[hpsdr] Pure Signal RF Sampler

[Scott Traurig]

Luke,

See here for more information about PureSignal feedback levels:

https://apache-labs.com/community/viewtopic.php?f=20&t=2384

You can certainly switch coupling methods when operating at 100W and below,
and I noted that in my email. However that requires one to change settings,
and having to change things takes time and can lead to mistakes. It would
all be so much simpler if Elecraft chose to provide a 50dB coupling factor.

On early serial number 200Ds you would have to rely on crosstalk, which
will provide less than optimal results. If it is a later serial number unit
with the Rev. 24 RF board you will actually be relying on an internal
coupled path, so it's a "legit" solution.

Linearization works in all modes. On CW you have to use the non-automatic
"single cal" mode using the two tone test signal to set it up, and its
benefits are minimal.

73,

Scott/w-u-2-o


On Sun, Sep 9, 2018 at 6:00 AM List Mail <mail10 at barefoothorse.com.au>
wrote:

> Scott,
>
> In the SPE 1.5kFA, there is a 60 dB coupler provided for pre-distortion. I
> am using an ANAN-200D transceiver. I have not yet connected the
> pre-distortion cable.
>
> Please clarify for me;
> “It is most unfortunate that Hilberling chose to use a 60dB coupling
> factor. This does, of course, result in a coupled output level of 0dBm at
> 1KW (60dBm). With that configuration, the PureSignal linearization function
> becomes unusable on the ANAN-7000 and -8000 below approx. 100W, which is
> the point at which the step attenuator on the receive path reaches the
> bottom limit its dynamic range, i.e. 0dB attenuation.”
>
> If I am going to be using <100 watts, I will not be using the PA. I
> understand there is sufficient cross-talk within the transceiver to enable
> the functioning of Pure Signal. With insufficient feedback coming from the
> coupler at the output of the PA, will Pure Signal still function with the
> internal cross-talk in the transceiver?
>
> I almost exclusively use CW, does Pure Signal even function in this mode?
>
> 73,
>
> Luke VK3HJ
>
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