[Elecraft] Re: FD W4ZV 1B QRP Single Op

[wayne burdick]

Hi Bill,

Congratulations on your excellent showing on Field Day. With that many 
QSOs, I'm sure you'll do very well in your division. Yes, FD is a bit 
of work, but it's also a great chance to get outdoors and try your hand 
at emergency communication setup. I think you'll  be back next year  ;)

> ...seemed to me that the CW bands were surprisingly empty.  ...

Wow -- that wasn't my impression at all. I heard wall-to-wall CW 
signals on 20 and 40 meters most of the time, and a good number on 15 
and 80 meters. Having done FD for some 10 years in a row now, I'd say 
that CW activity is about the same as ever.

When using QRP on Field Day, you need a lot of patience and the best 
possible antenna. What I usually do is put up at least two antennas 
(typically, orthogonal long wires that favor N-S and E-W). You can 
connect both to the KAT2 or KAT100 at the same time, since both ATUs 
have dual antenna jacks. You can then quickly test both antennas, even 
on a per-signal basis, using the front panel ANT1/2 switch.

>  QSK...

Where did you have T-R set in the menu? At T-R = 0.00, the receiver is 
unmuted very fast, which can cause a small receive artifact with 
certain narrow crystal filter and DSP settings. But we recommend using 
T-R = 0.01 or higher anyway. For casual operation, use T-R = 0.02 to 
0.05.

The time required to cleanly switch the VCO between RX and TX is around 
10-15 ms. We put a high value on completely clickless and chirpless CW 
keying, and adjusted firmware delays accordingly. Still, wiith TR = 
0.01, you should be able to hear between characters (not words) even at 
50 WPM. If not, you may have an assembly or component problem 
somewhere.

It's likely that we could improve VCO lock time and obtain between-dits 
receive at such speeds. This is one item on my list of possible future 
mods for the K2.

> Power meter...

It's a good idea to adjust POWER when not keying. During transmit, a 
small additional amount of hysteresis is added to the POWER control to 
improve noise margin, and this can increase the power-control step 
size.

You can also usually adjust one resistor value in the BFO attenuator to 
improve power-setting accuracy. Some JFETs (Q24) have much higher 
transconductance than average, leading to coarser steps from the 8-bit 
DAC. To compensate, try increasing the value of R98 from 270 to as high 
as 470-820 ohms. (This experiment is best done with a small trim pot 
installed; replace the pot with a fixed resistor close to the final pot 
value.) If you adjust R98's value, make sure that the rig can still 
reach at least 10 watts on all bands with POWER set to 10.0.

> CW messages...

In order to store the maximum possible characters in the K2's CW 
message memories, the firmware "quantizes" your sending into 
standard-length dots, dashes, and spaces. This is not as forgiving as 
using a "times-8 clock" for recording, which is characteristic of some 
keyers. But such keyers have a much larger EEPROM than the K2 does, or 
they don't provide as many characters of storage. It's conceivable that 
we could go to a larger part in the future and use a times-8 or even 
times-16 sample clock. (Another item on my future mods list....)

73,
Wayne,
N6KR