>From what I've read. The original PRO had very steep skirts on the dsp cw
filters which caused a rather unpleasant sound. The filter's can be
modified in the menu. The Pro II comes with a menu choice of either soft
or hard filtering giving the user an easy way to choose between them. The
QST review addressed this pretty well.
As for the pops and crackles in the Pro. It's hard to interpret what you
mean but one of the characteristics of DSP receivers ie. TS870 and Pro is
that the skirts on the filters are so steep that you can be very close to
a strong signal and hear his key clicks but not hear his tone. This was
addressed in the QST review of the 870. Further testing proved that the
key clicks were really present but went unnoticed in other receivers
because they were blended or masked by the interfering tone which made
it's way through the filter. So the blame should be placed on the
transmitters and not on the dsp receivers.
I did own an early version TS-570 which has both xtal and audio dsp.
Being a cw only operator, I spend a few days doing A/B test between it
and the Omni V. During heavy QRN, the 570 was totally useless and I found
myself switching to the Omni V just to complete a QSO. Static crashes
would simply blip out cw characters. No matter what setting of AGC speed
I tried, the cw would be bliped out on each crash. It's as if the AGC
responded too quickly. I don't know if this was fixed in the newer 570g.
As for your RF gain....That's typical Icom. It's not really a problem but
just the way they work. The IC-706 is the same way. The RF gain control
seems to have a lag in it's response which is confusing.
Anyway. I'm expecting a pair of Conar Twins to arrive today. Hopefully I
can put these on the air tonight!
N4LQ
-----Original Message-----
From: Tim and Nancy Logan <cyr999@extremezone.com>
To: tentec reflector <tentec@contesting.com>
To: <tentec@contesting.com>
Date: Thu, 14 Mar 2002 06:54:08 -0700
Subject: [TenTec] Carl, Pmni, 756 etc
> Hi folks -
> I'm aiming this comment/question to Carl, but would like to share it
> with all. Carl has the benefit of owning a truly great TenTec DSP rig
> which he commented about yesterday as being the best receiver he's had.
> With that in mind I'd like to share some somewhat confusing
> observations
> and see if Carl has had similar experiences. Carl also still has, I
> believe, an OMNI V.9 (I could be wrong).
>
> After operating the 756PRO for a few weeks, I fired up my OMNI next to
> it last night. A/B testing is tuff with these rigs, but I THINK the
> following is about right (hard to know if I'm tricking myself:
>
> 1) - The OMNI has a smoother more pleasent sound to it's cw; the 756
> has
> a slighly more "percussive" sound to it. Normally not a huge issue but
> see number two.
>
> 2) - In high noise conditions the 756PRO seems to have a few pops and
> crackles associated with keying. The OMNI V.9 does not. I believe this
> may have something to do with AGC but I'm no techno wizard. A small
> percentage of the time it can be a bit quite annoying. It's possible it
> could be from RFI - but I'm still checking this out.
>
> 3) - If you want to tune out background noise by turning back the RF,
> you have a greater range and sensitivity to do this on the OMNI. The
> 756 has a much shorter range before the RF gain completely hides the
> signal as well as background noise.
>
> 4) - The 756 seems to be able to hear weaker signals a bit better.
>
> 5) - When there are a number of signals close together, the 756 seems
> to
> have a harder time sorting them out so that you just hear one. Part of
> this is getting used to being willing to use its tighter filters - so
> that for instance you might have the OMNI at 250 and the 756 at 150. It
> also might be that the 756 is hearing more signals than the OMNI -
> since
> sometimes I cannot locate these other signals on the OMNI. This is an
> area where it gets confusing. It is a no-mans land between
> understanding
> the noise floor, the best way to use DSP controls, selectivity, etc
> etc.
>
> I would be interested in hearing Carl's experiences and observations as
> he went from crystals to DSP. Did he have similar questions and
> solutions?
>
> As I say, when you try to be objective - and are not depending on lab
> tests - these are two different beasts and hard to compare. I thought
> you all might find this interesting and, if Carl has time to respond,
> his comments will likely be much more interesting!
>
> Have a good day all!
>
> 73/Tim Logan KB7OEX
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