It is well known 3-phase power line transmission is more efficient than the
regular single phase. The PA is OK. Can anyone provide a circuit diagram
for a 3 -phase SWR/Forward & Reflected Power meter. Thanks in advance.
----
Reg.

In message , Reg Edwards
writes
It is well known 3-phase power line transmission is more efficient than the
regular single phase. The PA is OK. Can anyone provide a circuit diagram
for a 3 -phase SWR/Forward & Reflected Power meter. Thanks in advance.

You will need the 3-phase aerial first, Reg.

Mike
--
M.J.Powell

Reg Edwards wrote:
It is well known 3-phase power line transmission is more efficient than the
regular single phase. The PA is OK. Can anyone provide a circuit diagram
for a 3 -phase SWR/Forward & Reflected Power meter. Thanks in advance.

Most three-phase power meters in my old college textbooks assume
that the voltages are balanced. Is that a good assumption?
--
73, Cecil http://www.qsl.net/w5dxp



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M. J. Powell wrote:
You will need the 3-phase aerial first, Reg.

That's easy to model with EZNEC and three sources.
What I want to know is whether it is Y fed (four wires)
or delta fed (three wires)?
--
73, Cecil http://www.qsl.net/w5dxp



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In message , Cecil Moore
writes
M. J. Powell wrote:
You will need the 3-phase aerial first, Reg.

That's easy to model with EZNEC and three sources.
What I want to know is whether it is Y fed (four wires)
or delta fed (three wires)?

Star feed would mean that there would be an earth up there. Might be
useful for grounding?

Mike
--
M.J.Powell

Cecil Moore wrote:

Reg Edwards wrote:

It is well known 3-phase power line transmission is more efficient
than the
regular single phase. The PA is OK. Can anyone provide a circuit
diagram
for a 3 -phase SWR/Forward & Reflected Power meter. Thanks in advance.


Most three-phase power meters in my old college textbooks assume
that the voltages are balanced. Is that a good assumption?

Only if the three sources and three loads are balanced!

Hmmm ... Three phase coherent amplifiers, 0, 120, and 240 degree phase
shift, driving three antennas with uniform mutual coupling coefficients,
being measured by a three phase SWR/Forward & Reflected Power meter.

Sounds like an interesting system!!

I think the US Navy found an easier solution with variable phased arrays!

DD, W1MCE

What I want to know is whether it is Y fed (four wires)
or delta fed (three wires)?

If it is Y fed, and the voltages are balanced, you don't need a fourth wire.
Everything will be nice like a balanced delta feed. As you know, when things
get unbalanced, both systems have their disadvantages.
73 Gary N4AST

Reg, G4FGQ wrote:
"Can anyone provide a circuit diagram for a 3-phase SWR / Forward &
Reflected Power meter?"

Sure. It is provided by Bird Electronic Corporation.

Connect the 3-phase source and load in the Y-configuration. This permits
(3) 50-ohm coax cables to be used between source and load, the shields
being the common connections for the Y-configuration. Circuit delay in
the three cables must be made the same to preserve the 120-degree phase
relationship between phases. Equal length cables or phasing networks can
be used to acomplish this.

Because of the foregoing, W1, W2, and W3, measured in the loads by the
Bird wattmeter are valid regardless of power factor, degree of balance,
etc.

The total power:

PT = W1 + W2 + W3

The above is from "Industrial Electricity (Part 2)"
by Chester L. Dawes, McGraw-Hill 1942, page 141, which was one of my
first text books, and surprisingly to me, I still have it. A GI-Bill
gift from the U.S. Government at the end of WW-2.

Best regards, Richard Harrison, KB5WZI

On Tue, 30 Dec 2003 18:52:47 +0000 (UTC), "Reg Edwards"
wrote:

Can anyone provide a circuit diagram
for a 3 -phase SWR/Forward & Reflected Power meter. Thanks in advance.
----
Reg.

On Wed, 31 Dec 2003 17:06:18 +0000 (UTC), "Reg Edwards"
wrote:
SWR meters and the corresponding reflected power
meters, are a hoax, a scam, a swindle.

Ah Punchinello,

In the space of less than 24 hours and we find you on both sides of
the argument ringing in the new year. Thus was it ever.... :-)

Would you like to super-size your Friis?

73's
Richard Clark, KB7QHC

Dear Richard,

Your complete lack of success in searching for technical reasons for
objections to my proposals is noted. Your support for the abolition of
so-called SWR-meters is appreciated.


Let's make 2004 "The Year of the TLI".

( Readers will understand the problems involved with explaining
revolutionary ideas when obliged to use misunderstood, flogged-to-death
terminology. )
---
Reg, G4FGQ

===============================

SWR meters and the corresponding reflected power
meters, are a hoax, a scam, a swindle.

Ah Punchinello,

In the space of less than 24 hours and we find you on both sides of
the argument ringing in the new year. Thus was it ever.... :-)

Would you like to super-size your Friis?

73's
Richard Clark, KB7QHC