LF: Re: Direct Upconversion from audio

[Andy Talbot <andy.g4jnt@gmail.com>]

There was precisely ONE person interested in this project, and interested in PCBs, so needless to say that won't be going ahead, nor will I boteh rlaying out a PCB for the complete things   Is no one interested in converting from soundcard modes ?

My own version is now finished, made up from two separate PCBs, one for the tone conversion to baseband, the other a legacy upconverter.  I'll write up the design and publish full details on my website - you'll just have to muddle though with construction techniques instead of a nice ready to go PCB

For users of the AD9850 DDS source (which still seem to be available on Ebay) , I now have a PIC driver for them using  up / down push buttons in 1Hz steps for LF use, instead of the rotary encoder at http://www.g4jnt.com/AD9850-Controller.pdf    Code for the pushbutton version  will be on the website before too long

Andy  G4JNT

On 25 January 2016 at 10:37, Andy Talbot <andy.g4jnt@gmail.com> wrote:

Once fully developed, I could be persuaded to put the entire design onto a single PCB and if there is enough interest have this made commercially and make PCBs available.  This would be subject to the following caveats:

There will be no RF LO, you'll need to do your own 4X input signal, from a crystal oscillator, DDS etc. 

Output filtering is not included.   The use of a switching gate mixer means odd order harmonics of the RF LO are very strong and must be removed with a low pass filter appropriate to the band of interest.  I could place pads on the PCB for filter bread boarding.

Construction will be in SMT - I use nothing else, and haven't done  any wire-ended construction now for nearly two decades.  So you'll just have practice SMT soldering and accept the facts of life.  All the ICs are basic  SOIC devices with 1.27mm pitch, and components are 0805 or larger, so even the "older" constructors (like me, now, I guess) should be able to manage them.  In fact, even those SOIC packages themselves look a bit dated now compared with the TSSOP and QFP packages I regularly use.

In order to gauge interest in   a) bothering to lay out all bits on  a single PCB, or b) having it made commercially, could I get an idea of who / how many would be interested.  Please reply directly to me to avoid clogging up these groups unless you have comments applicable to a wider audience.   I just want a feel if it would be worthwhile.   

It will be several weeks before things are finished and written up, and then another few weeks for PCBs.  Cost each will be consistent with all other PCBs offers of similar size - I use a professional good quality UK based supplier, and don't try to cut costs on cheap Chinese PCB manufacture; however good others claim they now are. 

Andy  G4JNT