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[SECC] ARRL 160 AA4LR Single Op LP

Subject: [SECC] ARRL 160 AA4LR Single Op LP
From: aa4lr at arrl.net (Bill Coleman)
Date: Wed, 6 Dec 2006 21:54:15 -0500
                     ARRL 160-Meter Contest

Call: AA4LR
Operator(s): AA4LR
Station: AA4LR

Class: Single Op LP
QTH: GA
Operating Time (hrs): 5.8

Summary:
Total:  QSOs = 370  Sections = 54  Countries = 2  Total Score = 41,608

Club: South East Contest Club

Comments:

Antennas:
Shunt-fed 15m tower w/ tribander
Half-size single K9AY loop pointed north

Equipment:
Elecraft K2/100 w/ KAT100 running 90 watts

Comments:

I was planning to put about 10 hours in this contest, about six on  
Friday night, and four more on Saturday. First sat down at the rig  
just after 0000z to find that the antenna had high SWR! I had just  
checked it the night before, and it was fine.

Fourty minutes later, I determined that a 150 pF silver mica cap had  
shorted. I had thought this was a 1 kV unit, but actually it was 100  
V. I replaced it with a 160 pF 4 kV disc ceramic. I could tune the  
antenna with the antenna analyser, but it was intermittently showing  
high SWR.

About this point, I got really frustrated. I had the same sort of  
problem last year that cost me the second night of the contest. I  
walked out of the shack and upstairs to watch some TV. After a while,  
I decided that the problem must be in the windings of the toroid of  
the matching network. This toroid is two stacked T200-2 cores wound  
with 44 turns of 16 gauge enameled wire. Evidentially, the turns must  
have rubbed against each other through heating and
cooling cycles being outside and worn through the insulation.

Later, I went back outside and took off the matching network  
assembly. I unwound the toroid and  re-wound 45 turns of 20 gauge  
insulated wire. Sure, the Q would be slightly affected by the smaller  
diameter wire, but maybe it wouldn't arc. Inspecting the wire I  
unwound, I could not find the definitive point of prior arcing.

Putting this all back together and mounting it on the tower, I was  
pleased to quickly find the matching point again. Back inside at  
0345z, I found a clear frequency and proceeded to CQ for the next  
hour. This is the part I like best about the 160m contest -- running  
stations at 60+ / hr. Thought I would call it a night around 0500z,  
but the stations kept calling so I didn't pull the plug  until 0635z.

After 0600z, I had one weird moment. A strong station came back to my  
CQ, signing M0AIH. I thought that couldn't be right, so I asked for  
it again. M0AIH. I thought, no way, this has to be W0AIH, he's so  
strong. So I send him my report and he comes back with 599  
<something>, which my brain thought might be WI. I correct the call  
and send W0AIH TU, and he comes back with "EU". At this point, I  
ignore my brain and change the callsign back.

It baffled me for the next ten minutes how he could be so strong from  
the UK. Then it occurred to me that 0600z is around dawn in that part  
of the world. Ah!

I was having so much fun running that I probably didn't S & P enough.  
Only DX was HI3A and the M0. Hopefully, I'll be able to get on for  
the Stew Perry, now that my matching network is working once again.

I list the half-size K9AY loop in my equipment, but I never found a  
case where it was actually useful. All the signals I tried it with  
were louder on the transmitting antenna. It's probably too short to  
be effective on 160m.


Posted using 3830 Score Submittal Forms at: http://www.hornucopia.com/ 
3830score/

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901


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