Hi to all,
After "alignment and Test - Part III", I got more power on 20 m (3.8 W) than
40 m (3.2 W).
As the manual says, for best harmonic rejection, it should be the opposite
(0.3...0.6 W more power on 40 m).
Following some previous posts (thanks Don), I checked very carefully all the
components, soldering, relay K2 working OK and even the complete TX path
from the DDS output to the BNC connector.
So, as the manual says, I "squeezed" L2 on the lower pass filter, in order
to get the best harmonic rejection.
Here are some tests I've made (all measurements at 12 V & with OUTPUT POWER
MOD done; NO TUNER):
1. L2 turns not squeezed (according Fig. 16 on the manual)
a) 40 m
- output power: 3.17 W
- current drain: 490 mA
- 2nd harmonic: 44 dB
- 3rd harmonic: 62 dB
b) 20 m
- output power: 3.77 W
- current drain: 623 mA
- 2nd harmonic: 54 dB
- 3rd harmonic: 56 dB
2. L2 turns squeezed to 75 % (now, 0.3 W more power on 40 m)
a) 40 m
- output power: 3.06 W
- current drain: 585 mA
- 2nd harmonic: 58 dB
- 3rd harmonic: 59 dB
b) 20 m
- output power: 2.74 W
- current drain: 563 mA
- 2nd harmonic: 48 dB
- 3rd harmonic: 56 dB
Comments:
with L2 turns well spaced I get: more power on 20 m and even a better
harmonic rejection. At 40 m, the current drain is lower, and even the
harmonic rejection is 44 dB for the 2nd harmonic, it is between specs (40
dB).
tests done at 9 V (with L2 squeezed): harmonic rejection results similar to
12 V tests.
all tests done with Rohde & Schwarz CMTA-54 Radiocommunication Analyzer &
Tektronix 495 P Spectrum Analyzer.
So, in my case, for my KX1 s/n 1881 and with output power mod done (R11 =
4.7 Ohm; R30 = 33 Ohm), I will left L2 "not squeezed" !!.
Hope this helps.
73,
Paco
_________________________________________________________________
Moda para esta temporada. Ponte al día de todas las tendencias.
http://www.msn.es/Mujer/moda/default.asp
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