gt;
>Subject: Re: [Elecraft] K2: KPA100 fan issue + current question
>
>Not at all unusual for the currents to be different on different bands.
>
>Since most power meters are voltage sensing devices, the value of the
>dummy load will affect the power indication. Thus as the R
:37 AM
To: Jim KO5V , Bob McGraw K4TAX , Elecraft
List
Subject: Re: [Elecraft] K2: KPA100 fan issue + current question
Jim,
That 11 amps would sound more reasonable to me if you can say that the
base K2 is being powered separately, but I would expect something closer
to 50% efficiency rather than
at 50W or so
and see what happens.
73, Jim KO5V
-Original Message-
>From: Don Wilhelm
>Sent: Nov 9, 2018 5:15 PM
>To: Jim KO5V , Bob McGraw K4TAX ,
>Elecraft List
>Subject: Re: [Elecraft] K2: KPA100 fan issue + current question
>
>Jim,
>
>That is normal.
Jim,
That is normal. The Transmit RF Gain varies from band to band, and that
will cause the current draw to vary. I am surprised that 12M is so low,
it is normally on a par with 10 meters.
Part of the RF Gain variation is in the base K2 and some more of it is
in the KPA100.
Remember
O5V , Bob McGraw K4TAX ,
>Elecraft List
>Subject: Re: [Elecraft] K2: KPA100 fan issue + current question
>
>Jim,
>
>That 11 amps would sound more reasonable to me if you can say that the
>base K2 is being powered separately, but I would expect something closer
>to 50%
Efficiency is an interesting point in a linear amplifier. As the linear is
“efficiency” modulated when it is driven to full power output it does in fact
approach the 70% efficiency level of a class C amplifier. Not quite but it
closes in. The 30% to 50% rating a linear amplifier normally
still going to remeasure it with a newer
meter and see if the measurements check.
73, Jim KO5V
-Original Message-
From: Bob McGraw K4TAX
Sent: Nov 9, 2018 10:29 AM
To: Jim KO5V
Cc: Elecraft List
Subject: Re: [Elecraft] K2: KPA100 fan issue + current question
At 13.8 volts, 11amps
: [Elecraft] K2: KPA100 fan issue + current question
>
>At 13.8 volts, 11amps is about 152 watts input. 100/152 = .658 * 100 for about
>66% efficiency.
>
>All in all , looks about right to me. AKA - I wouldn't be concerned.
>
>
>Bob, K4TAX
>
>
>Sent from my iPhone
&
At 13.8 volts, 11amps is about 152 watts input. 100/152 = .658 * 100 for about
66% efficiency.
All in all , looks about right to me. AKA - I wouldn't be concerned.
Bob, K4TAX
Sent from my iPhone
> On Nov 9, 2018, at 10:46 AM, Jim KO5V wrote:
>
> Well, after checking that all of the
report what I find.
Thanks!
73, Jim KO5V
-Original Message-
>From: Don Wilhelm
>Sent: Nov 9, 2018 9:56 AM
>To: Jim KO5V , Elecraft List
>Subject: Re: [Elecraft] K2: KPA100 fan issue + current question
>
>Jim,
>
>I would expect that the current at 100 watts wou
Jim,
I would expect that the current at 100 watts would be closer to 17 or 18
amps.
Has the bias been set correctly for a 400mA rise in PA current with no
RF input? That bias setting will alter the operating class of the
amplifier and it must be correct to be linear.
73,
Don W3FPR
On
Well, after checking that all of the components in the fan circuit were
correct, I decided to follow Don's usual advice about checking my soldering, so
I re-flowed all of their joints. None looked bad, but now the fan works as it
should, so...
I'm still curious about my 11A @ 100W measurement.
I just finished building and testing the KPA100 that goes with K2 #7225. This
kit was a rev C, and I have brought it up to the latest specs. U1 says PA 1.1.
#1: It has passed all of the tests, except it apparently has no low fan speed.
I have set the temperature of the heat sink using CAL tPA,
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