[Elecraft] K3S QST Article

[Kevin]

Yaesu's secret was the ARRL. Unless things have changed they test at one 
frequency and assume the other bands produce the same results.

I'll reverse the question, what has Yaesu done to rigs since 1991 that 
they can't reproduce those numbers?


On 10/14/2016 10:03 PM, Dave Hachadorian wrote:
> Yaesu FT-990, 12V finals
> 3rd order TX IMD  -38dB
> ARRL Review 11/91
>
> ARRL heaped glowing praise upon this rig way back in 1991 for its
> Tx IMD performance.  So, what was Yaesu's secret, and why haven't 
> manufacturers figured it out and capitalized on it ever since?
>
> Dave Hachadorian, K6LL
> Yuma, Arizona
>
>
> -----Original Message----- From: Kevin
> Sent: Friday, October 14, 2016 5:14 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] K3S QST Article
>
> The cause for this is the use of 12V finals. It would be much
> improved
> by moving to 24 or 50V finals.
>
> Move the /K3s II/ to 50V finals, say a pair of MRF 150's, limited
> to 150
> or 200W max output. Design/Sell an outboard 50V switching supply
> capable
> of 15-20A continuous current, with a 10A 12V switcher built in
> for the
> rest of the radio.
>
>
> On 10/14/2016 1:33 PM, Bill Leonard N0CU wrote:
>> I would not expect the synthesizer (old or new) to be a
>> contributor the IMD
>> issue. Hopefully someone will correct me if that is a bad
>> assumption. To me,
>> the primary issue appears to be the linearity of the two RF
>> power
>> amplifiers.
>>
>>
>

-- 
R. Kevin Stover
AC0H
ARRL
FISTS #11993
SKCC #215
NAQCC #3441


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