Hi Ed,
You are right... I think the best solution is to get hold of this good
accurate QRP Wattmeter :)
It will also save my accumulator and make the portable operation longer and
more pleasant!
Why burn up useful watts into an attenuator? :) They can be used far better
than that!
72/73 / Mats
2006/9/12, Ed - K9EW <k9ew57@gmail.com>:
>
> Don't forget that an attenuator will also be in the line for the
> Receive mode. A few db won't be noticeable, but 10db might be.
>
> 72/73,
> ed - k9ew
>
> On 9/12/06, Mats Strandberg <sm6lrr@gmail.com> wrote:
> > Hello Jerry,
> >
> > Thank you indeed for all useful information. I should remember all those
> > things from physics classes, but I have been into sales of building
> > materials all my life, so you needed to refresh my memory :)
> >
> > Best regards,
> > Mats
> >
> >
> > 2006/9/12, Dr. Gerald N. Johnson <geraldj@storm.weather.net>:
> > >
> > > On Tue, 2006-09-12 at 15:27 +0200, Mats Strandberg wrote:
> > > > Hello!
> > > >
> > > > I am the happy owner of a Ten-Tec 509 that according to the manual
> > > should be
> > > > capable of delivering 3 Watts RF Output.
> > > >
> > > > In the Swedish Portable Contest, there is a Power Multiplier that
> > > demands
> > > > the RF output to be less than 1 Watt.
> > > >
> > > > Can anyone supply me with information of suitable Power attenuators
> that
> > > > could be used to reduce the 3 Watts down in several steps, for
> example
> > > > 1,5W/1W/500mW/100mW?
> > > >
> > > > Thanks in advance for any possible help.
> > > >
> > > > SJ6R - Mats
> > >
> > > There are tables of attenuator resistor values in many radio
> handbooks,
> > > ARRL and some RSGB included and sometimes formulae for designing them.
> > > Use 2 watt metal film resistors and they will handle all your power.
> > >
> > > You need 3 dB to get from 3 to 1.5 watts, 5 dB to get from 3 to 1
> watt,
> > > 3 dB more to get from 3 watts to 1/2 watt and ten dB to get from 1 w
> to
> > > 0.1 watt. All can be cascaded in any order so long as all are built
> with
> > > 2 watt resistors.
> > >
> > > The closer you match the resistor values to the computed values, the
> > > more accurate the attenuation will be, so looking for closer precision
> > > than 20% tolerance resistors can help that precision. I worked up
> > > computer programs once for picking attenuation values using standard
> > > value resistors and trimming impedance with more than one resistor in
> > > the center element of the T, but its in CP/M and hard to access these
> > > days.
> > > --
> > > 73, Jerry, K0CQ,
> > > All content copyright Dr. Gerald N. Johnson, electrical engineer
> > >
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> > >
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