[Elecraft] question for psk users

[Jim Brown]

On 5/1/2012 8:46 PM, Jon Perelstein wrote:
> 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.

This is urban myth that keeps getting propagated and eventually everyone 
believes it as gospel. It's only basis in fact is that folks using 
el-cheapo radios can find it difficult to separate small signals from 
big ones.  That's nothing new -- it's been true as long as radio has 
existed, and it's why it's worth spending money on better receivers.  
It's why I dumped my S38D in 1957 for a BC348, and why I was thrilled 
when an OT loaded me an SX101 a year later.  It's why I bought an Omni A 
in 1980, an Omni V in 2003, then a K2, then an MP and finally a K3 a few 
years ago.  And it's a big part of why the serious DXpeditions all use K3s.

There are MANY factors that contribute to signal strength, including 
antenna efficiency and gain, antenna pattern, propagation, and yes, 
transmit power.  Of those factors, transmit power is the SMALLEST.  The 
difference between 50W and 500W is 10 dB. The difference between a short 
indoor random wire with no counterpoise and a resonant outdoor dipole 
will often be 15-20 dB. A 3-el Yagi is typically good for another 5-6 
dB, add 3 more dB for making it twice as long.

What is FAR, FAR more important to prevent interference is making sure 
that your signal is CLEAN -- no sidebands produced by audio distortion, 
or by distortion in a poorly adjusted rig or power amp.

73, Jim K9YC