Dave Platt wrote:
The Ten-Tec does not
(according to the manual it's SWR-protected in a different way).

My Ten_tec 516 measures heat sink temperature.

"Sal M. Onella" wrote in message
...

"Dave Platt" wrote in message
news
In article ,
Sal M. Onella wrote:

snip

I have two HF radios, (Kenwood TS-120, TS-870) and I often observe the
forward power climbing as I manually tune and reduce the reflected
power.
At first glance, this would seem to indicate the rig had previously
throttled back its output in response to the consequences of a
mismatch.


snip
So, it's entirely possible that Kenwood uses a transmit-power
throttleback algorithm which is sensitive to the output SWR, rather
than to the absolute level of reflected power seen by the finals.

Could be. I have not analyzed the innards of the beast, but the -870
detects and displays SWR at all power levels -- so it _knows_. That's
one
of the bar-graph metering choices and if there's more than a watt or two
out, it will report SWR, good or bad.

Kenwood typically looks at forward, reflected current (or voltage) and
adjusts ALC voltage in response to a rise in either. In my TS130, I adjust
tuner into the ballpark, advance carrier, and fine tune for minimum ALC
reading.

"Cecil Moore" wrote in message
...
Jeff Liebermann wrote:
Bird is very specific that their 50 ohm wattmeters are only useful in
a 50 ohm system.

What you seem to be missing is that it takes only a few
inches of 50 ohm coax on each side of the directional
wattmeter to force a "50 ohm system". 50 ohm coax *IS*
a 50 ohm system, i.e. the load doesn't matter.

All this is easily proven by wading through the math.
--
73, Cecil http://www.w5dxp.com
"According to the general theory of relativity,
space without ether is unthinkable." Albert Einstein

The accuracy of a Bird for measuring power goes out the window for an SWR
other than 1:1. Are you saying that if you put an unterminated 3 inch piece
of coax on the Bird you have a 50 ohm system? That sounds like semantics
rather than Math. In fact you would have a 50 ohm system if you left the
antenna port disconnected, Then you could say you had an unterminated 50
ohm system. Real handy huh?

"Jeff Liebermann" wrote in message
...
On Mon, 29 Sep 2008 12:22:35 -0700, Jim Kelley
wrote:

Jeff Liebermann wrote:
Half the power, 1/4th the voltage.

You probably mean half the voltage, 1/4 the power.
73, ac6xg

Complex concepts I can easily understand. It's the simple things that
drive me nuts. Thanks. Gone sulking...

Consult db charts, voltage and power.

JB wrote:
"Cecil Moore" wrote in message
...
--
73, Cecil http://www.w5dxp.com
"According to the general theory of relativity,
space without ether is unthinkable." Albert Einstein

The accuracy of a Bird for measuring power goes out the window for an SWR
other than 1:1. Are you saying that if you put an unterminated 3 inch piece
of coax on the Bird you have a 50 ohm system? That sounds like semantics
rather than Math. In fact you would have a 50 ohm system if you left the
antenna port disconnected, Then you could say you had an unterminated 50
ohm system. Real handy huh?


Geesh! In the class, "Transmission Line 101", most basic fact is a
transmission line only is valid at its' stated impedance if terminated
in its' proper load/impedance ...

I think he took it for granted his text was formatted for the proper
audience ... he was simply mistaken, in your particular case. :-(

Regards,
JS

JB wrote:
"Jeff Liebermann" wrote in message
...
Consult db charts, voltage and power.


And, he responds, repeat the "Transmission Line 101" class ...

Regards,
JS

"John Smith" wrote in message
...
JB wrote:
"Jeff Liebermann" wrote in message
...
Consult db charts, voltage and power.


And, he responds, repeat the "Transmission Line 101" class ...

Regards,
JS

I'm afraid these things don't always jump out at you from the General Class
license training seminar.

"John Smith" wrote in message
...
JB wrote:
"Cecil Moore" wrote in message
...
--
73, Cecil http://www.w5dxp.com
"According to the general theory of relativity,
space without ether is unthinkable." Albert Einstein

The accuracy of a Bird for measuring power goes out the window for an
SWR
other than 1:1. Are you saying that if you put an unterminated 3 inch
piece
of coax on the Bird you have a 50 ohm system? That sounds like
semantics
rather than Math. In fact you would have a 50 ohm system if you left
the
antenna port disconnected, Then you could say you had an unterminated
50
ohm system. Real handy huh?


Geesh! In the class, "Transmission Line 101", most basic fact is a
transmission line only is valid at its' stated impedance if terminated
in its' proper load/impedance ...

I think he took it for granted his text was formatted for the proper
audience ... he was simply mistaken, in your particular case. :-(

Regards,
JS

Now if you take 1000' of RG-174 and left it dangling over the end of a
cliff, the reflections wouldn't be able to climb back up the coax!

On Tue, 30 Sep 2008 16:58:51 GMT, "JB" wrote:


"Jeff Liebermann" wrote in message
.. .
On Mon, 29 Sep 2008 12:22:35 -0700, Jim Kelley
wrote:

Jeff Liebermann wrote:
Half the power, 1/4th the voltage.

You probably mean half the voltage, 1/4 the power.
73, ac6xg

Complex concepts I can easily understand. It's the simple things that
drive me nuts. Thanks. Gone sulking...

Consult db charts, voltage and power.

Yeah, yeah. I seem to have contracted a temporary case of dyslexia.
Not only am I getting power and voltage backwards but I'm also
spending money instead of receive it, and voting Democrat instead of
Republican. Probably caused by too much exposure to RF which is
hopefully reversible.

Back to sulking... I just hate making misteaks.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Jeff Liebermann" wrote in message
...
On Tue, 30 Sep 2008 16:58:51 GMT, "JB" wrote:


"Jeff Liebermann" wrote in message
.. .
On Mon, 29 Sep 2008 12:22:35 -0700, Jim Kelley
wrote:

Jeff Liebermann wrote:
Half the power, 1/4th the voltage.

You probably mean half the voltage, 1/4 the power.
73, ac6xg

Complex concepts I can easily understand. It's the simple things that
drive me nuts. Thanks. Gone sulking...

Consult db charts, voltage and power.

Yeah, yeah. I seem to have contracted a temporary case of dyslexia.
Not only am I getting power and voltage backwards but I'm also
spending money instead of receive it, and voting Democrat instead of
Republican. Probably caused by too much exposure to RF which is
hopefully reversible.

Back to sulking... I just hate making misteaks.

Just remember: What's bad for the country is good for the democrats. Maybe
we just need another depression or maybe a nuclear attack to show how badly
Bush has failed and how badly this country needs a diaper change!

Favorite Obummer quote: "This is the greatest country in the world!... and
we need change!"