[Elecraft] K4 pre-distortion?

[Roger]

-----Original Message-----
From: elecraft-bounces at mailman.qth.net [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Dave
Sent: Sunday, June 16, 2019 8:40 AM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K4 pre-distortion?

In a word yes. Given that in order to match the RX performance of my existing K3/P3 (dual RX, K3S synths) it would require me to purchase the most expensive K4 version, then to me the only possible advantages over my
K3 would be improved SSB TX IMD and improved RX DSP noise reduction.

---------------------------Any numbers out about TX IMD of the K4?

The K3 noise reduction is very poor, I have never found it useful on SSB, and certainly not on CW. The K3 TX SSB 3rd/5th/7th/9th IMD products spread very wide and resemble a felled Christmas tree laid on its side. So a significant improvement in these areas is where the K4 needs to start.

---------------------------True - there are much better noise reduction algorithms around these days. The noiseblanker in the K3/K3S needs some revision too! TX IMD in the K3S (can´t speak of the K3) can be improved somewhat by increasing the bias however what is possible with a pair of RD100HHF final transistors @ 13,8 VDC is clearly demonstrated by the TS-590 and the new TS-890 by Kenwood (I am not a Kenwood promoter or fan but a clean signal promoter!). Even with increased bias the K3S is not as good............................

Reading between the lines on both the Elecraft FAQs and this list, from the lack of an official mention of pre-distortion or improved TX IMD, I take it to mean the provision is a possible future upgrade and not included initially. Kinda like Icom including a frequency reference input socket on the IC9700 and buyers (incorrectly) assuming the IC9700 locks to an external reference (which it doesnt).

--------------------------Amplifier manufacturers and radio manufacturers alike seem to have accepted that predistortion is the future however only ONE manufacturer so far has implemented it as soon as the algorithm became available for Ham Radio. Other than that it is easy and inexpensive to add an additional sampler in the output of an amplifier and/or an extra jack on a radio and label it RF SAMPLE OUTPUT/INPUT. For the moment it is more marketing than technical necessity

73 Roger, DL5RBW

73 Dave

>On Sat, 15 Jun 2019 at 12:31, Michael >Walker wrote:

> >Would having if be a deal breaker?
> >
> >Mike
> >
> >Sent from my iPad
>
>
> --
Sent from my iPhone SE
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