Thank you for your explanation on the DSP 599sx. John k2lot
On Jan 30, 2010, at 1:48 PM, Richards wrote:
> I don't understand the bit about it adding greater selectivity.
>
> It is an audio filter, which applies after the radio has completed its work.
> I cannot see how it would improve "selectivity" - it merely uses an
> algorithm to reduce background noise. Are you using this term in a
> relative manner, as in making the wanted signal easier to distinguish
> from unwanted noise? If so, then it does that, but that is not how I
> would describe its operation.
>
> The value of the Timewave DSP 599zx depends upon what you expect from
> it. It will reduce background noise, and the more aggressive you do
> that, the more unwanted digital artifact and distortion will be
> introduced.
>
> I once used used the Timewave 599+ and now use a Timewave DSP-599zx with
> all my HF receivers. I like it, and it is very useful- but one must
> recognize it is not a cure for background noise and you may not want to
> use it all the time.
>
> What is good about it -
>
> It DOES reduce random background noise and it can make a noisy signal
> more readable. The auto notch ("Tone") button kills unwanted tones and
> squeals and that, alone, can be a huge benefit. Faster and easier to
> use than the notch filter on the rig. Instantly, gone.
>
> It has high an low pass audio filters - you can tailor the audio as if
> you had a two or three band equalizer - you can roll off the low and
> high frequencies - I like to cut the audio between 250 Hz and 3000 Hz
> which kills a lot of high pitch hiss and eliminates low pitch hum.
> There is a low cut and high cut control, and it is easy to tune that on
> the fly - far easier than working the rig menu and the adjusting the rig
> settings. Also the rig settings are quasi-permanent, in that you have
> to enter the rig menu to change them. In contrast, the knob on the DSP
> filter is out front and always available and quickly, and easily,
> adjusted, at least easier than accessing the rig's equalizer menu
> settings. It has a few, not many, memories so you can have multiple
> settings for different needs. I have a light, med, and heavy
> (aggressive) filter settings, respectively.
>
> I do do much with digital modes, but those who do like the DSP 599zx for
> what it can do for those modes. I understand it really shines on the
> digital
> modes, whereas it use with SSB signals is less effective. But I like
> mine on SSB work and would not sell or trade it at this point. Not a
> cure, but sometimes a big help.
>
>
> What is bad about it -
>
> It DOES introduce some unwanted digital artifact and can distort the
> signal if you over do it. Using this filter aggressively involves a
> trade-off between noise reduction and signal distortion. Finding the
> sweet spot is essential, but in a pinch, it can make the difference
> between working a station or not. Also, it cannot cure all noise and
> only provides a help. You want to avoid overloading it - easy to avoid,
> but you do want to watch the little red light that tells you it is being
> overloaded.
>
> Bottom line -
>
> Only you can decide if it is worth the cost. The DSP_599zx currently
> available is, in my view, much better than the older model DXP-59+ I
> used to have. I purchased the WestMountainRadio Clear-DSP unit at
> Dayton, but have yet to try it out. I will likely do that soon. I
> expect it will have less aggressive filtering effect, but also less
> deleterious impact on the final audio. Time will tell as I work it on
> line and try it.
>
> That is MY take... anyway.
>
> ==================== K8JHR ==============================
>
>
>
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