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Fw: [AMPS] Anode load line calculations.

To: <amps@contesting.com>
Subject: Fw: [AMPS] Anode load line calculations.
From: itr@nanoteq.co.za (Ian Roberts)
Date: Mon, 21 Dec 1998 14:23:29 +0200


John Fielding wrote:

>
> As far as the other aspect of the argument regarding the linearity versus
> anode voltage - it is a well documented fact that the greater the anode
> supply available the more linear the operation will be for a given output
> power.  Why else do we use such high voltages if we could use lower and
> safer voltages?  Look again at the formula - here you can plainly see that
> the predominant factor in obtaining high output power is the voltage term!
>

This is not peculiar to tubes.
And is why the ICOM IC-781 running the PA transistors at 28 V achieves 37 dB
IMD, compared to the typical 24-28 dB from 13 V transistors (IC-565, 476, Yeasu
847, 920, etc). 50 V transistors are even better, but as long as hams use 13 V,
we will have to continue enjoying 40 kHz-wide SSB signals, as generated by a
nearby 400 W 13 volt USA-made linear on 6m.

Ian, ZS6BTE



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