Re: RF power chain mods and improvements..

Kelly Jack
 

Hi all,

Some more testing and mods.

Measured efficiency of the PA only when RV1 adjusted for 10W output on each band (current measured through the PA-PWR line, current is zero during receive):
80m  29%
40m  29%
30m  33%
20m  30%
17m  34%
15m  45%
12m  41%
10m  45%

Not good.

Changed T11 to BN43-3312 same wire and turns ratio, 2 primary to 4 secondary.

Power measured using same method as above with BN43-3312 no cap across the primary, each band set to 10W by adjusting RV1.

80m  40%
40m  39%
30m  46%
20m  44%
17m  41%
15m  49%
12m  48%
10m  50%

Much better and finals are cooler but still get hot with key down for 30 seconds. Some acceptable numbers there but why is efficiency increasing with higher frequency?

Note that power efficiency measurements are for the finals only.

73



Simon
VK3ELH



 

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