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KX3 Amp

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w7aqk

KX3 Amp

Hi All,

To echo Jim Brown's cautionary statement about IMD with the RM Italy HLA
series amps, there is some good info on Tom Rausch's (W8JI) website
concerning the HLA-150. That amp will run up to 150 watts or so, but
according to some testing that Rausch did, if you go much over 100 watts,
the IMD gets pretty marginal! Presumably the HLA-300 have some similar
optimal point below it's maximum capability. Apparently this is not at all
uncommon, particularly with 12 V. amps. Even the K3 loses some of it's IMD
quality if you go over 100 watts, which you can do somewhat.

Dave W7AQK

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Igor Sokolov-2

Re: KX3 Amp

I do not have equipment to accurately measure IMD of my combo of KX3 and HLA
300 Plus. Having said that I drive HLA 300 with 5 w from KX3. It gives me
200 + watt on all the bands. Listening to the radiated signal using TS590
and different antenna reveals that the occupied bandwidth is within the same
boundaries which I have determined by transmitting 100 W from my K3.
Therefore I assumed that IMD of the above mentioned combo is no worth then
30db.

73, Igor UA9CDC

----- Original Message -----
From: "Dyarnes" <[hidden email]>
To: <[hidden email]>
Sent: Monday, March 25, 2013 10:40 PM
Subject: [Elecraft] KX3 Amp

> Hi All,
>
> To echo Jim Brown's cautionary statement about IMD with the RM Italy HLA
> series amps, there is some good info on Tom Rausch's (W8JI) website
> concerning the HLA-150. That amp will run up to 150 watts or so, but
> according to some testing that Rausch did, if you go much over 100 watts,
> the IMD gets pretty marginal! Presumably the HLA-300 have some similar
> optimal point below it's maximum capability. Apparently this is not at
> all uncommon, particularly with 12 V. amps. Even the K3 loses some of
> it's IMD quality if you go over 100 watts, which you can do somewhat.
>
> Dave W7AQK
> ______________________________________________________________
> 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

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Geoffrey Mackenzie-Kennedy-3

Re: KX3 Amp

Hello Igor,

If you want to measure (with useful accuracy) the level of the IMD products
generated by your KX3 and HLA 300 Plus, all that you would need in addition
to your TS590 is a Two Tone (AF) Generator, an AF Spectrum Analyser and your
computer. If you Google Tcube you will find a program called Tcube, which
can be downloaded at no cost. This program will provide you with a Two Tone
Generator and an AF Spectrum Analyzer. The frequency range covered by the
generators and the Spectrum Analyser is 0 to 10 kHz. I have found this
program to be useful when running 3 or 4 tone tests, two of the tones from a
"hardware" generator.

73,

Geoff
LX2AO

On March 25, 2013 at 7:14 PM, Igor Sokolov wrote:

>I do not have equipment to accurately measure IMD of my combo of KX3 and
>HLA 300 Plus. Having said that I drive HLA 300 with 5 w from KX3. It gives
>me 200 + watt on all the bands. Listening to the radiated signal using
>TS590 and different antenna reveals that the occupied bandwidth is within
>the same boundaries which I have determined by transmitting 100 W from my
>K3. Therefore I assumed that IMD of the above mentioned combo is no worth
>then 30db.
>
> 73, Igor UA9CDC

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Don Wilhelm-4

Re: KX3 Amp

There is a 2 Tone generator built into the KX3. See the menu listing
for details.

73,
Don W3FPR

On 3/26/2013 10:59 AM, Geoffrey Mackenzie-Kennedy wrote:

> Hello Igor,
>
> If you want to measure (with useful accuracy) the level of the IMD
> products generated by your KX3 and HLA 300 Plus, all that you would
> need in addition to your TS590 is a Two Tone (AF) Generator, an AF
> Spectrum Analyser and your computer. If you Google Tcube you will
> find a program called Tcube, which can be downloaded at no cost. This
> program will provide you with a Two Tone Generator and an AF Spectrum
> Analyzer. The frequency range covered by the generators and the
> Spectrum Analyser is 0 to 10 kHz. I have found this program to be
> useful when running 3 or 4 tone tests, two of the tones from a
> "hardware" generator.
>

Geoffrey Mackenzie-Kennedy-3

Re: KX3 Amp

Don,

If the output of the 2 Tone generator which is built into the KX3 is
injected into the audio chain before any speech processing circuitry, yes
the internal 2 Tone generator could be used.

73,

Geoff.
LX2AO

On March 26, 2013 at 4:19 PM, Don Wilhelm wrote:

> There is a 2 Tone generator built into the KX3. See the menu listing for
> details.
>
> 73,
> Don W3FPR

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Igor Sokolov-2

Re: KX3 Amp

In reply to this post by Geoffrey Mackenzie-Kennedy-3

Geoff,

Thank you for the idea on how one can measure relative IMD of the amplifier,
I have finally managed to do that with my HLA 300 Plus that I use with KX3.
K3 of my friend was used as the source. Measurements were done with QS1R SDR
receiver.
K3 itself, with 2 tone engaged and running 100 W showed 3dr order IMD at -
28db.
HLA 300 Plus was driven by the same K3 (5W drive) and at the output of
around 180 W (20 m band) showed -25db of the 3rd order IMD. Anything above
200 W makes IMD unacceptable (- 10db at 300W). The situation is a bit better
on lower bands (160 and 80m ) where one can go up to almost 250 W.
Anyway it seems that with 5 W drive and output power of below 200W, HLA 300
Plus can be used on all the bands quite successfully.
I have also modified the amp to work from PTT signal only, and disabled RF
VOX in it.
RF band sensing remained intact.

73, Igor UA9CDC

----- Original Message -----
From: "Geoffrey Mackenzie-Kennedy" <[hidden email]>
To: "Igor Sokolov" <[hidden email]>
Cc: "Elecraft Discussion List" <[hidden email]>
Sent: Tuesday, March 26, 2013 8:59 PM
Subject: Re: [Elecraft] KX3 Amp

> Hello Igor,
>
> If you want to measure (with useful accuracy) the level of the IMD
> products generated by your KX3 and HLA 300 Plus, all that you would need
> in addition to your TS590 is a Two Tone (AF) Generator, an AF Spectrum
> Analyser and your computer. If you Google Tcube you will find a program
> called Tcube, which can be downloaded at no cost. This program will
> provide you with a Two Tone Generator and an AF Spectrum Analyzer. The
> frequency range covered by the generators and the Spectrum Analyser is 0
> to 10 kHz. I have found this program to be useful when running 3 or 4
> tone tests, two of the tones from a "hardware" generator.
>
> 73,
>
> Geoff
> LX2AO
>
>
> On March 25, 2013 at 7:14 PM, Igor Sokolov wrote:
>
>>I do not have equipment to accurately measure IMD of my combo of KX3 and
>>HLA 300 Plus. Having said that I drive HLA 300 with 5 w from KX3. It gives
>>me 200 + watt on all the bands. Listening to the radiated signal using
>>TS590 and different antenna reveals that the occupied bandwidth is within
>>the same boundaries which I have determined by transmitting 100 W from my
>>K3. Therefore I assumed that IMD of the above mentioned combo is no worth
>>then 30db.
>>
>> 73, Igor UA9CDC
>

Geoffrey Mackenzie-Kennedy-3

Re: KX3 Amp

Igor,

Thank you for letting me know that you have managed to make some 3rd Order
IMD measurements on your HLA 300 Plus amplifier, and for the data.

My apology for not replying sooner, I managed to fracture one of my leg
bones (femur) on 30th March and have been in hospital recovering from the
surgery.

Home now :-)

73,

Geoff
LX2AO

----- Original Message -----
From: "Igor Sokolov" <[hidden email]>
To: "Geoffrey Mackenzie-Kennedy" <[hidden email]>
Cc: "Elecraft Discussion List" <[hidden email]>
Sent: Saturday, April 06, 2013 9:16 PM
Subject: Re: [Elecraft] KX3 Amp

> Geoff,
>
> Thank you for the idea on how one can measure relative IMD of the
> amplifier,
> I have finally managed to do that with my HLA 300 Plus that I use with
> KX3.
> K3 of my friend was used as the source. Measurements were done with QS1R
> SDR receiver.
> K3 itself, with 2 tone engaged and running 100 W showed 3dr order IMD
> at - 28db.
> HLA 300 Plus was driven by the same K3 (5W drive) and at the output of
> around 180 W (20 m band) showed -25db of the 3rd order IMD. Anything above
> 200 W makes IMD unacceptable (- 10db at 300W). The situation is a bit
> better on lower bands (160 and 80m ) where one can go up to almost 250 W.
> Anyway it seems that with 5 W drive and output power of below 200W, HLA
> 300 Plus can be used on all the bands quite successfully.
> I have also modified the amp to work from PTT signal only, and disabled RF
> VOX in it.
> RF band sensing remained intact.
>
> 73, Igor UA9CDC