Friday, August 30, 2013

Low Pass Filter (About Time!!!)

Using a kit - and my own wire - I constructed a 20m low pass filter with the clear intention of putting my radio on the air. 

The insertion loss was not nearly as high as I had expected - a good thing in my case.   The insertion loss was about 0.70dB around 14.3MHz, while the attenuation at 28MHz was over 50dB. 

Sunday, August 18, 2013


I woke up this morning with my head spinning.  (No, I didn't get drunk last night).

I had a long discussion last night with a fellow VWS member about radio designs and trying to get a kit together as if I had already volunteered.   I was so tired, I did not have the defense to argue.  He had a lot of good ideas, but he was pushing me to do his design as if it were my own.

I really need to draw the line on that.  I am not willing to take on any new designs beyond my own right now.  I got a lot of good ideas, but that is why my design is stuck!   If a website could feel, I feel like a website that is being overloaded with requests for information and data uploads.

I don't mean to sound ungrateful, but I really need to hit the brakes on volunteering for any kit building designs until I get mine working.  I do not have enough time to do any more. 

Sorry to my friends at VWS.

Sunday, August 11, 2013

Updated DDS-60 controller coming. Working on a EIM377 DDS controller.

Just got a nice email from Far Circuits...they are sending me samples of an updated PCB design for interfacing the AMQRP DDS-60 with a PICAXE 28x2 in an RF-friendly PCB.  I had to open up some holes and fix some ground clearances.  They had to fix some off-center etching issues from the previous design.  If these work out, I will definitely send them an order for a full etch of boards in the hope to make a few of them. 

My next big project on the DDS front is an RF-friendly interface for the EIM377 DDS controller.  For the un-informed, the EIM377 is one of the AD9850-based DDS oscillators that have been selling for prices as cheap as $5 to $10.  I bought four of them to play with.  As my previous entry indicates, I was able to interface the EIM377 with the PICAXE 28x2.  I did add a encoder interface to demo at the VWS club meeting, but it was taken apart again for a new mechanical layout.

I will forward new photos as the units are coming in for construction.