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KPA-1500 power reading ?

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Ed Stallman-2

KPA-1500 power reading ?

The KPA1500 is new to me and very happy with my purchase . I'm using the
LP-100A watt meter and comparing it with the KPA-1500 they both read
close enough 10 to 160 . On 6m I'm seeing a bigger spread with the
LP-100A reading 1500w the KPA-1500 is showing 1375w . If you look at
this in DB , it's nothing. I know the LP-100A is very accurate and the
only way to know for sure is to have Larry at Telepost test it. Most
likely wont do wont do that. Are their others that see a difference on 6m ?

Thanks Ed N5DG

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Lou W0FK

Re: KPA-1500 power reading ?

Ed Stallman-2 wrote

> The KPA1500 is new to me and very happy with my purchase . I'm using the
> LP-100A watt meter and comparing it with the KPA-1500 they both read
> close enough 10 to 160 . On 6m I'm seeing a bigger spread with the
> LP-100A reading 1500w the KPA-1500 is showing 1375w . If you look at
> this in DB , it's nothing. I know the LP-100A is very accurate and the
> only way to know for sure is to have Larry at Telepost test it. Most
> likely wont do wont do that. Are their others that see a difference on 6m
> ?
>
> Thanks Ed N5DG

I have the same setup Ed (KPA1500/LPA-100A). I've always seen a difference,
and never really paid much attention to it. When I read your email I ran
some very quick and dirty tests, here's what I'm seeing:

80M: LPA -- 1322, KPA1500 -- 1513
40M: LPA -- 1325, KPA1500 -- 1504
6M: LPA -- 1345, KPA1500 -- 1550

Pretty consistent with your 6M readings. Are you seeing much closer numbers
than mine?

73, Lou W0FK

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Ed Stallman-2

Re: KPA-1500 power reading ?

Lou , just checked again on the HF bands

80m LPA=1495 and KPA=1501

40m LPA=1476 and KPA=1421

6m LPA=1512 and KPA=1325

This is not concerning to me at all . My curiosity and a cold rainy told
me to see how others compared . I suspect this is the case with any two
watt meters . I know it's adjustable in the KPA 1500 but I'll not bother
. Thanks everyone for ur reply .

73 Ed N5DG

On 2/5/2021 5:06 PM, Lou W0FK wrote:

> Ed Stallman-2 wrote
>> The KPA1500 is new to me and very happy with my purchase . I'm using the
>> LP-100A watt meter and comparing it with the KPA-1500 they both read
>> close enough 10 to 160 . On 6m I'm seeing a bigger spread with the
>> LP-100A reading 1500w the KPA-1500 is showing 1375w . If you look at
>> this in DB , it's nothing. I know the LP-100A is very accurate and the
>> only way to know for sure is to have Larry at Telepost test it. Most
>> likely wont do wont do that. Are their others that see a difference on 6m
>> ?
>>
>> Thanks Ed N5DG
> I have the same setup Ed (KPA1500/LPA-100A). I've always seen a difference,
> and never really paid much attention to it. When I read your email I ran
> some very quick and dirty tests, here's what I'm seeing:
>
> 80M: LPA -- 1322, KPA1500 -- 1513
> 40M: LPA -- 1325, KPA1500 -- 1504
> 6M: LPA -- 1345, KPA1500 -- 1550
>
> Pretty consistent with your 6M readings. Are you seeing much closer numbers
> than mine?
>
> 73, Lou W0FK
>
>
>
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
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Jim Brown-10

Re: KPA-1500 power reading ?

In reply to this post by Ed Stallman-2

On 2/5/2021 10:22 AM, Ed Stallman wrote:
> I'm using the LP-100A watt meter and comparing it with the KPA-1500 they
> both read close enough 10 to 160 . On 6m I'm seeing a bigger spread
> with the LP-100A reading 1500w the KPA-1500 is showing 1375w .

I also have an LP100A inline between my amp and my antenna switching.
What coax is between the amp and the LP100A, and how long is it? The
loss in this cable increases with frequency. Also, I believe that the
KPA1500 reads power on the amplifier side of the tuner, and it's not
lossless. I nearly always see a fractional dB between them.

73, Jim K9YC
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Ed Stallman-2

Re: KPA-1500 power reading ?

Jim, using 4ft of low loss Davis RF Bury Flex between LPA and KPA , 6m
is the one band with the biggest difference , KPA1500 reading 125 to 150
watts less . I've decided with the LP-100A in better line of site , I'm
going with it .

Ed N5DG

On 2/5/2021 6:52 PM, Jim Brown wrote:

> On 2/5/2021 10:22 AM, Ed Stallman wrote:
>> I'm using the LP-100A watt meter and comparing it with the KPA-1500
>> they both read close enough 10 to 160 . On 6m I'm seeing a bigger
>> spread with the LP-100A reading 1500w the KPA-1500 is showing 1375w .
>
> I also have an LP100A inline between my amp and my antenna switching.
> What coax is between the amp and the LP100A, and how long is it? The
> loss in this cable increases with frequency. Also, I believe that the
> KPA1500 reads power on the amplifier side of the tuner, and it's not
> lossless. I nearly always see a fractional dB between them.
>
> 73, Jim K9YC
> ______________________________________________________________
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Bill K9YEQ

Re: KPA-1500 power reading ?

In reply to this post by Ed Stallman-2

I accept differences do to cable lengths and different points of monitoring. No two will ever be the same when sampling rf at different points. Unless all connections and cables are perfectly perfect "-)

Bill
K9YEQ

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of Ed Stallman
Sent: Friday, February 5, 2021 12:23 PM
To: [hidden email]
Subject: [Elecraft] KPA-1500 power reading ?

The KPA1500 is new to me and very happy with my purchase . I'm using the LP-100A watt meter and comparing it with the KPA-1500 they both read close enough 10 to 160 . On 6m I'm seeing a bigger spread with the LP-100A reading 1500w the KPA-1500 is showing 1375w . If you look at this in DB , it's nothing. I know the LP-100A is very accurate and the only way to know for sure is to have Larry at Telepost test it. Most likely wont do wont do that. Are their others that see a difference on 6m ?

Thanks Ed N5DG

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Ron Manfredi

Re: KPA-1500 power reading ?

I see something similar with my (non-Elecraft) amp. The amp's display
matches a Bird 43 I had connected with a 12 inch cable from the amp and
then goes into an accurate 50 Ohm dummy load. I usually do not leave
the Bird in-line, but had this set up for testing the amp when I first
got it.

The remote LP100 sensor I have is actually on a cable that is about 3
feet from the amp and it usually reads HIGHER than the amp does, even
into the same dummy load.

Ron WA2EIO

On 2/5/2021 10:48 PM, Bill Johnson wrote:

> I accept differences do to cable lengths and different points of monitoring. No two will ever be the same when sampling rf at different points. Unless all connections and cables are perfectly perfect "-)
>
> Bill
> K9YEQ
>
> -----Original Message-----
> From: [hidden email] <[hidden email]> On Behalf Of Ed Stallman
> Sent: Friday, February 5, 2021 12:23 PM
> To: [hidden email]
> Subject: [Elecraft] KPA-1500 power reading ?
>
> The KPA1500 is new to me and very happy with my purchase . I'm using the LP-100A watt meter and comparing it with the KPA-1500 they both read close enough 10 to 160 . On 6m I'm seeing a bigger spread with the LP-100A reading 1500w the KPA-1500 is showing 1375w . If you look at this in DB , it's nothing. I know the LP-100A is very accurate and the only way to know for sure is to have Larry at Telepost test it. Most likely wont do wont do that. Are their others that see a difference on 6m ?
>
> Thanks Ed N5DG
>
>
> ______________________________________________________________
> Elecraft mailing list
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>
> 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]
> ______________________________________________________________
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>
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