I forgot to add, after the step attenuators at the output of the combiner, there is a 10 dB pad right at the back of the radio to provide a better return loss to the combiner.
Rob, NC0B Sent from my iPad > On Mar 26, 2016, at 6:34 PM, "Rob Sherwood." <[email protected]> wrote: > > I use two ZHL-32A buffer amps, the appropriate Mini-Circuits LPFs, and 20 dB > pads into a 4-way Mini-Circuits combiner. I believe it is ports 2&3 that have > even better isolation than a 2-way combiner. These buffer amps run on 24 > volts, where the ZFL-500LN doesn't have the output capability to test 100+ dB > radios. Some tests need a third signal source and complimentary buffer amp > and associated items. > > To test a K3S or an IC-7851, it also requires HP 8642A generators that have > lower phase noise than these top of the line rigs. Even my 8662A generators > are not good enough, though they were 5 years ago. Now add the Flex 6700 and > the ANAN-200D, the RMDR performance of a hand full of rigs is amazing. > > Unfortunately transmitter performance has not kept pace with receiver > improvement. > > It will be interesting to test the new IC-7300 DSR with knobs (and lots of > menus). > > Rob > NC0B > > Sent from my iPad > >> On Mar 26, 2016, at 6:00 PM, "jimlux" <[email protected]> wrote: >> >> >> >>> On 3/26/16 2:30 PM, Rob Sherwood. wrote: >>> You cannot add the directivity and gain. Doesn't work that way. Rob, NC0B. >> >> Yeah, I kind of figured that after getting the S parameters from >> minicircuits. >> >>> Sent from my iPad >>> >>>> On Mar 26, 2016, at 2:00 PM, "jimlux" <[email protected]> wrote: >>>> >>>> >>>> >>>> Consulting the time-nuts hive mind here.. >>>> >>>> I'm looking for off the shelf connectorized amplifiers with very good >>>> reverse isolation for doing things like intermod measurements (e.g. 2 >>>> signal generators followed by amps/pads into a combiner) and phase noise >>>> measurements for a digital receiver. >>>> >>>> 1-100 MHz kind of frequency range.. >>>> >>>> I've used ZFL-500LN (30dB gain, 27 dB directivity in the data sheet, which >>>> I interpret as 57dB reverse) , ZX60-4016 (really more of a microwave amp, >>>> and not so hot reverse wise.. 25 dB) >>>> >>>> I'm not particularly cost constrained, so a higher power amp (which also >>>> reduces distortion products from the amp) followed by pads is always an >>>> alternative. >>>> _______________________________________________ >>>> 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. >>>> >>>> >>>> >>>> -- >>>> If this email is spam, report it to >>>> https://support.onlymyemail.com/view/report_spam/ODExMjI6MTg2NjQ0MTI4Mjpyb2JAbmMwYi5jb206ZGVsaXZlcmVk >>> _______________________________________________ >>> 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. >> >> >> >> -- >> If this email is spam, report it to >> https://support.onlymyemail.com/view/report_spam/ODExMjI6MTg2NjQ2NDY5Nzpyb2JAbmMwYi5jb206ZGVsaXZlcmVk >> _______________________________________________ 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.
