[Amps] 4CX10 000J

[Karl-Arne Markström]

There are a few of the early Collins 208U-10's in the hands of radio amateurs...
10 - 12 kW PEP or CW, with IM3 at least 36 dB down from one tone, assumíng a very good exciter and
correctly adjusted RF NFB.

The 208U-10A or HF-8022 (>15 kW PEP, power supply limited) 
are also in amateur hands, and I know of at least two owners in Sweden 
(both have lent my ex-Air Force manual set for copying...).

Nowadays, after that amateur radio has been deregulated in Sweden, it has most probably
become quite safe from a legal point-of-view to run such power levels, as long as no EMC related interference 
or out-of-band operations are present.

The power limits in the current Swedish amateur radio rules are quite vaguely worded, 
and there are no legal means of revoking an amateur radio license any longer.

Incidentally, the mu of 4.5 stated in the Eimac data sheet refers to the screen grid to control grid amplification factor,
which is quite unrelated to amplifier RF power gain. It is however of some interest when dimensioning bias supplies and networks.

The power gain of a grounded cathode tetrode amplifier in class AB1 can be extemely high, only limited by
the transit time and grid circuit losses, but practical considerations usually 
limits the usable power gain to 100 or 20 dB. If RF NFB is used, the gain may be further reduced.

Hence the proliferation of parallel 4CX350A's in class A as drivers for 4CX10000 and 4CX15000's.

73/

Karl-Arne
SM0AOM


----- Original Message ----- 
From: "Jan Erik Holm" <sm2ekm at telia.com>
Cc: <amps at contesting.com>
Sent: Sunday, July 02, 2006 5:55 PM
Subject: Re: [Amps] 4CX10 000J


> surely no ham would use a thing like that, or?
> 
> / Jim SM2EKM
> ----------------
> 
> Peter Voelpel wrote:
> 
> > All the J-types are low distortion, gain of both is about 20db
> > 
> > 73
> > Peter, DF3KV
> > 
> > -----Original Message-----
> > From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
> > Behalf Of Joe Subich, W4TV
> > What are the differences between the 4CX1000J and 4CX10000D - 
> > particularly to explain the 10 KW vs. 15 KW output difference 
> > in the "normal operation" figures on the Eimac short form 
> > catalog (www.cpii.com/eimac)?  Of course, with a listed gain 
> > of 4.5, it would seem to take 2500 W or so to drive either of 
> > them to their full capability ... 
> > 
> 
> 
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