Thanks for showing us that, Gerry, be nice to see more of the water works. Do
you have any pics of the build?
David
G3UNA
- Original Message -
From: Gerry Hull
To: David Cutter
Cc: Reflector Elecraft
Sent: Tuesday, December 16, 2014 3:19 AM
Subject: Re: [Elecraft] LDMOS
myronschaf...@gmail.com
To: Kevin Stover kevin.sto...@mediacombb.net
Cc: elecraft@mailman.qth.net elecraft@mailman.qth.net
Subject: Re: [Elecraft] LDMOS for QRO
Message-ID: 5524275a-b2d7-4a9d-86bf-d0e9f1bc0...@gmail.com
Content-Type: text/plain; charset=utf-8
Soon GaN will hold possibilities
If one wanted to use one of these to cool an LDMOS VHF KW, where would
one find the design info to calculate which cold plate would provide
sufficient
cooling ?
I envision a stack something like this:
LDMOS PC Board
Copper Heatsink (thickness need be determined)
Cold Plate
Aluminum Heat Sink
Unless you want to run fresh water down the drain (in Arizona we don't do this)
you have to get the heat into the air someplace. I'm not sure that running
water lines to outside air is much easier than getting coax through a concrete wall.
Speaking of difficult, the U.S. Navy AIM-54A Phoenix
.
73
David
G3UNA
- Original Message -
From: Richard Solomon w1...@earthlink.net
To: elecraft@mailman.qth.net
Sent: Tuesday, December 16, 2014 4:44 PM
Subject: Re: [Elecraft] LDMOS for QRO [OT]
If one wanted to use one of these to cool an LDMOS VHF KW, where would
one find the design info
here will check my sums I'm sure.
73
David
G3UNA
- Original Message - From: Richard Solomon
w1...@earthlink.net
To: elecraft@mailman.qth.net
Sent: Tuesday, December 16, 2014 4:44 PM
Subject: Re: [Elecraft] LDMOS for QRO [OT]
If one wanted to use one of these to cool an LDMOS VHF KW
, 2014 4:44 PM
Subject: Re: [Elecraft] LDMOS for QRO [OT]
If one wanted to use one of these to cool an LDMOS VHF KW, where would
one find the design info to calculate which cold plate would provide
sufficient
cooling ?
I envision a stack something like this:
LDMOS PC Board
Oops typo. F-14 aircraft
On 12/16/2014 10:27 AM, Wes (N7WS) wrote:
Unless you want to run fresh water down the drain (in Arizona we don't do
this) you have to get the heat into the air someplace. I'm not sure that
running water lines to outside air is much easier than getting coax through a
this as there are going to be some amps showing
up this coming year using these LDMOS devices.
-
From: Kevin Stover kevin.sto...@mediacombb.net
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] LDMOS for QRO
Message-ID: 548dafbd.7000...@mediacombb.net
Content-Type: text/plain; charset=ISO-8859
Neither morse (loosely called CW), nor JT65, are pure sine waves, so
they will have IMD, although it may well be less than the key clicks (as
conventionally understood for morse, and because of the abrupt frequency
changes in JT65). True CW cannot convey any more information than its
I did a random selection of 3 of their alleged distributors and found
nothing on
their sites.
Too bad, they look like they could be useful. Guess I'll ping them
directly and see
what I get.
73 es HH, Dick, W1KSZ
On 12/14/2014 4:32 PM, David Cutter wrote:
I'm a little surprised that folks
Here's a 144MHz 1.5Kw water-cooled LDMOS amplifier putting out full power
in a June VHF contest, with me operating at W2SZ/1.
It was a cloudy day, and the amp was so cool, in fact, we were worried
about condensation. Look at the size! The power supply is a 50v/50a
surplus PC supply off of ebay.
Joe,
You are correct that the specs are for pulse and one can run CW/JT65
at this level since there is no IMD produced by a single sine
wave. So combining two running 750w each gets you 1500w in linear
operation with 2400w dissipation.
1500w mobile!!! Are you serious? I'd guess 200-250w
On 12/14/2014 2:10 AM, Edward R Cole wrote:
1500w mobile!!! Are you serious? I'd guess 200-250w would be adequate for
mobile. But I do not do serious HF'ing.
When you get serious, here's how to do it. My Elmer, W7UVR, ran a high level
modulated 4-1000A mobile in the 1950s. Later went to
Your issue with heat sinks and copper spreaders is already solved
and one can run simple fans instead of blowers. And combining two
devices is more complicated than combining 8 or 16? Huh?
I'm not saying it isn't possible - nor that is hasn't been solved.
Only that is it not less expensive
W6PQL has designed and built a 1KW SSPA for 1.8-54MHz using an LDMOS
device. Freescale I think.
he has also designed a pretty stout Low Pass filter designed for 1.5KW
1.8-54 MHz.
He can get 1.2KW out of it at saturation with 2-3 W drive.
A pair of these devices @ 750W could do 1500W all day any
Soon GaN will hold possibilities.
Myron WVØH
Printed on Recycled Data
On Dec 14, 2014, at 8:41 AM, Kevin Stover kevin.sto...@mediacombb.net wrote:
W6PQL has designed and built a 1KW SSPA for 1.8-54MHz using an LDMOS device.
Freescale I think.
he has also designed a pretty stout Low Pass
Kevin Stover wrote
W6PQL
A pair of these devices @ 750W could do 1500W all day any mode. but then
the power supply becomes the limiting factor.. 50V at 70amps?
Expert 2k-fa uses a commercial 50v 60A (more peak) PS that weights perhaps 5
lb and is pretty small. Costs $500 in single
I'm a little surprised that folks in this group haven't suggested liquid
cooling for this modest application. Semiconductor cold plates have been
around for a long time, are economical to use and in my view a much better
solution than forced air cooling. They are compact, quiet, require far
. As I remember, many years ago,
it was rated at removing 5KW of heat. I know should have the BTU but I don't
remember.
Mel, K6KBE
From: David Cutter d.cut...@ntlworld.com
To: elecraft@mailman.qth.net
Sent: Sunday, December 14, 2014 3:32 PM
Subject: Re: [Elecraft] LDMOS for QRO [OT
There are 3,413 btu per KW HR consumed.
Mel Farrer via Elecraft wrote...I know should have the BTU but I don't
remember.
Nick N1KMP
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Sent: Sunday, December 14, 2014 3:32 PM
Subject: Re: [Elecraft] LDMOS for QRO [OT]
I'm a little surprised that folks in this group haven't suggested liquid
cooling for this modest application. Semiconductor cold plates have been
around for a long time, are economical to use and in my
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