Topband: Symbol Rates (was [ARRL-LOTW] BoD votes LoTW initiatives)

Bill Cromwell wrcromwell at gmail.com
Wed Jul 24 08:42:34 EDT 2013


On 07/24/2013 08:09 AM, Brian Machesney wrote:
> Joe,
>
> I don't understand your objection to removal of the symbol rate language.
> Under the existing band plan, CW is expected to co-exist with other
> "digital" modes of all kinds.
>
> Now, I don't like to hear even narrow-bandwidth PSK or RTTY signals when
> I'm operating in the "traditionally CW" portions of the bands, but I don't
> believe this is even primarily a question of symbol rate. When CW contest
> activity extends into, through and beyond the "traditionally digital"
> portions of the bands, I find it very difficult to pick a CW signal out of
> a densely-packed cluster of PSK carriers or RTTY stations. In my
> experience, it is not the symbol rates of the PSK and RTTY stations that
> cause the interference, but the ability of my brain to discriminate against
> the natures of modulation of those signals.
>
> I agree with you that we need to review the band plans. But to me that
> doesn't mean that we should allow the persistence of language which may
> hold back technical progress.
>
> 73 -- Brian/K1LI
>

Hi,

I have started using DSP with computer sound card software and also with 
dedicated hardware. Those have made it possible for me to dig weaker 
signals out of the noise and pick out CW signals from between those 
"densely packed" digital signals. It also gets rid of the neighbors' 
QRMing appliances stacked right next to the desired signal. I can slice 
the junk right off. Even with my *old* receivers - including a couple of 
regens. The waterfall and spectrum (panadapter) displays in the 
soundcard software helps identify where those signals are before I can 
hear them in all the din. I am finding those things to be effective 
tools to use against modern "rotten QRM". I frequently use a bandwidth 
narrower than 100 Hz yet can see where there are CW signals and dial 
them in. If you are not using any of those you should give then a try. 
The one that has been most useful for me is "Spectran". It's not to hard 
to figure out how to use and it works very well. Not a lot of bells and 
whistles to get in the way. Being *free* is a good feature, too.

I do NOT use the computer to actually decode CW for me. Computers are 
just not good enough to do that with CW out in "the wild". YMMV.

73,

Bill  KU8H


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