On 9/28/2015 1:51 PM, Jerry Stuckle wrote:
On 9/28/2015 1:42 PM, rickman wrote:
On 9/28/2015 12:54 PM, Jerry Stuckle wrote:
On 9/28/2015 12:47 PM, rickman wrote:
On 9/28/2015 10:38 AM, Jerry Stuckle wrote:
On 9/28/2015 12:03 AM, rickman wrote:
On 9/27/2015 10:39 PM, Jerry Stuckle wrote:
On 9/27/2015 9:46 PM, Wayne wrote:


"John S" wrote in message ...

On 9/27/2015 1:20 PM, Wayne wrote:


"rickman" wrote in message ...

On 9/27/2015 10:41 AM, kg7fu wrote:

Matching the antenna won't make the Return Loss go away but it
will
make
the transmitter happy.

Can you explain this? I thought matching the antenna would
*exactly*
make the return loss go away because it would eliminate the
mismatch.

Not wanting to put words in his mouth....
I read that to mean that the high SWR between the ATU and the
antenna
would remain, but the transmitter would be happy with the SWR on
the
transmitter/ATU coax.


# Rick is correct. If the antenna (load) is matched to the line,
there is
# no return loss, hence no SWR. The ATU will be adjusted
(hopefully) to
# make the transmitter operate properly with the impedance as
seen at
the
# transmitter end of the line.

# Yes, the SWR due to mismatch of the antenna (load) and line will
remain.
# Even if the real part of your load impedance is matched to the
line, you
# will still have a high SWR if the reactance remains.

# Does this make sense?

Yes. That's what I was trying to say using SWR instead of return
loss.
Return loss numbers get bigger with lower SWR.
For example: SWR 1:1 = infinite return loss.


Incorrect. Return loss increases with an increased SWR. An SWR
of 1:1
has no return loss because there is no returned signal to lose.
100% of
the signal is radiated.

From LUNA web site regarding optical measurements which should be no
different from RF...


It "shouldn't be" - but optical measurements are handled differently
than electrical measurements. Fiber Optics have their own way of
measuring loss, reflection and refraction (which doesn't exist in
feedlines).

That's like applying electrician's color codes to electronics. They
both have color codes - but don't hook the electrician's black wire to
ground - or the transformer's green wires to safety ground.

I thought you would claim optical was different. That's why I included
the VSWR vs return loss table link. You didn't comment on that.


I didn't because I thought it was obvious. But I guess not to you.

Return loss is calculated with logs. Logs of values 1 are negative.
And -10db is smaller than -5 db.

As the SWR approaches 1:1, the reflected power approaches 0, and the
returned loss approaches NEGATIVE infinity. Note that I said NEGATIVE
infinity. At the same point, the returned power measured in watts is 0.

I believe that is exactly what I said in the portions of my post which
you trimmed. These values for RF return loss match exactly the equation
which you are saying is not used in RF. So which is it, the return loss
table is correct with negative values of return loss or the equation I
posted is incorrect even though it gives the values in the table?


You said return loss increases with lower SWR. It does not.


It does.

On 9/28/2015 7:12 PM, John S wrote:
On 9/28/2015 1:51 PM, Jerry Stuckle wrote:
On 9/28/2015 1:42 PM, rickman wrote:
On 9/28/2015 12:54 PM, Jerry Stuckle wrote:
On 9/28/2015 12:47 PM, rickman wrote:
On 9/28/2015 10:38 AM, Jerry Stuckle wrote:
On 9/28/2015 12:03 AM, rickman wrote:
On 9/27/2015 10:39 PM, Jerry Stuckle wrote:
On 9/27/2015 9:46 PM, Wayne wrote:


"John S" wrote in message ...

On 9/27/2015 1:20 PM, Wayne wrote:


"rickman" wrote in message ...

On 9/27/2015 10:41 AM, kg7fu wrote:

Matching the antenna won't make the Return Loss go away but it
will
make
the transmitter happy.

Can you explain this? I thought matching the antenna would
*exactly*
make the return loss go away because it would eliminate the
mismatch.

Not wanting to put words in his mouth....
I read that to mean that the high SWR between the ATU and the
antenna
would remain, but the transmitter would be happy with the SWR on
the
transmitter/ATU coax.


# Rick is correct. If the antenna (load) is matched to the line,
there is
# no return loss, hence no SWR. The ATU will be adjusted
(hopefully) to
# make the transmitter operate properly with the impedance as
seen at
the
# transmitter end of the line.

# Yes, the SWR due to mismatch of the antenna (load) and line will
remain.
# Even if the real part of your load impedance is matched to the
line, you
# will still have a high SWR if the reactance remains.

# Does this make sense?

Yes. That's what I was trying to say using SWR instead of return
loss.
Return loss numbers get bigger with lower SWR.
For example: SWR 1:1 = infinite return loss.


Incorrect. Return loss increases with an increased SWR. An SWR
of 1:1
has no return loss because there is no returned signal to lose.
100% of
the signal is radiated.

From LUNA web site regarding optical measurements which should
be no
different from RF...


It "shouldn't be" - but optical measurements are handled differently
than electrical measurements. Fiber Optics have their own way of
measuring loss, reflection and refraction (which doesn't exist in
feedlines).

That's like applying electrician's color codes to electronics. They
both have color codes - but don't hook the electrician's black
wire to
ground - or the transformer's green wires to safety ground.

I thought you would claim optical was different. That's why I
included
the VSWR vs return loss table link. You didn't comment on that.


I didn't because I thought it was obvious. But I guess not to you.

Return loss is calculated with logs. Logs of values 1 are negative.
And -10db is smaller than -5 db.

As the SWR approaches 1:1, the reflected power approaches 0, and the
returned loss approaches NEGATIVE infinity. Note that I said NEGATIVE
infinity. At the same point, the returned power measured in watts
is 0.

I believe that is exactly what I said in the portions of my post which
you trimmed. These values for RF return loss match exactly the equation
which you are saying is not used in RF. So which is it, the return loss
table is correct with negative values of return loss or the equation I
posted is incorrect even though it gives the values in the table?


You said return loss increases with lower SWR. It does not.


It does.

Sorry, a lower SWR does not increase the amount of loss.

Please cite a reliable reference that says it does. Even the table Rick
cited shows a negative value for return SWR.

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On 9/28/2015 6:54 PM, Jerry Stuckle wrote:

You said return loss increases with lower SWR. It does not.


It does.

Sorry, a lower SWR does not increase the amount of loss.

It increases the amount of loss that is reflected. Hence, return loss.

Please cite a reliable reference that says it does. Even the table Rick
cited shows a negative value for return SWR.

No, the table is correct and does not show negative values for return
loss. What is return SWR?

On 9/29/2015 3:27 AM, John S wrote:
On 9/28/2015 6:54 PM, Jerry Stuckle wrote:

You said return loss increases with lower SWR. It does not.


It does.

Sorry, a lower SWR does not increase the amount of loss.

It increases the amount of loss that is reflected. Hence, return loss.

Please cite a reliable reference that says it does. Even the table Rick
cited shows a negative value for return SWR.

No, the table is correct and does not show negative values for return
loss. What is return SWR?



No, a 1:1 SWR has no reflection, therefore no reflective loss.

And yes, it does show negative values. Don't you see the '-' sign?

--
==================
Remove the "x" from my email address
Jerry, AI0K

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

On 9/29/2015 8:14 AM, Jerry Stuckle wrote:
On 9/29/2015 3:27 AM, John S wrote:
On 9/28/2015 6:54 PM, Jerry Stuckle wrote:

You said return loss increases with lower SWR. It does not.


It does.

Sorry, a lower SWR does not increase the amount of loss.

It increases the amount of loss that is reflected. Hence, return loss.

Please cite a reliable reference that says it does. Even the table Rick
cited shows a negative value for return SWR.

No, the table is correct and does not show negative values for return
loss. What is return SWR?



No, a 1:1 SWR has no reflection, therefore no reflective loss.

And yes, it does show negative values. Don't you see the '-' sign?


No. I see a hyphen, not a minus sign. It indicates that the data column
is in units of dB.

On 9/28/2015 6:54 PM, Jerry Stuckle wrote:

You said return loss increases with lower SWR. It does not.


It does.

Sorry, a lower SWR does not increase the amount of loss.

Please cite a reliable reference that says it does.


From the ARRL:

http://www.arrl.org/news/amateur-radio-quiz-a-log-of-dbs

"9) D -- Higher positive values of Return Loss (RL) in dB indicate less
power returning from a load, indicating a lower SWR."

On 9/29/2015 3:36 AM, John S wrote:
On 9/28/2015 6:54 PM, Jerry Stuckle wrote:

You said return loss increases with lower SWR. It does not.


It does.

Sorry, a lower SWR does not increase the amount of loss.

Please cite a reliable reference that says it does.


From the ARRL:

http://www.arrl.org/news/amateur-radio-quiz-a-log-of-dbs

"9) D -- Higher positive values of Return Loss (RL) in dB indicate less
power returning from a load, indicating a lower SWR."



OK, I'll have to take that up with N0AX. My university professors and
the IEEE disagree with him from an engineering view.

However, hams often try to make things easier - and not always correctly.

--
==================
Remove the "x" from my email address
Jerry, AI0K

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

On 9/28/2015 6:54 PM, Jerry Stuckle wrote:

You said return loss increases with lower SWR. It does not.


It does.

Sorry, a lower SWR does not increase the amount of loss.

Please cite a reliable reference that says it does. Even the table Rick
cited shows a negative value for return SWR.

OH! I see your problem. You think the column heading dashes are minus
signs. They are not. Loss - dB indicates that the column data have the
units of dB, not that they are negative. I usually use Loss (dB) for my
column headings.

In message , Jerry Stuckle
writes
On 9/28/2015 7:12 PM, John S wrote:
On 9/28/2015 1:51 PM, Jerry Stuckle wrote:
On 9/28/2015 1:42 PM, rickman wrote:





You said return loss increases with lower SWR. It does not.


It does.

Sorry, a lower SWR does not increase the amount of loss.

Of course it doesn't. No one said it did. It does the opposite, ie a
lower SWR gives less loss on the feeder.

Please cite a reliable reference that says it does. Even the table Rick
cited shows a negative value for return SWR.

What is this 'Return SWR'? I'm not familiar with it.

Do you mean Return Loss Ratio (RLR)? This is a simple, easily
measurable, and meaningful statement of how strong the returning
reflected signal is compared with the outgoing forward signal.

The reflected signal is a weaker version of the forward signal. It's
expressed as a loss, an attenuation, or relatively how much down the
level of the reflection is. You can express this as a numerical ratio -
the reflection coefficient (rho) - or (as often more convenient) rho in
dB.

As others have suggested, what is apparently a negative sign in the
chart is presumably more artistic licence than scientific accuracy. If
you lose $10, you don't say that you lost 'minus $10'. Similarly, when
you lose 10dB of signal, you don't say you lost 'minus 10dB'.
--
Ian

On 9/29/2015 3:47 AM, Ian Jackson wrote:
In message , Jerry Stuckle
writes
On 9/28/2015 7:12 PM, John S wrote:
On 9/28/2015 1:51 PM, Jerry Stuckle wrote:
On 9/28/2015 1:42 PM, rickman wrote:





You said return loss increases with lower SWR. It does not.


It does.

Sorry, a lower SWR does not increase the amount of loss.

Of course it doesn't. No one said it did. It does the opposite, ie a
lower SWR gives less loss on the feeder.

Please cite a reliable reference that says it does. Even the table Rick
cited shows a negative value for return SWR.

What is this 'Return SWR'? I'm not familiar with it.


Sorry, writing too quickly. I meant return loss.

Do you mean Return Loss Ratio (RLR)? This is a simple, easily
measurable, and meaningful statement of how strong the returning
reflected signal is compared with the outgoing forward signal.

The reflected signal is a weaker version of the forward signal. It's
expressed as a loss, an attenuation, or relatively how much down the
level of the reflection is. You can express this as a numerical ratio -
the reflection coefficient (rho) - or (as often more convenient) rho in dB.

As others have suggested, what is apparently a negative sign in the
chart is presumably more artistic licence than scientific accuracy. If
you lose $10, you don't say that you lost 'minus $10'. Similarly, when
you lose 10dB of signal, you don't say you lost 'minus 10dB'.

Which is greater - 10db or -30db?

--
==================
Remove the "x" from my email address
Jerry, AI0K

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