Just a little information from the BIRD catalog.
"Higher power Elements have flatter frequency charateristics than thighter
coupled lower-power units. Beyond the stated frequency range, measurement
results cannot be predicted"
The graph next to the text showes a 100-250MHz element in different power
classes.
The 10W one seams to be pretty good 10-250MHz , and the 500W 40-500MHz.
BUT its a pretty poor graph to read any accurate numbers from, but gives you a
general idea.
So I guess its not only 10% as a rule but what power element you use.
73/Petter SM3PXO
-----Ursprungligt meddelande-----
Från: Phil Clements [SMTP:philk5pc@connect.net]
Skickat: den 1 juni 1998 07:08
Till: amps@contesting.com; topband@contesting.com
Ämne: [AMPS] Bird Wattmeter Error on 160 Meters
It only took me 44 years to learn this little tidbit, so I thought
I would pass it on as it is of interest to all bird Wattmeter users.
The standard Bird HF slugs like we all use are marked 2-30 mhz. I
always figured that 1.830 mhz was close enough to the edge to not
make any difference. Not so...there is a 10% error on the low side
in the reading!
I was visiting in a friend's shack recently, and we were discussing
our recent purchases of several models of R.F. Applications, Inc.
watt meters. (and what fine products they are!) I said my only complaint
with my P-3000 meter was that it read 10% higher than my Bird 43 on 160
meters; otherwise it was "right on" with the Bird on all the other bands
in the 2-30 mhz range. He then performed this demonstration...he loaded his
amp to 1500 watts output on his Bird 43, with the standard 2-30 mhz slug.
He then replaced the slug with the Bird slug rated for 800 khz-2 mhz.
When he keyed up, the Bird 43 then read 1650 watts! I guess I have been
running 10% more power for 44 years on 160 meters and never knew it.
You probably have also!
(((73)))
"To do is to be".....Sartre
"To be is to do".....Aristotle
"To be or not to be".Shakespeare
"Do be do be do".....Sinatra
"Yabba dabba do......Flintstone
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