ping Telamon: re resistive Vs transformer splitters
 

Sorry for the multiple posts on this same thread,
but I consider this an im[ortant topic, and I wanted
to be sure you saw it and had a chance to respond.
I will be away from computer access until Friday evening
at the earliest.
And I am sorry the fomrating seems to vary depeingind on
which computer I posted this on.
----------------------------------------------------
Please review the informatin at:
http://www.microwaves101.com/encyclo..._splitters.cfm

And note that a resistive splitter has:

"Resistive power dividers are easy to understand, can be made very
compact, and are naturally wideband, working down to zero frequency
(DC). Their down side is that a two-way resistive splitter suffers
3 dB of real resistive loss, as opposed to a lossless splitter like
a hybrid. Accounting for the 3 dB real loss and the 3 dB power split,
the net power transfer loss you will observe from the input to one of
the two outputs is 6.04 dB for a two-way resistive splitter.
(Thanks, Dr. BKS, for helping us clarify that point!)"

I own a Mini Circuits ZFSC-2-1.
It has a measured insertion loss of less then 3.5dB for 100KHz
through 30MHz

Another strength of tranformer based hybrids/power splitters is
the greater isolation between power out ports.

The Mini circuits ZFSC-2-1 is rated for:
5 MHz 25dB isolation
midband (~450MHz) 20dB isolation
500MHz 20 isolation
These are minimum not typ[ical.

My unit has been measued to have better then 25dB
isolation between the power out ports from ~250KHz
to above 30MHz. The isolation start to creep up below
250KHZ reaching a minimum of ~21dB at 100KHz. Below
100KHz the loss starts increasing and by 10KHZ the
loss is just over 9dB and the isolation is down to
just less then 15dB.

The "roll your own splitter" page gives some real
world loss and isolation data:
http://www.dxing.info/equipment/roll...own_bryant.pdf

MiniCircuits isloation PDF
http://www.minicircuits.com/appnote/pwr2-4.pdf

MiniCircuits hybrid/power splitter PDF
http://www.minicircuits.com/appnote/psc2-2.pdf

Quoting again frm the article on resistive splitters:
"To put it simply, the resistive splitter has double
the dBs compared to a lossless splitter's insertion
loss. Thus a two-way resistive splitter transfers -6.04
dB power to each arm, a three-way splitter transfers
-9.44 dB, a four-way transfers -12.08 db, etc."

And:
"The isolation of a resistive splitter is equal to
its insertion loss."

I hope that we can all agree that 3.5 dB loss is much
better then 6dB loss and that 20dB isolation is better
then 12dB isolation. I ued the worst case bad specs
from minicircuits for loss and isolation.

In the microwave world resitive splitters are the
rule. In HF/VHF/UFH transformer splitters appear
to dominate.

Terry