[Elecraft] K2 receive sensitivity

[Don Wilhelm]

Paul,

I am quite familiar with the late Doug DeMaw, and have a lot of respect for
his work.

That 'test' he described is a quick check to determine if a particular
receiver has enough internal gain to hear above the atmospheric noise
present on a particular band at any particular time.  The receiver bandwidth
is an important factor in how much atmospheric noise is heard.  It is not a
valid 'test' with which to compare one receiver to another - MDS measurement
(also at a given bandwidth) does provide a valid comparison.

If the 10 meter band is quiet, and you do not hear an increase in noise when
the antenna is attached, that says that more internal receiver gain can be
used, so you can switch on the preamp.  If you can hear an increase in noise
without the preamp, you are better off (from a dynamic range standpoint) not
turning on the preamp.  That is the limit of what can be said about this
simple 'test' - it should not be extended to mean anything more that alone.

10 meters is quiet right now - we are in a sunspot low, and many of the
characteristics of the low VHF bands (low background and atmospheric noise)
is currently present on 10 meters.  That will change in a couple years.

73,
Don W3FPR

> -----Original Message-----
> >
> Thanks for your reply, Don... it has been my experience that there is
> always some level of atmospheric noise on 10 meters, even when the band
> is not open.  The method of sensitivity quick-test I described was
> endorsed by many notable amateurs, including the late Doug DeMaw, W1FB,
> who I'm sure you have heard of.   That's where I got the method from.
> But I guess what I'm asking of the guys on the reflector is whether or
> not they are experiencing the same result using this quick-test
> with the K2.
> 72 Paul N2PD
>
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