[AMRadio] Junior Collins on AM


VJB wa3vjb at yahoo.com
Mon Jan 22 12:35:40 EST 2007


Bob, I should think any linear amplifier, when given
enough headroom, should be able to cleanly boost the
signal of a good sounding lower-power transmitter.
There's no real fidelity question to consider. It's
parameters of RF in/out.

As such, Joe's point that the 30S cannot produce "full
legal limit" AM remains valid, on a power basis, not
audio quality.

But it's an audio problem with the KWS-1, and its
companion 75A4. Both reflect a very deliberate attempt
by Collins to transition to the pinched and narrow
SSB, in which higher distortion was also considered an
acceptable design factor.

Distortion and limited frequency response in the stock
audio circuitry of the 75A4 ruins good quality
reception of AM, regardless of the choice of filter.

The poor audio quality designed into the speech amp
stages of the KWS-1 also need to be addressed to bring
that transmitter toward what's available stock from
the senior Collins models KW-1, 30K and 32V.

And yes, I admit that I like messing with the amen
chorus of those who collect the S-Line products and
think they're "better" than anything prior. That's why
I refer to those radios as the "junior" models, since
they lack the capability of running wholesome AM.  

(feed your ears, it's good for ya)

Paul/VJB




 
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