[Elecraft] rcvr designs prc-2000 USES DIRECT CONVERSION!

[stephen Farthing]

Gentlefolk,

    I am part of a group of fellow Amateurs who have been working on 
homebrew phasing Direct Conversion Tranceivers for a while now.
Details of our first attempt can be found at: -

www.stevef.demon.co.uk/qrp2k/qrp2000home.htm

and the later iteration is at 
http://www.qrp2001.freeserve.co.uk/background.htm .


 Design and prototyping for the QRP2004 is well underway and will be 
published when we can get round to it. These are homebrew designs, the sad 
thing is that we were trying to get someone with more time that we have to 
kit them however there was little interest at the time we presented the 
QRP2000 at Dayton. I think we have all built, or in my case are building K2s 
as well. There is something about the clarity of the audio from a DC RX 
which superhets never manage to achieve. The first ham project I ever made 
was a Sudden DCRX uring the venerable NE602...I had a lot of fun with 
it....and was hooked....

Bye for now,

Steve




----- Original Message ----- 
From: "Geoffrey Mackenzie-Kennedy" <gmk at gm4esd.fsworld.co.uk>
To: <WA2JJH at aol.com>
Cc: "Elecraft Discussion List" <elecraft at mailman.qth.net>
Sent: Tuesday, March 15, 2005 9:43 AM
Subject: Re: [Elecraft] rcvr designs prc-2000 USES DIRECT CONVERSION!


> Another example is the Collins 95S-1A produced some years ago. This 
> receiver
> is 'Software Driven' and covers the range from 5 kilohertz to 2 GHz in 
> steps
> down to 1Hz. Its architecture is hybrid. Antenna signals between 5 kHz and
> 30 MHz are upconverted to 51.2 MHz and directly converted from there to
> baseband - e.g. audio.  Antenna signals between 20 MHz and 2 GHz are
> Directly Converted to baseband, and yes there is an overlap between 20 MHz
> and 30 MHz. Baseband signals are processed by DSP. Modes handled are CW,
> L.SB, U.SB, I.SB, FM and AM.
>
> IMHO Direct Conversion has great performance potential, and the techniques
> in circuitry developed during the past decade could perhaps make Direct
> Conversion the architecture of choice sometime in the future. There is no
> doubt in my mind that SSB signals sound "better" from a DC receiver,
> likewise CW.
>
> 73,
> Geoff
> GM4ESD
>
>
> ----- Original Message -----
> From: <WA2JJH at aol.com>
> To: <elecraft at mailman.qth.net>
> Sent: Tuesday, March 15, 2005 3:41 AM
> Subject: [Elecraft] rcvr designs prc-2000 USES DIRECT CONVERSION!
>
>>   He would joke about my K2 manpack. His used PRC-2000 cost over  $2000.
>> The receiver used.   DIRECT CONVERSION. THEY DID FIND A WAY TO  GET RID
> OFALL
>> THE AUDIO  ARTIFACTS AND IMAGES THAT WERE THE REASON WHY  SUPERHET BET
> DIRECT
>> CONVERSION AS THE GOLD STANDARDOF RCVRS.
>
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