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Yaesu FT-101E tubes heaters question

neazoi

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Hi this set was wired for 220v, which was the voltage my country had in the past. There is also a sticker (220v) at the back of the set.
Nowadays in Europe we use 230V. The set works on 230v ok but of course the heaters voltage and the output power goes up.
The heaters voltage is within limits (checked from the datasheet) but at the edge. The limit for the finals, from the datasheet, is 13.8v and my set has 13.69v. This is just about true for the driver tube.
Shall I worry about fast tubes deterioration or am I ok because the voltage is barely within limits?

I could rewire the set, but I like the extra output power, if it does not hurt. Bias is set correctly and monitored form the front panel meter to 60mA or less.
 

danadakk

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Generally speaking component manufacturers over the years published
specs incorporated margin above and beyond the data sheet limits. So
what you described seems alright to me, especially as you have set the
plate current properly.

As far as incremental power out in Tx it really does not affect your "reach".




Regards, Dana.
 

neazoi

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the longevity will suffer - if that is acceptable, then no worries.
Even if I rewire the transformer for 228v, I see 13.5v in the heaters. This is just 200mV difference from 13.69v. The RF output power goes down by 15W or so. It depends on other voltages not just on the heaters.
As far as I remember, when I rewired the set for 230v (234v actually) the heater voltage did not got less than 13v.
 

danadakk

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Last edited:

Aussie Susan

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(Totally off topic - I used to lust over an FT101 when I started in Amateur Radio in the 70's. I'm amazed that they are still around.)
The most important thing in my mind is if you can get replacement vacuum tubes. If you can then I wouldn't worry about the 220V vs 230V. If you can't then I think you have larger problems than that - ultimately any valve will give up.
Susan VK3ANZ
 

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