I.F. DSP now uses frequencies of 12-15 Khz. This will undoubtedly change and
higher I.F. frequencies will become possible. When they do many of the
problems with internally generated anomalies will disappear.
73, Dave, VE1ADH
----- Original Message -----
From: "Duane Grotophorst" <n9dg@yahoo.com>
To: <RMcGraw@InfoAve.Net>; "LORONAAL A-USAex3" <al_lorona@agilent.com>;
<tentec@contesting.com>
Cc: <Tentec@contesting.com>
Sent: Wednesday, June 27, 2001 11:34 PM
Subject: [TenTec] Future of Radio (Was) ARRL product review test change
>
>
> This being catch 22 is true to a limited point, but it
> has more to do with the evolution of technology. These
> issues of DSP and other digital artifacts are akin to
> the transition from tube receivers to solid state. Did
> solid state technology improve receivers? Absolutely,
> were there some undesirable side effects, especially
> for the first couple generations, of course. Once the
> undesirable side effects were recognized the various
> companies proceeded to correct them, and they have,
> virtually all solid state receivers today dramatically
> exceed tube receivers in just about every respect. I
> see DSP and software defined radios (SDR) of today
> being like the circa 1970 solid state receiver
> technology, clearly the future direction of radio
> design, but also has room for improvement and
> tremendous technological advancement.
>
> There really is no point in building software radios
> that will only do what the previous, often simpler
> designs already do quite well. What DSP and SDR can
> give us are new capabilities that were simply not
> possible before.
>
> As write this, I have the two Peg's listening and
> watching the excellent opening on 6M, by using a DEM
> 50-28 transverter and N4PY's software in dual Pegasus
> mode. I have one of them actually listening to a
> particular signal and the other sweeping the band from
> 50.075 to 50.225. So every 4 seconds or so I get a
> nice visual snapshot of a 150KHz chunk of spectrum,
> continuously.
>
> Operationally I can be listening to a signal on say
> 50.155, and then perhaps see a new "spike" on 50.198,
> "Hmmm gee, I wonder who that might be", one click of
> the mouse on the sweep display, and I'm instantly
> there. Can a traditional radio design do that? Nope.
> Thanks to the excellent work by Carl, N4PY and the
> truly computer controllable Pegasus's this is now
> possible, and all of this capability without a lot of
> end user work or a huge investment. Currently there
> are no other radios in the amateur market that can do
> this (with proper control software development the
> Kachina should be able to do this as well). And the
> best part is that even better fun things can be done
> by anyone with programming skills and ambition (I'm
> definitely not a programmer, won't comment on
> ambition). I'd really hate to see Ten Tec lose this
> competitive edge they now have.
>
> That is why it is important to not let the seemingly
> little peculiarities of the new technologies go on
> without some feedback to the manufacturers from us end
> users in the field. But it is also important for us
> customers to actually reward companies that do
> incorporate the true "future of radio", not just bells
> and whistles, by buying it. If we only buy the same
> old radio concept, they will continue to only build
> the same old thing, and then one day somebody else
> will (build the new technology) and they will go out
> of business. Just look at what companies are around
> today that didn't exist in the early to mid 60's, and
> who was around then and are gone today, and why?
>
> Duane
> N9DG
>
>
>
> --- Bob & Linda McGraw K4TAX <RMcGraw@InfoAve.Net>
> wrote:
> >
> > Al:
> >
> > You are absolutely correct. I wish the other folks
> > understood this
> > fact.
> >
> > 73
> > Bob K4TAX
> >
> > LORONAAL A-USAex3 wrote:
> > >
> > > Hi, Everybody,
> > >
> > > An interesting discussion. Practically, I can
> > understand those who say they
> > > don't care about a spurious tone in the audio
> > output that is so far down
> > > that it cannot interfere with normal
> > communications. Practically, that's
> > > absolutely true. Virtually all radios have
> > by-products, birdies, audio
> > > intermod, phase noise, and other junk if you look
> > closely enough. On the
> > > other hand, Larry (VA3LK) is perfectly right to
> > say that, for his extreme
> > > weak-signal work, the distortion can't be
> > tolerated. In the worst case I
> > > suppose it would fool his decoding software into
> > thinking that there were a
> > > very weak signal there, when there really weren't!
> > And that would be bad.
> > >
> > > What an interesting test, to put a spectrum
> > analyzer on the audio output and
> > > show the result in the product reviews. I'd like
> > to see that.
> > >
> > > R,
> > >
> > > Al W6LX
> > >
> > > -----Original Message-----
> > > From: Jim Cox [mailto:jcox@digitalexp.com]
> > > Sent: Wednesday, June 27, 2001 6:54 AM
> > > To: Duane Grotophorst; dslosty;
> > tentec@contesting.com
> > > Subject: Re: [TenTec] ARRL product review test
> > change
> > >
> > > If you have to turn the volume up 100 percent to
> > hear it, why worry about
> > > it? How many of us run our radios at 100 percent
> > volume?
> > > I bet if you ran your car at 100 percent you'll
> > hear some strange noises
> > > too.
> > >
> > > ----- Original Message -----
> > > From: Duane Grotophorst <n9dg@yahoo.com>
> > > To: dslosty <dslosty@pipeline.com>;
> > <tentec@contesting.com>
> > > Sent: Tuesday, June 26, 2001 10:44 PM
> > > Subject: Re: [TenTec] ARRL product review test
> > change
> > >
> > > >
> > > >
> > > > I would like to see the ARRL add a product
> > review test
> > > > where they show the audio output spectrum of the
> > RX
> > > > audio passband with a 50-ohm load on the RX
> > input.
> > > >
> > > > With today's digitally based radios (DSP IF or
> > > > otherwise) there is a potential for, and
> > frequently
> > > > is, extraneous noises and other artifacts in the
> > RX
> > > > audio signal.
> > > >
> > > > At the risk of re-opening old heated debates
> > here on
> > > > the reflector, I have also seen the persistent
> > tone in
> > > > the middle of the RX filter passband the Larry,
> > VA3LK
> > > > saw with the Pegasus. It is actually quite easy
> > to
> > > > see, I used SR5 Spectrum Analyzer program (from
> > > > www.ar5.com) to look at the audio passband. I
> > can also
> > > > see it on the waterfall display of the PSK31
> > program I
> > > > use. In fact both of the Peg's I have exhibit
> > the
> > > > exact same behavior. That tone is actually
> > audible if
> > > > you crank up the volume 100%. For what its worth
> > > > though, the fact that you can turn the volume up
> > all
> > > > the way and not be driven out of the room by
> > white
> > > > noise is a testament to what Ten Tec has done
> > well
> > > > with their RX design.
> > > >
> > > > Anyone who is already wired up to do PSK31 or
> > any of
> > > > the other "sound card" modes, can simply
> > download any
> > > > number of freeware spectrum analyzers and look
> > at the
> > > > audio signal of you RX. I've used both SR5 and
> > > > Spectrogram for my tests; I'm sure there are
> > others.
> > > >
> > > > I haven't turned the audio spectrum analyzer
> > loose on
> > > > my other radios yet, but I do expect to find
> > some
> > > > interesting things. Bottom line is that whatever
> > > > internally generated noises or other artifacts
> > that
> > > > may appear in the RX audio passband are actually
> > every
> > > > bit as important as all of the dynamic range and
> > phase
> > > > noise measurements that product reviewers are so
> > > > focused on.
> > > >
> > > > 73,
> > > > Duane
> > > > N9DG
> > > >
> > > > --- dslosty <dslosty@pipeline.com> wrote:
> > > > >
> > > > >
> > > > >
> > > > > I don't know if this has been mentioned on the
> > > > > reflector but I
> > > > > found the changes announced in July's QST
> > > > > interesting.
> > > > >
> > > > > The League is now going to use a 5KHz standard
> > > > > spacing versus the
> > > > > former 20 KHz spacing while testing receiver
> > dynamic
> > > > > range
> > > > > and intercept points. This should better
> > > > > characterize crowded band conditions.
> > > > >
> > > > > On page 80 of July's QST is a listing of
> > several
> > > > > current HF
> > > > > transceivers. According to the new tests, the
> > > > > Elecraft K2 and
> > > > > the Ten-Tec Omni 6+ have far better figures
> > than the
> > > > >
> > > > > IC-756PRO, FT-1000MP, etc.
> > > > >
> > > > > Of course, most of us already knew this.....
> > > > >
> > > > >
> > > > > 73,
> > > > > Doug/WA1TUT
> > > > >
> > > > >
> > > > > --
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> > > > > tentec-REQUEST@contesting.com
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> > > > >
> > > >
> > > >
> > > >
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> === message truncated ===
>
>
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