[Amps] Fw: Needed, quality watt meter

[Jim Thomson]

Date: Wed, 11 Aug 2010 17:02:33 -0700
From: "Bill, W6WRT" <dezrat1242 at yahoo.com>
Subject: Re: [Amps] Fw: Needed, quality watt meter



>
>The BEST display for adjusting stuff is the kind of 
>display (meter) with a moving pointer.   Right behind 
>that is the bargraph. 

REPLY:

There are two different kinds of bargraphs. One just lights the
segments one at a time, full on. The other (better) fades in the next
segment as the measurement increases. That type is as good as a
pointer, IMO. Alpha uses that type on the model 89 I had and probably
others. 

73, Bill W6WRT

## agreed.   And I forgot to mention that on my description of the Array solutions
watt meters.    The AS bar graph  does exactly this.    Each segment slowly lights up, from zero 
to fully illuminated .   Then the next segment starts up.    I think there at least 80  segments on the 
AS display..so tuning an amp is a snap.  Heck, you can even tune up..while talking !  Once tuned for max
using the bargraph... If I switch to the numerical display... I'm very lucky if I can get all of 1-2 watts more out of the
amp. 

##  OK. I did notice one anomaly.   Once I got up to 700+ watt dead cxr.... I would notice that
the last 2 x segments on the bargraph  were...'dithering' .   It was worse with max power [1290 w cxr]

## Then I put the RF scope on... and could see what the 'problem'  was  at a glance.  I had 3% ripple
in the stock L4B  B+ supply  [when sucking  800 ma].    The 3%  ripple  also shows up as  'dithering' on the 
last 2 x segments of the AS bargraph.   The AS wattmeter coupler /display unit is so fast..it will show ripple
in any B+ supply  very easily !      I temp paralleled  a 50 uf  oil cap with the stock 25 uf set up...and tripled the C.  
Ripple dropped down to 1%.    Later, I increased the filter C  to a  whopping 287 uf..and ripple is now down to
just .26% 

##  I have since taken the bird pep, and CD pep meter's offline.  Other than 2m, I have no use for them.   Both the 
3 kw and 10 kw AS coupler's   will cover 160-6m.      They give you a separate set of calibration pointS  [ FWD  + RVS] 
 to program in..when using 50-54 mhz.     The bargraph is superb..and so is the hi/lo pwr alarms..+ the high swr alarm. 
You can see all 4 x displays on my qrz page. 

later... Jim    VE7RF