Re: [Elecraft_K3] upgraded synthesizers more quiet ?


Rob Sherwood
 

Hi Dave,

 

Quote: I just state all that to say that there is definitely more to daily operation than the Sherwood rating alone. 

 

Of course this is true.  Lab measurements can never approximate CQ WW !  I say this every time I give a presentation.

Using a radio in daily operation or in contests / DX pileups is very important to see how they perform in the heat of battle.

Often (if not usually) reciprocal mixing dynamic range (RMDR – phase noise) dominates over the dynamic-range (DR3 – third-order product)  measurement.

 

That is why the 7800 / 7700 or the TS-990S sort lower than some other radios by 2-kHz measurements.

Is the Flex 1500 a competition radio?  Of course not.

The K3 (or K3S) with the new synth is no longer RMDR limited, as the improvement in phase noise is 15 to 20 dB, and the new synth is also NOT microphonic like the old one. In a multi-transmitter environment this is huge.  (Multi-Multi, Multi-2, Field Day, ham down the street)

 

The KX3 sorted higher than the original K3 simply because the phase noise of the KX3 is better than the old K3 synthesizer. Is the KX3 better in a CW pileup than the original K3?  No it is not.

 

There no one metric that can quantify a radio.  Close-in DR3 numbers, however, can sort out some really poor performers.  The FTdx-1200 comes in at 70 dB for DR3, like almost all the up-conversion radios that came out from 1990 – 2002.  That is disappointing.  Its RMDR values aren’t very good either.

 

Lots of things are important:  Clean receive audio, clean transmit IMD (hard to find), an AGC that doesn’t go nuts with impulse noise (clicks, ticks and pops), no ALC overshoot problem, ergonomics, reliability, factory service, long term factory support after the radio goes out of production, etc.  The list goes on as to the big pictures when it comes time to choose a radio. 

 

73,

Rob Sherwood

NC0B

 

 

 

From: Elecraft_K3@... [mailto:Elecraft_K3@...]
Sent: Saturday, May 16, 2015 4:05 PM
To: Elecraft_K3@...
Subject: Re: [Elecraft_K3] upgraded synthesizers more quiet ?

 

 

Interesting.... But that rating puts it high based on narrow spaced 3rd order IMD. T

 

hat may be important in some situations. But it also ranks my lowly Flex-1500 higher that an IC-7700 or IC-7800. I can tell you from personal experience, every day in my shack, that while I enjoy all of my different radios, there is no comparison between the Flex-1500 and my IC-7700. Most of the time I run my K3 in tandem with the IC-7700. I like all of my radios. But if push came to shove, I'd probably have to go with the Icom. Tough decision because the K3 is also terrific. 

 

I just state all that to say that there is definitely more to daily operation than the Sherwood rating alone. 

 

I was just notified that my pair of new synths were just shipped from Elecraft. It will be interesting to see if they quiet the K3 down to the level of the IC-7700. Some hams on 40m have stated that the new synths almost completely remove the low level hash from the P3 display. We'll see...

 

73 de Dave, N7AIG

Dr. David McClain

Tel: (+1) 520-529-2437

 


On May 15, 2015, at 21:21, Phil Wheeler w7ox@... [Elecraft_K3] <Elecraft_K3@...> wrote:

 

Yes.  Look here: http://www.sherweng.com/table.html

Phil W7OX

On 5/15/15 6:31 PM, medical35@... [Elecraft_K3] wrote:

 

I have two K3's. My main K3 is serial number 63XX.
Would the RX be any quieter if I upgraded synthesizers or would it not have anything to do with it?
I also have a KX3 and it's a lot quieter on RX than my K3. Signals just as loud as K3 just a lot less QRN.
I don't even have to roll the RF gain back any the KX3 is so quiet.
The serial number on the KX3 is 69XX.
Thanks
Jim K4KOR

 

 

 


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