[Amps] NXP 65V LDMOS 1K80H-1800W
catherine.james at att.net
Sun Dec 24 14:34:04 EST 2017
Can it handle continuous 100% duty cycle on MID?
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On Sun, Dec 24, 2017 at 12:50 PM, Paul Baldock<paul at paulbaldock.com> wrote: SPE say 1.5KW SSB and CW, no limit. Continuous duty modes, should be
used on the lower 1KW or 500W ranges.
This will by my 6M amp / instant on HF / backup HF amp. I plan to limit it 1KW.
From the manual :
"Note: ATTENTION: Never stress the amplifier with long periods in
as this can stress the amplifier components. However, sophisticated
transmitting a continuous signal in the "MAX" condition for long
periods by switching
to "MID" power.
Note: In SSB, use of high compression is not encouraged as this can
cause a rapid increase
in the temperature of the amplifier."
"Appears when a continuous signal is transmitted in
"MAX". After 15 sec. the amplifier will switch
automatically to "MID"."
At 08:49 AM 12/24/2017, Jim Thomson wrote:
>Date: Sun, 24 Dec 2017 01:01:39 +0000
>From: Bill Turner <dezrat at outlook.com>
>To: Amps group <amps at contesting.com>
>Subject: Re: [Amps] NXP 65V LDMOS 1K80H-1800W
><I checked the website for SPE, looking for duty cycle specs but didn't
><see any. Does anyone know what they are?
><73, Bill W6WRT
>### Excellent question. And ditto with the new Flex...power
>genius..with its mystery 100% ICAS rating.
>IMO, 100% ICAS means talk on ssb or cw all day long.... but dont do
>something stupid, like a rtty contest.
>## These SS amps are typ 50% eff at best, so with 1.5 kw out
>requires 3 kw dc input.
>Dissipation of course is 1.5 kw. Thats a bunch. And a huge
>amount if running rtty,
>FT8, any other digital mode, or FM etc.
>## any tube amp running just 60% eff, would only require 2.5 kw dc
>is now down to just 1 kw.
>## On the lower 3 bands, with the same tube amp on
>160-80-40, 68-70% eff is readily achievable.
>Now the diss is down even more, to just 706- 643 watts.
>## helluva big difference between 1500 watts ccs diss on the SS
>amp..and the 643- 1000 watts
>CCS diss of the SS amp.
>## It would require some exquisite heat sink design to be able to
>dissipate 1500 watts CCS of heat.
>This is where the SS amp should be using a 19 inch wide rack mount
>heat sink, very deep, and very tall,
>like 12 inches or more, and lotsa air on it. Loads of fins, and
>very thin fins.
>## that or some elaborate cooling setup, with a liquid cooled heat
>sink and an external air cooled radiator +
>mating water pump.
>## ideally the way to manage heat is to generate less of it in the
>1st place, like through higher eff, which
>appears is not going to happen any time soon with typ class AB SS amps.
>## I would like to see what both these amp manufacturers have to
>say about duty cycle.
>If they are 1.5 kw ICAS, I will pass on em for now, not for the
>$7K price tag.
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