Topband: For K3 users

[Tom W8JI]

> I currently live in a city of average size but quite industrialized.
> Also very close, about 1km (3 miles), a AM broadcast station 882khz with 
> 10kw.
> My currently  rig is an IC-756PRO3, and noise in 80 and 160m is 9/9 +10.
> To RX, I use a loop (kc2tx) plus a preamplifier (w7iuv) and a bandpass 
> filter.
> I'm thinking of changing my actual rig and acquire one that is more immune 
> to city noise and intermodulation  of BCB.
> My first choice is a K3, but first I would like to ask a question ...
> Will I get to improve my reception (on low bands) with this rig ?


Jose,

You will get many answers because of how different systems behave.

A receiver with wider selectivity before the noise blanker will always blank 
noise better. This is because of the wide bandwidth of noise, and the very 
narrow bandwidth of signals. A wide system ahead of the blanker has a 
sharper and more profound sample of the noise, and the wide noise sample is 
not influenced or covered by the narrow signal.

A narrow filter ahead of noise reduction makes noise power and signal power 
closer, and makes waveshapes of noise and signals closer.

The best overall noise reduction systems have the widest response at and in 
front of the blanking system.

If someone is limited by close-spaced signals, then a narrow filter near the 
front end works best. A city location has few problems with close-spaced 
in-band signals, and has more problems with wide bandwidth noise.

A city location is not the best place to show off a K3.

Someplace like I have, where I have to listen through strong east coast 
signals and I have no local noise, is far better with a receiver scheme like 
the K3. In the city almost anything will work, and you might even do better 
with a wider filter ahead of any noise reduction.

None of us can tell others which will be best when the results are depend on 
local conditions, unless we have the same situation.

73 Tom