a suitable > ULN/HDR preamp to feed antennas to multiple receivers, and it performs > superbly. > > For an output at the typical instrumentation level of 1Vrms (13dBm), you will > need an amplifier with a 50 ohm output impedance that puts out ~26dBm > (=400mW, =4.5Vrms, =6.3Vpk, =12.6Vp-p). The peak output current is >125mA. > If you are going to realize the 50 ohm output impedance with a low impedance > amplifier and a 50 ohm buildout resistor for back-termination, the amplifier > will need to put out over 25Vp-p into 100 ohms. If you want the outputs at > the same level as the original source, the amplifier will need to have a bit > more than 12dB of gain. Have you decided what you are going to use? > > Best regards, > > Charles > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
