XPost: rec.radio.amateur.moderated

amateur radio - Hackaday

///////////////////////////////////////////
Homebrew Wattmeter Pays Homage to Sturdy Original

Posted: 27 Sep 2021 07:00 PM PDT https://hackaday.com/2021/09/27/homebrew-wattmeter-pays-homage-to-sturdy-original/


If theres one instrument that hams and other radio enthusiasts covet, its
the venerable Bird 43 Thruline wattmeter. The useful RF tool has barely
changed in the nearly 70 years since it was first introduced, and theyre
built like a tank. This makes Bird meters highly desirable, and therefore
quite expensive either brand new or on the swap-meet circuit.

But radio amateurs are nothing if not resourceful, and building a homebrew version of the Bird wattmeter (in Portuguese; Google translate tool at the bottom of the page) as Brazilian ham [Luciano Sturaro (PY2BBS)] did is a
good way to get your hands on one. Granted, [Luciano] had a head start: a
spare line set, which is the important bit from a Bird wattmeter. The
machined metal part is in effect an air-insulated section of coaxial cable
that the RF signal passes through on its way from transmitter to antenna. A slug is inserted into the cavity in the line set to sense the RF and couple
it to the meter electronics; the slug can be rotated to measure RF
traveling in either direction, allowing the user to determine how much RF
is getting reflected by the antenna system.

[Luciano]s version of the meter is faithful to the sturdy construction of
the original, with a solid steel case that mimics its classic lines the
case even sports the same color scheme and stout leather carry handle.
There are some changes to the electronics, and the meter movement itself is different from the original, but all in all, the Buzz 50 looks fantastic.
We especially love the detailed nameplate as an homage to Bird.

The thing about Bird and Bird-like meters is that the slugs are like
potato chips; you cant have just one. Curious as to how these slugs work?
Check out this slug repair project.

[Featured image of Bird 43 Wattmeter: Martin RF Supply]

Thanks to [Niko Huenk] for the tip!

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)