Re: ERA-3+ Version passes the smoke test


Michael McShan <n5jky@...>
 

Jerry,

Thanks for info.  I've done a bit of surface mount work, so it is not a real problem.  On the other hand, I don't mess with these tiny components just for grins. :-)


73,
Mike W5RST, ex-N5JKY

On Nov 10, 2013, at 2:46 PM, Jerry Haigwood <w5jh@...> wrote:


Hi Mike,

     The DDS board has a lot of loss in the on board filter.  I am guessing the Q of the components is not good.  By eliminating the on board low pass filter and using the one on the ERA-3 board, you get a flatter amplitude output.  It will still have a small roll off at the upper frequencies but not nearly as bad as if you leave the DDS on board low pass filter.

Jerry W5JH

"building something without experimenting is just solder practice"

 

From: PHSNA@... [mailto:PHSNA@...] On Behalf Of Michael McShan
Sent: Sunday, November 10, 2013 11:16 AM
To: PHSNA@...
Subject: Re: [PHSNA] ERA-3+ Version passes the smoke test

 

 

Jerry,

 

Yesterday we were getting ready to throw a birthday party for a friend at our house last night, so there wasn't any time for playing with the SSNA.  Before I hack the board, what are the advantages of doing so versus leaving it stock?

 

73,

Mike W5RST, ex-N5JKY

 

 

On Nov 8, 2013, at 10:28 PM, Jerry Haigwood <w5jh@...> wrote:


Mike,

    Once you check out the DDS fix, you will need to put your power meter calibration into the program at line 125.  Also, you will need to run a sweep from 1-30 MHz with the generator output connected to the power meter and the power meter feeding back into the SSNA.  You will need to record the data using a step size of 100000 Hz (TERM232 allows you to capture a file).  You can send this file to Jim and he will do a curve fit for you (to flatten the response of the DDS).  He will send you 6 coefficients that you will enter into the program at lines 29-34 (C0 through C5).  Then you should be all set to go!

Jerry W5JH

 

 



Join PHSNA@groups.io to automatically receive all group messages.