[hpsdr] Linear amplifier for HPSDR

[Helmut Oeller]

Hi Hans and Kjell,
 
unfortunately not too much changed since Helge O. Granberg published the
fundamental applications and results of RF devices in the ‘Motorola
Cookbook’, when you compare it with current ANs of Mitsubishi e.g.
AN-VHF-27-B . To save the excellent IM performance of Penelope as long as
possible I made a similar approach like Hans: I’m using a Philips BLF278
push pull VHF FET providing a flat gain of 22dB (negative feedback
necessary!) up to 30 MHz at 48 Volt and Iq= 1A.  At 50 MHz gain decreased to
17 dB probably due to loss of the transformers. Driven directly by Penelope
an average IM3 of -40 dBc was measured between 80 -10 m band at an output
level of 50 Watts PEP (1 dB compression of the amp: 280 W !). These 50 Watts
are more than necessary to drive four combined push pull strips with MRF
429s to the legal level in DL. Total IM3 is around -33 dBc. What a decline,
but probably at least 6 dB better than any combination with standard
analogue transceivers.
BTW preliminary tests with IXYS's new RF push pull type XZ2210N50L featured
no significantly better results.
 
73 Helmut, DC6NY

-----Ursprüngliche Nachricht-----
Von: hpsdr-bounces at lists.openhpsdr.org
[mailto:hpsdr-bounces at lists.openhpsdr.org] Im Auftrag von Kjell Karlsen
Gesendet: Mittwoch, 4. Januar 2012 11:14
An: h-hartfuss at t-online.de
Cc: hpsdr at openhpsdr.org
Betreff: Re: [hpsdr] Linear amplifier for HPSDR

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

Hi Hans.

Thanks for reminding me of your tests.

By using one of the latest MOSFETS it seems like it may be possible to use  
only one stage following Penny, PellyLane or Hermes to achieve 100W PEP.  
Only 23 dB amplification is needed and that may be possible using one of  
the new VHF units.

73, Kjell




På Wed, 04 Jan 2012 08:43:38 +0100, skrev h-hartfuss at t-online.de  
<h-hartfuss at t-online.de>:

> Please see TAPR-PSR #115


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