[hpsdr] Linear amplifier for HPSDR

[h-hartfuss at t-online.de]

Hi all,
I tried to check what is feasable with respect to IMD with 48V and
class-A.
Please see TAPR-PSR #115 p. 08
73, Hans, DL2MDQ.






-----Original Message-----
Date: Tue, 03 Jan 2012 19:57:31 +0100
Subject: Re: [hpsdr] Linear amplifier for HPSDR
From: "Kjell Karlsen" <la2ni at online.no>
To: "'Steven Doyle'" <steve_doyle at o2.co.uk>, "'Tim O'Rourke'"
<w4yn at earthlink.net>, "'Giovanni Santin'" <gsantin at mclink.it>,
hpsdr at openhpsdr.org, "Helmut Oeller" <dc6ny at gmx.de>

***** High Performance Software Defined Radio Discussion List *****

Hi All.

I agree with Helmut that most of the 12V transistors are not the best to
 
use when driving a High power amplifier. But if you look at 90% of the  
transceivers used by hams all over the world they use exactly the same.

So to Munin, the amplifier I have constructed: It seems as the results
we  
have obtained with the Beta build (at the time 4 finished units) are as 

expected. When driven at 13,8V the output is > 100W PEP at better than  
-30dBc IM3. It can be used at 20V without problems and then the IM3 is
at  
least 5 dBc better at 100W and the maximum output at -30 dBc is > 150W.

I am preparing the schematics and Final Gerber files for Scotty at TAPR.
 
We will let you know when the production can start.

73, Kjell





PÃ¥ Tue, 03 Jan 2012 16:24:50 +0100, skrev Helmut Oeller <dc6ny at gmx.de>:

> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi,
>
> all 12 Volt devices  – the bipolar MRF492s of Hercules as well the
FET
> RD100HHF1s of Munin – are featuring  the same limited IM3
performance not
> exceeding -30dBc when operated under linear conditions. That’s no  
> problem if
> you run the amps barefoot, but when driving a real final amp things  
> become
> critical. The excellent IM3 performance of Penelope/Pennylane of -60
dBc
> even at 0.5W PEP output should not be wasted and requires better 50
–  
> 100 W
> amps with e.g. 48 Volt supply voltage, class A driver - if necessary
–  
> and
> operation far below the 1dB compression.  Predistortion  will be a
future
> challenge.
>
> 73 Helmut, DC6NY
>
> -----Ursprüngliche Nachricht-----
> Von: hpsdr-bounces at lists.openhpsdr.org
> [mailto:hpsdr-bounces at lists.openhpsdr.org] Im Auftrag von Steven Doyle
> Gesendet: Dienstag, 3. Januar 2012 14:41
> An: Tim O'Rourke; Giovanni Santin; hpsdr at openhpsdr.org
> Betreff: Re: [hpsdr] Linear amplifier for HPSDR
>
> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi,
>
> I don't think Munin is very far away. I was one of the Beta testers
and I
> can confirm that it works well.
>
> Maybe Kjell could give us an update.
>
> cheers
>
> Steve
> G1YLB
>
> -----Original Message-----
> From: Tim O'Rourke
> Sent: Tuesday, January 03, 2012 1:30 PM
> To: Giovanni Santin ; hpsdr at openhpsdr.org
> Subject: Re: [hpsdr] Linear amplifier for HPSDR
>
> ***** High Performance Software Defined Radio Discussion List *****
>
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