High Tx IMD with new K3s/10

[Benny Aumala-2]

The only measurements I have seen are from N0CU:

1W        -36dB

4W        -31dB

4,5W    -33dB

6W        -34dB

8W        -25dB

10W        -21dB

Several anwers said this IS NOT normal.

Are there measures which ARE normal?

I am looking for a midway 4...6W values to feed

kW amplifier without additional 100W PA.

Benny   OH9NB


______________________________________________________________
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]

[Bill W4ZV]

Running DC input voltage close to the specified limit of 15.0 V will improve IMD.  Perhaps the results you posted were with lower input voltage.

73,  Bill  W4ZV

[Bill Leonard N0CU]

Benny,

I recently had Elecraft replace a KLPA3A again. They also did the Tx IMD mod and an alignment.
I am now seeing the following 3rd order IMDs:

4W   -40 dBc
8W   -40 dBc
9W   -35 dBc
10W -30 dBc
12W -20 dBc

What is also encouraging is that now the higher order IMDs (5, 7 & 9th) stay at least 10 dB below the 3rd.
Some of these were equal or higher than the 3rd last summer when I was discussing the problem with Elecraft. Obviously they have made some notable improvements since then.
The two tone envelope still looks more like a square wave at 12W, but this radio is spec'd as a 10W transmitter that is clean to -30 dBc, so it appears they are now meeting their advertised spec.

Bill  N0CU

[Robert Nobis - N7RJN]

Bill,

Just wondering, how are yu measuring Tx intermods?

73,


Bob Nobis
[hidden email]

> On Feb 24, 2017, at 16:24, Bill Leonard N0CU <[hidden email]> wrote:
>
> Benny,
>
> I recently had Elecraft replace a KLPA3A again. They also did the Tx IMD mod
> and an alignment.
> I am now seeing the following 3rd order IMDs:
>
> 4W   -40 dBc
> 8W   -40 dBc
> 9W   -35 dBc
> 10W -30 dBc
> 12W -20 dBc
>
> What is also encouraging is that now the higher order IMDs (5, 7 & 9th) stay
> at least 10 dB below the 3rd.
> Some of these were equal or higher than the 3rd last summer when I was
> discussing the problem with Elecraft. Obviously they have made some notable
> improvements since then.
> The two tone envelope still looks more like a square wave at 12W, but this
> radio is spec'd as a 10W transmitter that is clean to -30 dBc, so it appears
> they are now meeting their advertised spec.
>
> Bill  N0CU
>
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/High-Tx-IMD-with-new-K3s-10-tp7627317p7627339.html
> Sent from the Elecraft mailing list archive at 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]
>

______________________________________________________________
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]

[Benny Aumala-2]

Thank you Bill,

You made my day.

When K3s is driving my JUMA PA1000 without 100W PA, the drive is

better than excellent up to 8W.

I need 2W for 600W clean output (-40dB) in SSB.

For CW 4W is enough for a 1000W output (measured with LP100 power meter).

Juma use this active element, and here are some interesting measurements
for 144MHz:

http://www.nxp.com/products/rf/rf-power-transistors/rf-broadcast-and-ism/144-148-mhz-

1250-w-cw-50-v-2-meter-amateur-reference-design:RDMRFE6VP61K25H_2M_AMATEUR?fpsp=1&tab=Documentation_Tab

Benny   OH9NB

==============================================

Message: 6
Date: Fri, 24 Feb 2017 16:24:11 -0700 (MST)
From: Bill Leonard N0CU<[hidden email]>
To:[hidden email]
Subject: Re: [Elecraft] High Tx IMD with new K3s/10
Message-ID:<[hidden email]>
Content-Type: text/plain; charset=us-ascii

Benny,

I recently had Elecraft replace a KLPA3A again. They also did the Tx IMD mod
and an alignment.
I am now seeing the following 3rd order IMDs:

4W   -40 dBc
8W   -40 dBc
9W   -35 dBc
10W -30 dBc
12W -20 dBc

What is also encouraging is that now the higher order IMDs (5, 7 & 9th) stay
at least 10 dB below the 3rd.
Some of these were equal or higher than the 3rd last summer when I was
discussing the problem with Elecraft. Obviously they have made some notable
improvements since then.
The two tone envelope still looks more like a square wave at 12W, but this
radio is spec'd as a 10W transmitter that is clean to -30 dBc, so it appears
they are now meeting their advertised spec.

Bill  N0CU

______________________________________________________________
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]