|
VE2HAR > MT63 12.03.05 23:31l 91 Lines 2625 Bytes #-7309 (0) @ WW
BID : 41165SENTTO
Read: GUEST
Subj: Re: [MT63] Crest Factors
Path: DB0FHN<DB0CL<DB0PDF<DB0SM<PI8DAZ<DB0ACC<DB0GOS<ON0AR<ON0AR<VA2HAR<
VE2HAR
Sent: 050312/2227z @:VE2HAR.#MTL.QC.CAN.NOAM Laval #:41845 $:41165sentto
At 02:09 PM 3/12/2005, karl larsen wrote:
>Mark Miller wrote:
>
> >Karl,
> >
> >My setup is a Bird 4431 (model 43 with a sampling port)
> >
> Sorry I do not know that Bird 4431. What is the bandwidth of the
>sampled data? And what is it sampling? Is it sampling the power or the
>voltage?
You do know what a Bird model 43 is don't you? The 4431 has a power sample
output that is adjustable from -15 to -70 dB. It is a directional
coupler. The frequency range is from 2 to 1000 MHz.
> I assume you have a dummy load on your Bird watt meter. I did some
>peak power measurements using my Heathkit Antenna. It has a diode that
>picks off the voltage across the resistor which you can hook a scope to.
>It is quite accurate I found from testing.
>
> With the antenna it would be easy to measure the difference from the
>resting power with the transmitter turned on, and then the peak power
>with data flow.
What is this resting power? Please define.
> > and a Tektronics
> >2225 scope. I first calibrate my scope. I use a single tone to set the
> >output of my IC-746pro to 40 watts as shown on the Bird, then adjust the
> >trace on the scope for some convenient deflection. I ended up with 4
> >gradicules peak to peak. Then I fire up MT63. Since crest factor is Peak
> >voltage/RMS voltage,
> >
>Nope. The Crest factor is a Power measurement. And peak voltage is
>defined as the peak of the sine wave.
I disagree with you. The definition of crest factor is the peak-to-rms
voltage ratio of an alternating current (ac) signal. The crest factor of a
pure sine wave is 1.414. It is definitely voltage.
> I define peak power as the actual power when MT63 is being modulated
>continuously by digital data.
What do you mean by actual power?
> I'm afraid your measuring something else.
I am afraid you do not understand crest factor.
73,
Mark N5RFX
------------------------ Yahoo! Groups Sponsor --------------------~-->
Listen to Internet Radio! Access to your favorite Artists!
Click to listen to LAUNCHcast now!
http://us.click.yahoo.com/_mKGzA/GARHAA/kkyPAA/CPMolB/TM
--------------------------------------------------------------------~->
<< Try MT63 on 80m - great fun!>>
- The MT63 Reflector -
MT63@egroups.com
(To unsubscribe. send email to
MT63-unsubscribe@onelist.com)
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/MT63/
<*> To unsubscribe from this group, send an email to:
MT63-unsubscribe@yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
Read previous mail | Read next mail
| |