Wow,
Thanks for that.
I clearly heard each of the different stations, just by concentrating on
them. Of note there is a music station which is clearly not stereo. But
that is using my Bose QC 25 headphones I use for contesting. On my
speakers, there is a noticeable left and right spread to the music station.
On the headphones, stations are more spread out, with stations in the
middle and the music station clearly with that monaural music playing on a
single speaker sound.
Of interest, I compared my Bose QC25 with older Sony MDR-7506 "Studio
Monitor" or "Professional" headphones and the two shack speaker systems.
The Bose is the best defined, with noise cancelling off. The noise
cancelling clearly muddles the sound stage a bit. Results: 1) QC25 without
noise cancel; 2) Sony Pro; 3) QC25 with noise cancel. 4) Elecraft SP3
speakers. 5) Logitech "HiFi" amplified PC speakers. I will need to remember
this for contests. I think in the recent past I've had noise cancel on all
the time, with a fresh AAA in the headset if a serious attempt and a fresh
AAA in the desk drawer. Got a really good test for that coming up in the
Big Stew Perry.
Did some listening to RTTY signals. Clearly one RTTY signal, the mark and
space are not subject to identical treatment from the ionosphere. Mark and
space in different places on the sound stage, quite wobbly "left to right",
easily 2/3 the time. And in the background a much weaker signal, always in
the same place on the sound stage. Other signals have far less sound stage
variation between mark and space. Using 910 Hz.
73,
Guy K2AV
On Fri, Dec 20, 2024 at 6:48 PM Tree <tree@kkn.net> wrote:
> Here is my favorite diversity recording to show it off. Done with a K3
> back in Boring:
>
> kkn.net/n6tr/160/Diversity1590.wav
> <https://www.kkn.net/n6tr/160/Diversity1590.wav>
>
> You can "feel" the ionosphere breathing. :-) This is with one antenna
> north and the other south on 1590 kHz.
>
> Many other sounds on this page are in diversity. Back out the filename
> from the URL.
>
> Tree N6TR
>
> On Fri, Dec 20, 2024 at 1:41 PM Jim Brown <jim@audiosystemsgroup.com>
> wrote:
>
> > On 12/20/2024 1:05 PM, Guy Olinger wrote:
> > > There is a particular type of "diversity" that I have found
> particularly
> > > useful.
> >
> > BTW, as long ago as the early '80s, I was utilizing diversity reception
> > professionally with wireless mics operating high band VHF TV channels
> > (that is, Ch 7-13, which are above 170 MHz). These were very good
> > quality commercially mfd products from a SoCal-based company called
> > Cetec-Vega.
> >
> > I was also doing frequency coordination for my clients (mostly local
> > broadcasters, but also theatrical and sports facilities like Wrigley
> > Field and Sox Park), using inter-mod-prediction software that Cetec-Vega
> > provided, after modifying the source code to make the print-out more
> > user friendly.
> >
> > The two receivers also implemented narrowband bandpass filters to
> > prevent overload and intermod from strong local stations operating on
> > those high-band channels.
> >
> > In those days, the radios were crystal-controlled. Within decade or two,
> > the industry had migrated to UHF and implemented programmable
> > synthesized frequency control. The market also became dominated by
> > microphone companies like Shure, Sennheiser, Audio-Technica and
> > Lectrosonics, a non-mic mfr near ABQ.
> >
> > 73, Jim K9YC
> >
> >
> >
> >
> >
> > _________________
> > Searchable Archives: http://www.contesting.com/_topband - Topband
> > Reflector
> >
> _________________
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
|