[hpsdr] Horton with Trumpet??

[pvharman at arach.net.au]

My 2c worth.

I have a PA design that the group could use if wanted. If takes 300mW in and 
gives 100w out on all HF bands.  It even has its own switching PSU that I 
built from scratch. It uses a PIC to control all the band switching and was 
designed to be totally idiot proof i.e. it measures the input frequency and 
selects the LPFs, shuts down on high SWR, power out, low gain, high current, 
high voltage, high temperature, wrong color shirt etc, and adjusts for drive 
level, auto 
switches on RF input. 

I built it like this so I could use it with what ever experimental radio I was 
working with and so could just shove RF into it and not have to worry about 
blowing anything up. I all fits into a  K2 enclosure and has a 4 line LCD on 
the front with the usual bar graph meters etc. 

As I said I will gladly give the design and all the C code to the group if 
anyone wants this.

However, I suggest that this is NOT the way to go. For now just cobble 
together anything that will get you on the air with what ever power level you 
need. 

I suggest what we should be doing is to push the envelope and develop an 
Envelope Removal and Restoration amplifier.  Getting the necessary envelope 
for the Switching PSU  and carrier, with the correct phase relationship, with 
the DSP 
skills  we have in the group should be straight forward. We should be aiming 
at spectacular IMD and 120w DC power in for 100w out. 

See the latest QEX for an example of a tube amplifier that uses this 
technique. 

73's Phil...







Quoting Bill Tracey <bill at ewjt.com>:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> The 100mW in 5 watt out bit can be had from HFProjects.com  -- see their 
> newsletter section.  They've got a 100mw to 5 watt amp originally intended 
> as a pre amp for a 100 watt amp, but it can also be built with a filter 
> board to run 5 watts to an antenna (SlimGem project).   I've got one of 
> these in my stack of things to build.   I built their original HF Packer 
> Amp a few years back for my 1 watt SDR and have been quite happy with it.
> 
> To use this with HPSDR @ the 5 watt level we'd probably have to add T/R and 
> band selection logic to it.  The 100 watt gizmo they've got is auto sensing 
> so may not need a lot of interfacing work.
> 
> Regards,
> 
> Bill (kd5tfd)
> 
> At 07:34 PM 7/10/2006, Lyle Johnson wrote:
> >***** High Performance Software Defined Radio Discussion List *****
> ><....>
> >I'd rather see 100 mW or some other power level suitable for driving a 5
> >to 10 watt output PA.    <....>
> >
> >I suspect boosting 100 mW to 5W+ is not a big deal in a push-pull linear
> >PA.  <...>
> >Maybe someone needs to take on the HF PA with bandpass filters, etc., as
> >a project?  I know there already exists the HF packer amp, and perhaps
> >others of similar ilk, but they tend to be a little messy to deal with.
> >Having the PA and bandpass filters, with T/R switch as an integrated
> >assembly on a single PC board that is easily assembled, and directly
> >controlled by I2C or SPI or ??? has appeal.  Maybe borrow a page from
> >the K2 Tx lineup?  Maybe with the G6ALU amplifier as the core?
> 
> <....>
> 73,
> 
> >Lyle KK7P
> 
> 
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