Featured: Coaxial Dynamics 82009 Wattmeter Element (2-30 MHz, 2,500 W) at DX Engineering.
This is an affiliate link: Hood's Finds may earn a commission from DX Engineering at no extra cost to you. We have not tested this product; the specifics below come from the product listing.
Plenty of amplifier benches have a plug-in element wattmeter on them, often a Bird Model 43 bought used years ago. These meters are simple and durable, but the meter body alone does not measure anything. The plug-in element decides the frequency range and the full-scale power, so the right element matters as much as the meter. The Coaxial Dynamics 82009 is an HF element made for exactly this kind of meter.
What the 82009 is
DX Engineering lists the 82009 as a wattmeter element, plug-in, 2-30 MHz, 2,500 W, sold individually. Coaxial Dynamics describes it as a standard plug-in element for its own wattmeters, and says the calibration is for any 30 microampere full scale meter movement, including Bird Model 43 and Coaxial Dynamics meters, so the elements may be used interchangeably.
The listing also says the elements are calibrated for interchangeability with Coaxial Dynamics and Bird Electronic RF power instruments in the 7/8 in. line size, whether the meter was purchased today or 20 years ago. Element accuracy is maintained by calibrations using NIST traceable RF Power Standards, and each element carries a Coaxial Dynamics Two Year Limited Warranty.
How a plug-in element meter works
An element wattmeter is directional. The element sits in a line section between the amplifier and the load and responds to power travelling one way through the line. Turn the element around and the same meter reads power travelling the other way. That is how one meter gives you both forward and reflected power, and from those two readings you can judge how well the load is matched.
Because the element sets the full-scale reading, an HF element covering 2-30 MHz with a 2,500 W full scale suits testing a legal-limit amateur amplifier into a dummy load, with headroom above the power you expect to see.
Choosing and using elements
- Match the element to the job. A high-power element is right for full output, but low readings sit near the bottom of its scale where they are harder to read. Many owners keep a lower-power element as well for drive levels and reflected power.
- Check the frequency range. An element is only meant for the range marked on it, so use an HF element for HF work.
- Test into a dummy load. A proper dummy load gives a steady, known load for output measurements and keeps signals off the air.
- Keep connections sound. Worn connectors and poor jumpers can upset readings and heat up at high power.
Worth knowing before you buy
This is an element only, not a complete meter, so it is for people who already own a compatible plug-in meter or plan to buy one. Check that your meter uses the same line size and meter movement described above before ordering.
And a reminder whenever amplifier power is discussed: external linear amplifiers are not legal for use on CB radio. Accurate power measurement belongs in any licensed amateur station and on any repair bench.
Where to get it
Check current price and availability: Coaxial Dynamics 82009 Wattmeter Element (2-30 MHz, 2,500 W) at DX Engineering.
This is an affiliate link: Hood's Finds may earn a commission from DX Engineering at no extra cost to you. More picks on the gear page.
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