Bird Wattmeter Line Section Disassembly & Cleaning

[@cliffbyers1997]

I got my tools out and cleaned my unit the SAME way you showed in you video! I used Connoisseur Silver wipes on mine. Thanks for the great how-to video!! "Holy black fingers Batman, it glitters like new!!"

[@ericdee6802]

Great demonstration using the mathematical formula to determine the ohms rating. I personally use the "Coaxial Dynamics" slugs, they are actually made from brass abd steel as for the Bird elements are a brass plated plastic along with other plastic garbage. Dont know why Bird is leaning towards plastic besides costs, but just makes for a crapier product.

[@davideisenberger6197]

Hi! As an ex Bird Cal Technician (12 Years) thought I might pass along to you that the center conductor has a very slight bend to it. This is used in the final Cal of the Bird 43 Meter. We have a special wrench that turns the centerline. Once disassembled, you may find it difficult to get the Cal back. 73’s de David. K8KEM

[@ElPasoTubeAmps]

Wow... that is great to know but too late for me... I suppose it would make more of a difference the higher in frequency we go. I use the Bird line section with the Bird 432-28 and 431-20 elements for 2.4 GHz and have wondered how accurate the 4230-058 line section is at those frequencies as I suppose it was not designed to work at 2.4 GHz. I don't have a problem with it and am using it again as I write but I would appreciate your thoughts on it because these elements say, "Out of the Scope of the RoHS Directive 2002/95/EC".

[@DonDegidio]

Thanks for all your videos. After watching this video, went to Ebay and ordered everything needed to assemble a wattmeter as good as a Bird for about $135. Still need to acquire a few slugs. I subscribed to your channel. WB3BJU

[@zeljkoadzic1692]

awesome video thank you

[@reginaldharris1906]

How do you take the white pieces out

[@hamrad88]

Nice job. Tom

[@tabajaralabs]

Thanks for the interesting video! But I have a question: Besides cleaning the hole where you put the element, and the contact tip, what is the pratical use of the internal cleaning of the device? Just for looks or is there something I don't know? 73 de PU2SEX! =)

[@ElPasoTubeAmps]

Quite honestly, unless there is real corrosion, I don't think it does anything at all for it - except clean it. There is a comment below from a Bird tech that says there is a slight bend in the center conductor used for calibration. I certainly can't argue that but I have no issues with any of my line sections or elements reading exactly the same. I have thought of making a video where I have had to deal with flaky cal pots in the slugs by carefully matching the slug under calibration with a known good element then carefully measuring the cal pot and replacing it with a couple of fixed resistors of the same value as the pot setting. No more flaky cal pot issues after that... you do need 1/4 watt or smaller resistors to fit under the top but it works great.

[@zeljkoadzic1692]

Hi Sir. Do you know the screw pitch of tread for bird connectors

[@ElPasoTubeAmps]

They are a US thread, #8-32 by 1/4 inch long.

[@bain5872]

Very interesting indeed. Being some what new to radio, I would be very appreciative if you could explain the role of the slugs in these watt meters. Thanks in advance.

[@ElPasoTubeAmps]

bain5872 The slugs, or elements, as we all call them, determine the RF frequency range and power range that can be measured. For the venerable model 43 the output of these elements all drive a 30 uA meter movement. Digital readouts are also available. With the element arrow facing the load, forward power measurements are indicated. Then you can mechanically rotate the element so the arrow points towards the source and measure the reflected power and determine reflection coefficient or VSWR. There about eighty (80) different elements that allow measurements from 450 KHz to 1.8 GHz at power levels from five watts to 10,000 watts with a bunch of specialty elements that will allow milliwatt power measurements and frequency measurements up to 2.5 GHz. I don't know the exact average price of new elements but it would probably be around $150 for a grand total of $12K - $15K if you bought them all - fortunately, us ham radio operators need only a few. I have tried all my career to build these types of elements using copper water pipe and connectors and one can come close but if you want something you can trust that is reliable and accurate it seems we have to buy instruments of this quality.

[@bain5872]

ElPaso TubeAmps OK, It makes sense to me now. The elements are only for taping off enough current for driving the display meter. The load impedance is a factor built in by design of the inner conductor to the outer shield. Thanks much for explaining it for me I really appreciate it!

[@JesusvonNazaret]

nice that you use SI units now :)

[@cl5ltd]

What could go 'wrong' with a line section? I have a coaxial dynamics line section which appears perfectly good, cleaned per your videos yet consistently reads inaccurately? Using the same element, in two different meters, with two line sections, one is spot on, the other considerably low? The user Manual does state to never disassemble, but when not working correctly, you have to inspect!

[@ElPasoTubeAmps]

These things are so rock-solid, you can't put them together wrong or harm them. I don't know why yours reads low. I think I showed how to use a micrometer and measure the exact inner diameter of the outer section, (D2) then the outer diameter of the inner rod (D1) and do the formula: 138*log(D2/D1) This should come up pretty darn close to 50. Could you possibly have a 75 ohm line section? Measuring it with a good micrometer and doing the formula should tell you. I have some CD slugs and generally they do differ from my Bird elements. Seems like, if I remember correctly, they usually read a bit higher. Here is a link to more formulas. www.rfcafe.com/references/electrical/transmission-lines.htm You don't need the expanded formula if the dielectric is air. The simple formula above will work. Also, the distance the element is from the inner line, when seated, is important. That could be a challenge to measure accurately and I don't know what it should be. I would only know to compare it to a known good line section. Good Luck 73. WA4QGA

[@davideisenberger6197]

Christopher Larwood you will need to readjust the center line as it has a very slight bend to it that is turned in final Cal. 73’s David. K8KEM

[@tabajaralabs]

@@davideisenberger6197 I know it is from a loong time ago, but could you say more about this calibration procedure? I wasn't able to find anything on the net...Thanks!