[Elecraft] KX3 Amp

[Igor Sokolov]

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" <lx2ao at pt.lu>
To: "Igor Sokolov" <ua9cdc at gmail.com>
Cc: "Elecraft Discussion List" <elecraft at mailman.qth.net>
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
>