I agree Steve, the narrower filter(s) do make the ssb sound like *&%%*#@.
When listening to the majority of QSOs in ssb, I almost always select the
Paragon's 6.0 khz bandwidth. Sounds much more easy and natural on the ears,
especially when listening to the hi-fi guys on 14.178. But there are times
when using cw that it would be better to have a narrower IF to really make
the PBT perform. The 1.8khz filter does just that.
Lane
Ku7i
>From: Steve Katz <stevek@jmr.com>
>To: "'2'" <2@vc.net>, doug@nc.rr.com, AMPS <amps@contesting.com>
>Subject: RE: [AMPS] pair 572Bs $70 shipped or trade
To: <amps@contesting.com>
>Date: Thu, 20 Dec 2001 16:11:31 -0800
>
>
>On this subject (which has substantially deviated from pairs of 572Bs,
>somehow), I have purchased both Kenwood and INRAD 1.8 kHz filters and
>sincerely regret all the above. The slope tuning, IF shift, passband
>tuning
>(or whatever your particular receiver happens to have) is far more
>effective
>at eliminating adjacent frequency QRM (and allowing the AGC to work
>normally
>and not be pumped by that strong offending signal) than using narrower
>filters. I absolutely hate the sound of the 1.8 kHz filters made by
>anyone,
>used in anything. As I grow older, I think I hate it even more.
>
>-WB2WIK/6
>
>
>
> > >
> > >> >I have a set of 572Bs for sale for $70 shipped in the lower 48.
> > >> These are at
> > >> >least 90% emission (600 watts out on 40 meters in my SB-200). Or
> > >> will trade
> > >> >them even for a ten tec model 288 1800 hz filter for the
> > >> Paragon. The tubes
> > >> >are American made.
> > >> >
> > >> // In the 1930s, Bell labs found that a male voice needs 2700Hz of
> > >> bandwidth for optimal intelligibility. Narrower bandwidths will work
> > >> acceptably with a female voice. I use a pair of TS-930S filters to
> > >> achieve a 2700Hz bandwidth in my TS-440S.
> > >>
> > >> cheers, Lane
> > >>
> > >> - R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
> > >
> > >Indeed, even restricting the bandwidth of a voice signal to 2000 Hz has
> > been
> > >shown to reduce intelligibility by more than 50%. In this case,
>however,
> > >intelligibilty is nearly always measured by the listener's ability to
> > >distinguish between words that sound alike. (Do a web search on the
> > >Diagnostic Rhyme Test.) Tests conducted more recently indicate that if
> > the
> > >restriction in bandwidth also eliminates an interfering SSB signal then
> > >intellibibility may actually increase in certain subjects.
>Psychoacoustic
> > >research indicates that some people have extreme difficulty dealing
>with
> > the
> > >off-pitch syllabic rate of an interfering SSB voice signal. If you know
> > what
> > >you're listening for (like your name or your callsign) then you're less
> > >likely to miss it if the interference is reduced/removed.
> > >
> > >More importantly, if the offending SSB signal is S9 and the desired
> > signal
> > >is S2 then the 1800 Hz filter can reduce the AGC pumping effects caused
> > by
> > >the operator just up the band. In these cases intelligibility may
> > increase
> > >dramatically.
> > >
> > // May
> >
> > >Remember, Rich, not everyone can turn on a "tetrode with handles" when
> > the
> > >going gets rough.
> > >
> > // And that turned out to be the problem. When I ran a tetrode with
> > handles to get over jammers, I found that the jammers quickly learned to
> > jam only the station I was trying to talk to since jamming the "Plywood
> > Box" successfully was somewhat less than likely. The workaround was for
> > me to telephone the person who was being jammed, leave the VOX on and
>the
> > RX Audio gain on 0 at both ends, then carry on the simulcast
>conversation
> > as if the jammers were not being heard -- which was assuredly the case
> > with both Audio Gain controls at "0". The jammers eventually realized
> > that they were not being heard by the jamees and went away with their
> > tails between their legs.
> >
> > cheers, Doug
> >
> > - R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
> > end
> >
> >
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