On 7/11/2015 5:38 AM, Ian Jackson wrote:
In message , Jeff writes



A load in isolation without any transmission line connected cannot
have a standing wave, but it is still common to quote the mismatch as
a VSWR which is plain wrong, but still very common.

But as I've said (nitpickingly), any length of connection (no matter how
short) where the load is not a perfect match for its characteristic
impedance, will have a very tiny portion of a standing wave on it.

And as I've also said, the normal SWR meter DOESN'T measure (respond) to
SWR. It is a reflectometer, and it responds independently to the
forward-going signal and the reverse-going signal. It's really telling
you what the return loss ratio (RLR) is - but it's still perfectly
legitimate for it to be scaled in terms of SWR. It's a darned sight
easier way of finding out what the equivalent SWR would be than to try
and measure the Vmax and Vmin 'for real' along a long line.

Why don't we use the RLR in all these measurements instead of SWR?
Isn't that what we are really after?

--

Rick

rickman wrote:
On 7/11/2015 5:38 AM, Ian Jackson wrote:
In message , Jeff writes



A load in isolation without any transmission line connected cannot
have a standing wave, but it is still common to quote the mismatch as
a VSWR which is plain wrong, but still very common.

But as I've said (nitpickingly), any length of connection (no matter how
short) where the load is not a perfect match for its characteristic
impedance, will have a very tiny portion of a standing wave on it.

And as I've also said, the normal SWR meter DOESN'T measure (respond) to
SWR. It is a reflectometer, and it responds independently to the
forward-going signal and the reverse-going signal. It's really telling
you what the return loss ratio (RLR) is - but it's still perfectly
legitimate for it to be scaled in terms of SWR. It's a darned sight
easier way of finding out what the equivalent SWR would be than to try
and measure the Vmax and Vmin 'for real' along a long line.

Why don't we use the RLR in all these measurements instead of SWR?
Isn't that what we are really after?

What we are really after is a convenient way to determine the quality
of an impedance match.

VSWR is about as convenient as there is.


--
Jim Pennino

On 7/11/2015 10:49 AM, Jeff wrote:

Why don't we use the RLR in all these measurements instead of SWR? Isn't
that what we are really after?


A very good question. One possible answer is that RL is normally quoted
in dB, and VSWR linear scales are perhaps easier to envisage.

eg 3:1 ~6dB RL
2:1 ~9.5dB RL
1.5:1 ~14dB RL
1.1:1 ~26dB RL

Personally I find log scales more intuitive for most things as they more
closely relates to factors of significance, no? But I see right away
that RL scales the non-intuitive way, a larger number is a less
significant value. While SWR scales the right way with 1 being no
effect. SWR can also be given in dB which would make the numbers very
intuitive.

--

Rick

rickman wrote:
On 7/11/2015 10:49 AM, Jeff wrote:

Why don't we use the RLR in all these measurements instead of SWR? Isn't
that what we are really after?


A very good question. One possible answer is that RL is normally quoted
in dB, and VSWR linear scales are perhaps easier to envisage.

eg 3:1 ~6dB RL
2:1 ~9.5dB RL
1.5:1 ~14dB RL
1.1:1 ~26dB RL

Personally I find log scales more intuitive for most things as they more
closely relates to factors of significance, no? But I see right away
that RL scales the non-intuitive way, a larger number is a less
significant value. While SWR scales the right way with 1 being no
effect. SWR can also be given in dB which would make the numbers very
intuitive.

Perhaps the world is ready for the Rickman, where Rickman = 10 * log (VSWR).

0 Rickman = 1:1 VSWR.
1.76 Rickman = 1.5:1 VSWR.
3.01 Rickman = 2:1 VSWR.

At the very least, it would eliminate any arm waving about standing waves.


--
Jim Pennino

On 7/11/2015 1:47 PM, wrote:
rickman wrote:
On 7/11/2015 10:49 AM, Jeff wrote:

Why don't we use the RLR in all these measurements instead of SWR? Isn't
that what we are really after?


A very good question. One possible answer is that RL is normally quoted
in dB, and VSWR linear scales are perhaps easier to envisage.

eg 3:1 ~6dB RL
2:1 ~9.5dB RL
1.5:1 ~14dB RL
1.1:1 ~26dB RL

Personally I find log scales more intuitive for most things as they more
closely relates to factors of significance, no? But I see right away
that RL scales the non-intuitive way, a larger number is a less
significant value. While SWR scales the right way with 1 being no
effect. SWR can also be given in dB which would make the numbers very
intuitive.

Perhaps the world is ready for the Rickman, where Rickman = 10 * log (VSWR).

0 Rickman = 1:1 VSWR.
1.76 Rickman = 1.5:1 VSWR.
3.01 Rickman = 2:1 VSWR.

At the very least, it would eliminate any arm waving about standing waves.

I believe it would be 20 * log (VSWR)

--

Rick

rickman wrote:
On 7/11/2015 1:47 PM, wrote:
rickman wrote:
On 7/11/2015 10:49 AM, Jeff wrote:

Why don't we use the RLR in all these measurements instead of SWR? Isn't
that what we are really after?


A very good question. One possible answer is that RL is normally quoted
in dB, and VSWR linear scales are perhaps easier to envisage.

eg 3:1 ~6dB RL
2:1 ~9.5dB RL
1.5:1 ~14dB RL
1.1:1 ~26dB RL

Personally I find log scales more intuitive for most things as they more
closely relates to factors of significance, no? But I see right away
that RL scales the non-intuitive way, a larger number is a less
significant value. While SWR scales the right way with 1 being no
effect. SWR can also be given in dB which would make the numbers very
intuitive.

Perhaps the world is ready for the Rickman, where Rickman = 10 * log (VSWR).

0 Rickman = 1:1 VSWR.
1.76 Rickman = 1.5:1 VSWR.
3.01 Rickman = 2:1 VSWR.

At the very least, it would eliminate any arm waving about standing waves.

I believe it would be 20 * log (VSWR)

We could split the difference and call it 15 * log (VSWR).


--
Jim Pennino

On 7/11/2015 2:29 PM, wrote:
rickman wrote:
On 7/11/2015 1:47 PM, wrote:
rickman wrote:
On 7/11/2015 10:49 AM, Jeff wrote:

Why don't we use the RLR in all these measurements instead of SWR? Isn't
that what we are really after?


A very good question. One possible answer is that RL is normally quoted
in dB, and VSWR linear scales are perhaps easier to envisage.

eg 3:1 ~6dB RL
2:1 ~9.5dB RL
1.5:1 ~14dB RL
1.1:1 ~26dB RL

Personally I find log scales more intuitive for most things as they more
closely relates to factors of significance, no? But I see right away
that RL scales the non-intuitive way, a larger number is a less
significant value. While SWR scales the right way with 1 being no
effect. SWR can also be given in dB which would make the numbers very
intuitive.

Perhaps the world is ready for the Rickman, where Rickman = 10 * log (VSWR).

0 Rickman = 1:1 VSWR.
1.76 Rickman = 1.5:1 VSWR.
3.01 Rickman = 2:1 VSWR.

At the very least, it would eliminate any arm waving about standing waves.

I believe it would be 20 * log (VSWR)

We could split the difference and call it 15 * log (VSWR).

If it is my unit, I'm not sharing with anyone! It would be dBrickman I
think with the reference value 1:1 VSWR.

--

Rick

rickman wrote:
On 7/11/2015 2:29 PM, wrote:
rickman wrote:
On 7/11/2015 1:47 PM, wrote:
rickman wrote:
On 7/11/2015 10:49 AM, Jeff wrote:

Why don't we use the RLR in all these measurements instead of SWR? Isn't
that what we are really after?


A very good question. One possible answer is that RL is normally quoted
in dB, and VSWR linear scales are perhaps easier to envisage.

eg 3:1 ~6dB RL
2:1 ~9.5dB RL
1.5:1 ~14dB RL
1.1:1 ~26dB RL

Personally I find log scales more intuitive for most things as they more
closely relates to factors of significance, no? But I see right away
that RL scales the non-intuitive way, a larger number is a less
significant value. While SWR scales the right way with 1 being no
effect. SWR can also be given in dB which would make the numbers very
intuitive.

Perhaps the world is ready for the Rickman, where Rickman = 10 * log (VSWR).

0 Rickman = 1:1 VSWR.
1.76 Rickman = 1.5:1 VSWR.
3.01 Rickman = 2:1 VSWR.

At the very least, it would eliminate any arm waving about standing waves.

I believe it would be 20 * log (VSWR)

We could split the difference and call it 15 * log (VSWR).

If it is my unit, I'm not sharing with anyone! It would be dBrickman I
think with the reference value 1:1 VSWR.

Fair enough...

--
Jim Pennino

In message ,
writes
rickman wrote:
On 7/11/2015 10:49 AM, Jeff wrote:

Why don't we use the RLR in all these measurements instead of SWR? Isn't
that what we are really after?


A very good question. One possible answer is that RL is normally quoted
in dB, and VSWR linear scales are perhaps easier to envisage.

eg 3:1 ~6dB RL
2:1 ~9.5dB RL
1.5:1 ~14dB RL
1.1:1 ~26dB RL

Personally I find log scales more intuitive for most things as they more
closely relates to factors of significance, no? But I see right away
that RL scales the non-intuitive way, a larger number is a less
significant value. While SWR scales the right way with 1 being no
effect. SWR can also be given in dB which would make the numbers very
intuitive.

Perhaps the world is ready for the Rickman, where Rickman = 10 * log (VSWR).

0 Rickman = 1:1 VSWR.
1.76 Rickman = 1.5:1 VSWR.
3.01 Rickman = 2:1 VSWR.

At the very least, it would eliminate any arm waving about standing waves.

Haven't you just reinvented the reflection coefficient, rho?



--
Ian

In message , Jeff writes

Why don't we use the RLR in all these measurements instead of SWR?

Tradition!

Isn't
that what we are really after?

As long as you know what you're after, and get close to it, it doesn't
really matter.


A very good question. One possible answer is that RL is normally quoted
in dB, and VSWR linear scales are perhaps easier to envisage.

eg 3:1 ~6dB RL
2:1 ~9.5dB RL
1.5:1 ~14dB RL
1.1:1 ~26dB RL

Isn't there somehow something sort-of unnatural about trying to aim for
an infinite value?


--
Ian