I have measured the Cantenna with 4 different ohmmeters, HP-410B,
HP-410C, a DVM, and VIZ multimeter. They all read the same, +/- 1 ohm.
Who knows what the Cantenna has been subjected to. I bought it at a
hamfest several years ago.
David
KW4DH
Steve Katz wrote:
> Yep, there is. An accurate power measurement with the model 43 is P(actual)
> = Pf (indicated) - Pr (indicated). With a 70 Ohm load you should have a VSWR
> of 1.4, a return loss of about 15.6 dB, or about 3% reflected power, so the
> Bird should read "high" by about 3% when viewing indicated Pf.
>
> But I'd look into why the load measures 70 Ohms! Check your Ohmmeter if you
> can to verify its accuracy, and if that seems good, probably the load's been
> overheated and the resistor should be replaced.
>
> WB2WIK/6
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]On
> Behalf Of David C. Hallam
> Sent: Wednesday, December 02, 2009 9:16 AM
> To: AMPS List
> Subject: [Amps] Dummy Loads & Wattmeters
>
>
> A little education, please.
>
> I am working on restoring an old transceiver and linear. I have a Bird
> 43 wattmeter and a Heath Cantenna dummy load. The wattmeter is for 50
> ohm impedance and I measure the DC resistance of the Cantenna at 70 ohm.
>
> Is there any effect on the wattmeter reading from this mismatch?
>
> David
> KW4DH
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