[Yaesu] Bird Wattmeter...

[Jerry Flanders]

Don't know anything about your meter, but to 
determine accurate power levels for reference, I 
would use a calorimetric technique. See: 
http://broadcastengineering.com/products/transmitter-power/index1.html 
and read up on calorimeters. Usually only thought 
of as a chem lab instrument, calorimeters can be 
used to measure electrical power accurately with 
simple kitchen materials. Make it with styro cups and medical thermometer.

Jerry W4UK

At 10:12 PM 7/30/2010, KBØNLY wrote:
>There is a good article on this on the Repeater 
>Builder website, full writeup with pictures and everything.
>
>http://www.repeater-builder.com/projects/bird-element-tour/bird-element-tour.html
>
>After taking numerous Bird elements apart to 
>repair them I have to say I totally lost faith 
>in their product.  Some of them were NOS 
>elements that spent their short life on a shelf 
>until I got a hold of them.  I sold my Bird 43 
>years ago in favor of a Telewave.  Recently 
>though I got a hold of this Bird 6154 model 
>which doesn't use any slugs and figured it would 
>be a good bench meter since it has a dummy load 
>rated to 150w.  Well looks like I'm still going 
>to have to use another meter because this one 
>isn't any good readings wise either.  Reads off 
>on both scales.  And nobody seems to know the 
>voodoo that Bird somehow magically uses to calibrate this model.
>
>I mean come on, months of searching and asking 
>and nobody knows?  I sent Bird an email and they 
>said ship it to us, $180 and it will be 
>fine...  What??  How could it cost $180 to 
>calibrate a meter, especially one that everybody says cannot be calibrated??
>
>73,
>
>Scott
>
>
>
>
>From: k5cbl at juno.com
>Sent: Friday, July 30, 2010 8:59 PM
>To: k5bm at swbell.net
>Cc: kb0nly at mchsi.com
>Subject: Re: [Yaesu] Bird Wattmeter...
>
>
>Evening Tom,
>
>I don't have any slug that is torn down to shoot 
>some pictures, but hear goes some info...
>
>1.) The meter is a 0-30 Ua movement....not standard to any replacement meter.
>
>2.) The slug can be calibrated for what range 
>you might want the slug to read...think there 
>are 5-7 different slugs but calibrated to different power range...
>
>3.)  You will need to remove the front 
>plate....they used some type of glue like a 
>rubber cement...I have taken a heat gun 
>(depending on age of slug a hair dryer works) 
>and heat the front plate and using a real thin 
>screw driver (probably will damage or scar the 
>alum plate where you lift it) just don't melt 
>the slug (don't overheat) just enough to lift plate....
>
>4.)  Under the plate you will see a 6-32 screw 
>head and a hole and the hole will have a screw 
>driver slot way down deep, use an insulated thin 
>blade screwdriver.....seems like in the past the 
>adjustment was a small pot (value depending on 
>the slug) and some of the slugs the adjustment 
>is a small variable cap....just can't remember 
>if I ever wrote down which slug has what....
>
>5.)  If the internal diode or in most a series 
>resistor is burnt or open the white plastic on 
>the end that is inserted into the Bird can be 
>removed by using the thin blade screw driver 
>again and pry it away from the element....the 
>cap has a lip and pops or snaps back on if you 
>haven't damaged it removing it...
>
>6.)  When its removed you can see the resistor 
>that is soldered to a loop that goes back into 
>the element.....you will need to remove the 6-32 
>screw to go deeper where the diode is affixed to 
>the resistor and variable pot....in doodle bug 
>style....(hanging in the air)....I can't 
>remember the diode I have used, seems like it 
>was a 1n100 just can't remember but seems like 
>most germanium diode will work....probably 
>someone that really knows whats going on can 
>specify the correct diode if needed....
>
>Hope this will not get you in trouble...I had to 
>destroy an old one to fix the others ...
>
>PS broke slugs are cheap at ham fests....HI
>
>Lots of luck.....73 Troy K5CBL
>
>
>
>
>
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