On 7/6/2015 12:19 AM, wrote:
John S wrote:
On 7/5/2015 7:21 PM, wrote:
John S wrote:
On 7/5/2015 5:24 PM, wrote:
Roger Hayter wrote:
wrote:


The output impedance of an amateur transmitter IS approximately 50 Ohms
as is trivially shown by reading the specifications for the transmitter
which was designed and manufactured to match a 50 Ohm load.

Do you think all those manuals are lies?

You are starting with a false premise which makes everything after that
false.


A quick google demonstrates dozens of specification sheets that say the
transmitter is designed for a 50 ohm load, and none that mention its
output impedance.

If the source impedance were other than 50 Ohms, the SWR with 50 Ohm
coax and a 50 Ohm antenna would be high. It is not.

Where is the source impedance found on a Smith chart? Also, if you have
EZNEC, you will not find a place to specify source impedance but it will
show the SWR.

A Smith chart is normalized to 1.


So, it can't be used in a 50 ohm environment? What does that have to do
with anything? The chart has a SWR graph and nowhere does it need source
impedance. If you disagree, please link to one.


EZNEC allows you to set the impedance to anything you want and assumes
the transmission line matches the transmitter.

Please show the EZNEC statement that "assumes the transmission line
matches the transmitter". Look in the help section if you have EZNEC and
can cut and paste or just refer me to the chapter and verse. Also, if
you have EZNEC, you can insert a transmission line with arbitrary
characteristic impedance, put a load on the far end matching the line,
and look at the SWR. It will still be 1:1 because the LOAD matches the
LINE. Not because EZNEC assumes a source impedance. Try it with and
report back here.

There is no way that a source initiates reflections. That is a property
of the line and load only. It may re-reflect a wave reflected from the
load, but that is all.

You can also verify this in LTSPICE if you wish.

What happens if you take any off the shelf commercial amateur radio
transmitter that does not have a built in tuner and:

Attach a 10 Ohm load.

Attach a 200 Ohm load.

Attach a 1,000 Ohm load.

Attach a 1 Ohm load.

Attach a 50 Ohm load.



Please address my questions first before setting up another strawman.

John S wrote:
On 7/6/2015 12:19 AM, wrote:
John S wrote:
On 7/5/2015 7:21 PM, wrote:
John S wrote:
On 7/5/2015 5:24 PM, wrote:
Roger Hayter wrote:
wrote:


The output impedance of an amateur transmitter IS approximately 50 Ohms
as is trivially shown by reading the specifications for the transmitter
which was designed and manufactured to match a 50 Ohm load.

Do you think all those manuals are lies?

You are starting with a false premise which makes everything after that
false.


A quick google demonstrates dozens of specification sheets that say the
transmitter is designed for a 50 ohm load, and none that mention its
output impedance.

If the source impedance were other than 50 Ohms, the SWR with 50 Ohm
coax and a 50 Ohm antenna would be high. It is not.

Where is the source impedance found on a Smith chart? Also, if you have
EZNEC, you will not find a place to specify source impedance but it will
show the SWR.

A Smith chart is normalized to 1.


So, it can't be used in a 50 ohm environment? What does that have to do
with anything? The chart has a SWR graph and nowhere does it need source
impedance. If you disagree, please link to one.


EZNEC allows you to set the impedance to anything you want and assumes
the transmission line matches the transmitter.

Please show the EZNEC statement that "assumes the transmission line
matches the transmitter". Look in the help section if you have EZNEC and
can cut and paste or just refer me to the chapter and verse. Also, if
you have EZNEC, you can insert a transmission line with arbitrary
characteristic impedance, put a load on the far end matching the line,
and look at the SWR. It will still be 1:1 because the LOAD matches the
LINE. Not because EZNEC assumes a source impedance. Try it with and
report back here.

There is no way that a source initiates reflections. That is a property
of the line and load only. It may re-reflect a wave reflected from the
load, but that is all.

You can also verify this in LTSPICE if you wish.

What happens if you take any off the shelf commercial amateur radio
transmitter that does not have a built in tuner and:

Attach a 10 Ohm load.

Attach a 200 Ohm load.

Attach a 1,000 Ohm load.

Attach a 1 Ohm load.

Attach a 50 Ohm load.



Please address my questions first before setting up another strawman.

Start with Electromagnetics by Kraus and Carver, Chapter 13.


--
Jim Pennino

On 06/07/15 17:48, wrote:
John S wrote:
On 7/6/2015 12:19 AM, wrote:
John S wrote:
On 7/5/2015 7:21 PM, wrote:
John S wrote:
On 7/5/2015 5:24 PM, wrote:
Roger Hayter wrote:
wrote:


The output impedance of an amateur transmitter IS approximately 50 Ohms
as is trivially shown by reading the specifications for the transmitter
which was designed and manufactured to match a 50 Ohm load.

Do you think all those manuals are lies?

You are starting with a false premise which makes everything after that
false.


A quick google demonstrates dozens of specification sheets that say the
transmitter is designed for a 50 ohm load, and none that mention its
output impedance.

If the source impedance were other than 50 Ohms, the SWR with 50 Ohm
coax and a 50 Ohm antenna would be high. It is not.

Where is the source impedance found on a Smith chart? Also, if you have
EZNEC, you will not find a place to specify source impedance but it will
show the SWR.

A Smith chart is normalized to 1.


So, it can't be used in a 50 ohm environment? What does that have to do
with anything? The chart has a SWR graph and nowhere does it need source
impedance. If you disagree, please link to one.


EZNEC allows you to set the impedance to anything you want and assumes
the transmission line matches the transmitter.

Please show the EZNEC statement that "assumes the transmission line
matches the transmitter". Look in the help section if you have EZNEC and
can cut and paste or just refer me to the chapter and verse. Also, if
you have EZNEC, you can insert a transmission line with arbitrary
characteristic impedance, put a load on the far end matching the line,
and look at the SWR. It will still be 1:1 because the LOAD matches the
LINE. Not because EZNEC assumes a source impedance. Try it with and
report back here.

There is no way that a source initiates reflections. That is a property
of the line and load only. It may re-reflect a wave reflected from the
load, but that is all.

You can also verify this in LTSPICE if you wish.

What happens if you take any off the shelf commercial amateur radio
transmitter that does not have a built in tuner and:

Attach a 10 Ohm load.

Attach a 200 Ohm load.

Attach a 1,000 Ohm load.

Attach a 1 Ohm load.

Attach a 50 Ohm load.



Please address my questions first before setting up another strawman.

Start with Electromagnetics by Kraus and Carver, Chapter 13.



Do the experiment.

Brian Reay wrote:

Do the experiment.

Did it decades ago in electromagnetics lab with calibrated test equipmemnt,
not with amateur radio equipment.


--
Jim Pennino

On 7/7/2015 1:52 PM, wrote:
Brian Reay wrote:

Do the experiment.

Did it decades ago in electromagnetics lab with calibrated test equipmemnt,
not with amateur radio equipment.

Post the original lab notes, please. That way we cannot challenge the
accuracy of your memory.

John S wrote:
On 7/7/2015 1:52 PM, wrote:
Brian Reay wrote:

Do the experiment.

Did it decades ago in electromagnetics lab with calibrated test equipmemnt,
not with amateur radio equipment.

Post the original lab notes, please. That way we cannot challenge the
accuracy of your memory.

Sorry, that was decades ago.

If you are so convinced, do the experiments yourself and post the results.

Or you could read an electromagnetics text on transmission lines and
show me the errors of my statements.


--
Jim Pennino

On 7/8/2015 1:18 PM, wrote:
John S wrote:
On 7/7/2015 1:52 PM, wrote:
Brian Reay wrote:

Do the experiment.

Did it decades ago in electromagnetics lab with calibrated test equipmemnt,
not with amateur radio equipment.

Post the original lab notes, please. That way we cannot challenge the
accuracy of your memory.

Sorry, that was decades ago.

If you are so convinced, do the experiments yourself and post the results.

Or you could read an electromagnetics text on transmission lines and
show me the errors of my statements.

I did, decades ago. The results are that you are wrong. You surely trust
my memory as well as I trust yours, yes?