[Elecraft] K2 Strangeness on 160

[Bill Tippett]

	Over the past month or so, I've been taking
my K2 (#4119) to a remote mountaintop cabin for
R&R with my XYL.  This location is quite remote
and previous visits seemed to be very RFI-quiet on
the other bands, so I decided to install a Beverage
on October 12 and try listening on 160.  It is ~800'
long and oriented NE to Europe.  I have no transmit
antenna but was just curious to see how Top Band
sounded from an extremely RFI-quiet location.

	When I first listened, I was surprised to hear
what sounded like a BCI carrier image on 1837.5.
With LCW mode selected, the K2 acted like it was
in UCW when tuning past the carrier.  My K2 was
powered by a 7AH SLA, so the only connection to
it was the Beverage feed line.  I thought possibly I
was getting some common mode, so on my latest
trip I took along a section of coax with about 50
ferrite beads to attenuate any common mode.
This did not help but I was even further surprised
to copy audio from the BCI speaking in German!
Also, I heard another image below 1810.  Both of
these were well before my sunset so I'm assuming
they were images from somewhere higher in frequency.
I should have listened long enough to get an ID but
was more interested in listening for DX at the time.
Has anyone ever seen anything like this on 160?

	While listening with the K2, I also noticed the
following:

1.  The image was worse on the RX port than
on the Main port.  I did use a 50 ohm termination
on the unused antenna port when checking.

2.  I noticed with only the 50 ohm termination and
using battery power, I heard a drifty warbling tone that
reminded me of switching power supply birdies.  It
is not very strong, but noticeable with both RF and
AF gain near maximum.  I wondered it it could have
been my battery, so I tried a linear supply when I
got home but I still hear the same sound.  Again, it
sounded slightly worse when listening on the RX
antenna port than the Main port, although it was
clearly audible in both.  This is something that
can probably be verified in any unit since it seems
to be internal to the K2.

3.  I have a KAF2 in my K2, and noticed when the
clock is selected I hear a "chuff...chuff...chuff"
sound which is in synch with the KAF2's clock
update.  This is not a big deal since I can easily
turn it off, but I wonder if anyone has found where
to add a ferrite to eliminate it?

	All of these things would not normally be
audible, but I was listening near the K2's noise floor
on an extremely quiet band.  160 was amazing from
this location since I heard F5IN at 2028z yesterday,
which was nearly 2 hours before my sunset.  I went
on to log nearly 50 DX stations including RA6AX at
2121z who is very deep into EU Russia (near Asia),
about 1 hour before my sunset.

	My K2 seems to work well but I am wondering
if there is something that can cure the things I've
noticed above.

				73,  Bill  W4ZV