[Amps] Time for New Power Meter

[Jim Thomson]

Date: Fri, 1 May 2015 11:16:58 -0400
From: Gerald Williamson via Amps <amps at contesting.com>
To: drkirkby at kirkbymicrowave.co.uk, k7fm at teleport.com
Cc: amps at contesting.com
Subject: Re: [Amps] Time for New Power Meter

Hi All, I also use a Bird 43 as a gold standard. Why? Because I have it  
already. A 5% error amounts to about .2 dB which is close enough for my 
amateur  needs. 
 
The capability of easily changing connectors is a plus not available on  
most if not all of the other meters.
 
Maybe we should call the 43 a "Brown Standard"? 
 
73,
Gerald K5GW

##  What freq does bird /cd  calibrate their  slugs on ??  talking abt the typ 2-30 mhz slug. 
On a side note, IF a CD pep board is installed, or the model 83000 is used, the accuracy is
+/- 7%.....when switched to pep mode.  When a bird  pep board is installed on a bird 43, the
accuracy is now +./- 8%...when switched to pep mode.   Both are +/- 5% in average mode. 

##  The problem with the bird  /cd meters /slugs is... they are +/-  5/7/8 %  of full scale...any where on the scale.  
IE: 5% of a 1 kw slug = 50 watts.   So if meter reads 800 watts....the true pwr could be  750w...and meter
is reading 50 watts high.    Or true pwr could be 850 watts..and meter is reading 50 watts low. 

##  If meter reads 100 watts.... true power could be as little as 50 watts......or as high as 150w.  In this
last case, the error could vary from  50-100%  outa whack. Bottom line is..u gotta use the smallest slug
for the job.  

##  with a 5 kw slug, my L4B  reads 700w.    ( low power mode, 1900v).   With a 2.5 kw slug, it then reads 650w.
With a 1 kw slug, it no reads 625 watts..which is very close to dead on. 
Dunno if a bird slug is most accurate on the freq its calibrated for..vs  extremes in freq.   IE:  IF they calibrate it
at say 16 mhz..... what is accuracy at 2 mhz + also 30 mhz. 

##  IMO, the array solutions power master blows both the bird /cd slugs away..hands down.   If u don’t like their
NIST calibration, u are free to re-calibrate it urself.... since the calibration can be changed in 1% increments....
and with a +/- 15% range.   +/- 15%...in 1% increments is as good as is gets.    The calibration points are printed on each
individual coupler..for both frwd and rvs power...for  both HF...and again for 6m.   160-6m  on one coupler is pretty good.
Then they have couplers for 144/220/432 etc. 

##  with no high swr alarm etc, etc, the bird doesnt cut it anymore.   Bird doesn’t sell wattmeters...they sell slugs. 
The only advantage the bird /cd has..is it reads average power if u want to.   the array solutions will only read pep. 
U cant see the effects of increased average power when using processor on ssb mode.
Flip side is..the pep bargraph on the array solutions wattmeter is so sensitive, it will easily show..dithering
when 3 % ripple is present on a B+  supply..which is typ when 8  series 200 ufs cap are used.   Any RF scope
will also show that effect. 

##  the only connectors I use are  SO-239  and also 7-16 DIN.  I don’t use Type N.... but can easily add an inter series
adaptor if needed.  My  3 kw coupler get the so-239....and my  10 kw coupler gets the 7-16 din. 

Jim  VE7RF 

adaptpr