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Re: [TenTec] Omni VI+ the best and other great radios

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] Omni VI+ the best and other great radios
From: Richards <jruing@ameritech.net>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sat, 30 Jan 2010 13:48:24 -0500
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
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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