CWops Mini-CWT Test - 1900Z Jan 16
Call: OH3BCX
Operator(s): OH1ZAA
Station: OH3BCX
Class: Single Op HP
QTH: KP20XW
Operating Time (hrs): 0.9
Summary:
Band QSOs
------------
160:
80: 12
40: 13
20:
15:
10:
------------
Total: 25 Mults = 22 Total Score = 550
Club: Contest Club Finland
Comments:
I am running the Amp Supply LK-550Z followed by a Bencher YA-1 LPF.
Between CWT’s I decided to inspect the output spectrum for the first time
using a Spectrum analyzer (HAMEG HM5511) and a directional coupler…
Without the LPF the low bands up to 14 MHz were surprisingly good, with
the second harmonic down -48 dBc at least, and higher harmonics still much
weaker. But 21 MHz was poor with a strong 4th harmonic (84 MHz). So the
LK-550Z should always be run with the LPF in series. 28 MHz was not as bad,
but needing the LPF…. A couple of spooky things happened during measurement.
Suddenly on 1.8 MHz the Daiwa CN-101L cross-needle SWR-meter developed
an open circuit between in/out center SO-239 pins. Physically it was not
possible, but I resoldered everything, and now it seems OK…. The old
Heathkit HN-31 Cantenna RF Load Resistor (nominal 50 ohm dummy-load)
showed 76 ohms resistance, and subsequently 18 ohms with the pins of the
universal meter reversed. I thought it was damaged by overload, but there
seems to be an internal two-metal joint, causing a ’battery’ in series
with the multimeter… With the antenna connected so much RF-came into
the shack that the baseline of the Hameg HM5511 analyzer was jumping
halfway up the screen. Meaning insufficient shielding of the instrument…
As far as the 1900Z CWT goes:
condx were poor to bad, except for a very narrow 2000 km skip bracket
on 7 MHz (F6HKA HB9DAX LZ1HW UR5MM + EA8OM). One band lower it was a
bit better, but with the eternal local industrial QRN at S7 - S9.
Cheers/73, Zaba OH1ZAA #1856
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