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QDX Small output power in some of the bands

#qdx #power

Bela Mucs All Messages By This Member #90531 I struggle with low output power on some of the bands.? 80m: 5W - OK 60m: 5W - OK 40m: 2W - not OK 30m : 3.8W - not OK 20m: 2W - not OK I did reduce the L4, and L10 (LPF3) also L3 L8 (LPF2) inductors by one turn. Still it is too low on 20,30,40m bands. I am running on 12 Volts. T1 output transformer is quite worm. Supposed to have 2:3 rate. Would you have a suggestion? I am dreaming 5W on each of the bands.... Could it be that one of the BS170 is broken down? Does anyone experience with losing one of them? ? 73 de 叠é濒补 HA4BM
Evan Hand All Messages By This Member #90536 Hi Bela, I would first check that the low-pass filter selection is working correctly.? You measure the voltage on the banded (cathode) side of the six diodes used to select the filter.? ?The two for the selected filter should be close to 0volts; the other four should be around 5volts.? You do the test using the terminal RF Sweep program to choose the bands without transmitting.? You should not transmit while doing the check. If the switching selection is OK, verify that you have the capacitors in the correct location.? I have not found a need to add or remove windings from the low-pass filter toroids.? I did have to adjust the wire spacing to tweak the output on the 20/30 shared low-pass filter L4.? That was the only one I needed to tweak. How is the receiver working? 73 Evan AC9TU
Bela Mucs All Messages By This Member #91045 Hi Evan,? I checked the LPF selection.? The cathodes are near 0 on the selected LPFs the un-selected ones are on 11V level. (not 5V) It is following the configuration: +---Band configuration-------------------------------------------------------+ ?\|? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? \| ?\|? Band name (m)? ? ? 80? ? ? ?60? ? ? ?40? ? ? ?30? ? ? ?20? ? ? ?0? ? ? ? ?\| ?\|? Audio gain (dB)? ? 60? ? ? ?60? ? ? ?60? ? ? ?60? ? ? ?80? ? ? ?0? ? ? ? ?\| ?\|? Frequency min.? ? ?1400000? 4000000? 6000000? 7500000? 10500000 0? ? ? ? ?\| ?\|? Frequency center? ?3573000? 5357000? 7074000? 10136000 14074000 0? ? ? ? ?\| ?\|? Frequency max.? ? ?4000000? 6000000? 7500000? 10500000 14500000 0? ? ? ? ?\| ?\|? Sweep start? ? ? ? 3200000? 4000000? 5000000? 8000000? 11000000 0? ? ? ? ?\| ?\|? Sweep step? ? ? ? ?20000? ? 50000? ? 50000? ? 50000? ? 100000? ?0? ? ? ? ?\| ?\|? BPF number (0-3)? ?0? ? ? ? 1? ? ? ? 1? ? ? ? 2? ? ? ? 3? ? ? ? 0? ? ? ? ?\| ?\|? LPF number (0-2)? ?0? ? ? ? 1? ? ? ? 2? ? ? ? 2? ? ? ? 2? ? ? ? 0? ? ? ? ?\| ?\|? Transmit? ? ? ? ? ?ENABLED? ENABLED? ENABLED? ENABLED? ENABLED? DISABLED? \| ?\|? PTT +5V positive? ?DISABLED DISABLED DISABLED DISABLED DISABLED DISABLED? \| ?\|? PTT grounded? ? ? ?DISABLED DISABLED DISABLED DISABLED DISABLED DISABLED? \| ?\|? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? \| ?+------------------------------------------------------------Ctrl-Q = Quit---+ The band sweep on 20m band looks like this:? 12 \|.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?. ? ? ? ? .? ? ? ? ?.? ? ? ? ?. ? ?\|.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?? ? ? ? . ? ? ?.? ? ? ? ?.? ? ? ? ?. ? ?\|.? ? ? ? ?.? ? ? ? ?.? ? ? .? ? ? ? ?.? ? ? ?.? ? ? ? .? ? ? ? ?. ? ?\|.? ? ? ? ?.? ? ? ? ?.? ?? ?.? ? ? ? ?.? ? ? ? ? ? ? ?. ? ?\|.? ? ? ? ?.? ? ? ? ?.*? ? ? .? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? . ? ?\|.? ? ? ? ?.? ? ? ?**? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?. ? ? ? ?. ? ?\|.? ? ? ? ?.? ? **? .? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? . ? ?\|.? ? ? ? ?.? *? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ?? ? ?. ? ?\|.? ? ? ? ?. ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? . ? ?\|.? ? ? ? ?*? ? ? ? .? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? . ? ?\|.? ? ? ? .? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ?? ?. ? ?\|.? ? ? ** .? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? . ? ?\|.? ? ?? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ?* . ? ?\|.? ? ? ? .? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? . ? ?\|.? ?? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ? 0? \|.. * . . ... . . . ... . . . ... . . . ... . . . ... . . . ... . . . .. . . ? ?\|.? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?. ? ?\|? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?. ? ?\|.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? * ? ?\|.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ?* -4 \|.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? ? ? ?.? ? * ? ? ---------------------------------------------------------------------------- The top is at 14MHz aprox, the max value is on 12... How is your sweep looking like?? L4 seems to be evenly tweaked... I adjust the turns see if that helps.? 叠é濒补 ?
Bela Mucs All Messages By This Member #91047 Ahhhh... Evan, this worked. I condensed the turns on L4 as much I could and Now I got about 4.5Watts output power on 20 meters. On 30meters even higher than 5volts.? Many thanks for your proposal. This was really helpful.? 73 de 叠é濒补 HA4BM

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