[Elecraft] OT: Bird watt meter?

Wed Jul 2 13:34:18 2003

During the 1980's, Bird slugs left something to be desired. We manufactured
RF generators for industrial applications. Most were for 13.56MHZ. Some were
for 27 and 50MHZ industrial frequencies. We had a box with over 100 new Bird
slugs that were off by greater than 20%. All wattmeters and slugs were
calibrated with a calorimeter. A slug was taped to the wattmeter so it
couldn't be changed or reversed. A new scale was derived by calorimeter
measurements at a particular frequency, such as 13.56MHZ.

One specific case comes to mind. A customer complained that they could only
get 12KW out of a 15KW generator into a dummy load. They had tried tow
different wattmeters and slugs. These were brand new Bird wattmeters and
slugs. We brought in a calibrated wattmeter to show the actual output of the
generator was 18KW.

I was told by our head RF design engineer that Bird had a great reputation
when the founders were running the company. Was told quality dropped off
when the "kids" started running the company.

So, have Bird slugs and wattmeters improved over the years? Can't answer
that. But would like to hear from someone who has checked calibration of
newer Bird units. By the way, I had my old W4 Drake wattmeter checked
against the standard. Was amazed how accurate it was on 20M.

I kind of look at these wattmeters as relative measurements.

N2TK, Tony
#3481

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of [email protected]
Sent: Wednesday, July 02, 2003 12:33
To: [email protected]
Subject: [Elecraft] OT: Bird watt meter?

Hi folks -
Could someone tell me:
1 - Why are Bird meters so well regarded?
2 - Are they still manufactured?
3 - What is a slug?
4 - Will they measure QRP levels? If so, better than OHR meter?
5 - What would be the recommended slugs, specific meter (if there is more
than one model), and accessories for measuring milliwatts up to 100 watts.
6 - What would be a reasonable price range to pay for the above?
7 - What would be the most common problem to look out for when shopping for
a used meter?

Thank you - probably should reply direct - but other Elecraft users may be
interested in learning from some of the pros :-) Thanks folks.
73/NZ7C

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