third attempt - part 2: K3 Test from Bavaria, translation draft, very long

[dj7mgq]

Somehow the two tries didn't work....


Hi,

for those who do not speak German, the below is the text of my current
draft of the translation of our K3 test report.

The English version includes a few things which are not in the German
version yet. Also to see the tables and graphs, please download the
German version <http://www.bavarian-contest-club.de/news/26,697.html>.

Enjoy...

vy 73 de toby


<< part 2 >>


4) Practical Experience

by Ben Büttner, DL6RAI

Toby also lent me his new rig für about a fortnight during the first
days of 2008. I used this chance to spend many concentrated hours with
the K3. I am the owner of 4 Kenwood TS-850 transceivers, one of which is
used a source of parts for the other three. Nonetheless these rigs are
slowly becoming very dated, and I have been looking for a persuasive
ersatz for some time now. Up to now, my search has been unsuccessful,
but the K3 gives me hope. When I compare the K3 with DL2NBU's (a leading
contester in the Bavarian Contest Club) "Survey About Contest Radios"
from 2004, it seems as though Elecraft read the results and implemented
them, because there is nothing on this 5 year old wish list which is
missing!

4.1) Front Panel

The front panel (see "Abbildung 3") is after a short familiarization
very clear. The optical design of this transceiver has been kept rather
simple. This is a plus point in my opinion.

All of the important control elements for contest operating are easily
reached. For me these include:

- VFO, A/B switching, memories, band switching and RIT
- AF volume and RF gain
- Filter employment (Hooray, no more cyclic switching)
- AGC slow, fast and off (important for many QRN situations)
- VOX/QSK switching and VOX delay adjustment
- CW sidetone (frequency and volume) as well as SSB monitor volume.

The continuously adjustable IF filtering (shift/width) with automatic
roofing filter switching is the hit, during contest operations, for
fighting QRM or fishing out a weak signal while searching and pouncing.

Fast QSY: One can configure the K3 so that the RIT knob functions as a
high speed VFO knob, when the RIT is not in use. In this mode the RIT
knob behaves a bit like the M.CH knob on the TS-850. This may also be
source for errors, when the OP bumps the knob by mistake. Time will tell
if this works well.

Pushing the Band Up and Band Down buttons does not always bring one to
the next amateur radio band. After a series of "random" button pushes
and knob twists, I suddenly had the following series bands: 160m, 20m,
60m, 40m, 30m, 20m, 17m, 15m, 12m, 10m, 6m. The 80m band had
disappeared. As Toby explained to me, this can occur when the A and B
VFOs are not set to frequencies in the same band. When one presses the
A/B button, then a band can "disappear". A further effect is, that when
one rotates the small VFO B knob, which next to the large and very
comfortable VFO A knob, the front end filters for the VFO B band are
switched in but the receiver stays on the VFO A band. The relais click
and the the receiver is suddenly almost deaf. When one rotates the VFO A
knob, the filters switch back to the correct band and everything is back
to normal. It took me awhile to understand what was going on. This bit
strangeness should be fixed in a future version of the firmware.

When operating in split mode the TX frequency is not distinctly
displayed. One feels uncertain if one is really transmitting on the
correct frequency. It would be nice if the large frequency display,
would display the TX frequency while transmitting.

4.2) The Rear

The connectors on the rear side of the K3 ("Abbildung 4") come
pleasingly close to fulfilling the Bavarian Contest Club norm:

- Foot switch: RCA socket.
- CW Key: 6.3mm phone sockets for straight key & paddles; paddles have
priority.
- Loud speaker: 3.5mm phone socket.
- PA Relay: RCA socket.
- Very useful is the 12V RCA socket, e.g. to provide a transceiver
interface with power.
- For the RX antenna and transverter: BNC, a very good choice,
experience has shown RCA a poor choice for RF.

The RS-232 interface for the transceiver control is built in, in other
words all one needs is a serial cable to connect the K3 to a computer.

One nice thing about the K3's RS-232 interface: While turning the VFO
knob the frequency information is updated continuously. The TS-850 does
not do this. It waits c. 1 second after the knob movement has ceased
before communicating the correct frequency.

The two input jacks for CW can for example be used for automatic CW
keying by an external computer while the second jack is connected a
paddles key, e.g. a Bencher BY1. Finally a rig with a built in, clean
solution for doing this! As soon as one starts keying with the paddles,
the other key input is ignored, in other words no more alphabet soup. A
really cool feature. I've been told that ICOM radios have had this
feature for quite a while now.

4.3) CW Mode

For all intents and purposes the CW mode is always a kind of QSK, even
when one activates Semi-BK. The PTT control output for PA can be
configured with a delay. Some people will probably prefer this. I,
however, would like to have the choice of turning off the noise between
characters . During CW contests, at times, I go as far as turning off
the side tone, or reducing its volume to a minimum, to give my ears a
short rest every time I transmit.

For people without absolute hearing there is a CW tuning display (CWT),
to help one tune to the middle of the filter. This must be turned on a
band by band basis. There are, by the way, many features in the K3 are
turned on or off per band, e.g. CW/CW-R. I am used to listening to CW
using the lower side band, in other words, while tuning from a lower
frequency to higher frequency, at first I hear high pitched a high audio
tone, which decreases as I move up the band. This is CW-R on the K3.

4.4) SSB

I did not spend much time doing SSB, so only a few short comments:

- When switching from CW to SSB in the same band, one must adjust the
filters per hand;

- The SSB modulation does not have enough punch, is not penetrating enough;

- The microphone socket (front panel): The pin outs are ok for dynamic
kenwood microphones but not for electret microphones. The microphone
voltage supply is on K3 pin 6 and the TS-850 uses pin 5. This means
existing microphone cables for Kenwood may need to be modified.

4.5) RTTY

The RTTY mode mode is straightforward and simple to use. The frequency
display in DATA mode is correct for the mark frequency, which is
important for DX spotting. The dual pass band feature for RTTY is also
very nice. This is a narrow filter with two small maxima for the mark
and space frequencies.

4.6 Antenna Tuner

I tested the K3's tuner with my puny 2x 13m dipole and 300Ώ twinline
feeder on all (German) bands except 160m. The tuner in the TS-850 can
handle this without any problems, and remembers the tuning values in
100kHz steps.

The K3 also has an intelligent tuner with memory but only saves one set
of values per band and not in the 100kHz steps I am used to from the
TS-850. This means that one may need to retune more than once when
moving around a band.

I also found what I think may be a bug in the firmware. If the tuner can
get the SWR down to about 1:1 the transmission power does not fold back.
The Elecraft tuner only managed to reach a SWR 2.3:1 on the 80m band
with my antenna. The K3 appeared, according to the its display, to
continue transmitting with a full power of 100W. I could not measure the
output power directly, but the power supply current also showed no sign
of folding back. Possibly the K3's 100W PA is robust enough to handle
this. It survived this unintentional test with no problems.

4.7 Resumè

The K3 left me with a very positive impression and can easily imagine
that this rig could end the TS-850 dynasty in my shack.

One last interesting aspect were the release notes of the new firmware
MCU 1.58 and DSP 1.48 (I would like to point out that when this version
of the firmware was released, Ben had already returned my K3 to me - Toby):

"NEW 100- AND 50-Hz DSP FILTERS: We’ve completed the addition of
high-performance 100- and 50-Hz "FIR" (finite impulse response) DSP
filters. These are flatter than the original "IIR" (infinite impulse
response) filters, and exhibit less ringing..."

New filters are available in software! Instead of grabbing a screwdriver
to install the new filters, all one needs to do is connect a serial
cable and start a programm to upload the firmware. It may take a while
to get used to this new modern paradigma. It does show the potential was
is still in this rig and the kinds of features which can be added to
this software defined radio long after delivery.

We will be running the K3 parallel to a Kenwood TS-850 during the CQWWDX
160m contest. This will provide us with new and interesting insights.

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com