[minima] Re: Sometimes it's the simplest of things

  • From: Andy <andy.g6lbq@xxxxxxxxx>
  • To: minima@xxxxxxxxxxxxx
  • Date: Sun, 16 Feb 2014 15:44:10 +0000

Hi Mark
I used the 4028 in a Digital VFO here so maybe you could utilise my switching arrangement. 

Regards

Andy de G6LBQ



On 16/02/2014 15:38, Mark G0MGX wrote:

Well team,

I find myself so near but yet so far.
I have D5 or pin 11 of the processor connected as per the schematic to drive the RX LPF switch. I also have another 4K7 resistor from D5 to one of my 4028 inputs.
When my D5 line goes HIGH (as the tuning passes 15MHz) my RX LPF switch operates but the voltage on the 4028 is just too low to make that transition. So I have tried a few alternatives including a PNP transistor to switch the +5V line but that seems to be suffering the same problems in that the voltage on the collector isn't doing as I expect (presumably because I dont understand what I am doing).
Can someone cleverer than I suggest how I can get my RX LPF relay and my 4028 to function on the same digital output (in this case D5) from Ardunio?
Pointers and suggestions very much appreciated before I try the larger of my hammers.... 

Mark
G0MGX

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