Re: this project, newbie


Mark Dunning
 

Jim

 

I finally got around to making some measurements here on my collection of the Chinese DDS module (7 in total brought from three suppliers). All ran okay at 3.3V.

 

Average current draw (DDS only) while sweeping at 3.3V was 93mA. At 5V it was 136mA. Best performers were the blue modules which have small 125MHz oscillators. The green modules I have, had both the largest current draw and were off frequency the most (400Hz at 10MHz) against 160Hz average for the blue modules. All are useable of course.

 

My test setup uses a PICAXE 18M2 to drive the DDS modules. I am worried about leakage from an Arduino arrangement interfering with minimum signal levels. When I get the time I want to package the DDS and 18M2 inside a shielded box using a serial connection for an interface. Probably not the way to go but still fun to play with. 

 

73's

 

Mark VK6WV

 

"Speaking of power requirements, here are some measurements I made a couple of weeks ago. Arduino and DDS powered from 12 V supply, DDS running on 3.3V regulated
did NOT include the buffer amp yet
while "idling"
         110 mA from 12 V supply
2 mA from USB port
while sweeping
130 mA from 12 V supply
2 mA from USB port

Jim, N5IB"

--- In PHSNA@..., <phsna@...> wrote:

I think that there are two directions that this type of project could take, the first is a bench top device, the second is a portable unit which could be used for all sorts of purposes including antenna analysis.

 

I have been working (very slowly) towards a sweep generator based upon these modules myself. VK5TM has a good post about his work in this area http://www.vk5tm.com/homebrew/dds/dds.php.

 

One problem for portable operation is the power demands of the Chinese DDS modules.

 

It will be interesting to see how things develop.

 

73

Mark

VK6WV

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