Your tubes are dead?
73, Alek VK6APK.
On 28/04/2025 8:48 pm, Fran?ois via
groups.io wrote:
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Make sure
the input circuit is lined up with the proper output band.
?
On
the input side, it seems fine. I'm driving L7 with
an FTDX-3000. I performed a TUNE, forcing the RLY relay to
close, and I have a VSWR of 1.
?
Test
conditions:
¡¤????????
Idle:
2600 V, 140 mA for a 6.5 V bias.
¡¤????????
At
the output, I'm on a 50-ohm dummy load; the L7 doesn't
indicate any output VSWR.
?
However,
I just noticed that on the 7.100 MHz band where I was
testing, the LOAD capacitors (C4, C47) are at their maximum.
I checked; they are indeed in parallel on this 40 m band.
The amplifier can't output more than 400 W.
?
On
3.650 MHz, the same problem: this LOAD capacitor is at its
maximum. The amplifier peaks at 400 W for 400 mA at 2300 V
and 25 W input.
?
At
14,200 MHz, the LOAD capacitor is at its midpoint, and a 25
W input produces 500 W (2300 V, 390 mA).
?
I
don't know what to think anymore.
De
la part de
mike repinski via groups.io
·¡²Ô±¹´Ç²â¨¦?: lundi 28 avril 2025 13:37
