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K2 Strangeness on 160

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Bill W4ZV

K2 Strangeness on 160

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

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Don Wilhelm-3

RE: K2 Strangeness on 160

Bill,

Congratulations on getting the beverage installed - I want to try one here
myself, but I will have to keep the length to less than 500 feet if I point
it toward Europe - that 800 ft beverage should hear quite well.

If I were in your shoes, my first attempt would be to put a parallel tuned
circuit tuned to 160 across the antenna terminals (the feedline to the
beverage). I know it is not the ideal solution, but if your beverage
interest is only in 160 (and not 80 and 40 too), the tuned circuit shoud
reduce any out of band energy significantly.

I just wonder how much energy that BC station is putting onto your beverage.
Also it could be rectification in the antenna connections that is causing
those occurrances - overlook nothing, especially the connections in the
antenna itself.

It would be interesting to try another receiver on that beverage to see if
anything similar appears. What I am saying is that the problem may be
somewhere outside the K2.

73,
Don W3FPR

> -----Original Message-----
>
> 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
>
>

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Bill W4ZV

RE: K2 Strangeness on 160

Hi Don,

At 02:47 PM 11/9/05, you wrote:

>I just wonder how much energy that BC station is putting onto your beverage.

I neglected to say the strongest image
(German language) was lighting 1 or 2 K2 meter
lights with preamp on (no external preamp in use).
I could hear it with all 3 Preamp/Attenuator settings
but of course it got weaker when switching through.

>Also it could be rectification in the antenna connections that is causing
>those occurrances - overlook nothing, especially the connections in the
>antenna itself.

My ground rods were fairly short so I may
try changing them if I hear the image on another rig.

>It would be interesting to try another receiver on that beverage to see if
>anything similar appears. What I am saying is that the problem may be
>somewhere outside the K2.

That's my next step but my Orion is
a little bulkier <ggg> and needs a real power
supply. I'm also curious to know if anyone
has heard the warbling sound (below) which
must be internal to my K2. I'm trying to
understand if that is a generic problem or
unique to my K2 on 160. I forgot to add that
the tone is only at discrete frequencies as you
tune across 160, and it seems to wander
around like a switching power supply birdie,
i.e. it is not at the same frequency every time
I check it.

73, Bill W4ZV

> > 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.