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 by amplifying 10 MHz from a GPS receiver and then splitting it 16 ways. Some had some concerns about that method, but I'd already bought the splitters. I purchased the ZFSC-16-3 (1-30 MHz) and the ZFSC-16-12 (0.1 to 200 MHz). At the time I did not have a VNA capable of making measurements at 10 MHz, so done some at 50 MHz which was the lower limit of my HP 8720D.
But some months back I got a 3 GHz HP 8753ES VNA, so can now make measurements at 10 MHz. With 17 ports on the spliters (including the input), and a 2-port VNA, it is not too practical to measure isolation between all 120 pairs of output connectors. Apart from being time-consuming, I think my fingers would drop off. I don't have a BNC calibration kit, do just did a simple response calibration, which corrects for the frequency tracking errors, but not the source match, load match, directivity or isolation of the VNA. That is plenty good enough for this purpose. Here are the ISOLATION results. 1) Column #1 is port numbers, so x-y means between ports x and y. 2) Column #2 is the isolation measured on the ZFSC-16-3 in dB 3) Column #3 is a / 4) Column #4 is the isolation measured on the ZFSC-16-12 in dB ports numbers / ZFSC-16-3 / ZFSC-16-12 1-16 57.7 / 72 2-16 57.6 / 72 3-16 57.7 / 72 4-16 57.6 / 72 5-16 57.5 / 73 6-16 57.6 / 73 7-16 57.6 / 72 8-16 57.4 / 74 9-16 51.4 / 41.6 10-16 51.4 / 41.7 11-16 51.4 / 41.6 12-16 51.4 / 41.6 13-16 44.1 / 33.6 14-16 44.1 / 33.6 15-16 44.1 / 41.0 9-1 57.6 / 73 9-2 55.4 / 73 9-3 55.5 / 74 9-8 55.4 / 73 9-11 44.6 / 33.6 9-12 44.6 / 33.7 9-13 56.2 / 41.6 9-14 51.4 / 41.7 INSERTION LOSS Input to 1 12.4 / 12.4 Input to 7 12.4 / 12.4 CONCLUSIONS 1) The insertion loss of both 16-way splitters is around 12.4 dB, irrespective of port tested. 2) Within a dB or so, each splitter appears to have 3 different isolation figures depending on what ports one connects to. 3) The worst case isolation measured on the ZFSC-16-3 (44.6 dB) is better than the worst case isolation measured on the ZFSC-16-12 (33.6 dB). 4) The best case isolation measured on the ZFSC-16-3 (57.7 dB) is poorer than the best case isolation measured on the ZFSC-16-12 (74 dB). 5) The spread of isolation results on the ZFSC-16-3 (57.7-44.1 = 13.6 dB) is narrower than the spread of isolation data on the ZFSC-16-12 (74 -33.6 = 40.4 dB). 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. 7) The measured data exceeds the minimum specifications Dr. David Kirkby Ph.D CEng MIET Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT, UK. Registered in England and Wales, company number 08914892. http://www.kirkbymicrowave.co.uk/ Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please) _______________________________________________ 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.
