Rolling your own splitter
 

It took a while to find the URL, but I think
many here will find the techniques shown to
be very usefull.
http://www.dxing.info/equipment/roll...own_bryant.pdf

And while we are at it here is another usefull URL:
making hi-Z to lo-Z transformers
members.aol.com/DXerCapeCod/z_transformers.pdf

Terry

thank you kind Sir...
for the URL.
Drifter...

In article .com,
wrote:

It took a while to find the URL, but I think many here will find the
techniques shown to be very usefull.
http://www.dxing.info/equipment/roll...own_bryant.pdf

And while we are at it here is another usefull URL: making hi-Z to
lo-Z transformers members.aol.com/DXerCapeCod/z_transformers.pdf

It doesn't have to be a transformer. It could be just three resistors
in a T or delta configuration.

--
Telamon
Ventura, California

In article

,
Telamon wrote:

In article .com,
wrote:

It took a while to find the URL, but I think many here will find the
techniques shown to be very usefull.
http://www.dxing.info/equipment/roll...own_bryant.pdf

And while we are at it here is another usefull URL: making hi-Z to
lo-Z transformers members.aol.com/DXerCapeCod/z_transformers.pdf

It doesn't have to be a transformer. It could be just three resistors
in a T or delta configuration.

You might be wondering why three resistors make up a splitter. The idea
is that looking into any port of the splitter (signal connection) is
supposed to look like 50 ohms with source and loads of 50 ohms on all
ports. If you do a few calculations you will find a 16 to 17 ohm
resistor (for all three) is about right for the T type.

--
Telamon
Ventura, California

True but a resistive hyrbid/splitter has much more loss.
And the isolation between ports is not near as high as
in a "good" transformer design.

Terry

In a pinch I have used simple "T" to split/parallel up to
three SW or scanners. While it did work, the LOs from
one radio would show up in the other receivers.
With VHF/UFH scanners this was a show stopper.

With HF raceivers that up convert "T" work better then
many of us would think. But I still prefer to use a tranformer
based spliter/power divider.

Terry

In article .com,
wrote:

True but a resistive hyrbid/splitter has much more loss.
And the isolation between ports is not near as high as
in a "good" transformer design.

It's the same loss. They are called power splitters for a reason. Think
about it.

--
Telamon
Ventura, California

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-.
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-2-1is 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 wort 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

In article om,
wrote:

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-.
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-2-1is 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 wort 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.

The higher you go in frequency the harder it is to make a transformer
splitter.

The loss figures are wrong.

You will get better isolation between the ports with the transformer
type which is why they are used at lower frequencies.

--
Telamon
Ventura, California