[Elecraft] FTDX5000 Design Flaw

[Wes (N7WS)]

This is why that on more than one occasion over the years I've said (only 
semi-facetiously) that the two-tone testing of the receiver portion of a 
transceiver should be performed using two other like transceiver transmitters, 
running rated output power, as the two test tones. When our transmitters are as 
pure as HP-8663s then we can go back to using them for receiver testing.

Wes  N7WS


  On 8/31/2014 3:40 PM, Jim Brown wrote:
> On Sat,11/20/2010 12:48 PM, John, KI6WX wrote:
>> The ARRL is aware of this issue.  This problem was discussed in my 1988
>> articles on phase noise in QST (March & April issues).  The article notes
>> that a high phase noise transmitter degrades the performance of a low phase
>> noise receiver to that of the transmitter.  This article started the ARRL
>> making composite transmit noise measurements.
>
> I've recently added fuel to the fire with an online document plotting ARRL TX 
> data for multiple radios on the same graphs, making comparison's easier. I did 
> that by taking data point by point off of ARRL's published plots, then putting 
> them in my own spreadsheet. I did that for both keying spectra and phase noise.
>
> Seeing that document, Bob Allison sent me the raw data for the CW keying 
> spectra for those radios, and I've been processing and plotting that data. He 
> was not able to provide the phase noise data in electronic form, so we're 
> stuck with what I am able to eyeball from the published plots.
>
> You can see an "in-progress" version at k9yc.com/TXNoise.pdf
>
> 73, Jim K9YC
>