[hpsdr] Horton with Trumpet??

[Alex]

Hi Lyle,

I'm all for someone picking up the bandpass filters and the PA as a project.
I suggest looking at the bandfilter switching (I2C if I remember correctly) for the CDG2000 
but use the Hittite RF switches instead of the relays. 

That would cut down CASMIR-HF to just the QSE, LO, and the MAX II to control everything. Would definitely fit on 100x120mm board.

If someone is willing to pick up the filters and PA as a separate project, I should be able to lock down the CASMIR-HF design real quick.
The only other thing we need to design is the LO and then the design is finished..

I thought we were doing HORTON as a cheaper alternative to MERCURY since the LTC2208 was quite expensive.

Alex, N3NP

----- Original Message ----
From: Lyle Johnson <kk7p at wavecable.com>
To: Alex <harvilchuck at yahoo.com>
Cc: CT1IZU <hands at iol.pt>; hpsdr at hpsdr.org
Sent: Monday, July 10, 2006 8:34:18 PM
Subject: Re: [hpsdr] Horton with Trumpet??

> An HF version covering 0-30MHz with a transmitter (CASMIR-HF) with
> a 1w output...

I'd rather see 100 mW or some other power level suitable for driving a 5 
to 10 watt output PA.  I realize the PA isn't likely to be integrated 
onto the Tx exciter board.  1 watt in general is too low to be very 
useful on the air, and much more than necessary drive for a 5 to 10 watt 
PA, which in turn is about right for driving 100W nominal PA.

The exciter should be very clean -- low intermod, etc - so it may need 
to be Class A.  This means about 25% DC-RF efficiency. I'd rather throw 
away 300 mW in the driver than 3 W.

I suspect boosting 100 mW to 5W+ is not a big deal in a push-pull linear 
PA.  It is about right to drive the output stage of the G6ALU 20W FET 
PA.  Or maybe we just need the exciter to provide 1 to 10 mW after the 
included, on-board bandpass filtering on the exciter module, and use 
that to drive the G6ALU amplifier as already designed?  See 
<http://myweb.tiscali.co.uk/radiokits/pic_a_star/20W_PA/index.htm>

My bottom line is I really want to have about 10 watts to a 50 ohm load 
for a useful HF transmitter.

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?

 >..., 192kHz wide bandwith receiver (HORTON-HF) and an
 > optional 30MHz wide panoramic receiver (MERCURY-HF).

Or maybe just use Mercury as *the* receiver?  I know, Horton is supposed 
to be a QSD-based receiver...

73,

Lyle KK7P





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