[3830] TBDC K1LT Single Op HP

[webform at b4h.net]

                    Stew Perry Topband Challenge

Call: K1LT
Operator(s): K1LT
Station: K1LT

Class: Single Op HP
QTH: EM89ps
Operating Time (hrs): 13

Summary:
Total:  QSOs = 327  Total Score = 1,196

Club: Mad River Radio Club

Comments:

This soapbox documents my continued adventures with contesting
with software defined radios and beam steering on 160 meters.
For previous installments, see k1lt.com.

I continue on my quest to eliminate the Beverage wires from my
field.  The goal this contest, besides to beat last years score
and besides staying awake all night, was to try and operate
using the beam steering phased array and not use the Beverages.

One part of the plan to meet that goal was to complete another
phased array to cover NW and SE, which is the weak directions of
the existing NE/SW broadside array.  So, to that end I have
constructed a 4 element end-fire array.  While 3 elements are
operational, I haven't finished the software to properly phase
an end-fire array.  Also, I need to invent a mechanism to
instantly switch from one phased array to another.

So I allowed myself the use of the Beverages in the right ear,
and the phased array in the left ear.  During the first half of
the test, when not expecting calls from JA & KL7, I tried
alternating between the two following search strategies:
frantically push buttons during the 3 seconds between CQs versus
listening in two directions simultaneously.

The frantic searching strategy replicates the same situation
with 12 Beverages.  If the caller is strong, then rapid button
pushing usually finds a suitable antenna on which to receive.
If the caller is weak, rapid button pushing may miss the one
antenna (or direction in the case of the phased array) that
hears him.

The listening in two directions simultaneously exposes the
problem that the SDR receiver has some latency compared to the
analog receiver.  The latency at this point is only 5.3
milliseconds, but that's enough to make weird echoing sounds on
strong signals.  But one can get used to it.  At least at 5 ms
the dots and dashes don't overlap as they did at 21 ms from last
year.
				   
The solution would be to "upgrade" the phased array software to
allow receiving from 2 or more directions at once.  This is
perfectly feasible, except that I mechanically switch from east
to west in the broadside array.  When I am able to build a
circle array (or some other radially symmetrical array), then
the simultaneous multiple directions should play very well.
sdr-core seems to support multiple receivers, although I don't
think sdr-shell makes use of that capability, yet.

The other issue I observed with using digital radio in a contest
was the "focus, pocus, who has the focus" issue (sorry, couldn't
resist the bad pun).  That is, I have two windows on the screen,
one is the sdr receiver interface (sdr-shell), and the other is
the beam steering control interface (my phasor program).
Several times during the test, the focus would be on the wrong
window while my fingers are pounding on the keyboard, which
would often screw up one or the other program.  If I use the
mouse exclusively, then the problem does not occur, but one
cannot make rapid and precise motions with a mouse.  If I use
the keyboard, then I can change settings quickly, but only if I
notice where the focus is located before typing.

BTW, the main receiver control issue is tuning for off-frequency
stations, which can be done with a mouse gesture, or extremely
tediously with the keyboard.  The second main receiver control
issue is adjusting the pass band to avoid interference and
accentuate weak stations, which can be done tediously with the
mouse, or reasonably expeditiously with the keyboard.

The main beam steering control issue is changing the beam
direction, which can be done very rapidly on the numeric keypad
(I've programmed the outer-edge keys to resemble a compass rose,
see below.)  The beam can be steered with the mouse, too,
although not quite as precisely.

So ultimately, I would like the keypad to always control the
beam direction, and the rest of the keys and the mouse should
control the receiver, without having to worry about which window
has the focus.  So, I have some research to do.

In general, I enjoyed this contest, because the activity is
light enough that everyone can find a frequency without
overlapping.  However, the European attendance seemed lighter
this year that last, although that may have been conditions, or
maybe the Worked All Germany test drew away some participants.
So, my score went down this year compared to last.

Best DX was ZL1AIH.  Couldn't find any VKs except VK9WDX, and I
assumed he was not looking for grid squares.  Missed KL7FH's
grid.  Didn't look very hard for JAs because I was getting quite
sleepy by that time of the morning.  I took only a 45 minute nap
around 0330Z so I could stay awake for any Pacific activity.
Didn't work Asia or Africa, but OA4TT supplied South America,
once I figured out to point a beam in his direction.

See you all in the main event in December, and all of the other
160 tests in-between.

        keypad compass - needs work
        +------+------+------+------+
        | Mich | N Eu |  Eu  | N Af |
        |      |      |      | Conn |
        | 00.0 | 35.0 | 45.0 | 75.0 |
        |      |      |      |      |
        +------+------+------+------+
        | Minn |      |      |      |
        | 310.0|      |      | A    |
        |      |      |      | f 9  |
        |      |      |      | r 0  |
        +------+------+------+ i .  +
        |  W7  |      |      | c 0  |
        | 295.0|      |      | a    |
        |      |      |      |      |
        |      |      |      |      |
        +------+------+------+------+
        |  W6  |      |      | C    |
        | 270.0|      |      | a    |
        |      |      |      | r 1  |
        |      |      |      | r 5  |
        +------+------+------+ i 0  +
        |    Texas    |South | b .  |
        |             |      | e 0  |
        |    240.0    |175.0 | a    |
        |             |      | n    |
        +------+------+------+------+


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