Posted by
Jim Dunstan on
May 02, 2012; 6:53pm
URL: http://elecraft.85.s1.nabble.com/Re-question-for-psk-users-tp7517322p7522904.html
At 07:45 AM 5/2/2012 -0400, you wrote:
Hi,
Brian is right. Just as you should drive according to conditions you
should operate according to conditions. Under certain propagation
conditions all signals are received within a narrow signal strength
range. Under these conditions it possible to set the receiver to operate
with a wide 3 khz BW and click and read many PSK signals at the same time
with the ability to pounce when a QSO ends. These conditions are not due
to all the stations operating at 20W ERP .... and almost any receiver
works well under these ideal PSK conditions. However more often than not
there is a large signal strength range which doesn't allow operation with a
3 khz BW ... and the difference in station signal strength at the receiver
is most often due to differences in propagation rather than the power the
station is running. Under these conditions the operator needs a better
receiver and an operating practice that is more 'nimble' hi hi. As Brian
put it you can't change propagation nor can you control the power the other
operator is using or the direction he points his directional antenna hi
hi. If you want to check the PSK band during a time with both strong and
weak signals you need to be able to move and adjust your bandwidth like a
maestro !! A pan adapter is a great tool under these conditions.
Of course one could simply stay narrow and call CQ ... but it is more fun
to use the dodge and pounce technique hihi
Jim, VE3CI
>Guys,
>
>This rational is bogus. The PSK users have to get used to decoding one
>signal at a time with narrow filters if that's what is necessary. To
>expect to have 2 or 3 KHz free of strong signals is crazy.
>
>Dealing with this reality puts the burden on the receiving end. No way
>can you control what the rest of the wold does. This isn't the Magic
>Kingdom.
>
>Given that PSK is a narrow bandwidth mode, why not use that to your
>advantage?
>
>Other modes deal with strong adjacent signals, why not PSK?
>
>You bought a K3 for its high dynamic range and high adjacent signal
>handling capability. Why not use it for this purpose?
>
>Of course the argument ignores all the laws of physics and
>propagation. I suggest you run some VOACAP prediction calculations
>with 25 watts and look at what you can't work with 25-75 watts. You
>may not be interested in working the other side of the world, but others
>are.
>
>PSK isn't magic.
>
>73 de Brian/K3KO
>
>
>
>
>
>On 5/1/2012 11:46 PM, Jon Perelstein wrote:
> > Eric KG6MZS asked why wouldn't you run more than 70w on PSK
> >
> > Because with the close spacing of signals in the various PSK sub-bands, a
> > signal of more than about 50watts will completely annihilate all the other
> > PSK signals and make that sub-band unusable for everyone else. The rule of
> > thumb for being polite on PSK is to operate 25-30w max. I won't claim that
> > there aren't some who are operating more (you Cuban stations know who you
> > are), but many/most of us will avoid QSOs with people who are obviously
> > running 50w+
> >
> > 73s
> > Jon, WB2RYV
> >
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