Smallest Dual-6146 HF Transmitter?

[Brian Wood]

I stand corrected. But it's still a lot by today's standards, where you
modulate the low-level signal prior to the final broadband transistor
amplifier. And that much power still takes big, heavy parts. So I still
think my idea to make the DX-100 much lighter and smaller might actually
work. It would be an interesting project!

Brian

-----Original Message-----
From: Heathkit Owners and Collectors List
[mailto:HEATH at LISTSERV.TEMPE.GOV]On Behalf Of Glen Zook
Sent: Thursday, August 23, 2007 2:09 PM
To: HEATH at LISTSERV.TEMPE.GOV
Subject: Re: [HEATH-TEMPE] Smallest Dual-6146 HF Transmitter?


Not true!

It takes 50% of the final amplifier input power to get
100% modulation.  Considering that the modulator is
definitely not 100% efficient the input to the
modulator output stage will be more than 50% of the
final amplifier stage.  But, the actual power required
to produce 100% modulation is 50% of the input power
to the final amplifier stage.

For example, the audio power required to modulate a
100 watt input transmitter is 50 watts.  If the
modulator has an efficiency of 66% then it will take
just over 75 watts input to the final modulator stage.
 But the actual power needed to modulate a class "C"
amplifier to 100% modulation is 50% of the input
power.

Glen, K9STH


--- Brian Wood <wood at LPBROADBAND.NET> wrote:

You ask a lot! In order to get 100% modulation at the
plate, you need to have the same power level as the
transmitted signal, namely 100W. That's why the DX-100
has such a big modulator, with concomitant big, heavy
transformers. And with tubes, you need high voltage,
which usually means big transformers too.









Glen, K9STH

Website:  http://k9sth.com



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