Re: Drake L7 [2 x 3-500Z] power ?
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Or run a pair of cheaper 4-250"s.
Hoping I don't get beat up for this question. If all you need or can have is 500 watts would it be better running one tube?
Your tubes are dead?
73, Alek VK6APK.
On 28/04/2025 8:48 pm, Fran?ois via
groups.io wrote:
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
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