[Yaesu] Fwd: RF Metering

[Dr. Gerald N. Johnson]

A rig showing 30 to 40% power on an average reading wattmeter is 
clipping, its being over driven. Should should be more like 20 to 25% of 
peak though that will depend on the voice, the microphone, and the SSB 
filter and their relative phase responses. Some combinations will do 
better, some will do worse.

73, Jerry, K0CQ

On 6/5/2011 11:36 AM, Bob wrote:
>
>
>
> -----Original Message-----
> From: Rob Atkinson<robk5uj at gmail.com>
> To: Bob<kc3vo at aol.com>
> Sent: Sun, Jun 5, 2011 11:41 am
> Subject: Re: [Yaesu] RF Metering
>
>
> Bob, I don't want to be the sole beneficiary of this; I suggest you
> share it with the entire Yaesu email list.
>
> 73
>
> Rob
> K5UJ
>
>
> On Sun, Jun 5, 2011 at 9:38 AM, Bob<kc3vo at aol.com>  wrote:
>
> The better "Peak-Reading" RF power meters use a DIODE detector, and
> store/hold the peak RF level, so it CAN be reasonably accurately
> displayed on an analog meter. A 100 watt SSB rig will typically show
> only 30 to 40 watts, if properly adjusted for 100 watt peak SSB voice
> power, when the power is measured by a thermocouple type CW power
> meter, or a diode type CW power meter, without the PEAK circuit.  A
> meter such as the bird #43P,  set to indicate PEAK power, will
> accurately show the power as 100 watts, and will also show a 100 watt
> CW level as 100 watts, without changing any meter settings.  (With a CW
> signal, the PEAK and AVERAGE power levels are the same-It STAYS at its
> PEAK level) The electronic circuitry holds the peaks long enough for
> the mechanical meter to display them.  (This is why the PEAK meters
> require a battery or power supply)--73, KC3VO-Bob Curry
>
>
>
>
> -----Original Message-----
> From: Rob Atkinson<robk5uj at gmail.com>
> To: Bob<kc3vo at aol.com>
> Cc: david.kirkby at onetel.net; yaesu at mailman.qth.net
> Sent: Sun, Jun 5, 2011 8:19 am
> Subject: Re: [Yaesu] RF Metering
>
>
> Well certainly the power being measured is carrier power or some
> continuous wave perhaps generated in SSB mode by a tone at a level the
> same as peak voice amplitude.  An electro-mechanical meter's ballistics
> won't allow for measuring the peak power from a speaking voice.   And
> always to this measuring into a 50 ohm resistance-J0 load, or whatever
> characteristic transmitter output and feedline Z the system is.
>
> 73
>
> Rob
> K5UJ
>
>
>