[TenTec] Where do the filters go
Tommy
aldermant at alltel.net
Sat Aug 14 12:44:41 EDT 2004
Thanks Carl.
W4BQF
----- Original Message -----
From: "Carl Moreschi" <n4py at earthlink.net>
To: "tentec" <tentec at contesting.com>
Sent: Saturday, August 14, 2004 10:20 AM
Subject: Re: [TenTec] Where do the filters go
> Tommy,
>
> The hiss you describe on the Orion can be easily eliminated. It is caused
> by the AGC in the Orion trying to bring all signals no matter how weak to
> the same volume level. The threshold control for AGC controls this. With
> no signal being received, if you increase the AGC threshhold, you will
find
> a point where the hiss completely stops. This is the best place to put
the
> threshhold for that band. With my N4PY software, I put this control on
the
> front panel.
>
> 73,
>
> Carl Moreschi N4PY
> Franklinton, NC
> ----- Original Message -----
> From: "Tommy" <aldermant at alltel.net>
> To: <tentec at contesting.com>
> Sent: Saturday, August 14, 2004 2:39 AM
> Subject: Re: [TenTec] Where do the filters go
>
>
> >
> >
> >
> > >
> > > > N1EU wrote:
> > > > >I tend to agree with W4BQF on the 2.4Khz 10-pole Inrad
> > > > as being unnecessary. However, the 1.8Khz filter
> > > > could be helpful if the rig is used for ssb
> > > > contesting.
> > > >
> > >
> > > > In my opinion, if you are a CW ONLY op, the only
> > > > optional filter you would ever need is the Inrad 762.
> > > > If you are also an SSB op, I would definitely add the
> > > > 1800 filter (either the TT 218 or Inrad 761). I used
> > > > the TT 218 last October in the CQ WW SSB and would not
> > > > be without it. If you are a casual operator...no serious
> > > > contesting, no heavy-duty low-band DX-ing, etc, you don't
> > > > really need ANY optional roofing filters.
> > > >
> > > > 73, Bill W4ZV
> > >
> > > >W4BQF wrote:
> > > Well, being a CW only op, I have to disagree with this just a little.
My
> > > Orion does not have the 1.8kc filter, so today when I received my
600hz
> > > filter, I moved the 1kc filter into the empty 1.8kc position, put the
> > 600hz
> > > fliter into the 1kc position, and kept my 500hz and 250hz installed.
> > > (Running v1.369 so I can switch the filters correctly and also so the
> > Orion
> > > does not crash while I'm using my Titan 3 in the Keying loop)
> > >
> > > Tom, as IMD reduction devices, the 500 and 250 filters are worthless.
> > Sure
> > > you can use them for simple bandpass filtering, but they are FAR worse
> > than the
> > > 1800/1000/600 for reducing IMD products, which is the true purpose of
> > roofing
> > > filters. Remember that we still have DSP filtering with filters every
> 10
> > Hz
> > > from 100 to 6000 Hz following the roofing filter.
> >
> > Bill, I'm well aware of the 'problems' with the 500 and 250 Hz filters,
> but
> > why would a company release an unfinished product? We all know the
reason
> > for that. And yes, they can be used as 'simple bandpass' filters, but
it's
> > my understanding that was not the intent, and the purchasers received an
> > unfinished product. Yes, 'we still have DSP filtering.....' and the loud
> > hissy audio noise that accompanies it. My Omni 6 is so much quieter than
> the
> > Orion, its almost shameful. And we won't go into the fact that the Ten
Tec
> > amp's will not work with the Keying Loop. Heck, I haven't even seen that
> on
> > the 'we're working on it' agenda.
> > >
> > > >I then used my Elecraft wide band noise generator and watched, using
> > > Spetragram, as I switched the filters. One thing that showed me was
how
> > far
> > > off I had my 500hz and 250hz filters adjusted. With the Orion,
> Spectrgram
> > is
> > > an invaluable tool when used with a wide band noise generator. You
can
> > SEE
> > > exactly what's really happening with the filters, and when you adjust
BW
> > and
> > > PBT....it's amazing how much your ear lies to you!! hihi.
> > >
> > > You don't need Spectrogram to properly center the 500 and 250 filters.
> A
> > > simple signal generator plus Orion's internal 6 dB attenuator will do
it
> > > nicely. However, to really understand the capability of Orion,
> > Spectrogram
> > > really does add some new insights...such as the one I recently had
> > regarding
> > > using PBT to shift the 600 Hz roofing filter +/- 300 Hz. This is
truly
> > > powerful and a capability that NO other radio has including the
> > IC-7800/756,
> > > FT-1000, and Omni families. Using this properly, it should be
possible
> > > to even further improve the 600 Hz filter's IMD rejection capability
for
> > > extremely close interfering signals.
> >
> > Well, with the Elcraft signal generator at 7.044 MHz, you sure can get
> those
> > filter 'close', that's for sure. But with the wideband noise generator
and
> > Spectragram, you can put the filters exactly centered on you offset
> > (sidetone) frequency and determine their 6dB bandwidth, and observe when
> > some of the roofing filters do not switch. Both are good, my first
> > 'centering' try was by using my Omni 6 into a dummy load, as a signal
> > generator and even that was pretty close. Just a users choice I guess.
> > >
> > > I hope you get your QSK problems solved in Omni and Orion. It may be
> that
> > > Ten-Tec is simply recognizing that >40 WPM QSK is an extremely small
> > segment
> > > of the total market. I operate a lot of CW contests and never go much
> > over
> > > 36 WPM. In fact, speeds much over 36 WPM are counter-productive in
> terms
> > > of maximizing overall rate. It always amazes me to hear an operator
> like
> > > W0UA calling CQ at 40+ WPM, getting no answers and then continuing to
> call
> > > CQ at speeds that 95% of average hams cannot copy.
> >
> > Sorry, but I disagree with you here. It is not 'MY' QSK problem. It
> would
> > be my QSK problem if I was the only person to have purchased an Orion.
The
> > label '>40 wpm' is misleading. Look at the jitter of a CW character at
30
> or
> > 34 wpm....better yet, don't look as it's not what you would expect from
a
> > 'world class' radio. In my opinion, the Orion has the potential to be a
> > world class radio........
> >
> > 73,
> >
> > Tom - W4BQF
> > >
> > > 73, Bill W4ZV
> > >
> >
> >
>
> --------------------------------------------------------------------------
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> > ----
> >
> >
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