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  #11   Report Post  
Old September 15th 03, 10:12 PM
Jack Smith
 
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Bill:

Your March 1995 QEX article says that you prepared an accompanying
construction article for QST. I haven't been able to find it in '95,
96 or '97 QST editions. Was it published? If so, when?

Jack K8ZOA


  #12   Report Post  
Old September 15th 03, 10:36 PM
AA
 
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I have two good reasons. My homebrew 100 watt
solid state MOSFET PA, 160 M to 10 M, provides the
signal cleanliness that I designed it for when the
power output on SSB is 100 W PEP


Hmmmm...plans available for this? QUITE interested!

Tnx de kilo golf 4 golf sierra charlie!!

mycall@arrl dot net
  #13   Report Post  
Old September 15th 03, 11:50 PM
Caveat Lector
 
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Main reason is that the diode detector types of VSWR Meters are very
inaccurate when any VSWR is present

Also I have found that running PA's at 90% gives a much cleaner output
(Usually) so I need a meter that will give reasonable accuracy when making
these adjustments.

Some cheapo VHF VSWR meters are so inaccurate as to be useless.
For Bird -- buy the appropriate slug -- slugs are very inexpensive on the
used market.
Not E-BAy -- hi hi

And Mil Surplus thru line meters are very cheap on the surplus market, Less
than new diode detector types.

--
73 From The Signal In The Noise
Caveat Lector Ya All



Why would a ham operator have a need for such accuracy ?
Isn't consistency enough ? For ensurance of not exceeding
the power output for those who want to equal the max then
a scope would be the way to go. For those that build then
there is a need for accuracy and bragging rights are fully
earned. Seems like this falls into the same catagory of
'I have six elements where you have only five'
Art




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Old September 16th 03, 01:07 AM
Richard Clark
 
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On Mon, 15 Sep 2003 15:50:26 -0700, "Caveat Lector"
wrote:

Main reason is that the diode detector types of VSWR Meters are very
inaccurate when any VSWR is present

Also I have found that running PA's at 90% gives a much cleaner output
(Usually) so I need a meter that will give reasonable accuracy when making
these adjustments.

Some cheapo VHF VSWR meters are so inaccurate as to be useless.
For Bird -- buy the appropriate slug -- slugs are very inexpensive on the
used market.
Not E-BAy -- hi hi

And Mil Surplus thru line meters are very cheap on the surplus market, Less
than new diode detector types.


Hi OM,

Art says why buy expensive equipment, and then extols a scope (easily
three to ten times expensive as a new Bird 43). He probably intends
to only measure flat power with perfect sine shape applied to perfect
designs. A CB SWR meter works better with even the slightest hint of
imperfection and just as well when every thing is hunky-dory. If you
want to watch a phosphor glow, get TV or build your meter with a Magic
Eye tube (more range than LEDs suggested elsewhere).

You say
diode detector types of VSWR Meters are very
inaccurate when any VSWR is present

and then extol the Bird or Mil Surplus - which are diode detector
types (what aren't - scopes? WHOOPZ back into that yarn).

Has anyone here actually measured SWR without using a diode? Form a
que here and tell your story. I want to hear the one about your
single device non-linear detector (a way of not saying diode while
still being a diode).

Caveat Reader,
Richard Clark, KB7QHC
  #15   Report Post  
Old September 16th 03, 01:58 AM
Caveat Lector
 
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Ah at URL:
http://www.hamradiomarket.com/articles/Wattmeters.htm

The cheapos are called "inexpensive cross needle, putt-putt SWR/wattmeters"
Interesting article

--
73 From The Signal In The Noise
Caveat Lector Ya All
"Caveat Lector" wrote in message
news:33t9b.134831$kP.127157@fed1read03...
Perhaps poor choice of words

Bird meters and monimatch type meters use the capacitive coupling of the
coupled line to couple voltage and magnetic coupling to the coupled line
to couple current. THEN the diode sees the vector sum of the two
couplings.


The cheaper ones - like Radio Shack had just diodes to detect peak V or I
and -- I always called em diode detector types -- what wud u call em

Any way I am sure you know the difference



--
73 From The Signal In The Noise
Caveat Lector Ya All
"Richard Clark" wrote in message
...
On Mon, 15 Sep 2003 15:50:26 -0700, "Caveat Lector"
wrote:

Main reason is that the diode detector types of VSWR Meters are very
inaccurate when any VSWR is present

Also I have found that running PA's at 90% gives a much cleaner output
(Usually) so I need a meter that will give reasonable accuracy when

making
these adjustments.

Some cheapo VHF VSWR meters are so inaccurate as to be useless.
For Bird -- buy the appropriate slug -- slugs are very inexpensive on

the
used market.
Not E-BAy -- hi hi

And Mil Surplus thru line meters are very cheap on the surplus market,

Less
than new diode detector types.


Hi OM,

Art says why buy expensive equipment, and then extols a scope (easily
three to ten times expensive as a new Bird 43). He probably intends
to only measure flat power with perfect sine shape applied to perfect
designs. A CB SWR meter works better with even the slightest hint of
imperfection and just as well when every thing is hunky-dory. If you
want to watch a phosphor glow, get TV or build your meter with a Magic
Eye tube (more range than LEDs suggested elsewhere).

You say
diode detector types of VSWR Meters are very
inaccurate when any VSWR is present

and then extol the Bird or Mil Surplus - which are diode detector
types (what aren't - scopes? WHOOPZ back into that yarn).

Has anyone here actually measured SWR without using a diode? Form a
que here and tell your story. I want to hear the one about your
single device non-linear detector (a way of not saying diode while
still being a diode).

Caveat Reader,
Richard Clark, KB7QHC







  #16   Report Post  
Old September 16th 03, 02:11 AM
Richard Clark
 
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On Mon, 15 Sep 2003 17:45:52 -0700, "Caveat Lector"
wrote:

Perhaps poor choice of words

Bird meters and monimatch type meters use the capacitive coupling of the
coupled line to couple voltage and magnetic coupling to the coupled line
to couple current. THEN the diode sees the vector sum of the two
couplings.


The cheaper ones - like Radio Shack had just diodes to detect peak V or I
and -- I always called em diode detector types -- what wud u call em

Any way I am sure you know the difference


Hi OM,

Not when you incorrectly describe them. They all use two diodes, or
in the case of the Bird, the single diode is used twice, once in each
direction. There is every chance someone tried to reduce the bottom
line (boost profits) by using one diode to read both - give us an
example.

Peak, Average, PEP, call it what you will is only a matter of meter
scaling (and in the case of SWR no different at all) and what the Time
Constant is with any particular resistor-capacitor pair used as the
meter load.

What is really sadistic, are digital numeric displays when SWR/Power
is swinging. Reading 8.88 because the numbers' segments blur is
pitiful in the extreme.

73's
Richard Clark, KB7QHC
  #17   Report Post  
Old September 16th 03, 02:55 AM
Caveat Lector
 
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Ok you win -- I retract all
Now where did I put the Bird


--
73 From The Signal In The Noise
Caveat Lector Ya All
"Richard Clark" wrote in message
...
On Mon, 15 Sep 2003 17:45:52 -0700, "Caveat Lector"
wrote:

Perhaps poor choice of words

Bird meters and monimatch type meters use the capacitive coupling of the
coupled line to couple voltage and magnetic coupling to the coupled line
to couple current. THEN the diode sees the vector sum of the two
couplings.


The cheaper ones - like Radio Shack had just diodes to detect peak V or I
and -- I always called em diode detector types -- what wud u call em

Any way I am sure you know the difference


Hi OM,

Not when you incorrectly describe them. They all use two diodes, or
in the case of the Bird, the single diode is used twice, once in each
direction. There is every chance someone tried to reduce the bottom
line (boost profits) by using one diode to read both - give us an
example.

Peak, Average, PEP, call it what you will is only a matter of meter
scaling (and in the case of SWR no different at all) and what the Time
Constant is with any particular resistor-capacitor pair used as the
meter load.

What is really sadistic, are digital numeric displays when SWR/Power
is swinging. Reading 8.88 because the numbers' segments blur is
pitiful in the extreme.

73's
Richard Clark, KB7QHC



  #18   Report Post  
Old September 16th 03, 04:22 AM
Cecil Moore
 
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Caveat Lector wrote:
Main reason is that the diode detector types of VSWR Meters are very
inaccurate when any VSWR is present


Why can't the diode be biased to improve the accuracy? Or a class-B
amp be used?
--
73, Cecil http://www.qsl.net/w5dxp



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  #19   Report Post  
Old September 16th 03, 04:52 AM
Jerry
 
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"Richard Clark" wrote in message
...
On Sun, 14 Sep 2003 14:31:08 -0700, "Ed Price"
wrote:
The little network, along with the section of coax line inside the main
housing, forms a directional coupler. A Bird 43 (or similar, but the 43's
are readily available, used, on eBay) is about the cheapest way to get
answers about the design and performance of your antenna and transmitter
system.

And if you think a Bird 43 is big money, you ain't seen nothing yet!

Ed
WB6WSN




..

73's
Richard Clark, KB7QHC



Bu, bu, bu, Richard it has to be expensive for a CBer. How else is he to get
them "bird" watts thar? (snicker)


Jerry


  #20   Report Post  
Old September 16th 03, 12:32 PM
William E. Sabin
 
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AA wrote:
I have two good reasons. My homebrew 100 watt
solid state MOSFET PA, 160 M to 10 M, provides the
signal cleanliness that I designed it for when the
power output on SSB is 100 W PEP



Hmmmm...plans available for this? QUITE interested!

Tnx de kilo golf 4 golf sierra charlie!!

mycall@arrl dot net


See QEX for Nov/Dec 1999.

Bill W0IYH

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