[time-nuts] Isolation and insertion loss of Minicircuits ZFSC-16-3 and ZFSC-16-3 16-way splitters @ 10 MHz

Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby at kirkbymicrowave.co.uk
Sat Jul 11 07:33:24 EDT 2015


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)


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