Which meter to trust?
Locked
 
|
Putting my brand new KPA-500 through its paces and I’m noticing a significant difference between the peak power displayed on the amp, and the peak power displayed on a Telepost LP-700 station monitor. With the amp peaking at 500 watts, the LP-700 will often show peaks in the 600+ watt range. The trapezoidal display on the LP-700 does not show any non-linearity during such operations.
Is this then simply a difference in how the power is metered? As always, your collective wisdom is both appreciated and valued. Paul, W2PIR Dare Mighty Things. -Jet Propulsion Laboratory ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
|
|
A man with two watches never knows what time it is
On Fri, Feb 7, 2020, 1:12 AM Paul Braiman via Elecraft < [hidden email]> wrote: > Putting my brand new KPA-500 through its paces and I’m noticing a > significant difference between the peak power displayed on the amp, and the > peak power displayed on a Telepost LP-700 station monitor. With the amp > peaking at 500 watts, the LP-700 will often show peaks in the 600+ watt > range. The trapezoidal display on the LP-700 does not show any > non-linearity during such operations. > > Is this then simply a difference in how the power is metered? > > As always, your collective wisdom is both appreciated and valued. > > Paul, W2PIR > > Dare Mighty Things. > -Jet Propulsion Laboratory > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
|
|
Different metering systems will have different attack and release times. Most won’t be able to follow the voice envelope accurately.
It is best to use steady state carrier when measuring power. 500 watts of carrier is the same as 500 watts PEP. If your transceiver drives the amp to 500 watts output with 20 watts, then the correct drive power for SSB is also 20 watts. The K3S feature of PWR PER BAND is excellent in this regard. 73 Bob, K4TAX Sent from my iPhone > On Feb 7, 2020, at 2:24 AM, Craig Buck <[hidden email]> wrote: > > A man with two watches never knows what time it is > >> On Fri, Feb 7, 2020, 1:12 AM Paul Braiman via Elecraft < >> [hidden email]> wrote: >> >> Putting my brand new KPA-500 through its paces and I’m noticing a >> significant difference between the peak power displayed on the amp, and the >> peak power displayed on a Telepost LP-700 station monitor. With the amp >> peaking at 500 watts, the LP-700 will often show peaks in the 600+ watt >> range. The trapezoidal display on the LP-700 does not show any >> non-linearity during such operations. >> >> Is this then simply a difference in how the power is metered? >> >> As always, your collective wisdom is both appreciated and valued. >> >> Paul, W2PIR >> >> Dare Mighty Things. >> -Jet Propulsion Laboratory >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
|
|
In reply to this post by Elecraft mailing list
Normally, I would think maybe a transient power issue, due to ALC overshoot
or poor 110/220 volt mains regulation. I don't think the latter would be the case with a KPA500. The LP-700 is very fast, and will respond to very short transients of power. You can slow the meter response down using the Peak Resp(onse) setting in SETUP if you like. I assume that you have the K3 power set to just enough to drive the amp to 500 watts. I like to use a small amount of CMP (6-10 dB) to set a stable upper limit, and then set drive to just at the threshold of ALC. Larry N8LP -- Sent from: http://elecraft.365791.n2.nabble.com/ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
|
|
I periodically (year or two) see power overshoots on my K3/KPA500, and
running TX CAL a couple of times fixes it. 73 Eric WD6DBM ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
«
Return to Elecraft
|
1 view|%1 views
| Free forum by Nabble | Edit this page |