[Elecraft] K3: KRX3 question

[Don Rasmussen]

I sense that a fair amount of folks view K3 crystal
filters in the traditional sense, for example the
"need" for a 500hz filter on if one is going to
operate CW. This ia a long way from the truth with K3.
Same thing for the 1.8khz filter, unless you're having
antennas that bring in contest strength signals, not
necessary at all. 

Buck can probably comment on this, I never owned
Orion, but it seems they never had the ability for a
roofing filter on the second receiver and if you put
K3's receiver or subreceiver head to head without a
roofing filter (DSP only), the Orion receiver would
suffer AGC pumping terribly since it's default roofing
filter is at more than 10 khz and K3 is at 2.7khz.
That's what my Argo V did. 

The point is, the stock K3 setup is majorly robust for
either the main receiver or the subRx in stock form. 



[Elecraft] K3: KRX3 question
Don Wilhelm w3fpr at embarqmail.com 
Sun Jul 6 09:24:31 EDT 2008 

Previous message: [Elecraft] K3: KRX3 question 
Next message: [Elecraft] K3: KRX3 question 


David,

In most instances, you are correct.  My K3 has only
the stock 2.7 
filter, but then I am not into heavy contesting nor
intense DX chasing - 
I do some contesting and work DX for fun only.  When
it gets to the 
point where I really need narrow roofing filters, it
is time for me to 
go listen to some relaxing music, so you will not find
me using 
diversity reception to pull out some obscure weak
signal.

One related point - the Hardware AGC should prevent
overload of the DSP, 
so the K3 will handle those strong signals nicely. 
The problem is that 
the AGC action when a strong unwanted signal is within
the roofing 
filter passband, the AGC will reduce the sensitivity
of the entire 
receiver, so your wanted signal gets weaker too - and
you may not even 
know the offending signal is there if you have the DSP
bandwidth at a 
narrow width - it will behave as though there is QSB
on the signal you 
are listening to.  Of course using diversity reception
with one antenna 
having lower gain, that QSB effect may be minimized.

73,
Don W3FPR