"Telamon" wrote in message
...
In article . com,
wrote:

Telamon wrote:

Remember to terminate all ports at all times or your results will
vary.

The transformer type of splitter will have a "U" shaped response
curve
so you need to be within that band for it to work right. The
resistive
type is good from DC to some max frequency and you need to be in that

range.

From the transmitter value each output port should be 3 dB down when
the
other output port is terminated in 50 ohms. The actual loss will be a

little larger then 3 dB by the splitters insertion loss.

Oh yeah, and your meter is probably a through type instead of a load
type so you need to put a 50 ohm load on the far side of the meter.

When you check each splitter also switch the meter and its load in
each
leg to see how balanced the splitter is in each output port.

Be sure to turn the transmitter off before all connections are made
or
you could damage your transmitter.

--
Telamon
Ventura, California

I made some measurements last night.
I decided to move from ~7MHz to 146 because 7MHz is just
too close to the lower limit on my mMc splitter.

I have an IC28A that is adjusted to give 1wt in low power.
I used a 10dB Narda 766-10 power attenuator in series with
the splitter input. I used another 766-10 attenuator in series
with the output and the sensor head on Boonton RF power meter.
I used a .5% 50 ohm terminator for the other port

The resitive splitter gave me 6dB of POWER loss.
The MC transformer based splitter gave me just over
3.2dB of loss.

I called a freshly frocked dual PHD, EE and physics, I know
and asked her what the heck is happening. The quick answer
is the resistive splitter is like any other resitive voltage
divider. The transformer unit is like a transformer step down,
or step up. The only losses in a transformer splitter are the
wire losses and the core loss. The R in the MiniCircuits dispates
no power if all ports are matched.

She invited me to "her" lab Friday afternoon and she will use
the modern equipment to verify my measurements.
She suggested that I treat the resistive network and use kichoff's
(?spelling?, it has been too long since college) law to show the
dissapation of each element. It is too late tonight and my head
hurts from this stuff.

Oh, and cctual S-meter measurements show the MC splitter has half
the loss of the resitive splitter.

On a good note, I picked up a 3 section "dB Products" heavy aluminium
mast and another MC splitter like mine and a 1 in 8 out RCA active
LF/HF
splitter rated for use from 100Kc to 40Mc. It used Nuvisters and
appears
to have selectable MB/BCB filters. No manual, and the only diagram is
stincyled on the inside of the lid. And no model number only an old
"Signal Corp" decal. My friend retired ATT microwave engineer and is
moving
to AZ because he is sick of the winter snow here. He has a storage
building full of such junk and I get to cherry pick it and haul it to
another friend.
I hope to check the RCA coupler before going to the university lab.
It would be nice to run a SN and frequency response.

Well, that's interesting results.

I've used resistive splitters in the past and have gotten the 6dB
division. The resistive splitters I have used in the past are the T and
the delta type. I usually work with scopes so I see 1/2 the voltage or
6dBV on the scope through the splitter and I have no explanation why
you are seeing more than that.

What is the make and model number of the resistive splitter?

--
Telamon
Ventura, California

I think you are both in violent agreement - 6dB loss means the output over
the input is 1/2 for voltage (constant impedance), 1/4 for power. A
resistive 2-way minimum loss splitter has 6dB loss; a transformer 2-way
splitter is 3dB.

Tom

In article ,
"Tom Holden" wrote:

"Telamon" wrote in
message

gy.com.. .
In article . com,
wrote:

Telamon wrote:

Remember to terminate all ports at all times or your results
will vary.

The transformer type of splitter will have a "U" shaped response
curve so you need to be within that band for it to work right.
The resistive type is good from DC to some max frequency and you
need to be in that range.

From the transmitter value each output port should be 3 dB down
when the other output port is terminated in 50 ohms. The actual
loss will be a little larger then 3 dB by the splitters
insertion loss.

Oh yeah, and your meter is probably a through type instead of a
load type so you need to put a 50 ohm load on the far side of
the meter.

When you check each splitter also switch the meter and its load
in each leg to see how balanced the splitter is in each output
port.

Be sure to turn the transmitter off before all connections are
made or you could damage your transmitter.

-- Telamon Ventura, California

I made some measurements last night. I decided to move from ~7MHz
to 146 because 7MHz is just too close to the lower limit on my mMc
splitter.

I have an IC28A that is adjusted to give 1wt in low power. I used
a 10dB Narda 766-10 power attenuator in series with the splitter
input. I used another 766-10 attenuator in series with the output
and the sensor head on Boonton RF power meter. I used a .5% 50 ohm
terminator for the other port

The resitive splitter gave me 6dB of POWER loss. The MC
transformer based splitter gave me just over 3.2dB of loss.

I called a freshly frocked dual PHD, EE and physics, I know and
asked her what the heck is happening. The quick answer is the
resistive splitter is like any other resitive voltage divider. The
transformer unit is like a transformer step down, or step up. The
only losses in a transformer splitter are the wire losses and the
core loss. The R in the MiniCircuits dispates no power if all
ports are matched.

She invited me to "her" lab Friday afternoon and she will use the
modern equipment to verify my measurements. She suggested that I
treat the resistive network and use kichoff's (?spelling?, it has
been too long since college) law to show the dissapation of each
element. It is too late tonight and my head hurts from this stuff.

Oh, and cctual S-meter measurements show the MC splitter has half
the loss of the resitive splitter.

On a good note, I picked up a 3 section "dB Products" heavy
aluminium mast and another MC splitter like mine and a 1 in 8 out
RCA active LF/HF splitter rated for use from 100Kc to 40Mc. It
used Nuvisters and appears to have selectable MB/BCB filters. No
manual, and the only diagram is stincyled on the inside of the
lid. And no model number only an old "Signal Corp" decal. My
friend retired ATT microwave engineer and is moving to AZ because
he is sick of the winter snow here. He has a storage building full
of such junk and I get to cherry pick it and haul it to another
friend. I hope to check the RCA coupler before going to the
university lab. It would be nice to run a SN and frequency
response.

Well, that's interesting results.

I've used resistive splitters in the past and have gotten the 6dB
division. The resistive splitters I have used in the past are the T
and the delta type. I usually work with scopes so I see 1/2 the
voltage or 6dBV on the scope through the splitter and I have no
explanation why you are seeing more than that.

What is the make and model number of the resistive splitter?

-- Telamon Ventura, California

I think you are both in violent agreement - 6dB loss means the output
over the input is 1/2 for voltage (constant impedance), 1/4 for
power. A resistive 2-way minimum loss splitter has 6dB loss; a
transformer 2-way splitter is 3dB.

I just calculated it and you are right Tom. I have been a real dufus and
giving Terry a headache for nothing. I generally don't think in terms of
power since I work with small signals.

The resistive splitter is burning half the power as the T types three
16.7 ohm resistors in series are 50 ohms.

Sorry about that Terry. Looks like your transformer type is more
efficient in its bandwidth than the resistive type. Since you measured
3.2 dB on the transformer type you are very close to the ideal splitter
and your measurement on the resistive is also correct at 6 dB so you can
stop scratching you head now.

--
Telamon
Ventura, California

Thank you!
I have been trying to understand what I was missing.

I have learned a lot in this experience. I am still going to visit
the lab Friday to see how these measuremnts are made with
modern equipment.

And the time wasn't wasted, I learned somethings and I picked up
some "cool" junk.

If I can get the RCA active multiset coupler running I will be set.
Sadly the power transformer is dead. Open primary.

I have removed ti and I hope it is just one of the leads has pulled
loose. Worst case I will find someway to power this sucker up.
The unit uses TNC RF connectors, how convenient! The guy
I got it from said it was dead wehn it was given to him hin the
early 1970's.

Terry

In article .com,
wrote:

Thank you! I have been trying to understand what I was missing.

I have learned a lot in this experience. I am still going to visit
the lab Friday to see how these measuremnts are made with modern
equipment.

And the time wasn't wasted, I learned somethings and I picked up some
"cool" junk.

If I can get the RCA active multiset coupler running I will be set.
Sadly the power transformer is dead. Open primary.

I have removed ti and I hope it is just one of the leads has pulled
loose. Worst case I will find someway to power this sucker up. The
unit uses TNC RF connectors, how convenient! The guy I got it from
said it was dead wehn it was given to him hin the early 1970's.

Some times the lead that protrudes from the transformer is not the wire
that is wound on the core. There may be a connection between the wires
just under the insulate tape wrapped around the core. If you carefully
cut and lift the tape to expose the wires you might find the connection
is open. If the connection is on top of the winding you can easily
repair it or you might discover a burned winding. Sounds to me you know
about that already.

--
Telamon
Ventura, California