[Elecraft] K3 to IC-7800 Comparison?

[Chester Alderman]

I certainly agree with Joe about Adam! I've never heard such prejudicial
explanations trying to justify Icom's innocence for final transistor
failures in the IC-7700's. He took all reports of final failures and said he
was going to forward them to Icom, but very few of us ever believed he
actually forwarded any information to Icom from IC-7700 users about the
failures. And IF did, there was never any response from Japan.
I sold my IC-7700, not because the finals failed, but because the threat of
failure was there every time I turned that radio ON.

73,
Tom - W4BQF


-----Original Message-----
From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Joe
Subich, W4TV
Sent: Sunday, September 13, 2015 8:09 AM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K3 to IC-7800 Comparison?

On 9/13/2015 2:10 AM, Jim Brown wrote:
> He seems quite genuine, no horses in the race, his objectives seem to 
> be the same as Rob Sherwood and my own -- to put mfrs feet to the fire 
> to improve the receive performance and signal quality of the stuff 
> they sell us. :)

Adam is an out an out Icom evangelist - not exactly unbiased.

> An example is in the footnote for the Flex-6700, which has no 
> preselector for the range where he had to do his measurements, which 
> may have caused that radio to measure worse than it would on the ham 
> bands.

On the other hand Adam limits noise power for direct sampling SDR designs to
a lower level than used with traditional up/down conversion transceivers.
The lower noise power input gives the direct sampling designs an unfair
advantage be ignoring strong signal environments.

73,

   ... Joe, W4TV


On 9/13/2015 2:10 AM, Jim Brown wrote:
> On Sat,9/12/2015 2:12 PM, Skip Cameron wrote:
>> If anyone has done a K3 to IC-7800 comparison,
>
> Here's another VERY interesting set of RX measurements. The Noise 
> Power Ratio (NPR), is essentially a measure of how broadband noise and 
> QRM outside the passband show up inside the passband. It combines the 
> effects of phase noise and various forms of non-linearity in the RX 
> system. First study the methodology, then the data. Big numbers are 
> better. :)
>
> http://www.ab4oj.com/test/docs/npr_test.pdf
>
> The guy who did this work is Adam Farson, VA7OJ, AB4OJ, an EE retired 
> from a career in telecom, now living in Vancouver, BC. He spoke to our 
> local ham club last weekend, and his presentation was quite interesting.
> Several of us had dinner with him. He seems quite genuine, no horses 
> in the race, his objectives seem to be the same as Rob Sherwood and my 
> own
> -- to put mfrs feet to the fire to improve the receive performance and 
> signal quality of the stuff they sell us. :)
>
> There's an important caveat to his work. The NPR measurements require 
> very sophisticated band-stop filters in his instrumentation setup, and 
> based on the filters he has been able to source, that limits the 
> frequency range where he can do his measurements. An example is in the 
> footnote for the Flex-6700, which has no preselector for the range 
> where he had to do his measurements, which may have caused that radio 
> to measure worse than it would on the ham bands.
>
> 73, Jim K9YC
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